2010 AU Crops

Cotton Research Report

Research Report No. 39 March 2011 Alabama Agricultural Experiment Station William Batchelor, Director Auburn University Auburn, Alabama

ACKNOWLEDGMENTS
This publication is a joint contribution of Auburn University, the Alabama Agricultural Experiment Station, and the USDA Agricultural Research Service and Soil Dynamics Laboratory. Research contained in the AU crops research reports was partially funded through the Alabama Cotton Commission, the Alabama Wheat and Feed Grains Producers, the Alabama Soybean Producers, and private industry grants. All funding is appreciated.

CONFIDENTIAL REPORT
Publication, display, or distribution of data contained herein should not be made without prior written approval. Mention of a trademark or product does not constitute a guarantee of the product by Auburn University and does not imply its approval to the exclusion of other products.

This report can be found on the Web at http://www.ag.auburn.edu/aaes/communications/researchreports/10cottonrr.pdf

Auburn University is an equal opportunity educational institution/employer. http://www.auburn.edu http://www.aaes.auburn.edu

CONTENTS
page Editors, Contributors ...........................................................................................................................................................................4

VARIETY TRIALS
Breeding Cotton for Yield and Quality in Alabama, 2010 .................................................................................................................5

CROP PRODUCTION
The Old Rotation and Cullars Rotation, 2010 ....................................................................................................................................7

IRRIGATION
Sprinkler Irrigation of Cotton for Biodiesel Production .....................................................................................................................9 Evaluation of Automatic Section Control Technology for Agricultural Sprayers ............................................................................11 Evaluating Pressure Compensating Subsurface Drip Irrigation for No-Till Row Crop Production on Rolling, Irregular Terrain, 2010............................................................................................................................................12 Subsurface Drip Irrigation-Fertigation for Site-Speciﬁc, Precision Management of Cotton ...........................................................13

FERTILITY
Alternative Sources of N for Corn and Cotton in Alabama ..............................................................................................................15 Fertilization of Cotton on Black Belt Soils .......................................................................................................................................17 FGD Gypsum Research and Demonstrations in Alabama ................................................................................................................19

INSECT MANAGEMENT
Development and Validation of a Low Input Insect Control System for Conventional Cotton in Alabama ....................................21 Evaluation of the Varying Genetic Technologies for Control of Fall Armyworm and Bollworm in Alabama Cotton .....................22 Development of a More Rapid Survey Technique for Monitoring Stink Bug Damage to Cotton ...................................................23

WEED MANAGEMENT
On-Farm Glyphosate-Resistant Palmer Amaranth Management in Roundup Ready Flex, Liberty-Link, and Conventional Cotton Varieties ............................................................................................................................................24

DISEASE MANAGEMENT
Evaluation of Seed Treatments and Seed Quality in Cotton Seedling Disease Management in Alabama, 2010 .............................25 Evaluation of Experimental Seed Treatments in Cotton Seedling Disease Management in Alabama, 2010 ...................................26 Cotton Resistance to Root-Knot and Fusarium Wilt in Alabama, 2010 ...........................................................................................27

NEMATODE MANAGEMENT
Evaluation of Cotton Seed Treatments for the Control of Root-Knot Nematode and Fusarium Wilt on Cotton, 2010 ...................28 Evaluation of Experimental Nematicides for the Control of Reniform Nematodes on Cotton in North Alabama, 2010 ................29 Evaluation of Experimental Nematicides for the Control of Reniform Nematodes on Cotton in South Alabama, 2010 ................30 Evaluation of Cotton Varieties for Reniform Management in Cotton in South Alabama, 2010.......................................................31 Evaluation of Seed Treatment Fungicides for the Control of Seedling Disease on Cotton in North Alabama, 2010 ......................32 Contributors Index ............................................................................................................................................................................34

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ALABAMA AGRICULTURAL EXPERIMENT STATION

EDITORS

K. S. Lawrence Associate Professor Entomology and Plant Pathology Auburn University

C. D. Monks Professor and Extension Specialist Agronomy and Soils Auburn University

D. P. Delaney Extension Specialist IV Agronomy and Soils Auburn University

CONTRIBUTORS

A. H. Abdelgadir Technician IV Biosystems Engineering Auburn University J. R. Akridge Director Brewton Agricultural Research Unit Brewton, Alabama J. Arriaga Research Associate IV Agronomy and Soils, Auburn University K. S. Balkcom Afﬁliate Assistant Professor and Agronomist Agronomy and Soils, Auburn University USDA-National Soil Dynamics Lab. W. C. Birdsong Regional Agronomist Southeast Alabama Alabama Cooperative Extension System C. Brodbeck Engineer II Biosystems Engineering, Auburn University A. Brooke Technician I Biosystems Engineering, Auburn University C. H. Burmester Extension Agronomist Tennessee Valley Research and Extension Center, Belle Mina, Alabama L. M. Curtis Professor and Extension Spec., Emeritus Biosystems Engineering, Auburn University D. P. Delaney Extension Specialist IV Agronomy and Soils, Auburn University B. A. Dillard Regional Extension Agent Alabama Cooperative Extension System M. P. Dougherty Assistant Professor Biosystems Engineering, Auburn University B. Durham Advisor II, Natural Resources Program Tennessee Valley Research and Extension Center, Belle Mina, Alabama J. P. Fulton Associate Professor Biosystems Engineering, Auburn University W. S. Gazaway Professor and Extension Spec., Emeritus Entomology and Plant Pathology Auburn University

K. Glass Advisor III, Natural Resources Program Agronomy and Soils, Auburn University W. R. Goodman Associate Professor, Emeritus Agricultural Economics and Rural Sociology Auburn University M. H. Hall Extension Specialist, Renewable Fuels Alabama Cooperative Extension System D. H. Harkins Associate Director Tennessee Valley Research and Extension Center, Belle Mina, Alabama J. Holliman Director, Black Belt Research and Extension Center, Marion Junction, Alabama G. Huluka Associate Professor Agronomy and Soils, Auburn University G. W. Lawrence Entomology and Plant Pathology Mississippi State University K. S. Lawrence Associate Professor Entomology and Plant Pathology Auburn University T. McDonald Associate Professor Biosystems Engineering, Auburn University C. C. Mitchell Professor and Extension Agronomist Agronomy and Soils, Auburn University C. D. Monks Professor and Extension Specialist Agronomy and Soils, Auburn University D. Moore Director Prattville Agricultural Research Unit Prattville, Alabama S. R. Moore Graduate Research Assistant Entomology and Plant Pathology Auburn University D. Mullenix Research Engineer Biosystems Engineering, Auburn University S. Nightengale Director, Plant Breeding Unit E. V. Smith Research Center Tallassee, Alabama

B. E. Norris Director Tennessee Valley Research and Extension Center, Belle Mina, Alabama B. V. Ortiz Assistant Professor and Extension Spec. Agronomy and Soils, Auburn University M. G. Patterson Professor Agronomy and Soils, Auburn University A. J. Price Afﬁliate Assistant Professor and Agronomist Agronomy and Soils, Auburn University USDA-National Soil Dynamics Lab. T. Z. Scott Graduate Research Assistant Entomology and Plant Pathology Auburn University A. Sharda Graduate Research Associate Biosystems Engineering, Auburn University J. Shaw Alumni Professor Agronomy and Soils, Auburn University R. H. Smith Professor and Extension Spec., Emeritus Entomology and Plant Pathology Auburn University T. Tyson Professor and Extension Specialist Biosystems Engineering, Auburn University E. van Santen Professor Agronomy and Soils, Auburn University D. Watts Soil Scientist USDA-National Soil Dynamics Lab. D. B. Weaver Professor Agronomy and Soils, Auburn University A. Winstead Regional Extension Agent Limestone County Alabama Cooperative Extension System R. P. Yates Regional Extension Agent Marengo County Alabama Cooperative Extension System

VARIETY TRIALS
BREEDING COTTON FOR YIELD AND QUALITY IN ALABAMA, 2010
D. B. Weaver

A cotton breeding project was initiated at Auburn University in 2001. Most of our work is centered on four primary objectives: (1) development of cotton germplasm or cultivars with improved yield and ﬁber properties, (2) evaluation and development of cotton germplasm for resistance to reniform nematode, (3) evaluation and development of cotton germplasm for resistance to abiotic stresses, particularly heat and drought, and (4) evaluation of effects of broadening the genetic base of upland cotton. In 2010, we evaluated experimental lines for yield and ﬁber properties at two locations: Tallassee and Prattville. Complete yield and ﬁber quality data are now available from the 2009 Regional Breeders Testing Network at 11 yield locations and two disease evaluation locations across the Cotton Belt. Auburn experimental lines ranked ﬁrst, eighteenth, and nineteenth in the 32-entry test (29 experimental lines plus three checks). New lines were submitted for evaluation in 2010, with the top-yielding line for 2009 being repeated in the test; results are unavailable as of the writing of this report. We are continuing to develop experimental lines using adapted cultivars and germplasm as parents and testing advanced lines We have made signiﬁcant progress in incorporating the LONREN source (RENlon gene) of resistance to reniform nematode into adapted germplasm and testing of advanced lines in both nematode-infested and nematode-free ﬁelds. We evaluated 100 F2:3 lines from the cross LONREN1 × Fibermax 966 in the greenhouse and identiﬁed 21 lines as having a high level of reniform resistance, at least equal to LONREN1. From this group we selected 20 highly resistant lines (Rf << 1; Rf is a reproduction factor and is the ratio between the ﬁnal nematode count and the initial count) and 20 highly susceptible sister lines (Rf >> 1) and conﬁrmed resistance/susceptibility phenotypes with SSR marker BNL 1066. We planted these lines along with checks—LONREN-1, LONREN-2, FM 966, and DP 393—in two ﬁelds with reniform nematode infestation near Belle Mina, Alabama, at the Tennessee Valley Research and Extension Center. One ﬁeld has been repeatedly inoculated in previous years with reniform nematodes, and populations were conﬁrmed by sampling previous to planting. The other ﬁeld was nematode-free, conﬁrmed by sampling. Resistant lines were 11 cm shorter in the nematode-infested ﬁeld than susceptible lines, but were not different in the reniform-free ﬁeld. Thus, there were no inherent effects of the RENlon gene on plant height in the absence of nematodes. Any height reduction caused by the RENlon gene appeared to be a result of reaction to nematode feeding. The LONREN germplasm lines also tended to be shorter than both their resistant progenies and the susceptible checks.

Yield in the nematode-infested ﬁeld was also signiﬁcantly reduced in the resistant lines compared to the susceptible progenies. This result was somewhat surprising, as we expected the resistance in the lines carrying the RENlon gene to result in higher yield. Susceptible lines yielded slightly higher than resistant lines in the nematode-free ﬁeld (1448 vs. 1372 pounds lint per acre) but the difference was not signiﬁcant (P = 0.21). Fiber quality was largely unaffected by presence of the RENlon gene. There were no differences between lines carrying the RENlon gene and those that did not except for one ﬁber quality trait: ﬁber strength. Lines that carried the RENlon gene had signiﬁcantly greater ﬁber strength than those that did not, regardless of nematode environment. In fact, average ﬁber strength of the resistant lines was more than 5 percent greater than susceptible lines in the nematode-infested ﬁeld and equal to the checks in both ﬁelds, indicating that there may be some positive impact of the RENlon gene on ﬁber strength. All other group mean differences were not signiﬁcant. Nematode populations were greatly reduced in the plots with lines carrying the RENlon gene, giving hope that this germplasm may yet play a signiﬁcant role in the management of reniform nematodes. With regard to this observed stunting problem, we conducted several greenhouse experiments to determine the effect of Cotoran®, reniform inoculation density, and secondary fungal organisms on LONREN and susceptible check lines in terms of root mass, shoot growth, and root/shoot ratios. Six genotypes were studied: LONREN-1, LONREN-2, and resistant line B104 of the cross LONREN-1 × FM 966 formed the group of resistant genotypes, whereas FM 966, Deltapine 555BR (DP555BGRR), and susceptible line B108 of the cross LONREN × FM966 constituted the group of susceptible genotypes. Inoculation levels were: 0, 500, 1,000, 5,000, 10,000 and 50,000 juvenile and vermiform life stages of Rotylenchulus reniformis. Shoot dry mass means from all genotypes decreased progressively with increase in nematode numbers. This was not the case with root dry mass means, where the group of resistant genotypes saw decreases with increased inoculation levels. All three susceptible entries recorded increases in root dry mass means with increased nematode population levels. The ratios in the resistant group showed limited variation in no particular direction. The ratios of the group of susceptible genotypes showed remarkable decreases, reaching up to 75 percent in the case of higher inoculation densities. The above-ground decrease in shoot mass of seedlings of resistant plants (stunting) appeared to be accompanied by decreases in root mass of near comparable magnitude. Shoots of susceptible genotypes also showed signs of stress at higher inoculation levels, either in reduced height or as a less vigorous stand.

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ALABAMA AGRICULTURAL EXPERIMENT STATION

Development of populations to examine the potential impact of introgression of exotic Gossypium hirsutum accessions as a means of broadening the genetic base of cotton on yield and ﬁber quality traits was begun in 2005 and continued through 2010. We have developed eight populations using a combination of four conventional adapted lines (Fibermax 966, Paymaster 1218, Delta Pearl, and Suregrow 747) and two exotic accessions (PI 165358, an accession from Mexico; and PI 530110, an accession from Brazil). Each population consists of a series of lines with 0, 25, 50, 75, and 100 percent exotic germplasm depending on how the cross was made. Six lines of each population per percent exotic were ﬁeld-tested in 2009 and 2010 at two locations. Data for 2010 are incomplete at present, but results from 2009 are presented. Across populations, except for days to ﬁrst ﬂowering and bolls per plant all other traits showed signiﬁcantly decreased mean line performance with an increase in percent exotic germplasm. Days to ﬁrst ﬂowering did not show any signiﬁcant difference up to 75 percent exotic whereas the 100 percent exotic parent signiﬁcantly differed from adapted parent. Bolls per plant showed a nonsigniﬁcant difference between 0 and all other population per percent exotic combinations except in 50 percent exotic, which showed a signiﬁcant decrease. All other agronomic traits such as boll mass, lint mass per seed, lint percent, seeds per boll, seed cotton yield, and lint yield signiﬁcantly decreased with increase in exotic percentage.

Fiber properties were lowered with an increase in percent exotic germplasm except for uniformity index, ﬁber elongation and short ﬁber content. Fiber elongation increased signiﬁcantly with increase in percent exotic germplasm. For short ﬁber content no signiﬁcant difference was observed. Uniformity index decreased signiﬁcantly with increase in percent exotic germplasm from 50 percent exotic onwards whereas no signiﬁcant difference was observed between 0 percent and 25 percent exotic. Another on-going related project is identifying germplasm accessions with tolerance to heat and drought. We have made some progress in this area during 2010. Our main focus is to identify techniques that can be used to evaluate genotypes in the growth chamber. We evaluated a select group of 44 accessions that had shown some promise of having heat tolerance from previous work and compared those to checks and a group of 44 randomly chosen accessions. As a group, the selected accessions performed better in terms of chlorophyll ﬂuorescence compared to the random group when exposed to temperatures as high as 50 degrees C. We believe we have identiﬁed a core group of genotypes that can tolerate and recover more rapidly from exposure to high temperatures than non-tolerant genotypes. Our focus in 2011 will be to reﬁne our technique and conduct experiments designed to measure plant growth parameters at high temperatures.

CROP PRODUCTION
THE OLD ROTATION AND CULLARS ROTATION, 2010
C. C. Mitchell, D. P. Delaney, and K. S. Balkcom

The “Old Rotation” experiment (circa 1896) is the oldest, continuous cotton study in the world and the third oldest ﬁeld crops experiment in the U.S. on the same site. The complete history of this experiment was published in 2008 in the centennial issue of Agronomy Journal (C.C. Mitchell, D.P. Delaney and K.S. Balkcom. 2008. A historical summary of Alabama’s Old Rotation (circa 1896): The world’s oldest, continuous cotton experiment. Agron. J 100:1493-1498). Non-irrigated crop yields in 2010 were below long-term averages for this experiment (Table 1). Dry matter yields of winter legumes (AU Robin crimson clover) have been disappointingly low for several years. Corn yields reﬂect N availability more than any other factor. Although we see a yield response to irrigation on corn, we cannot seem to break the 200 bushel-per-acre barrier. This may be due to the late planting of corn every year

(mid to late April). Cotton yields, like corn, reﬂect N availability. Unlike 2009 yields, the late-season drought in 2010 resulted in a dramatic response to irrigation by all crops. After eight years of irrigation versus no irrigation on the Old Rotation, we see a signiﬁcant (P<0.05) yield increase due to irrigation on all summer crops (Table 2). With corn and soybeans, the response to irrigation has been rather consistent, with positive yield responses in ﬁve of seven years. With cotton, we have seen yield increases from irrigation in only three of the seven years, but when irrigation was needed, the yield resonse was dramatic. In three of the seven years, we actually saw a negative response to irrigation, i.e. the non-irrigated plots actually yielded more than the irrigated plots. This is no doubt a problem associated with our timing of irrigation and should be corrected so excess water is not applied in wet years as in 2009. The Cullars Rotation (circa 1911) is the oldest, continuous soil fertility study in the TABLE 1. OLD ROTATION YIELDS, 2010 Southern U.S. This study is Clover dry matter Wheat –—Corn–— —Cotton— —Soybean— Plot Description Irrig. Non-irrig. Irrig. Irrig. Non-irrig. Irrig. Non-irrig. Irrig. Non-irrig not irrigated and yields reﬂect —lb/A— –bu/A– —bu/A— —lb/A— —bu/A— growing conditions during that 1 No N/no legume 0 0 488 207 season. Corn, cotton, and soy2 Winter legume 1812 2374 1076 795 bean yields were all dramati3 Winter legume 1352 2305 795 646 cally reduced due to the late 4 Cotton-corn 3434 3193 811 902 5 Cotton-corn + N 1479 2271 1506 869 season drought in 2010 (Table 6 No N/no legume 0 0 447 422 3). Wheat yields in 2010 were 7 Cotton-corn 977 2444 33.9 25.3 reasonable. Note the dramatic 8 Winter legume 2354 1394 844 670 yield response to added K by 9 Cotton-corn + N 896 1686 179.7 92.3 cotton and the apparent lack of 10 3-year rotation 0 0 28.6 56.2 21.1 11 3-year rotation 0 0 1026 803 response to added micronutri12 3-year rotation 1991 4355 196.0 98.3 ents. No added P (Plot 2) dra13 Continuous cotton 0 0 927 861 matically reduced wheat and No legume + N soybean yields more than cotMean 136.5 72.0 880 686 ton yields. The Cullars Rotation experiment is an excellent TABLE 2. EFFECT OF IRRIGATION ON MEAN CORN, COTTON, AND SOYBEAN YIELDS site to see dramatic nutrient deON THE OLD ROTATION, 2003-2009 ﬁciencies compared to healthy Plot Treatment Irrigated yield Non-Irrigated yield CORN (bu/A) crops each year. 4,7 Legume N only 64.7 b 69.9 ab The Cullars Rotation will 5,9 Legume N + 120 lb N/A 167.4 a 98.9 a celebrate 100 years of continu10,11,12 3-yr rotation/legume N 131.1 a 52.6 b ous crop production research in 73.8 7-yr mean 121.11 COTTON (lb lint/A) 2011.
1,6, 2,3, 8 13 4, 7 5,9 No N/no legume 514 d Legume N only 1020 c 120 lb N/A; no legume 1330 ab Corn rotation with legume 1270 b Corn rotation with legume + 120 lb N/A 1500 a 3-yr rotation/legume only 1190 bc 7-yr mean 10401 SOYBEAN (bu/A) 3-yr rotation 7-yr mean 53.41 390 d 990 b 930 b 1120 ab

10, 11, 12

1250 a 720 c 861 39.4

1

Signiﬁcant at P<0.05

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ALABAMA AGRICULTURAL EXPERIMENT STATION

Trt. no. A B C 1 2 3 4 5 6 7 8 9 10 11

TABLE 3. CULLARS ROTATION YIELDS, 2010
Description no N/+legume no N/no legume nothing no legume no P complete 4/3 K rock P no K 2/3 K no lime (pH~4.9) no S complete+ micros 1/3 K Clover dry wt. lb/A 3000 0 0 0 1578 2803 2825 3161 891 3200 0 2821 4402 3243 Wheat bu/A 17.8 15.2 0.0 39.8 32.7 42.7 40.2 41.1 40.8 50.1 0.0 44.8 54.9 46.9 Corn bu/A 36.6 18.0 0.0 37.6 17.7 45.5 24.4 34.2 4.3 32.7 0.0 24.1 42.1 33.0

Cotton lb lint/A 588 588 0 588 248 637 488 538 0 521 132 455 546 414

Soybean bu/A 18.2 18.0 0.0 18.2 10.7 17.9 15.1 17.1 10.1 15.9 4.1 15.1 17.8 13.8

IRRIGATION
SPRINKLER IRRIGATION OF COTTON FOR BIODIESEL PRODUCTION
Cottonseed response to a sprinkler irrigation study was initiated in 2008 at the Tennessee Valley Research and Extension Center (TVREC). The intent of this study was to understand seed oil-free fatty acid variations and how that might impact biodiesel production. The study consisted of a continuous rotation of cotton that was evaluated for yield, oil, and oil-free fatty acid (FFA) responses to six sprinkler irrigation treatments ranging from 0 percent (rainfed) to 125 percent of calculated pan evaporation adjusted for percent canopy cover. Cottonseed yield and characteristic responses to irrigation are important to assess the economic feasibility and environmental impacts of irrigation for biodiesel production and quality with high yield and oil content and low FFA desired. The study was conducted on 48 plots (39 feet x 39 feet) arranged in a randomized split plot design with four replications and two rotations. One rotation was a nontraditional energy crop rotation but the other, containing 24 plots of continuous cotton rotation, is the focus of this report. Total
D. Mullenix, J. P. Fulton, M. P. Dougherty, M. H. Hall, C. H. Burmester, B. Durham, and C. Brodbeck

seasonal rainfall (June to August) at TVREC for 2008, 2009, and 2010 was 11.3 inches, 12.4 inches, and 5.3 inches, respectively, with the 82-year average being 11.4 inches. In 2008, slight yield mean separation was determined with highest and lowest yields exhibited in 100 percent and rainfed treatments, respectively (Table 1). While insigniﬁcantly different, seed oil yields tended to increase with increasing irrigation, a ﬁnding documented in published literature by various researchers. Theoretical biodiesel yields correspond to seed cotton yield and all FFA levels remained within recommended tolerances (less than 2 percent), suggesting no oil pretreatment is necessary for biodiesel production. Statistical differences in yield and seed oil content were not found in 2009, most likely due to above average seasonal rainfall (Table 2). Seed oil concentration, while not signiﬁcantly different, was 2 percent to 3 percent higher in all treatments for 2009 and attributed to increased rainfall. FFA levels in 2008 were less than 1 percent for all treatments, but approximately 10 times TABLE 1. IRRIGATION DEPTH, YIELD, OIL-FREE FATTY ACID, AND THEORETICAL BIODIESEL higher in 2009 with signiﬁcant PRODUCTION, 2008 differences observed. FFA levIrrigation Applied Seed cotton Oil-free Seed Biodiesel els from the 2009 cotton crop treatment irrigation yield Yield fatty acid oil production are not conducive to biodiesel 1 in lb/A bales/A % % dry basis gal/A production since the oil would Rainfed 0.0 2782 b 2.2 a 0.5 a 19.5 a 32.3 25% 3.2 3596 ab 2.9 a 0.7 a 20.6 a 44.5 require extensive pretreatment 50% 3.7 3044 ab 2.4 a 0.6 a 20.4 a 36.3 if biodiesel production is de75% 5.9 2908 b 2.3 a 0.5 a 20.2 a 34.9 sired. Lower than expected 100% 7.9 3901 a 3.1 a 0.6 a 21.7 a 51.0 yields in 2009 were due to boll 125% 17.3 3746 ab 3.0 a 0.4 a 22.2 a 50.6 shedding with the higher FFA Average — 3330 2.7 0.6 20.8 41.6 1 Assume a conversion ration of oil to biodiesel of 1:1 and 80 percent oil extraction efﬁciency. levels a result of high moisture Means followed by same letter do not signiﬁcantly differ according to Fischer’s least signiﬁcant difference and cool weather at the end of test (P < 0.05). the season, which prolonged harvest and allowed cottonTABLE 2. IRRIGATION DEPTH, YIELD, OIL-FREE FATTY ACID, AND THEORETICAL BIODIESEL seeds to be overly exposed to PRODUCTION, 2009 moisture. Excessive moisture Irrigation Applied Seed cotton Oil-free Seed Biodiesel is speculated to have activated treatment irrigation yield Yield fatty acid oil production 1 key enzymes that began the in lb/A bales/A % % dry basis gal/A Rainfed 0.0 2691 a 2.1 a 8.1 ab 22.6 a 35.6 germination process. The result 25% 3.1 2501 a 2.0 a 6.7 b 22.1 a 33.6 was breakdown or oxidation 50% 6.5 2633 a 2.1 a 10.0 ab 22.0 a 35.1 of lipids inside the seed, lead75% 9.6 2350 a 1.9 a 7.8 ab 22.3 a 31.2 ing to the extremely high FFA 100% 12.8 2711 a 2.1 a 11.5 a 23.2 a 38.8 values (Table 2). Although oil 125% 16.6 2420 a 1.9 a 10.3 ab 22.2 a 32.6 Average — 2,551 2.0 9.1 22.4 34.5 content was consistently higher 1 Assume a conversion ratio of oil to biodiesel of 1:1 and 80 percent oil extraction efﬁciency. for 2009, average theoretical Means followed by same letter do not signiﬁcantly differ according to Fischer’s least signiﬁcant difference biodiesel production was down test (P < 0.05). from the 41.6 gallons per acre estimated in 2008 due to overall lower seed cotton yields. Seed cotton yield responses to irrigation treatments were notable in 2010 (Table 3).

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ALABAMA AGRICULTURAL EXPERIMENT STATION

While the total seasonal rainfall for 2010 was only 5.3 inches, rainfed treatment yields were not unlike rainfed treatment yields observed in 2008 and 2009. However, treatments of 100 percent and 125 percent yielded favorably to irrigation and were the highest yields experienced for the duration of the experiment, producing 3.5 and 3.3 bales per acre, respectively. Seed oil FFA

concentrations were well below 1 percent for all treatments and theoretical biodiesel production, like seed cotton yield, increased as irrigation increased with an experiment high average estimated yield of 54.1 gallons per acre.

Irrigation treatment 0% 25% 50% 75% 100% 125% Average
1

TABLE 3. IRRIGATION DEPTH, YIELD, OIL-FREE FATTY ACID, AND THEORETICAL BIODIESEL PRODUCTION, 2010
Applied irrigation in 0 4.0 8.4 12.0 16.2 21.0 _ Seed cotton yield lb/A 2787 c 2957 bc 3833 abc 3965 ab 4396 a 4119 a 3676 Yield bales/A 2.2 c 2.4 bc 3.0 abc 3.2 ab 3.5 a 3.3 a 2.9 Oil-free fatty acid % 0.4 a 0.4 a 0.4 a 0.4 a 0.4 a 0.5 a 0.4 Seed oil % dry basis 22.7 a 22.1 a 22.9 a 22.8 a 22.8 a 23.5 a 22.8 Biodiesel production gal/A 1 40.0 41.5 56.0 59.1 66.3 61.6 54.1

Assume a conversion ration of oil to biodiesel of 1:1 and 80 percent oil extraction efﬁciency. Means followed by same letter do not signiﬁcantly differ according to Fischer’s least signiﬁcant difference test (P < 0.05).

2010 AU CROPS: COTTON RESEARCH REPORT

11

EVALUATION OF AUTOMATIC SECTION CONTROL TECHNOLOGY FOR AGRICULTURE SPRAYERS
A. Sharda, J. P. Fulton, D. Mullenix, T. McDonald, A. Winstead, M. H. Hall, and B. V. Ortiz

Automatic section control (ASC) technology has been readily adopted by farmers over the past few years on agricultural sprayers. However, recent research at Auburn University has illustrated that off-rate application can occur more frequently than expected when utilizing this technology in conjunction with spray controllers. Therefore, a study was conducted to evaluate the application performance on sprayers when using ASC. A combination of laboratory and ﬁeld experiments were conducted to quantify off-rate errors and nozzle ﬂow stabilization. High frequency pressure sensors were installed near the boom-section control valves and at the nozzle bodies to document pressure variations during ﬁeld operation and ASC actuation. A ﬂow meter was also used to measure overall system ﬂow to determine control system response and compute off-rate errors. For this study, off-rate represents the ﬂow deviation from the desired target rate established by the operator and uploaded to the rate control system. The impact of different valve calibration numbers was investigated. While the term valve calibration number may have different names within manufacturer literature, this three-digit number is usually an operator-set parameter that controls how the primary control valve on the sprayer responds to required rate changes due to such things as ground speed changes. This value determines such things as valve response speed (quickness of change), brake point (when valve starts slowing down), and dead-band (acceptable tolerance to target point). We found that ASC technology on sprayers can provide a savings between 2 percent and 12 percent per ﬁeld with an approximate average of 4.3 percent across most farms in Alabama. Field shape and size affect savings. These savings are due to minimizing double-application areas within ﬁelds. These savings alone showed that the technology would pay for itself within two years (in several cases, less than one year) for most Alabama farm operations. In terms of sprayer performance, results from this study determined that tip pressure variations can occur more frequently than realized by sprayer operators. These variations normally happen during quick ground speed changes and automatic section control actuation (sections turning on and off). Of interest, these pressure variations can impact droplet size and thereby application efﬁcacy, which can be a concern when applying fungicides and similar products. Further, selection of the correct valve calibration number is important to minimize sprayer off-rate errors. These errors are due to delay times (over 10 seconds in

some cases) when rate changes are required. These rate changes occurred during acceleration or deceleration of the sprayer and automatic section control actuation (on-off of boom sections). Additional results from this study indicated that off-rate errors and high pressure spikes happen most frequently at headlands or points rows where turning is required. Based on these results, the following are suggestions to sprayer operators to minimize off-rate errors and large pressure ﬂuctuations: ▪ Consulting manufacturer literature and company support is important to make sure of the following: − The valve calibration number is proper for the sprayer and operating conditions. − The ﬂow meter is properly calibrated for the product bein sprayed. − GPS offset and/or “look-ahead” values in the rate controller are correctly speciﬁed within the setup menus. ▪ Operator driving habits are important to consider. Quick speed changes greatly increase the risk of large pressure variations within hoses and tubing, causing off-rate errors for several seconds. Gentle sprayer acceleration and deceleration at ﬁeld ends when turning helps provide time for the controller to properly respond to maintain the set target rate. ▪ A visible pressure gauge located in view of the sprayer operator is suggested so that the operator can observe any unnecessary pressure ﬂuctuations. Based on this feedback, the operator can recognize when excessive pressure variations occur and can then respond accordingly to minimize this potential issue. ▪ The use of guidance systems on sprayers is recommended to help operators maintain parallel, adjacent passes. Guidance technology can help reduce overlap between adjacent passes down to around 1 percent to 2 percent from around 10 percent using traditional guidance methods (e.g. foam markers). In summary, ASC technology can provide Alabama farmers substantial savings on inputs with an average savings of 4.3 percent determined in this study. For those adopting ASC, make sure to follow the manufacturer recommendations on setup and calibration for the rate controller but also recognize the operator can impact performance. You can learn more about ASC on sprayers from the Alabama Precision Ag Website, www.AlabamaPrecisionAgOnline.com under the topic Section Control Technology. An Extension publication “Automatic Section Control (ASC) Technology for Agricultural Sprayers” is also available.

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ALABAMA AGRICULTURAL EXPERIMENT STATION

EVALUATING PRESSURE COMPENSATING SUBSURFACE DRIP IRRIGATION FOR NO-TILL ROW CROP PRODUCTION ON ROLLING, IRREGULAR TERRAIN, 2010
J. P. Fulton, M. Dougherty, J. Shaw, C. H. Burmester, B. Durham, L. M. Curtis, A. Brooke, T. Tyson, D. H. Harkins, A. Winstead, D. Mullenix, and J. Arriaga

This investigation was conducted on a 12-acre ﬁeld located at the Tennessee Valley Research and Extension Center (TVREC), Belle Mina, Alabama. The objective was to evaluate cotton production on rolling terrain irrigated with subsurface drip irrigation (SDI) in conjunction with cover crops. The experimental design was a randomized block design with two irrigation treatments (irrigated and non-irrigated) and two cover crop treatments (cover and no-cover) with four replications. Plots measured 27 feet by 1,250 feet with SDI tape installed in 1,250-foot runs on 80-inch spacing (every other row of 40-inch row cotton) and buried at an average depth of 13 inches. Plots receiving a cover crop treatment were planted with rye at a rate of 90 pounds per acre. High moisture and cool weather during the fall of 2009 caused the rye to be planted late (November 29, 2009). The cover crop was desiccated on April 12, 2010. Cotton, variety ST 4554 B2RF, was planted on April 22, 2010. A quality analysis was conducted by harvesting 50 cotton bolls collected at six locations within each plot (96 total samples; six locations x 16 plots) prior to harvesting. Quality factors considered were micronaire, strength, uniformity, and lint length. Accumulated yield per treatment was determined using a weighing system. Yield data were analyzed to determine signiﬁcant differences (α=0.10). The irrigated treatments produced the highest seed cotton yields in 2010 (Table 1), with yields of approximately 3,800 pounds per acre or 3.2 bales per acre for each treatment. The two non-irrigated treatments yields were not signiﬁcantly different but yielded less (42 percent non-irrigated/cover and 46 percent non-irrigated/no-cover) when compared to the irrigated yields. When compared to yields in 2009, overall mean treatment yields were higher in 2010 except for the non-irrigated/no-cover treatment, which had equal yields each year. Cover crop treatments had a greater impact on yields in 2009 than irrigated versus nonirrigated treatments. In that year sufﬁcient rainfall occurred during the growing season. Due to wet conditions late in 2009, rye was planted late, resulting in limited biomass production prior to desiccation. The biomass samples collected in 2010 ranged from 51 percent to 62 percent less dry matter in the four treatments than in the measured biomass in 2009. Thus, 2010 yields were driven more by available water than by the cover crops. In general, this longterm study demonstrates that cover crops provide a yield beneﬁt especially during growing seasons with limited rainfall. Micronaire values for both irrigated treatments averaged 4.9,thereby not receiving a gin discount, while the 5.2 average

value for the non-irrigated cotton did receive a discount (Table 2). Cotton ﬁber for all treatments was similar in strength and was within the premium range. The treatments with a cover crop produced stronger ﬁbers than the treatments without a cover crop. Likewise, the irrigated treatments were on average stronger. The cotton did not receive any discounts for uniformity. Both irrigation treatments were graded as premium with the non-irrigated falling in the base level. The irrigated treatments were slightly higher in uniformity by around 1.5 percent. The lint length for the non-irrigated was the shortest at 1.07 inches, while the irrigated treatments were longer at 1.12 and 1.13 inches for no-cover and cover, respectively. In general, the cover crops provided little or no beneﬁt on cotton quality. In summary, the use of pressure compensated SDI has provided signiﬁcant yield beneﬁts over the 2006 to 2008 and 2010 years of this study. In 2010, the yield differences between irrigated and non-irrigated treatments were signiﬁcant. While the 2010 results did not indicate a beneﬁt from cover crops, this outcome was attributed to low biomass yields for the cover crop. However, previous years have conﬁrmed a beneﬁt to cover crops in terms of cotton yield such as the 0.5 bales per acre increase for 2009. The cotton quality analysis indicated that the irrigation treatments generally provide improvement in cotton quality. There was a slight beneﬁt to the irrigated treatments in that the non-irrigated treatments were discounted for micronaire and had shorter lengths, but overall there was no signiﬁcant difference in uniformity or strength.

TABLE 1. YIELD AVERAGES BY TREATMENT, 2009 AND 2010
Treatment Irrigated/Cover Irrigated/No-Cover Non-Irrigated/Cover Non-Irrigated/No-Cover ——2009—— Seed cotton Lint lb/A bales/A 2921 a 2.4 2311 b 1.9 2720 a 2.3 2064 b 1.7

——2010—— Seed cotton Lint lb/A bales/A 3798 a 3.2 3811 a 3.2 2208 b 1.8 2025 b 1.7

Mean yields with similar letters within columns indicate they are not statistically different (α=0.10).

Treatment

Micronaire Strength Uniformity Length g/tex % in Irrigated/Cover 4.9 30.9 83.5 1.13 Irrigated/No-Cover 4.9 30.2 83.7 1.12 Non-Irrigated/Cover 5.2 30.4 82.0 1.07 Non-Irrigated/No-Cover 5.2 29.6 82.0 1.07

TABLE 2. COTTON QUALITY BY TREATMENT, 2010

2010 AU CROPS: COTTON RESEARCH REPORT

13

SUBSURFACE DRIP IRRIGATION-FERTIGATION FOR SITE-SPECIFIC, PRECISION MANAGEMENT OF COTTON
M. Dougherty, A. H. Abdelgadir, J. P. Fulton, C. H. Burmester, B. E. Norris, D. Harkins, L. M. Curtis, and C. D. Monks

A subsurface drip irrigation study was installed at the Tennessee Valley Research and Extension Center (TVREC) in 2005 to evaluate four precision fertigation management scenarios. Approximately 7,500 feet of subsurface drip irrigation (SDI) tape and four positive displacement liquid fertilizer injectors were installed on ﬁve nutrient timing treatments with four replications in a randomized complete block design. The twenty treatment plots were made up of eight, 345-foot rows of cotton on 40-inch row spacing, with drip tape between every other row of cotton. The four fertigation treatments and one non-fertigated control are described in Table 1. Total seasonal rainfall at TVREC during June to August 2010 was 5.27 inches (Figure 1), which was drier than the 82year average (11.44 inches). Yield results for 2006 to 2010 are shown in Figure 2. Seed cotton yields for the 2010 season were high, above 2 tons per acre and similar to the 2008 yield. The 100 percent fertigated treatments (3 and 4) gave statistically (α = 0.1) similar yields to

the surface-applied control treatment in this season. Treatments 2 and 5, which contained 15 percent and 30 percent surfaceapplied fertilizer, produced signiﬁcantly higher yield than the surface-applied control treatment. The highest statistical yield for this season was obtained from treatment 5 (30 percent surface application and 70 percent fertigation). Cotton yield (bales per acre), lint quality parameters, and leaf nutrient analyses are presented in Table 2. Lint strength or uniformity was signiﬁcantly affected by different fertilizer treatments. Treatment 4 (100 percent fertigated) gave signiﬁcantly (α=0.1) higher lint length and lower micronaire than other fertigated treatments and surface-applied control. Plant uptake for N was signiﬁcantly (α=0.1) higher in the surface-applied control treatment (treatment 1) than the fertigated treatments without surface application. Uptake of K was relatively low at mid-bloom and not affected by any treatment, while Phosphorus, Ca, and Mg contents were signiﬁcantly affected by different treatments.

Treatment1 1. Control – drip irrigated, but all fertilizers are surface applied. 2. Timing 1 – with surface preplant 3. Drip timing 1 – no preplant 4. Drip timing 2 – no preplant “spoon-fed” 5. Timing 2 – with surface preplant
1

TABLE 1. TREATMENT DESCRIPTION, FERTIGATION MANAGEMENT TRIALS, 2006-2009
Description Preplant – 60 lb/A N and K Post-Plant – 75 lb/A N, sidedressed at early square Preplant – 20 lb N and K, surface applied Drip – 40 lb N and K, square to bloom (25 days) Drip – 75 lb N and K, bloom to 25 days Planting Drip – 20 lb N and K Drip – 40 lb N and K, square to bloom (25 days) Drip – 75 lb N and K, bloom to 25 days Planting Drip – 20 lb N and K Drip – 40 lb N and K, square to bloom (25 days) Drip – 75 lb N and K, bloom to 40 days Preplant – 40 lb of N and K, surface applied Drip – 95 lb N and K, square through bloom (50 days)

All treatments received 135 pounds per acre of nitrogen and potassium (K2O), 20 pounds per acre of sulfur, and l.0 pound per acre of boron. Phosphorus fertilizer was surface-applied to maintain P at high soil test levels. Drip fertilizer was 8-0-8-1.2S-0.06B applied using 32 percent liquid N, potassium thiosulfate, fertilizer grade KCL, solubor, and water.
14.00

12.39
12.00 10.00

11.27

11.44

Rainfall (inch)

8.00

6.63
6.00 4.00 2.00 0.00 2006

6.06

5.27

2007

2008

2009

2010

82-YR Mean

Figure 1. Total seasonal rainfall during June, July, and August vs. the 82-year average at Belle Mina, AL,

14

ALABAMA AGRICULTURAL EXPERIMENT STATION
2006 2007 2008 2009 2010

5000 4500 4000 Seed cotton yield (lb/ac) c 3500 3000 2500 2000 1500 1000 500 0 1 2 3 Fertilizer treatment 4 5 a a a a a c a a b b b b a a bc b bc b b b ab b

b

a

Figure 2. Seed cotton yield, lb/ac, drip tier fertigation management study, Belle Mina, AL, 2006-2010. N = 4. Turnout = 41.5 percent. Different letters within a year indicate signiﬁcant difference (α = 0.1).

Trt.1 1 2 3 4 5

—————Cotton yield and quality analysis————— Yield 2 Micronaire Length Strength Uniformity 3.5 c 5.02 a 1.12 c 29.7 a 82.9 a 3.8 b 4.90 a 1.13 b 29.6 a 83.2 a 3.6 bc 5.10 a 1.14 ab 29.8 a 83.4 a 3.7 bc 4.62 b 1.16 a 30.6 a 83.5 a 4.0 a 5.10 a 1.14 ab 29.6 a 83.4 a

TABLE 2. COTTON LINT YIELD AND QUALITY ANALYSIS AND PLANT TISSUE ANALYSIS, COTTON FERTIGATION MANAGEMENT TRIALS, 2010

———————Plant tissue analysis——————— N% P% K% Ca% Mg% 3.39 a 0.19 b 1.35 a 2.42 d 0.57 a 3.15 c 0.20 ab 1.32 a 2.79 a 0.55 bc 3.26 b 0.22 a 1.35 a 2.70 ab 0.54 c 3.24 bc 0.22 a 1.38 a 2.59 c 0.52 d 3.32 ab 0.19 b 1.32 a 2.65 bc 0.56 ab

1 Treatments: 1. Surface applied N-P-K with drip irrigation (control). 2. Preplant 20# N-K surface with 2 N-K drip timings. 3. 20# N-K drip at planting with 2 N-K drip timings (to 25 days after bloom). 4. 20# N-K at planting with 2 N-K drip timings (to 40 days after bloom). 5. Preplant 40# N-K surface with 1 N-K drip timing (square through bloom). Different subscripts in a column denote statistical difference (α=0.1). N=4. Turnout = 41.5%. 2 Yield in bales per acre.

FERTILITY
ALTERNATIVE SOURCES OF N FOR CORN AND COTTON IN ALABAMA
C. C. Mitchell, K. S. Balkcom, D. Watts, and D. Moore

Rapidly increasing N fertilizer costs have left Alabama cotton and corn producers with few alternatives. Using legumes as winter cover crops and using poultry broiler litter as a source of nutrients are the only alternatives for many producers. Dry urea (46-0-0) is a less expensive alternative to ammonium nitrate (340-0) for surface application but the risks of volatilization losses can be high. This is especially true when applied during the hot, sometimes dry, summer months on residue in a well-limed soil. Agrotain® (N-(n-butyl) thiophosphoric triamide), a urease inhibitor, is marketed to reduce volatilization losses from urea-containing fertilizers. Several new technology, controlledrelease N sources are also available for row-crop farmers. Thus, our objectives were to compare alternative sources of N fertilization for non-irrigated cotton and corn in Central Alabama. Treatments are designed to compare products. Ammonium nitrate is the standard of comparison and the two rates selected were chosen based upon recommendations for that site of 120 pounds total N per acre for non-irrigated corn and 90 pounds total N per acre for cotton. The two rates of ammonium nitrate are to verify the optimum N rate (Table 1). Liquid Urea-ammonium nitrate (UAN) is the most widely used N source for cotton and corn in Alabama. In this study, a 28-00 UAN solution was used. It was applied by spraying a band about 8 inches wide on either side of the row. Dry urea is usually the least expensive N material available. Widespread concerns about ammonia volatilization losses on hot, dry soils with a good residue cover often discourage its use as a sidedress N source on no-till/conservation-tilled corn and cotton in Alabama. However, in 2008, dry urea produced the highest cotton yield of any material studied. Agrotain® has become the standard urease inhibitor product currently being used in the Southeastern U.S. Agrotain was mixed with dry urea at the highest recommended rate to give 14-day pro-

tection under adverse soil conditions. The rate was 5 quarts per ton. For 28 percent or 32 percent UAN solutions, the rate was 2.4 quarts per ton. Nutrisphere N® is formulated to be used with both dry urea and UAN solutions. Both formulations were included at the manufacturers’ recommended rates. Nitamin Nfusion® is a 22 percent N product of which 94 percent is slowly available to be blended with UAN solutions. However, in this study it was used at the full rate as a sidedress N application. Poultry litter is abundant in most areas of Alabama. An 11-year study showed rather conclusively that it could be used on conservation tillage corn and cotton based on the total N in the litter. Conservatively, most growers assume about two thirds available N. In this study, poultry broiler litter was applied at two rates of total N (120 and 180 pounds total N per acre for corn and 90 and 120 pounds total N per acre for cotton). All poultry litter was applied at planting. No additional N was applied to these treatments. Calcium chloride. In 2007, 2008, and 2009, very similar studies were conducted that included rates of a liquid calcium chloride product. There were claims that calcium chloride could help reduce volatilization losses of urea-based N sources. We saw no evidence of this in these earlier tests, so calcium chloride was dropped as a treatment in 2010. The site was on a Lucedale sandy clay loam (ﬁne, loamy, siliceous, Thermic Rhodic Paleudults) testing “high” in P and K. No additional P and K was recommended and none was applied. Corn (Pioneer 31G97) was planted no-till into the previous crop’s residue on April 7 and harvested by machine on August 23. Cotton (Phytogen 440W) was planted no-till into the previous crop’s residue on April 26 and harvested by machine on September 22. Plot size was 12 feet wide (four, 36-

Trt. no. 1 2 3 4 5 6 7 8 9 10 11 12 13
1 2

TABLE 1. TREATMENTS AND YIELDS FOR CORN, 2010

Total N rate at Corn grain Source N sidedressing yield —————lb/A————— None 0 0 1125 d 1 Ammonium nitrate 120 100 4096 ab Ammonium nitrate 180 160 3945 abc UAN solution 2 120 100 4592 a UAN + Agrotain® 120 100 4616 a Urea 120 100 4592 a Urea + Agrotain® 120 100 4296 ab Urea + Nutrisphere N® 120 100 4229 ab UAN + Nutrisphere N® 120 100 4344 ab Nitamin Nfusion 22-0-0® 120 100 3806 abc Urea-am. sulfate blend 120 100 4386 ab Poul. litter @ ~120# N/a 120 0 3213 c Poul. ltter @ ~180# N/a 180 0 3739 bc

Trt. no.

TABLE 2. TREATMENTS AND YIELDS FOR COTTON, 2010
Source

1 2 3 4 5 6 7 8 9 10 11 12 13
1 2

Total N rate at Cotton lint N sidedressing yield —————lb/A————— None 0 0 390 b 1 Ammonium nitrate 90 70 460 ab Ammonium nitrate 120 100 460 ab UAN solution 2 90 70 420 ab UAN + Agrotain® 90 70 420 ab Urea 90 70 420 ab Urea + Agrotain® 90 70 470 ab Urea + Nutrisphere N® 90 70 420 ab UAN + Nutrisphere N® 90 70 400 b Nitamin Nfusion 22-0-0® 90 70 460 ab Urea-am. sulfate blend 90 70 560 a Poul. litter @ ~90# N/a 90 0 460 ab Poul. ltter @ ~120# N/a 120 0 510 a

DMRT P <0.05. 28-0-0-5S

DMRT P <0.05. 28-0-0-5S

16

ALABAMA AGRICULTURAL EXPERIMENT STATION

inch rows) and 35 feet long. Yields were harvested from the two center rows. Leaf samples were taken from the outside rows. In 2010, corn ear leaf samples were taken on June 24 at early tassel (R1 stage). On the same day, uppermost mature leaf blades were sampled from the cotton plots during early bloom. Samples were dried and ground and total N was determined on all leaf samples using a nitrogen analyzer (combustion). Both corn (Table 1) and cotton (Table 2) yields were low in 2010 due to an extended drought and extreme heat during the critical growth stages for both crops. In spite of low yields, there were some signiﬁcant differences in treatments. All the products produced similar yields when applied at the recommended rate of 120 pounds total N per acre. The most notable exception was poultry broiler litter. Poultry broiler litter applied at planting to corn at either 120 or 180 pounds total N per acre was not adequate for optimum grain yields compared to the other treatments. While it did not affect cotton yields as much as corn yields, leaf analyses from both crops (Table 3) indicated low N concentrations in the leaves compared to the other treatments. The new-technology sources such as Agrotain®, Nutrisphere®, and the controlled release, Nitamin® , did not increase yields or

N concentration in the leaves compared to more conventional sources such as urea, ammonium nitrate, or UAN solution. This is the fourth year of this study at the same location. Treatments have changed as new products became available to evaluate. The ﬁrst year, 2007, was during a record drought and no yields were harvested. Low, but reasonable corn and cotton yields were harvested in 2008 and 2009. Additionally, in 2007, 2008, and 2009, ammonia volatilization was measured from selected treatments. While certain treatments, e.g., Agrotain®, did reduce estimated N losses from volatilization, volatilization of these treatments had minimal affect on corn and cotton yields as it did in 2010. The newer controlled release N products have not shown any yield advantage to more conventional N sources such as urea, ammonium nitrate, UAN solution, or the urea-ammonium sulfate blend, which is being sold as a substitute for ammonium nitrate. In 2008 and 2009, higher ammonia volatilization losses occurred if UAN solutions were broadcast when we had an unusually heavy surface residue cover. Agrotain® seemed to reduce these losses. However, we did not have a heavy residue in 2010 and apparently the risk of ammonia volatilization from UAN solutions was lower.
Trt. no.

TABLE 3. CORN EAR LEAF AND COTTON LEAF NITROGEN1
Corn ear Cotton leaf blade leaf total N total N —————%————— None 3.20 d 2 1.36 c Ammonium nitrate 4.25 a 2.09 ab Ammonium nitrate 4.24 a 2.13 a UAN solution 3 3.96 abc 2.10 ab UAN + Agrotain® 4.04 ab 2.17 a Urea 4.19 a 2.06 ab Urea + Agrotain® 4.07 ab 2.03 ab Urea + Nutrisphere N® 3.91 abc 2.18 a UAN + Nutrisphere N® 4.19 a 2.23 a Nitamin Nfusion 22-0-0® 3.83 bc 1.90 b Urea-am. sulfate blend 3.97 abc 2.08 ab Poul. litter @ ~120# N/a 3.33 d 1.54 c Poul. ltter @ ~180# N/a 3.66 c 1.56 c Source

1 2 3 4 5 6 7 8 9 10 11 12 13
1

Ear leaf sampled June 24 at full tassel; cotton leaves taken from uppermost, mature leaf blade at early bloom on June 24. 2 DMRT P <0.05. 3 28-0-0-5S

2010 AU CROPS: COTTON RESEARCH REPORT

17

FERTILIZATION OF COTTON ON BLACK BELT SOILS
C. C. Mitchell, G. Huluka, R. P. Yates, D. P. Delaney, and J. Holliman

This experiment was laid out in 2004 and was designed to This problem has become a serious limitation to cotton produccomplement the “Rates of NPK Experiment” (circa 1929) on tion on Black Belt soils in Alabama but it is also unpredictable. other outlying units of the Alabama Agricultural Experiment Leaf spot also occurred in 2009 but did not hurt yields as much as Station. The purpose of this experiment is to identify optimum 2008 because it occurred later in the season. Cotton in 2009 was rates of N, P2O5, and K2O for cotton on Black Belt soils and to harvested late (November 13) due to an extremely wet fall season. calibrate soil test P and K for these soils. The site is on an acid, If the 2006 through 2009 crops had been machine harvested, very Vaiden clay (very ﬁne, smetitic, thermic, Vertic Hapludalfs) and little of the lint would have been saved because of hard locks and is the only soil fertility experiment in Alabama on Black Belt weak bolls. Extreme heat and a late-season drought may have reduced yields in 2010. Severe apparent 2,4-D damage was noted soils. Initial soil tests from the site indicated a very uniform in mid-summer (June10 through early July) in 2010. Surprisingly, site typical of unfertilized Black Belt area cropland (Table the cotton recovered and made a modest yield. Selected treatments were tested each year for lint quality. No 1). Phosphorus was rated “low” using the Mississippi/Lantreatment differences were observed in 2007 but there were sigcaster extract, which is the preferred method for these soils and is used by both the Auburn University and Mississippi niﬁcant difference in 2008, 2009, and 2010 (Table 2). The “No K” State University soil testing laboratories. Potassium was rat- treatment had signiﬁcantly lower overall ﬁber quality (Table 3). Because of the higher yields and signiﬁcant differences in ed “very high.” Soil samples have been taken from each plot treatments on yield in 2007 through 2010, these data probably are every year of this experiment and are reported under a sepamore relevant to producers (Table 2). rate project. N rates. Optimum total N rates over the ﬁve years of the The experiment consists of six N rates, four P rates, ﬁve K experiment appear to be around 60 pounds N per acre. Although rates, and a no-lime treatment and an unfertilized treatment replicated four times in a randomized block design (Table 2). Plots there was a more dramatic response to N rates in 2005, yields consisted of ﬁve rows on 36-inch centers, 15 feet wide and 25 feet were low because excessive rainfall resulted in severe denitriﬁlong. Each tier was separated by a 5-foot alley. Because of disap- cation losses on these poorly drained soils. The current recompointing yields in 2005 when cotTABLE 1. INITIAL, MEAN PLOW-LAYER SOIL TEST VALUE, 2004 1 ton was planted no-till into a rye Extract used Soil pH P K Mg Ca cover crop and excessive rainfall ————————mg/kg and rating——————— occurred, the decision was made Mehlich-1 6.0 4 Very Low 88 High 35 High 2330 (not rated) to switch to a ridge tillage sys- Miss/Lancaster 6.0 16 Low 180 V. High 60 High 10,000+ tem with no cover crop for 2006 1 N = 4. through 2010. All the P and K and half of total N were applied TABLE 2. FERTILIZER TREATMENTS AND COTTON LINT YIELDS ON A VAIDEN CLAY within one week of planting in IN WEST ALABAMA, 2005-2010 late April. The other half of N –Rates of nutrients applied– —————Cotton lint yields————— P2O5 K2O 2005 2006 2007 2008 2009 2010 was applied in mid-June. Lint Trt. no. Description N ———————————————lb/A——————————————— yields were estimated by handN variables picking 20 feet from the two 1 No N 0 100 100 177 311 870 960 812 329 middle rows in each plot. Rela2 Low N 30 100 100 214 380 1040 1070 760 466 tive yields are yields compared 3 Moderate N 60 100 100 265 403 990 1220 855 934 5 Control 90 100 100 388 393 1076 1350 830 802 to the mean yield of Treatment 4 High N 120 100 100 237 400 1037 1340 858 848 5, the control treatment, which 6 No S/VH N 150 100 100 320 387 1040 1360 877 858 receives 90-100-100 pounds P variables N-P2O5-K2O per acre each year 7 No P 90 0 100 280 378 910 1310 995 793 (see ﬁgure). 8 Very low P 90 20 100 205 394 940 1350 974 676 9 Low soil P 90 40 100 274 375 1091 1260 892 829 Excessive rainfall and anaer10 Moderate P 90 60 100 233 388 1027 1470 951 867 obic soil conditions dramatically 5 Control 90 100 100 388 393 1076 1340 830 802 reduced yields in 2005. Extreme K variables drought plagued the test in 2006 11 No K 90 100 0 157 353 585 600 470 717 through 2007. Yields in 2008 12 Very low K 90 100 20 170 324 784 770 444 637 13 Low K 90 100 40 253 295 803 1030 815 878 were the highest of the six-year 14 Moderate K 90 100 60 341 335 922 1030 747 809 study averaging 1154 pounds of 15 High K 90 100 80 319 349 806 1150 1005 918 lint per acre in spite of severe 5 Control 90 100 100 388 393 1076 1340 830 802 leaf spot diseases (Alternaria, Other variables Cercospora, and Stemphylium) 16 No lime 90 100 100 196 413 1027 1350 852 864 17 Nothing 0 0 0 160 300 649 670 475 541 which defoliated some plots, LSD P<0.1 135 ns 220 210 179 153 especially the low K treatments.
Mean yield 261 366 934 1154 804 756

18

ALABAMA AGRICULTURAL EXPERIMENT STATION

Relative lint yield, %_

mended N rate is 90 pounds N TABLE 3. FIBER QUALITY AS AFFECTED BY SELECTED TREATMENTS, 2007-2010 per acre for these soils. Trt. no. Description Lint % Micronaire Length Strength Uniformity P2O5 rates. One would 2007 have anticipated more dramatic 1 No N 43 4.23 1.01 26.6 81.9 11 No K 43 3.60 1.02 25.9 81.6 responses to rates of P than we 15 High K (80 lb K2O/A) 42 4.23 1.00 26.8 82.0 found in these tests because of 2008 the low soil test P rating. Ex1 No N 49.5 a 4.05 a 1.04 27.8 ab 81.9 ab cept for the low-yielding, wet 4 High N (120 lb N/A) 46.5 bc 4.22 a 1.07 28.8 a 83.0 a year of 2005, and the drought 7 No P 47.2 b 4.18 a 1.05 27.8 ab 81.0 b 11 No K 45.2 c 3.15 b 1.06 26.8 b 80.5 b year of 2007, the “no P” treat15 High K (80 lb K2O/A) 46.0 bc 3.78 ab 1.06 28.8 a 82.0 ab ment has produced relative 2009 yields between 96 and 120 1 No N 47 a 4.65 a 1.07 c 26.9 ab 82.0 a percent of the control treat4 High N (120 lb N/A) 43 c 4.05 b 1.14 a 28.5 ab 83.3 a ment which gets 100 pounds 7 No P 45 b 4.50 a 1.10 bc 28.6 a 82.4 a 11 No K 43 c 3.47 c 1.10 bc 26.6 b 80.7 b P2O5 per acre per year. There 15 High K (80 lb K2O/A,) 43 c 4.32 ab 1.12 ab 27.9 ab 82.7 a was never a signiﬁcant yield 2010 response to added P. This calls 1 No N 0.47 a 4.58 a 1.01 25.0 b 80.4 into question the current “low” 4 High N (120 lb N/A) 0.46 b 4.88 a 1.04 27.6 a 81.8 rating for this soil test value 7 No P 0.46 b 4.87 a 1.04 26.5 ab 81.4 11 No K 0.46 ab 4.90 a 1.04 27.2 a 81.4 for cotton. The deﬁnition of a 15 High K (80 lb K2O/A) 0.45 b 4.12 b 1.02 25.9 ab 81.3 “low” soil test rating indicates Values followed by the same letter are not signiﬁcantly different at P<0.05. that the soil will produce less than 75 percent of its potential without fertilization of that nutri140 ent. 120 K2O rates. In spite of this soil initially testing “very high” 2005 100 2006 in K, there were signiﬁcant increases in yield with higher rates 80 2007 of K2O up to 100 pounds per acre each year except 2006. These 2008 60 results provide credibility to grower’s claims that additional K 2009 40 seems to increase yields even when soils are rated “high” or “very 2010 20 high” for K and none is recommended from the Auburn Univer0 sity Soil Testing Laboratory. The most dramatic yield response to 0 50 100 150 200 added K occurred in 2008 with the highest yields of the six-year Total N rate (lb/acre) study but also the most severe defoliation due to foliar diseases. There may be justiﬁcation to change soil test K ratings for these soils and increase K recommendations for cotton. Additional stud140 ies are on-going. 120 2005 In spite of extreme weather conditions at this site and some 100 2006 problems, e.g., phenoxy herbicide drift in 2010, we have ob80 2007 served some consistent trends in cotton response to N, P, and K 2008 60 after six years of fertilization and cropping. Only four of six years 2009 40 (2007, 2008, 2009, and 2010) have produced reasonably good lint 2010 20 yields (approximately 1.5 to 2 bales per acre). Surprisingly, yield responses to increasing N rates above 60 pounds per acre have not 0 0 50 100 150 been evident. Signiﬁcant differences in 2007 through 2010 sugTotal P2O5 rate (lb/acre) gest a need for modiﬁcation of soil test ratings for both P and K on these soils. Phosphorus may be currently rated too low and potassium may be rated too high for cotton on these soils. Since these 140 are the only established soil fertility variable plots on the Black Belt Research and Extension Center, we hope that they will be 120 2005 maintained indeﬁnitely as are the “Rates of NPK” experiments at 100 2006 six other Alabama locations to provide more conclusive evidence 80 2007 for changes in soil test calibration for similar soils. Plans are to 2008 60 evaluate soybean response to residual fertility in 2011.
Relative lint yield, %_
Relative lint yield, %_

40 20 0 0 50 100 150

2009 2010

Figure (at right) Effect of rates of N, P2O5, and K2O on relative cotton lint yields in ﬁve years on a Vaiden clay in West Alabama.

Total K2O rate (lb/acre)

2010 AU CROPS: COTTON RESEARCH REPORT

19

FGD GYPSUM RESEARCH AND DEMONSTRATIONS IN ALABAMA
C. C. Mitchell and D. Watts

A by-product of ﬂue gas desulfurization (FGD) in coal-ﬁred electric generating plants is large quantities of FGD gypsum (calcium sulfate) which is produced when sulfur gases react with a slurry of ground limestone in the scrubbers. Agricultural gypsum has been used for decades as a source of calcium and sulfur for crop production. It is also widely used to reclaim sodic soils in arid regions. In Alabama, agricultural gypsum is routinely recommended at rates of 500 to 1000 pounds per acre as a source of calcium for pegging peanuts, especially the largeseeded types and peanuts grown for seed. Although gypsum is a neutral salt, it has been found to reduce the toxic effects of aluminum in acid subsoils and improve surface soil structure (aggregation) in some situations. Over 50 demonstrations in Alabama, Georgia, Mississippi, and Florida sponsored by the Southern Company showed positive crop responses on farmers ﬁelds to applications of 1 to 4.5 tons per acre of FGD gypsum. FGD gypsum is reported to reduce the shrinking and swelling of Vertisols in the Blackland Prairie region in northeastern Mississippi. Agricultural gypsum is usually a mined product imported from Spain, South America, or the western U.S. By-product gypsum is produced from both the ﬂue gas desulfurization process and from the manufacture of phosphate fertilizers. Phospho-gypsum has been known to contain radium which limits its widespread use on crops. It is also concentrated in phosphate mining areas such as Central Florida and is too expensive to transport long distances. Analyses of the FGD gypsum from Power South and of the agricultural gypsum used in this study do not indicate any properties that could potentially harm crops or the soil. Objectives of the study were to • Demonstrate to local farmers and landowners the use of FGD gypsum. • Determine the beneﬁts and potential problems associated with applying FGD gypsum to cotton on a South Alabama Coastal Plain soil and a Black Belt clay. One research site and one on-farm test/demonstration were set up with cotton in the Coastal Plain of South Alabama in 2009. An additional on-farm test/demonstration was set up on a bermudagrass hayﬁeld in South Alabama in 2009. In 2010, a test was added on a Vaiden clay on the Black Belt Research and Extension Center in Central Alabama. Huxford research site. Soil at the research site near Huxford is a Bama ﬁne sandy loam, 0 to 2 percent slope (Fine-loamy, siliceous, subactive, thermic Typic Paleudults). The ﬁeld has had a history of cotton production although it has been fallow the past three years. Treatments (Table 1) were applied on June 10, 2009, after cotton had emerged. In 2010, cotton was planted in the same rows using no-till. Soil tests indicated the site is “low” in P and “medium” in K and would normally require ground limestone to reach a pH of approximately 6.5. Ground agricultural dolomitic limestone was applied to selected treatments. Lysimeters were installed in the row before spreading treatments. All treatments received 90-90-90 pounds N-P2O5-

Sites for FGD gypsum research and demonstrations in Alabama.

K2O during the growing season. Treatments were arranged in a randomized block design in plots 18 feet (6 rows) wide x 25 feet long. Cotton yields were measured by machine harvesting the two center rows in each plot on October 29. Neither FGD gypsum nor agricultural gypsum had an effect on cotton lint yields at the Huxford site in 2009 or 2010. Uriah demonstration site. FGD gypsum was applied by the producer in strips across an existing cotton ﬁeld prior to planting. Rates applied were 0, 1, 2, and 4 tons per acre. Strips were replicated three times. Cotton was planted using conservation tillage. Fertilization and pest control was uniform across the entire ﬁeld. Cotton was planted on May 20 and harvested by machine on November 13, 2009. There were no differences in lint yields (Table 2). The Uriah site was not harvested in 2010.

Gypsum rate appl. in 09 —ton/A— 1. Check 0 2. FGD gypsum 1 3. FGD gypsum 2 4. FGD gypsum 4 5. Ag. gypsum 1 6. Ag. gypsum 2 7. Ag. gypsum 4 8. Lime(1 ton/A) + FGD gypsum 1 9. Lime only (1 ton/A) 0 Treatment applied in 2009

TABLE 1. COTTON LINT YIELDS, HUXFORD RESEARCH SITE, 2009 AND 2010
Cotton lint yields 2009 2010 —lb/A— 620 713 560 570 604 650 610 650 572 610 534 600 624 680 602 600 574 620 ns ns

20

ALABAMA AGRICULTURAL EXPERIMENT STATION

Opp demonstration site. An established, 11-acre Coastal bermudagrass hayﬁeld on the farm of Brett Mack near Opp, Alabama, was used for another strip test. FGD gypsum was applied to strips across the ﬁeld using a pull-type buggy spreader. Rates used were 0, 1, 2, and 4 tons per acre. Each treatment was replicated two times. Treatments were applied on May 22, 2009. Each strip was approximately 1 acre. Soil at the site is an Orangeburg sandy loam, 0-5 percent slope. An initial, composite soil test indicated the following: pH = 6.0; P = very high (248 pounds extractable P per acre); K = medium (126 pounds per acre); Mg = high (137 pounds per acre); Ca = high (1268 pounds per acre). Hay was harvested on July 24 and again in October 2009. Yields were measured only on the July 24 harvest. After the hay was cut, forage was measured in 3-foot by 3-foot square areas. Four squares were measured in each plot. A grab sample was used to estimate moisture and to convert forage yield to oven dry

weight yields. In 2010, hay was harvested three times but yields and quality were measured only on the ﬁrst harvest in late May. Average dry matter forage yield was 2.3 tons per acre in 2009 and 3.0 tons per acre in 2010 (Table 3). There was no statistical difference in dry matter yield due to treatment because there was considerable yield variability across the ﬁeld (see standard deviation). Forage quality analyses were not replicated. Black Belt Research and Extension Center research site. In April 2010, a replicated test using FGD gypsum was established on a Vaiden clay (very ﬁne, montmorillonitic, thermic Vertic Hapludalfs) at the Black Belt Research and Extension Center near Marion Junction, Alabama. Four rates of FGD gypsum were used, 0, 2, 4, and 8 tons per acre. All plots were fertilized with 90-100-100 pounds N-P2O5-K2O with N rates applied in split applications. High rates (4 to 8 tons per acre) of FGD gypsum signiﬁcantly increased cotton lint yields on a Vaiden clay in 2010 (Table 4).

TABLE 2. COTTON LINT YIELDS, URIAH DEMONSTRATION SITE, 2009
Treatment and rate FDG gypsum, 4 tons/A FDG gypsum, 2 tons/A FDG gypsum, 1 tons/A No gypsum Cotton lint yields —lb/A— 640 750 770 690

Treatment and rate No gypsum FDG gypsum, 1 ton/A FDG gypsum, 2 tons/A FDG gypsum, 4 tons/A No gypsum FDG gypsum, 1 ton/A FDG gypsum, 2 tons/A FDG gypsum, 4 tons/A
1 2

—Dry matter Field Crude yield— moisture protein ADF1 NDF2 TDN3 Ca K Mg P S lb/A std. dev. ——————————————————%—————————————————— 2009 (second harvest) 4680 2070 11.4 9.3 37 61 48 0.39 3.15 0.21 0.33 0.33 4470 1090 10.4 7.4 34 65 46 0.42 1.98 0.16 0.27 0.67 3830 940 11.6 7.5 34 60 57 0..44 2.65 0.22 0.32 0.51 5450 2150 9.8 7.0 36 66 46 0.53 1.81 0.14 0.22 0.54 2010 (ﬁrst harvest) 3290 1280 10.0 10.4 35.6 — 48.1 1.11 1.03 0.54 0.25 — 2370 490 10.0 10.9 33.9 — 49.5 1.21 1..59 0.56 0.25 — 2680 880 10.0 9.9 35.8 — 48.0 1.27 1.43 0.62 0.25 — 3650 1550 10.0 10.8 35.5 — 48.2 1.28 1.86 0.44 0.22 —

TABLE 3. BERMUDAGRASS HAY YIELDS AND FORAGE QUALITY, OPP DEMONSTRATION SITE, 2009 AND 2010

ADF = Acid detergent ﬁber, which measures the cellulose and lignin content in the plant. NDF = Neutral detergent ﬁber, which measures all the ﬁber found in forage. 3 TDN = Total digestable nutrients.

TABLE 4. COTTON LINT YIELDS, BBREC RESEARCH SITE, 2010
Proposed treatment and rate 1 No gypsum 2 FGD gypsum, 2 tons/A 3 FGD gypsum, 4 tons/A 4 FGD gypsum, 8 tons/A Cotton lint yield —lb/A— 740 b 740 b 820 ab 920 a

Values followed by the same letter are not signiﬁcantly different at P<0.05.

INSECT MANAGEMENT
DEVELOPMENT AND VALIDATION OF A LOW INPUT INSECT CONTROL SYSTEM FOR CONVENTIONAL COTTON IN ALABAMA, 2010
R. H. Smith

Roundup Flex with no insect trait (DP 174RF), Widestrike with no herbicide trait (PHY 440W), and a conventional variety with no insect or herbicide traits (CT 210 or DP 491). Varieties with the highest yield potential were selected for each site. Input costs for seed, technology, and weed and insect control were recorded for each variety at each site. Yields were taken and the costs for all of the above listed inputs were calculated as “cost per pound of seed cotton.” All sites were impacted by drought, some more severely than others, just as the entire state. Therefore, potential yields were reduced by the lack of rainfall. Weed and insect control was COTTON SYSTEMS TRIALS not a limiting factor at any site. Variety/ Seed Technology Weed control Foliar insect Seed cotton Seed cotton The 2010 insect season could be Technology cost cost cost control cost1 yield lb/A cost/lb characterized as a lower-thanWiregrass Research and Extension Center, Headland, Alabama normal bollworm, tobacco budCT 210 $10.00 $37.50 $16.00 2,813 $0.023 PHY 440W $21.97 $18.00 $37.50 $16.00 2,789 $0.034 worm, fall armyworm, thrips, DP 174RF $23.89 $36.81 $31.00 $16.00 2,916 $0.037 and plant bug year but higher DP 121RF $23.89 $36.81 $31.00 $16.00 2,724 $0.040 than normal stink bug year. HarDP 0912B2RF $24.90 $70.00 $31.00 $16.00 3,230 $0.044 vested yields (pounds seed cotPHY 375 WRF $23.50 $65.00 $31.00 $16.00 3,140 $0.043 ton per acre) ranged as follows: ST 5288B2RF $24.90 $70.00 $31.00 $16.00 3,329 $0.043 PHY 485 WRF $23.50 $65.00 $31.00 $16.00 3,110 $0.044 from 1896 to 2761 at Prattville, DP 1034 B2RF $24.90 $70.00 $31.00 $16.00 3,041 $0.047 1922 to 2280 at Fairhope, 1850 DP 1048 B2RF $24.90 $70.00 $31.00 $16.00 2,784 $0.051 to 2067 at Shorter, and 2633 to PHY 565 WRF $23.50 $65.00 $31.00 $16.00 2,990 $0.045 3329 at Headland. Input costs DP 0949 B2RF $24.90 $70.00 $31.00 $16.00 2,940 $0.048 (per pound of seed cotton proDP 1050B2RF $24.90 $70.00 $31.00 $16.00 2,633 $0.054 E.V. Smith Research Center, Shorter, Alabama duced) ranged from $.036 to DP 1050B2RF $24.90 $70.00 $43.50 $8.00 1,850 $0.08 .067 at Prattville, $.04 to .07 at DP 174RF $23.89 $36.81 $43.50 $8.00 1,990 $0.06 Fairhope, $.05 to .08 at Shorter, PHY 440W $28.22 $21.11 $43.50 $8.00 2,067 $0.05 and $.023 to .054 at Headland. DP 491 $10.00 — $43.50 $8.00 1,854 $0.07 It was estimated that Gulf Coast Research and Extension Center, Fairhope, Alabama ST 5288B2RF $24.90 $70.00 $12.00 $18.00 1,922 $0.06 weather related yield losses DP 1050B2RF $24.90 $70.00 $12.00 $18.00 2,122 $0.06 ranged from 20 to 45 percent DP 0949B2RF $24.90 $70.00 $12.00 $18.00 2,280 $0.05 at the four sites. This factor had PHY 565 WRF $23.50 $65.00 $12.00 $18.00 2,167 $0.06 a major impact on the cost per DP 174 RF $23.89 $36.81 $12.00 $61.00 1,963 $0.07 pound of seed cotton produced. PHY 440 W $21.97 $17.99 $21.00 $61.00 2,018 $0.04 CT 210 $20.00 — $21.00 $61.00 2,155 $0.05 Based on the results of Prattville Agricultural Research Unit, Prattville, Alabama these trials, conclusions are DP 491 UT $10.00 — $43.60 $8.00 1,710 $0.036 that conventional cotton can DP 491 Sprayed $10.00 — $43.60 $16.00 1,896 $0.037 be grown in Alabama. HowDP 174R UT $23.89 $36.81 $32.50 $8.00 2,628 $0.038 ever, the economics would DP 174R Sprayed $23.89 $36.81 $32.50 $16.00 2,761 $0.040 PHY 440W UT $21.97 $17.99 $43.60 $8.00 2,301 $0.040 vary greatly depending on the PHY 440W $21.97 $17.99 $43.60 $16.00 2,339 $0.043 weather, severity of the insect Sprayed season and location. FurtherDP 1050B2RF UT $24.90 $70.00 $32.50 $8.00 2,587 $0.052 more, it would require much DP 1050B2RF $24.90 $70.00 $32.50 $16.00 2,501 $0.057 expertise in monitoring insect Sprayed ST 5288 B2RF UT $24.90 $70.00 $32.50 $8.00 2,232 $0.061 populations and selection of the ST 5288 B2RF $24.90 $70.00 $32.50 $16.00 2,150 $0.067 appropriate chemistry for the Sprayed target insect species present.
PHY 375 WRF UT $23.50 PHY 375 WRF $23.50 Sprayed
1

Large block (one acre or larger) non-replicated cotton trials with various levels of technology were conducted at four research stations in central and south Alabama: Prattville Agricultural Research Unit, E.V. Smith Research Center, Wiregrass Research and Extension Center, and Gulf Coast Research and Extension Center. Weed and insect control on each technology at each site was treated as if it were a 1000 acre block managed by an Alabama grower. The technology at each site included the following: Bollgard II and Widestrike Roundup Flex (multiple varieties),

$65.00 $65.00

$32.50 $32.50

$8.00 $16.00

2,738 2,503

$0.047 $0.055

Includes application

22

ALABAMA AGRICULTURAL EXPERIMENT STATION

EVALUATION OF THE VARYING GENETIC TECHNOLOGIES FOR CONTROL OF FALL ARMYWORM AND BOLLWORM IN ALABAMA COTTON
R. H. Smith

A ten-acre ﬁeld at the Wiregrass Research and Extension Center, Headland, Alabama, was planted to three different genetic technologies (conventional, WideStrike and Bollgard II) to evaluate their effectiveness against the fall armyworm, bollworm, and budworm species. Light pressure from all lepidopteran species occurred over an extended period during the 2010 season at this location. However, no species reached threshold level based on ﬁeld scouting. Therefore, no treatments of the newer novel chemistry (Tracer, Steward, Belt, or Diamond) were applied over each of these technologies. The varieties planted in this trial were DP174RF (conventional), PHY 565W RF, and DP 1050B2RF. Each varietal block was 76 rows wide by 222 feet long. This trial was planted on April 16 with Temik at 5 pounds per acre applied in-furrow. The entire trial area was oversprayed on June 29 (second week of bloom) with bifenthrin pyrethroid at the rate of 5 ounces per acre for control of stink bugs. The DP 174RF conventional variety was treated with Steward insecticide (11 ounces per acre) on July 15 for a mixture of bollworms and budworms. A subthreshold level of larvae three to seven days old were present from a moth ﬂight that had occurred over the previous 10 days. All subsequent lepidopteran infestations were at subthreshold levels. Field monitoring counts were made on August 4 and September 8 and are presented in the following table. Each count

is an average of four replicate surveys made on the respective dates. Yields were taken by harvesting the entire plot of each variety. Weights were determined by utilizing a boll buggy. DP 1050B2RF had less boll damage due to bollworm/budworm than did PHY 565WRF (0.3 versus 2.8 percent). Both the DP 1050B2RF and the PHY 565WRF had less boll damage than did the DP 174RF conventional (6 percent). This occurred even though one Steward application was made to the DP 174RF at an expense of $15 per acre plus application cost. Fall armyworm infestations in this test ﬁeld were much lighter than during the previous season, as in the remainder of the state. However, there was enough boll bract grazing (etching) to measure differences in the three technologies. Four percent of the bolls showed fall armyworm grazing in the DP 174RF conventional while the DP 1050B2RF had 0.5 percent and the PHY 565WRF had no boll etching. In conclusion, both varieties with lepidopteran technologies were superior to the conventional variety in reducing damage due to bollworms and budworms. The Bollgard II variety was slightly superior to the Widestrike variety in reducing bollworm damage while the Widestrike variety was superior to the Bollgard II in fall armyworm control. Yields from the DP 1050B2RF and PHY 565WRF were nearly identical and both yielded slightly higher than the DP 174RF conventional variety.

EFFECTIVENESS OF THREE GENETIC TECHNOLOGIES FOR CONTROL OF LEPIDOPTERAN SPECIES IN COTTON, 2010
Variety DP 174RF (Conventional) DP 1050B2RF (Bollgard II) PHY 565WRF (Widestrike)
1

Bollworm/Budworm damaged bolls Aug. 4 no/10 row ft 6 (3-10)1 0.3 2.8

Fall armyworm boll bract grazing Aug. 4 % 4% 0.5% 0%

Bollworm/Budworm damaged bolls Sept. 8 % 11% 0.5% 2%

Yield seed cotton lb/A 2216 2480 2440

All averages represent four replicate counts

2010 AU CROPS: COTTON RESEARCH REPORT

23

DEVELOPMENT OF A MORE RAPID SURVEY TECHNIQUE FOR MONITORING STINK BUG DAMAGE TO COTTON
R. H. Smith

Preliminary work conducted during the 2008 and 2009 seasons indicates that external stink bug injury may possibly be correlated to internal injury. If this technique can be developed, it would greatly enhance more effective, efﬁcient and economic decisions on controlling stink bugs. A larger sample size could be taken, which would reﬂect the level of stink bug damage throughout an entire ﬁeld. Several factors affect this correlation of external to internal injury.
Untreated
100 90 80 70 60 50 40 30 20 10 0 0 1 2 3+ 0 1 2 3+ 0 1 2 3+

g

Percent

External Internal

Level of Damage 4th Week of Bloom

Level of Damage 5th Week of Bloom

Level of Damage 7th Week of Bloom

Treated: Bidrin, 6 oz/A
100 90 80 70 60 50 40 30 20 10 0 0 1 2 3+ 0 1 2 3+ 0 1 2 3+ External Internal

Level of Damage 4th Week of Bloom

Level of Damage 5th Week of Bloom

Level of Damage 7th Week of Bloom

Treated: Endigo, 4.5 oz/A
100 90 80 70 60 50 40 30 20 10 0 0 1 2 3+ 0 1 2 3+ 0 1 2 3+

Externa Internal

Level of Damage 4th Week of Bloom

Level of Damage 5th Week of Bloom

Level of Damage 7th Week of Bloom

Treated: Fanfare (bifenthrin), 6.4 oz/A
100 90 80 70 60 50 40 30 20 10 0 0 1 2 3+

f

( f

)

/

External Internal

Two eight-row strips of cotton approximately 1400 feet in length were planted and grown through the middle of a peanut ﬁeld at the Wiregrass Research and Extension Center, Headland, Alabama. The peanuts served to insure abundant stink bug migration pressure throughout the cotton boll set period. Beginning the third week of bloom, when the earliest bolls were 10 to 12 days old (1 inch or 2.5 cm in diameter), stink bug controls were applied using two classes of insecticide chemistry. Each treatment covered eight rows by ﬁfty feet and was replicated four times. Treatments were applied on weeks three and ﬁve of bloom (two-week interval). No further treatments were applied due to drought stress and the absence of developing bolls in this non-irrigated trial. Evaluations were made at day 8 and 15 following application number one. The ﬁnal evaluation was made 14 days following evaluation number two. At each evaluation 40 bolls (10 per replicate) one inch in diameter were collected from rows two and three adjacent to the peanuts. Each 10-boll sample was bagged and transported to a lab for examination. Each boll was then examined for external stink bug feeding and placed in subgroups consisting of zero, one, two, or three or more external feeding lesions. Bolls from each subgroup were crushed and examined for internal damage (boll rot, stained lint, or carpal wall warts). Correlations were then made between external and internal injury based on the various treatments. Based on the data collected in this trial, as the number of external lesions per boll increase, a corresponding increase in internal damage also occurs. As the season progressed, especially in the untreated checks and the less effective stink bug treatments, more bolls had higher numbers of external feeding sites and corresponding internal damage. Conversely, in the most effective treatments for stink bug control (Bidrin), less internal damage was recorded as the season progressed. Based on this trial, one could conclude that stink bugs produce varying amounts of boll feeding and corresponding internal damage based on the effectiveness of the insecticide used for their control. The majority of the stink bug population in this trial was the brown species, Euschistus servus. In summary, several factors impact the correlation of external to internal stink bug boll injury to cotton. ▪ Time of season as expressed by week of bloom. ▪ Whether or not the ﬁeld has been previously treated for stink bugs. ▪ The length of time since the previous treatment. ▪ The number of previous stink bug applications. ▪ The effectiveness of previous treatments. ▪ Species of stink bug that dominates the population (brown versus green) ▪ The number of external stink bug boll lesions.

Percent

Percent

Percent

0
th

1

2

3+

0

1

2

3+

Level of Damage

Level of Damage k f l

Level of Damage

Percent of bolls with varying levels of external and internal damage.

WEED MANAGEMENT
ON-FARM GLYPHOSATE-RESISTANT PALMER AMARANTH MANAGEMENT IN ROUNDUP READY FLEX, LIBERTY-LINK, AND CONVENTIONAL COTTON VARIETIES
M. G. Patterson, C. D. Monks, B. A. Dillard, W. C. Birdsong, W. R. Goodman, and A. J. Price

A replicated ﬁeld trial was conducted on-farm in Barbour county, Alabama, in 2010 to evaluate optimum weed management systems for Roundup Ready Flex (RF), Liberty-Link (LL), and conventional (non-transgenic) cotton varieties in an area infested with glyphosate-resistant palmer amaranth (Amaranthus palmeri). Varieties used were DP 1048 B2RF, FM 1845 LLB2, and CT 210. Cotton was planted in a reduced tillage ﬁeld that had received a preplant foliar (burndown) application of Gramoxone Inteon (2 pints per acre) plus Diuron 4L (2 pints per acre) with surfactant two weeks prior to planting on May 12. Seed of each variety were put into four planters on a 12 row planter and three passes were made the length of the ﬁeld (800 feet). Seeding rate for all varieties was two seed per 11.5 inches of row. Immediately after planting a preemergence application of Prowl (2 pints per acre) plus Reﬂex (1 pint per acre) was made in all varieties. Cotoran 4L was added to this mixture for the conventional variety (CT 210). Early postemergence treatments were made prior to the four-leaf cotton stage and before

Herbicide, rate DP 1048 B2RF Prowl H2O, 2 pt/A $7.50 Reﬂex, 1 pt/A $11.00 Cotoran 4L, 2 pt/A — Dual Mag, 1 pt/A $11.00 Rdup Pmax, 32 oz/A $5.60 Ignite 280, 29 oz/A — Staple LX, 3 oz/A — Valor DF, 2 oz/A $7.75 Diuron 4L, 2 pt/A $5.00 MSMA, 2.7 pt/A $6.00 Total herbicide $53.85 Hand weeding $23.29 Total all control $77.14

TABLE 1. WEED CONTROL PROGRAMS FOR DIFFERENT COTTON VARIETIES
FM 1845 LLB2 $7.50 $11.00 — $11.00 — $9.50 — $7.75 $5.00 $6.00 $57.75 $2.69 $60.44

CT 210 $7.50 $11.00 $8.50 — — — $17.00 $7.75 $5.00 $6.00 $62.75 $20.49 $83.28

pigweed emergence. Roundup Power Max (22 ﬂuid ounces per acre) plus Dual Magnum (1 pint per acre), Ignite 280 (29 ﬂuid ounces per acre) plus Dual Magnum (1 pint per acre), and Staple LX (3 ﬂuid ounces per acre plus surfactant) were applied to RF, LL, and conventional cotton, respectively. A layby treatment of Valor DF (2 ounces per acre) plus Diuron 4L (2 pints per acre) plus MSMA 6 (2.7 pints per acre) was made when cotton was approximately knee high. All treatments were activated by timely rainfall (within 7 days) following application. Weed control ratings of Palmer amaranth were made on June 11 after early posttreatments (applied on June 2), at which time control in all varieties was 99 percent, and on June 29 when layby treatments were applied at which time control was 93, 92, and 88 percent for RF, LL, and conventional varieties, respectively. Palmer amaranth escapes were counted in each plot on July 16 showing 45, 5, and 39 plants per acre for RF, LL, and conventional varieties, respectively. These numbers were constant for the remainder of the season (cotton picked on October 5 and 6), primarily due to late-season drought. Lint yield for each variety was 1668, 1499, and 1331 pounds per acre for RF, LL, and conventional varieties, respectively. Input costs for seed and tech fees, herbicides, and hand weeding were $142, $89, and $89 per acre for RF, LL, and conventional varieties, respectively. Variable and ﬁxed costs for all three varieties outside of weed management was $447 per acre. Net returns to land, operator labor, and management at a lint price of $0.95 per pound were $1,115 for RF, $1032 for LL, and $854 per acre for conventional. At $0.55 per pound, the net returns were $305, $286, and $192 per acre for RF, LL, and conventional varieties, respectively.

Herbicide

TABLE 2. RETURN ON INVESTMENT AT $0.95 OR $0.55 PER POUND OF COTTON LINT
—DP 1048 B2RF— $0.95 $0.55 1668 1668 3819 3819 $167 $1585 $65 $77 $142 $447 $589 $1,115 $143 $917 $65 $77 $142 $447 $589 $305 —FM 1845 LLB2— $0.95 $0.55 1499 1499 3911 3911 $150 $1567 $28 $61 $89 $447 $536 $1,032 $147 $824 $28 $61 $89 $447 $536 $286

Lint yield, lb/A Seed cotton yield, lb/A Seed value Lint value Seed and tech fee (a) Weed control costs (b) Total control costs (a+b) Variable and ﬁxed costs Total all costs Net returns

——CT 210—— $0.95 $0.55 1331 1331 3441 3441 $128 $732 $6 $83 $89 $447 $536 $192

$133 $1264 $6 $83 $89 $447 $536 $854

DISEASE MANAGEMENT
EVALUATION OF SEED TREATMENTS AND SEED QUALITY IN COTTON SEEDLING DISEASE MANAGEMENT IN ALABAMA, 2010
K. S. Lawrence, S. R. Moore, G. W. Lawrence, C. H. Burmester, and B. E. Norris

Experimental seed treatments placed on high and low vigor cotton seed were evaluated for the management of cotton seedling disease in a naturally infested ﬁeld on the Tennessee Valley Research and Education Center in Belle Mina, Alabama. The ﬁeld had a history of cotton seedling disease incidence and was infested by Rhizoctonia solani, Pythium spp., Thielaviopsis basicola, and Fusarium spp. The soil was a Decatur silt loam (24 percent sand, 49 percent silt, 28 percent clay). The seed treatments were applied to the seed by Bayer Crop Science. Temik 15G (5 pounds per acre) was applied at planting on April 23 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with 40inch row spacing, and were arranged in a randomized complete block design with ﬁve replications. Blocks were separated by a 20-foot wide alley. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Plots were irrigated with a sprinkler system as needed. Seedling stand was determined at two and four weeks after planting on May 14 and 28. Plots were harvested on October 21. Data were statistically analyzed by GLM and means compared using Fisher’s protected least signiﬁcant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in April through harvest in September were 76.2, 81.2, 90.1, 93.1, 94.2, and 88.4 degrees F with average minimum

temperatures of 50.6, 61.2, 69.7, 71.0, 72.1, and 61.0 degrees F, respectively. Rainfall accumulation for each month was 4.07, 2.46, 4.99, 2.24, 3.70, 1.22, and 0.05 inches with a total of 18.74 inches over the entire season. Seedling disease pressure was high in 2010 due to excessive moisture and cool temperatures before and after planting. Plant stand was lower in the Low vigor Baytan + Vortex + Allegiance and Low vigor Treatment 2 + Dynasty CST fungicide treatments at 14 days after planting (DAP). By 28 DAP all fungicide treatments in the high vigor seeds increased stand over the non-treated controls. Only Dynasty CST increased stand over the untreated control in the low vigor seed treatments. The fungicide treatments increased stand as compared to the untreated control by 28 percent in the high quality seeds. The increase in stand was similar in the low quality seed treatments with an increase of 29 percent. Seed quality also affected yield. Seed cotton yields varied by 978 pounds per acre at harvest with an average of 3418.4 pounds per acre of seed cotton produced over all the fungicide treatments. The fungicide seed treatment combinations did not signiﬁcantly increase yield over the control in the high vigor seed in 2010. However, seed cotton yield was increased in the low vigor seed in all fungicide treatments over the untreated control. Fungicides increased yield (P ≤ 0.10) by an average of 302 pounds per acre in the low vigor seed as compared to the control.

Treatment and rate (oz/cwt)

YIELD AND STAND COUNT OF SEED COTTON, 2010

1 High vigor untreated 2 High vigor Baytan 0.5 + Vortex 0.08 + Allegiance 0.75 3 High vigor Trt 2 + Trilex Advanced 1.64 4 High vigor Trt 2 + Dynasty CST 3.94 5 Low vigor untreated 6 Low vigor Baytan 0.5 + Vortex 0.08 + Allegiance 0.75 7 Low vigor Trt 2 + Trilex Advanced 1.64 8 Low vigor Trt 2 + Dynasty CST 3.94 LSD (P ≤ 0.10)

——Stand/10-ft row—— Apr. 29 May 13 18.2 a 18.2 bc 19.2 a 25.4 a 21.0 a 22.8 a 16.0 ab 15.4 b 17.0 a 15.4 b 5.91 24.4 a 26.0 a 14.6 c 19.8 abc 20.2 abc 22.0 ab 4.08

Yield lb/A 3710.5 ab 3951.3 a 3528.5 ab 3357.9 ab 2973.0 c 3046.9 b 3123.8 b 3654.9 ab 432.4

Means within columns followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

26

ALABAMA AGRICULTURAL EXPERIMENT STATION

EVALUATION OF EXPERIMENTAL SEED TREATMENTS IN COTTON SEEDLING DISEASE MANAGEMENT IN ALABAMA, 2010
K. S. Lawrence, S. R. Moore, G. W. Lawrence, C. H. Burmester, and B. E. Norris

Experimental seed treatments were evaluated for the management of cotton seedling disease in a naturally infested ﬁeld on the Tennessee Valley Research and Education Center in Belle Mina, Alabama. The ﬁeld had a history of cotton seedling disease incidence and was infested by Rhizoctonia solani, Pythium spp., Thielaviopsis basicola, and Fusarium spp. The soil type was a Decatur silt loam (24 percent sand, 49 percent silt, 28 percent clay). The seed treatments were applied to the seed by Bayer CropScience. Fungicide treatments were mixed with CaCO3 at 7 ounces per hundredweight, Secure at 1 ounce per hundredweight, Cruiser at 9 ounces per hundredweight, and Color Coat Red at 1 ounce per hundredweight, and 2.75 percent RTU-PCNB. Water, CaCO3, Secure, Cruiser, and dye also were applied to the non-treated seed treatment at the same rate. Temik 15G (5 pounds per acre) was applied at planting on April 13 in the seed furrow with chemical granular applicators attached to the planter. Plots consisted of two rows, 25 feet long with 40inch row spacing, and were arranged in a randomized complete block design with ﬁve replications. Blocks were separated by a 20-foot wide alley. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Plots were irrigated with a sprinkler system as needed. Seedling stand was determined at 30 days after planting (DAP) on May 13. Plots were harvested on September 29. Data
Treatment and rate (oz/cwt)

were statistically analyzed by GLM and means compared using Fisher’s protected least signiﬁcant difference test (P ≤ 0.10). Monthly average maximum temperatures from planting in April through harvest in September were 76.2, 81.2, 90.1, 93.1, 94.2, and 88.4 degrees F with average minimum temperatures of 50.6, 61.2, 69.7, 71.0, 72.1, and 61.0 degrees F, respectively. Rainfall accumulation for each month was 4.07, 2.46, 4.99, 2.24, 3.70, 1.22, and 0.05 inches with a total of 18.74 inches over the entire season. Seedling disease pressure was high in 2010 due to optimum moisture and cool temperatures. Plant stand was signiﬁcantly greater in all the seed treatment combinations as compared to the untreated control at 30 DAP. The three and four fungicide combinations (Treatments 1 through 8, 10, and 13) increased plant stand as compared to the untreated control, RTU Baytan Thiram + Allegiance FL, RTU-PCNB, and Allegiance FL applied alone. Plant stands were low with 12.6 to 31.8 percent seedlings surviving producing 1.2 to 3.1 plants per foot of row. Rhizoctonia solani, Pythium ultimum, and Fusarium spp. were isolated from the diseased seedlings. Seed cotton yields were signiﬁcantly increased by all fungicides that increased plant stand. Yields varied by 652 pounds per acre at harvest with an average of 394 pounds per acre average increase of seed cotton produced over all the fungicide treatments as compared to the untreated control.
Yield lb/A 3653.8 a 3470.8 a 3608.1 a 3552.4 a 3579.5 a 3576.3 a 3765.7 a 3448.4 a 3472.3 a 3394.3 a 3111.4 b 3170.6 b 3401.1 a 3114.1 b 538.33

Stand/10-ft row May 13 1 Baytan 30 0.75 + Allegiance FL 1.5 + Vortex FL 0.08 + SP1020 0.32 28.2 ab 2 Baytan 30 0.5 + Allegiance FL 0.75 + Vortex FL 08 27.0 ab 3 Apron XL 0.64 + Maxim 4FS 0.04 + Systhan 40 WP 0.84 + Dynasty CST 4.0 29.4 ab 4 Apron XL 0.64 + Maxim 4FS 0.04 + Systhan 40 WP 0.84 + Dynasty CST 4.0 + 26.4 ab Bion 0.03 5 Apron XL 0.64 + Maxim 4FS 0.04 + Systhan 40 WP 0.84 + A16148C 0.5 27.6 ab 6 WECO 100 4.0 + Nu-Flow M HF 4.0 + Apron XL 0.32 + Nusan 30 EC 2.0 28.4 ab 7 WECO 100 4.0 + Nu-Flow M HF 1.75 + Apron XL 0.32 + Nusan 30 EC 2.0 28.8 ab 8 WECO 100 4.0 +Nu-Flow M HF 4.0 + Apron XL 0.32+ Nusan 30 EC 2.0 + 31.8 a WECO 1090 0.2 9 Vitavax-PCNB 6.0 + Allegiance 0.75 21.0 bc 10 RTU Baytan Thiram 3.0 + Allegiance FL 0.75 26.0 ab 11 RTU-PCNB 14.5 20.6 bc 12 Allegiance FL 1.5 17.0 c 13 Baytan 30 0.5 + Allegiance FL 0.75 + Vortex FL 0.081 31.8 a 14 Non treated control 12.6 c LSD (P ≤ 0.10) 6.50

EVALUATION OF EXPERIMENTAL SEED TREATMENTS, 2010

1

Cruiser insecticide was not addted to this treatment. Means within columns followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

2010 AU CROPS: COTTON RESEARCH REPORT

27

COTTON RESISTANCE TO ROOT-KNOT AND FUSARIUM WILT IN ALABAMA, 2010
T. Z. Scott, K. S. Lawrence, K. Glass, and E. van Santen

Cotton cultivars were examined to determine their response to pathogens, root-knot nematode (Meloidogyne incognita) and Fusarium oxysporum f. sp. vasinfectum, causing Fusarium wilt of cotton. The test was located at the E. V. Smith Research Center, Plant Breeding Unit, in Tallassee, Alabama. Plots consisted of one row, 20 feet long with 36-inch row spacing separated by 6-foot wide alleys, and were planted in a randomized complete block design with four replications. The set of four test cultivars submitted, was evaluated as a group with two control plots within each replicate. All plots were maintained throughout the season using standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Initial plant counts were made on June 9. Wilted plants were counted and removed on June 23, July 7, July 21, August 4, and August 19. Three plants per plot were removed on 22 July and root knot nematodes were extracted from the root systems using 0.6 percent NaOCl agitation for four minutes. Reisolation of the Fusarium wilt fungus, Fusarium oxysporum f. sp. vasinfectum, was conducted to conﬁrm the presence of the disease pathogen. The remaining live plants were counted and recorded on August 26. Data were statistically analyzed using Generalized Linear Mixed Models procedures as implemented in SAS® PROC GLIMMIX with a negative binomial distribution function for count variables.

Monthly average maximum temperatures from June to October were 90.1, 86.7, 87.1, 81.2, and 70.1 degrees F with average minimum temperatures being 66.7, 66.4, 66.9, 64.6, and 50.2 degrees F. Total rainfall amounts from June to October were 1.1, 5.5, 4.2, 4.6, and 6.5 inches. The total rainfall for the growing season was 21.9 inches. Root-knot nematode numbers increased throughout the season in all the cotton samples submitted. The standard susceptible cotton, Rowden, averaged 2,149 root-knot eggs per gram of root while the M-315 resistant cotton supported 88 root-knot eggs per gram of root. Nematode juveniles and eggs extracted from the root systems for all the submissions ranged from a high of 4,718 in PHY 565 to a low of 1,951 in DP 0949. The reproductive potential observed varied widely from highly susceptible to low susceptibilities, depending on the cotton submission. The average percent of wilted plants for the susceptible, Rowden, was 16 percent, with a range from 11 to 23 percent, and the resistant, M-315, had an average of 0.4 percent wilted with a range of 0 to 4 percent on an individual plot basis. The fungal pathogen was not found in the resistant M -315 cotton but was readily isolated from Rowden. From all the cotton submissions planted, 76.25 percent were colonized by Fusarium oxysporum f. sp. vasinfectum. Yields ranged from 3,467 to 1,151 pounds per acre, with PHY 367, PHY 565 ST 4288, and ST 5458 producing signiﬁcantly higher yields than Rowden.
Dunnett’s P-value vs. Rowden M-315 0.017 0.017 1.000 0.020 0.793 0.272 0.150 0.951 0.743 0.309 0.000 0.691 0.738 0.313 0.985 0.109 0.003 0.991 0.042 1.000 0.017 1.000

COTTON RESISTANCE TO ROOT-KNOT AND FUSARIUM WILT IN ALABAMA, 2010
Fusarium Variety wilted1 % M-315 0.4 Rowden 16.3 DP 0949 B2RF 7.6 DP 1028 B2RF 2.6 DP 1050 B2RF 3.7 FM 1740 B2F 5.4 PHY 367 WRF 1.1 PHY 375 WRF 2.5 PHY 485 WRF 3.3 PHY 565 WRF 6.9 ST 4288 B2RF 3.4 ST 5458 B2RF 1.6
1 2

Dunnett’s P-value M. vs. incognita/ Rowden M-3152 150 cm3 soil 0.013 77 0.005 77 0.378 0.044 174 0.013 0.326 97 0.011 0.172 116 0.019 0.080 290 0.001 0.790 251 0.011 0.335 97 0.006 0.207 695 0.065 0.046 773 0.004 0.188 77 0.001 0.560 77

Dunnett’s Dunnett’s Seed P-value M. P-value cotton vs. incognita/ vs. yield Rowden M-315 egg/g root3 Rowden M-315 lb/A 1.000 88 <.0001 2777 1.000 2149 <.0001 1151 0.973 0.973 775 0.318 0.003 1176 1.000 1.000 1092 0.734 0.001 1768 1.000 1.000 693 0.225 0.005 2316 0.680 0.680 1852 1.000 <.0001 1804 0.791 0.791 382 0.023 0.067 3467 1.000 1.000 1187 0.835 0.000 1808 0.376 0.376 1170 0.819 0.001 1535 0.112 0.112 1585 0.980 <.0001 3133 1.000 1.000 893 0.217 <.0001 2603 1.000 1.000 901 0.484 0.002 2784

Percent of wilted plants of the total per plot. Wilted plants were counted biweekly for 6 weeks. Dunnett’s P-value greater than 0.05 indicate signiﬁcant differences from the susceptible Rowden and the resistant M-315 standards. 3 Root-knot extracted from three cotton root systems collected on July 22.

28

ALABAMA AGRICULTURAL EXPERIMENT STATION

NEMATODE MANAGEMENT
EVALUATION OF COTTON SEED TREATMENTS FOR THE CONTROL OF ROOT-KNOT NEMATODE AND FUSARIUM WILT ON COTTON, 2010
S. R. Moore, K. S. Lawrence, and S. Nightengale

Selected seed treatments were evaluated to determine their effect on root-knot nematodes and Fusarium wilt in cotton. The test was located at the Plant Breeding Center of the E. V. Smith Research and Extension Center, near Tallassee, Alabama. The ﬁeld has a long history of root-knot nematode infestation, and the soil type was classiﬁed as a Kalmia loamy sand (80 percent sand, 10 percent silt, and 10 percent clay). Plots consisted of two rows, 25 feet long with 36-inch row spacing, and were planted in a randomized complete block design with ﬁve replications on April 22. Blocks were separated by a 20 foot-wide alley. All plots were maintained throughout the season using standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Stand counts and vigor ratings were conducted at 8 days after planting (DAP) on 10 feet of plot row and recorded. Soil samples were taken from each plot at 41 DAP. A 150 cm³ sub-sample from each plot was processed and root-knot nematodes were extracted by the sucrose centrifugation-ﬂotation methods and counted under the inverted microscope. Entire plots were harvested me-

chanically on September 30. Data were statistically analyzed by analysis of variance using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least signiﬁcant difference (LSD) test. Stand counts at 8 DAP were signiﬁcantly higher in Treatments 4 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Avicta Duo 4.03SC + Dynasty CST 125FS + A9625 + A16148) and 5 (Treatment 4 + Mertect Flowable) compared to Treatment 1 (Avicta Duo 4.03SC). Vigor ratings at 8 DAP were signiﬁcantly higher in Treatments 2 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Avicta Duo 4.03SC + Dynasty CST 125FS), 5, and 7 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Avicta Duo 4.03SC + Dynasty CST 125FS + A9625 + Dividend Extreme 0.96FS) compared to Treatment 1. Treatments 2 and 7 were signiﬁcantly higher than Treatment 3 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Avicta Duo 4.03SC + Dynasty CST 125FS + A9625). Root-knot nematode populations were the lowest in Treatment 7 and signiﬁcantly so compared with Treatment 2. Seed cotton yields averaged 1,673 pounds per acre and were similar for all treatments.

STAND COUNT, VIGOR, NEMATODE POPULATIONS AND YIELD OF COTTON IN CENTRAL ALABAMA TRIAL, 2010
Trt. no. 1 2 Stand/ 10 ft row 8 DAP 16.6 b 21.4 ab Vigor 1 8 DAP 2.6 c 3.3 a Meloidogyne incognita J2 and eggs/ g of root 41 DAP 841 ab 2791 a

3 4 5 6

7
1

Treatment1 Avicta Duo 4.03SC Apron XL 3LS Maxim 4FS Systhane 40WP Avicta Duo 4.03SC Dynasty CST 125FS Treatment 2 A9625 Treatment 3 A16148 Treatment 3 Mertect Flowable Allegiance-LS Baytan 30 Thiram 42-S Vortex 3.77FS Avicta Duo 4.03SC Dynasty CST 125FS Treatment 3 Dividend Extreme 0.96FS LSD (P ≤ 0.10)

Rate 0.5 mg/seed 15.0 g/100kg seed 2.5 g/100kg seed 31 g/100kg seed 0.5 mg/seed 0.03 mg/seed 1.0 g/100kg seed 20.0 g/100kg seed 20.0 g/100kg seed 15.0 g/100kg seed 10.0 mg/seed 31.0 g/100kg seed 5.0 g/100kg seed 0.5 mg/seed 0.03 mg/seed 10.0 g/100kg seed

Seed cotton yield lb/A 1775.4 a 1423.2 a

25.2 ab 27.8 a 26.0 a 24.2 ab

2.7 bc 3.0 abc 3.1 ab 2.9 abc

652 ab 1090 ab 691 ab 1951 ab

1809.5 a 1483.6 a 1369.8 a 1886.8 a

24.4 ab 8.84

3.3 a 0.49

141 b 2204.4

1964.1 a 606.27

Plant vigor estimated on a 1 to 5 scale with 3 being the control. 4 and 5 are progressively better than the control and 1 and 2 are similarly worse than the control. Means within columns followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

2010 AU CROPS: COTTON RESEARCH REPORT

29

EVALUATION OF EXPERIMENTAL NEMATICIDES FOR THE CONTROL OF RENIFORM NEMATODES ON COTTON IN NORTH ALABAMA, 2010
S. R. Moore, K. S. Lawrence, and B. E. Norris

Selected experimental seed treatments were evaluated to determine their efﬁcacy against the reniform nematode (Rotylenchulus reniformis) on cotton in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, 28 percent clay) that had a history of reniform nematode infestation. Soil temperature was 64 degrees F at a 4-inch depth on the day of planting with adequate soil moisture. All seed treatments were applied to the seed by the manufacturer. Orthene 90S (2 ounces per acre) was applied to all plots as needed for thrips control. Temik 15G was applied as a granular in-furrow treatment. Each plot consisted of four rows, 25 feet long with 40-inch row spacing, and plots were arranged in a randomized complete block design with ﬁve replications. Adjacent blocks were separated by 15-foot alleys. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used throughout the season. Population densities of the reniform nematode were determined at 26 and 61 days after planting (DAP). Ten soil cores, 0.5 inch in diameter and 6 inches deep, were collected from the center two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Ratings to determine plant vigor were recorded

at 26 days after planting (DAP). Plots were mechanically harvested on September 13. Data were statistically analyzed by analysis of variance using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least signiﬁcant difference (LSD) test. Vigor ratings at 26 DAP in all treatments were signiﬁcantly higher compared to Treatment 1 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Dynasty CST 125FS). Treatment 6 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Trilex Flowable + Baytan 30 + Allegiance-LS + STP15273) was signiﬁcantly higher compared to Treatment 4 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Dynasty CST 125FS + A16115 + Temik 15G). Nematode populations were the lowest for Treatments 5 (Treatment 1 + Temik 15G) and 6, and signiﬁcantly so compared to Treatments 2 (Treatment 1 + Cruiser 5FS) and 4. Treatment 6 produced signiﬁcantly lower numbers at 61 DAP compared to Treatment 2, with all other treatments producing similar populations. Seed cotton yields averaged 2968 pounds per acre in 2010 with Treatment 4 yielding the highest overall and signiﬁcantly so compared to Treatments 2 and 7 (Treatment 6 + STP17217 + STP17170).

VIGOR, NEMATODE POPULATIONS, AND YIELD OF COTTON IN NORTH ALABAMA, 2010
Trt. no. 1 Vigor1 26 DAP 2.2 c ——Rotylenchulus reniformis/ 150 cm3 soil—— 26 DAP 61DAP 386.3 abc 571.7 ab

Treatment1 Apron XL 3LS Maxim 4FS Systhane 40WP Dynasty CST 125FS 2 Treatment 1 + Cruiser 5FS 3 Treatment 1 + A16115 4 Treatment 3 + Temik 15G 5 Treatment 1 + Temik 15G 6 Apron XL 3LS Maxim 4FS Systhane 40WP Trilex Flowable Baytan 30 Allegiance-LS STP15273 7 Treatment 6 + STP17217 STP17170 Harpin LSD (P ≤ 0.10)

Rate 15.0 g/100kg seed 2.5 g/100kg seed 21 g/100kg seed 0.03 mg/seed 0.34 mg/seed 0.5 mg/seed 840 g/ha 840 g/ha 15.0 g/100kg seed 2.5 g/100kg seed 21 g/100kg seed 10 g/100kg seed 5 g/100kg seed 15 g/100kg/seed 0.375 mg/seed 0.375 mg/seed 10 mg/seed 31.2 g/100kg seed

Seed cotton yield lb/A 2802.3 ab

3.4 ab 3.4 ab 3.2 b 3.4 ab 3.8 a

633.5 a 278.1 bc 494.4 ab 139.1 c 154.5 c

710.7 a 463.5 ab 540.8 ab 278.1 ab 231.8 b

2445.7 b 3113.1 ab 3576.1 a 3294.9 ab 3035.9 ab

3.6 ab 0.55

370.8 abc 283.07

401.7 ab 471.20

2510.2 b 913.86

1

Plant vigor estimated on a 1 to 5 scale with 3 being the control. 4 and 5 are progressively better than the control and 1 and 2 are similarly worse than the control. Means within columns followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

30

ALABAMA AGRICULTURAL EXPERIMENT STATION

EVALUATION OF EXPERIMENTAL NEMATICIDES FOR THE CONTROL OF RENIFORM NEMATODES ON COTTON IN SOUTH ALABAMA, 2010
S. R. Moore, K. S. Lawrence, and J. R. Akridge

Selected experimental seed treatments were evaluated to determine their efﬁcacy against the reniform nematode (Rotylenchulus reniformis) in a naturally infested producer’s ﬁeld near Huxford, Alabama. The ﬁeld had a history of infestation by reniform nematodes and the soil type was a Ruston very ﬁne sandy loam (59 percent sand, 33 percent silt, 8 percent clay). Soil temperature was 90 degrees F at a 4-inch depth on the day of planting with adequate soil moisture. All seed treatments were applied to the seed by the manufacturer. Orthene 90S (2 ounces per acre) was applied to all plots as needed for thrips control. Temik 15G was applied as a granular in-furrow treatment. Each plot consisted of two rows, each 25 feet long with 36-inch row spacing, and plots were arranged in a randomized complete block design with six replications. Adjacent blocks were separated by 15-foot alleys. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used throughout the season. Population densities of the reniform nematode were determined at 28 and 72 days after planting (DAP). Ten soil cores, 0.5 inch in diameter and 6 inches deep, were collected

from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Ratings to determine plant vigor were recorded at 28 DAP. Plots were mechanically harvested on October 12. Data were statistically analyzed by analysis of variance using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least signiﬁcant difference (LSD) test. Plant vigor at 28 DAP was signiﬁcantly higher for all treatments compared to Treatment 1 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Dynasty CST 125FS) and all treatments with the exception of Treatment 1 were signiﬁcantly higher than Treatment 2 (Treatment 1 + Cruiser 5FS). Reniform nematode populations were similar for all treatments at both 28 and 72 DAP. All treatments produced numerically higher yields compared to Treatment 1 by an average of 539 pounds per acre. All treatments with the exception of Treatments 2 and 6 (Apron XL 3LS + Maxim 4FS + Systhane 40WP + Trilex Flowable + Baytan 30 + Allegiance-LS + STP15273) produced signiﬁcantly higher seed cotton yields compared to Treatment 1.

VIGOR, NEMATODE POPULATIONS, AND YIELD OF COTTON IN SOUTH ALABAMA, 2010
Trt. no. 1 Vigor1 28 DAP 3.0 c ——Rotylenchulus reniformis/ 150 cm3 soil—— 28 DAP 72 DAP 321.9 a 309.2 a

Treatment Apron XL 3LS Maxim 4FS Systhane 40WP Dynasty CST 125FS 2 Treatment 1 + Cruiser 5FS 3 Treatment 1 + A16115 4 Treatment 3 + Temik 15G 5 Treatment 1 + Temik 15G 6 Apron XL 3LS Maxim 4FS Systhane 40WP Trilex Flowable Baytan 30 Allegiance-LS STP15273 7 Treatment 6 + STP17217 STP17170 Harpin LSD (P ≤ 0.10)
1

Rate 15.0 g/100kg seed 2.5 g/100kg seed 21 g/100kg seed 0.03 mg/seed 0.34 mg/seed 0.5 mg/seed 840 g/ha 840 g/ha 15.0 g/100kg seed 2.5 g/100kg seed 21 g/100kg seed 10 g/100kg seed 5 g/100kg seed 15 g/100kg/seed 0.375 mg/seed 0.375 mg/seed 10 mg/seed 31.2 g/100kg seed

Seed cotton yield lb/A 1875.4 b

4.2 b 4.7 a 4.8 a 4.8 a 5.0 a

412.0 a 682.4 a 476.4 a 566.5 a 347.6 a

193.3 a 257.7 a 180.3 a 270.5 a 193.2 a

2253.0 ab 2414.7 a 2504.7 a 2510.0 a 2350.3 ab

5.0 a 0.39

515.0 a 501.80

245.0 a 149.68

2454.9 a 483.73

1

Plant vigor estimated on a 1 to 5 scale with 3 being the control. 4 and 5 are progressively better than the control and 1 and 2 are similarly worse than the control. Means within columns followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

2010 AU CROPS: COTTON RESEARCH REPORT

31

EVALUATION OF COTTON VARIETIES FOR RENIFORM MANAGEMENT IN COTTON IN SOUTH ALABAMA, 2010
K. S. Lawrence, S. R. Moore, W. S. Gazaway, G. W. Lawrence, and J. R. Akridge

Cotton varieties were evaluated with and without Telone II for the management of reniform nematodes in a naturally infested producer’s ﬁeld near Huxford, Alabama. The ﬁeld has a history of reniform nematode infestation, and the soil type is a Ruston very ﬁne sandy loam (59 percent sand, 33 percent silt, 8 percent clay). Telone II was injected with a modiﬁed ripper hipper at 3 gallons per acre 14 days before planting. The seed fungicide and insecticide treatments were applied to the seed by Bayer Crop Science. Orthene 90S at 4 ounces per acre was applied to all plots as needed for thrips control. Plots consisted of two rows, 25 feet long with 36-inch row spacing, and were arranged in a randomized complete block design with six replications. Blocks were separated by a 20-foot wide alley. All plots were maintained throughout the season with standard herbicide, insecticide, and fertility production practices as recommended by the Alabama Cooperative Extension System. Population densities of the reniform nematode were determined on May 13, June 8, July 22, and October 27. Ten soil cores, 1 inch in diameter and 8 inches deep, were collected from the two rows of each plot in a systematic sampling pattern. Nematodes were extracted using the gravity sieving and sucrose centrifugation technique. Plots were harvested on October 27. Data were statistically analyzed by SAS PROC GLM and means compared using Fisher’s protected least signiﬁcant difference test (P ≤ 0.10). Monthly

average maximum temperatures for May through October. were 88.1, 94.8, 95.1, 94.4, 93.4, and 85.2 degrees F with average minimum temperatures of 66.3, 72.3, 73.8, 75.3, 67.2, and 50.7 degrees F, respectively. Rainfall accumulation for each month was 5.09, 1.64, 3.76, 8.48, and 0.74 inches with a total of 19.71 inches. Reniform nematode pressure was moderate in 2010 probably due to the drought in July and August. Reniform nematode numbers were low at planting averaging 195 vermiform life stages per 150 cm3 of soil in the Telone II and control plots. Reniform numbers increased in the ﬁrst 30 DAP in the varieties with no nematicide as compared to the Telone II plots. Phytogen 367, FiberMax 1740, Stoneville 5458, and FiberMax 9170 all increased nematode numbers in the untreated plots as compared the Telone II plots. However, the lack of rainfall in July reduced nematode numbers in the soil in all plots and by harvest no differences were observed between any variety or Telone II treatment. Seed cotton yields varied by 714.4 pounds per acre at harvest with an average of 2143 pounds per acre of seed cotton produced over all varieties. Telone II produced an average yield over all varieties of 2251.7 pounds per acre or a 217.5 pounds per acre increase over the untreated varieties. The Fiber Max varieties responded to the Telone II with the greatest yield increase as compared to the Stoneville and Phytogen varieties.

EVALUATION OF COTTON VARIEITES FOR RENIFORM MANAGEMENT IN COTTON IN SOUTH ALABAMA, 2010
Trt. no. Variety and nematicide1 1 Phytogen 367 no nematicide 2 Fiber Max 1740B2R no nematicide 3 Stoneville 5458 B2RF no nematicide 4 Stoneville 5327 B2RF no nematicide 5 Fiber Max 9170 B2R no nematicide 6 Phytogen 367 + Telone II 3 g/a 7 Fiber Max 1740B2R + Telone II 3 g/a 8 Stoneville 5458 B2RF+ Telone II 3 g/a 9 Stoneville 5327 B2RF+ Telone II 3 g/a 10 Fiber Max 9170 B2R+ Telone II 3 g/a LSD (P ≤ 0.10)
1

—Rotylenchulus reniformis/150 cm³— May 13 June 8 July 22 Oct. 27 92.6 b 339.9 a 170.2 a 200.6 a 262.8 ab 448.1 a 201.2 a 278.2 a 232.0 ab 432.6 a 185.8 a 726.2 a 386.6 a 293.6 ab 154.8 a 834.4 a 293.8 ab 417.2 a 185.8 a 541.0 a 108.2 b 108.2 b 92.8 b 278.2 a 139.2 b 108.2 b 139.2 a 649.0 a 108.4 b 77.3 b 139.0 a 448.4 a 170.4 ab 154.5 b 108.4 a 432.8 a 154.8 ab 92.7 b 77.2 b 494.4 a 129.9 260.6 102.4 502.2

Seed cotton yield lb/A 2095.7 ab 1922.4 b 2222.7 ab 2177.4 ab 1753.4 b 2244.1 ab 2173.4 ab 2467.8 a 2205.9 ab 2167.3 ab 315.4

All seed also contain the fungicides Apron XL (3LS 15gai/100kg seed) + Maxim 4FS (2.5 gai/100kg seed) + Systhane 40 WP (21gai/100kg seed) + Dynasty CST 125 FS (0.3 mgai/seed). Means followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

32

ALABAMA AGRICULTURAL EXPERIMENT STATION

EVALUATION OF SEED TREATMENT FUNGICIDES FOR THE CONTROL OF SEEDLING DISEASE ON COTTON IN NORTH ALABAMA, 2010
S. R. Moore, K. S. Lawrence, and B. E. Norris

Selected experimental seed treatments were evaluated to determine their efﬁcacy against early season cotton diseases in north Alabama. The soil was a Decatur silt loam (23 percent sand, 49 percent silt, 28 percent clay) that had a history of seedling diseases. Soil temperature was 64 degrees F at a 4-inch depth on the day of planting with adequate soil moisture. All fungicide treatments were applied to the seed by the manufacturer. For the high incidence disease trial, plots were infested with millet seed inoculated with Rhizoctonia solani and Pythium ultimum. For the low incidence disease trial, plots were left naturally infested. Temik 15G (7.0 pounds per acre) was applied at planting on April 13 in the seed furrow with chemical granular applicators attached to the planter. Orthene 90S (2 ounces per acre) was applied to all plots as needed for thrips control. For each of the low and high disease pressure trials, each plot consisted of two rows, each 25 feet long with 40-inch row spacing. Plots were arranged in a randomized complete block design with ﬁve replications. Adjacent blocks were separated by 15-foot alleys. Standard herbicides, insecticides, and fertility production practices, as recommended by the Alabama Cooperative Extension System, were used throughout the season. Stand counts were recorded 16 and 30 days after planting (DAP) to determine stand

density and percent seedling loss resulting from cotton seedling diseases. Plots were harvested on September 13. Data were statistically analyzed by analysis of variance using the generalized linear models (GLM) procedure, and means compared using Fisher’s protected least signiﬁcant difference (LSD) test. Seedling disease pressure was high for early planted cotton in 2010. At 16 DAP, 62 percent and 81 percent of all seed planted did not emerge in the low and high disease incidence trials, respectively. Under low disease pressure there was no signiﬁcant difference in seedling stand at 16 DAP; however, by 30 DAP all treatments had signiﬁcantly higher stands compared to the Avicta Duo 4.03 SC control. All treatments produced higher seed cotton yields than the Avicta Duo 4.03 SC control by an average of 518 pounds per acre. Under high disease pressure, all treatments produced numerically higher stand counts at 16 DAP and signiﬁcantly higher stands at 30 DAP compared to the Avicta Duo 4.03 SC control. All treatments produced signiﬁcantly higher seed cotton yields compared to the Avicta Duo 4.03 SC control by an average of 2277 pounds per acre. While Treatments 1 through 8 produced comparable results under low disease pressure, Treatment 5 (Allegiance-LS + Baytan 30 + Thiram 42-S + A9625 +Avicta Duo 4.03 SC + Dynasty CST 125 FS) had superior performance under high disease pressure.

2010 AU CROPS: COTTON RESEARCH REPORT

33

EVALUATION OF SEED TREATMENT FUNGICIDES FOR THE CONTROL OF SEEDLING DISEASE ON COTTON IN NORTH ALABAMA, 2010
Treatment 1 Avicta Duo 4.03 SC 0.5 mg/seed 2 Apron XL 3 LS 15.0 g/100kg seed Maxim 4 FS 2.5 g/100kg seed Systhane 40 WP 31.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed 3 Allegiance-LS 15.0 g/100kg seed Baytan 30 10.0 mg/seed Thiram 42-S 31.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed 4 Apron XL 3 LS 15.0 g/100kg seed Maxim 4 FS 2.5 g/100kg seed Systhane 40 WP 31.0 g/100kg seed A9625 1.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed 5 Allegiance-LS 15.0 g/100kg seed Baytan 30 10.0 mg/seed Thiram 42-S 31.0 g/100kg seed A9625 1.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed 6 Apron XL 3 LS 15.0 g/100kg seed Maxim 4 FS 2.5 g/100kg seed Systhane 40 WP 31.0 g/100kg seed A16148 20.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed 7 Apron XL 3 LS 15.0 g/100kg seed Maxim 4 FS 2.5 g/100kg seed Systhane 40 WP 31.0 g/100kg seed A9625 1.0 g/100kg seed A16148 20.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed 8 Allegiance-LS 15.0 g/100kg seed Baytan 30 10.0 mg/seed Thiram 42-S 31.0 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Allegiance-LS 15.0 g/100kg seed Baytan 30 5.0 mg/seed Trilex Flowable 10.0 g/100kg seed 9 Apron XL 3 LS 15.0 g/100kg seed Maxim 4 FS 2.5 g/100kg seed Systhane 40 WP 31.0 g/100kg seed A9625 1.0 g/100kg seed A17823 21.1 g/100kg seed Avicta Duo 4.03 SC 0.5 mg/seed Dynasty CST 125 FS 0.03 mg/seed LSD (P ≤ 0.10) ——Low disease pressure—— —Stand/10 ft row— Seed cotton 16 DAP 30 DAP lb/A 13.6 a 11.8 c 2973.9 b 16.6 a 21.0 b 3634.9 a ——High disease pressure—— —Stand/10 ft row— Seed cotton 16 DAP 30 DAP lb/A 2.2 c 1.8 d 737.9 c 6.2 bc 10.2 abc 3170.4 ab

11.6 a

21.6 b

3481.9 a

15.8 a

10.4 abc

2979.7 ab

14.8 a

23.8 ab

3432.2 a

5.8 bc

8.0 bc

2713.1 b

14.4 a

23.2 ab

3499.1 a

7.2 bc

14.6 a

3396.6 a

16.6 a

27.0 a

3576.5 a

5.4 bc

7.4 c

3083.6 ab

14.2 a

22.2 ab

3385.1 a

8.4 bc

12.2 ab

2966.5 ab

14.6 a

21.2 b

3264.9 ab

6.2 bc

6.6 c

2856.3 ab

14.2 a

21.0 b

3655.3 a

9.6 ab

12.8 a

2955.1 ab

6.43

4.99

398.85

6.50

4.67

632.70

Means followed by different letters are signiﬁcantly different according to Fisher’s LSD (P ≤ 0.10).

34

ALABAMA AGRICULTURAL EXPERIMENT STATION

CONTRIBUTORS INDEX
Author Pages A. H. Abdelgadir 13-14 J. R. Akridge J. Arriaga K. S. Balkcom W. C. Birdsong C. Brodbeck A. Brooke 30,31 12 7-8,15-16 24 9-10 12 Author S. Nightengale B. E. Norris B. V. Ortiz Pages 28 13-14,25,26,29,32-33 11

M. G. Patterson 24 A. J. Price T. Z. Scott A. Sharda J. Shaw R. H. Smith T. Tyson E. van Santen D. Watts D. B. Weaver A. Winstead R. P. Yates 24 27 11 12 21,22,23 12 27 15-16,19-20 5-6 11,12 17-18

C. H. Burmester 9-10,12,13-14,25,26 L. M. Curtis D. P. Delaney B. A. Dillard M. P. Dougherty B. Durham J. P. Fulton W. S. Gazaway K. Glass 12,13-14 7-8,17-18 24 9-10,12,13-14 9-10,12 9-10,11,12,13-14 31 27

W. R. Goodman 24 M. H. Hall D. H. Harkins J. Holliman G. Huluka 9-10,11 12,13-14 17-18 17-18

G. W. Lawrence 25,26,31 K. S. Lawrence T. McDonald C. C. Mitchell C. D. Monks D. Moore S. R. Moore D. Mullenix 25,26,27,28,29,30,31,32-33 11 7-8,15-16,17-18,19-20 13-14,24 15-16 25,26,28,29,30,31,32-33 9-10,11,12