V BULLETIN No. 276 JUNE 1950 VALUE 4 IRRIGATION 0 A DIFFERENT FERTILITY TREATMENTS /0 VEGETABLE CROPS STATION AGRICULTURAL EXPERIMENT INSTITUTE POLYTECHNIC ALABAMA 4 4e M. J. Funchess, Director Auburn, Alabama CONTENTS Page IRRIGATION RESEARCH RAINFALL --------------- ------- 3 5 AND OTHER CLIMATIC FACTORS OF ALABAMA-------------Average Rainfall by Sections and Periods ---Variations in Rainfall-----------------------Evaporation and Evapo-Precipitation Ratio by Months- 5 7 7 METHODS AND PROCEDURES---- -------------------------- 9 ---------------------- 11 PRESENTATION OF DATA---------------Characteristics of the Soils----------------11 Rainfall Data for Years of Experiment---------------Effects of Irrigation in Different Years and Seasons------12 Effects of Irrigation as Influenced by Amount and Distribution of Rainfall---------12 Independent and Combined Effects from Use of Irrigation, Organic Materials, and Different Fertilizer Rates on Crop Yields ----------------------------- 15 Effects of Different Rates of Irrigation-------------Effects of Different Kinds or Organic Materials with Irrigation.---------------------------------------- 21 ----- 21 27 Effects of Irrigation and Organic Materials on Grade of Products ---------------------------------- Results with Individual Crops---------------------------------- 30 Economic Studies------------------------------------------------- 34 DISCUSSION------------------------------------------------- 39 40 Relation of Climate to Response from Irrigation---------40 Relation of Soil Characteristics to Irrigation Needs ------- Effects from Use of Practices in Combination-----------41 SUMMARY.------------------------------------------------ 43 47 LITERATURE CITED---------------------------------------------------- 45 APPElNDIX-------------------------------------------------- FIRST PRINTING 4M, JUNE 1950. VALUE 4 IRRIGATION 4A DIFFERENT FERTILITY TREATMENTS VEGETABLE CROPS L. M. WARE, Horticulturist W. A. JOHNSON, Laboratory Technician PRESENTED in this bulletin are the results of studies extending over 11 years. While designed primarily as an irrigation experiment, the investigation included studies of the independent and combined effects of irrigation, organic materials, and fertilizer rates on the yield, grade, and relative economic value of vegetable crops. IRRIGATION RESEARCH A survey of the literature reveals a large number of publications on irrigation. Much of the work in America has been done in the western states. A considerable amount of the literature is concerned with techniques and equipment relating to application of irrigation water by a number of different methods. Literature is especially abundant in formulas, tables, and instructions dealing with capacity of pumps, pipes, canals, and flumes; with loss of pressures, or head, as affected by size and length of pipe; and with movement and absorption of water by soils of different textures and depths. These have been reviewed by a number of writers (1, 7,19) and are the subjects of a number of popular publications (13,18). The amount of research on crop response and irrigation requirements of different crops in humid areas is somewhat limited. A review of published research and other reports dealing with 4 ALABAMA AGRICULTURAL EXPERIMENT STATION supplemental irrigation is given in Johns-Manville "Manual on Supplemental Irrigation" (1). Gaines and others (7) have prepared a rather complete bibliography on this and related subjects. Stallings (19), in serial releases by the Soil Conservation Service, "Abstracts of Recently Published Materials on Soil and Water Conservation," has reviewed current literature on irrigation. A very recent survey has been made of current research in the Southeast by a committee of the Southeastern Section, American Society of Agricultural Engineers (26). A number of textbooks are available on irrigation and related topics (8,11,12,14,25). A limited amount of research has been conducted in the South on irrigation of vegetable crops. The studies generally have been confined to measurements of crop yields with and without irrigation. Some studies have dealt with other effects. Data showing increases from irrigation have been published by the agricultural experiment stations of Georgia (3, 4), Tennessee (20, 21, 22,23) and Oklahoma (2), and by the Tennessee Valley Authority (1). Nettles and others (15) of Florida studied the effects of different types of irrigation and of different nitrogen rates on the yield and quality of cabbage and beans. Irrigation affected yields only to a minor extent one year, whereas in another year yields were markedly affected. Janes (9) of Florida studied the effects of three types of irrigation on the composition of two bean varieties. Irrigation was found to reduce the percentage composition of most of the 17 constituents studied. Cordner (6), working with sweet corn and tomatoes in Oklahoma, concluded that yields could be substantially increased by a few timely irrigations. Set of tomatoes and blossom-end rot were reduced, but other rots were increased by irrigation. Strand (22,23) in the Douglas Reservoir Area of Tennessee obtained from irrigation increases in yield of cabbage of 7.3 tons per acre with 600 pounds per acre of fertilizer, 8.3 tons with 900 pounds of fertilizer, and 8.5 tons with 1,200 pounds of fertilizer. Also, irrigation gave very marked increases in the yield of beans. Earlier reports have been made of certain phases of this investigation (28, 29). IRRIGATION STUDIES with VEGETABLE CROPS 5 RAINFALL AND OTHER CLIMATIC FACTORS OF ALABAMA AVERAGE RAINFALL BY SECTIONS AND PERIODS The average annual rainfall in the southeastern states ranges from 40 to 60 inches; in Alabama, Georgia, Florida, South Carolina, Tennessee, and Mississippi, the average is about 50 inches. In Table 1 is given the average annual rainfall by months in Alabama for the 53-year period, 1886 to 1938 (10). The average for the State in that period was 53 inches; for the spring season, it was 14.23 inches; for the summer, 14.34 inches; for the fall, 9.30 inches; and for the winter, 15.12 inches. The amount of rainfall varies by locations within the State. During a 27-year period, the average annual rainfall was 57 inches at Robertsdale, and during a 39-year period, it was 49 inches at Tuskegee. In Figure 1 is given the average rainfall by 10-day periods for five belts of the State for a period of 20 to 25 years. The graph shows that for the periods covered the average rainfall for each of the five parallel belts has been relatively low in October, November, and also low during the last 10 days of August and the first 20 days of September. Rainfall during the month of July and the first 20 days of August has been above TABLE 1. PRECIPITATION, EVAPORATION, AND EVAPO-PRECIPITATION RATIOS BY MONTHS, AUBURN, ALABAMA Month Precipitation Inches 1 Evaporation Inches 1.41 2.42 2 Evapoprecipitation Ratio 0.28 0.46 January February 4.98 5.24 March April May June 5.86 4.49 3.88 4.24 2.86 8.82 5.63 6.55 0.49 0.85 1.45 1.54 July 5.49 6.08 5.86 4.67 3.71 2.35 1.11 August September October November 4.62 3.28 2.79 3.24 1.27 1.42 1.33 0.73 December TOTAL 4.90 53.01 1.63 0.33 period, 1886-1938. 2 'Precipitation in inches equals the average rainfall by months for a 53-year Parsons, D. A. Summary of principal results, Project AL-R-3, Auburn, Ala- bama, for calendar year 1947. Unpublished report, Soil Conservation Service, United States Department of Agriculture. 6 ALABAMA AGRICULTURAL EXPERIMENT STATION ulODILr DISTRIBUTION OF ALABAMA'S RDAINFALL BY 10 DAY PERIODS. SALDWIII EACH GRhAPHI THlE AVERAGE OF DICOPDS IS FROMn 3 OR. 4 POINTS EXTENDING OVER A PERIOD OF' 20 TO 25 YEALR.. COMPILED BY M.J. 'UNCI-E3S ALABAMA EXPERIMENT STATIOI. FIGURE 1. Distribution of rainfall in Alabama by 10-day periods. IRRIGATION STUDIES with VEGETABLE CROPS 7 the average. While these data give the periods when rainfall is likely to be high, average, or low, they do not assure rainfall at these periods for any one year. VARIATIONS IN RAINFALL Although the average rainfall in Alabama is about 53 inches, it is very irregular. The amount of rainfall varies from year to year. The highest average annual rainfall recorded for the State during the 53-year period was 76.5 in 1929; the lowest was 39.2 inches in 1904. Between 1899 and 1938, rainfall for different sections of the State during the 10 wettest years ranged from 50 to 70 inches, while during the 10 driest years the range was 40 to 45 inches; rainfall for the 10 wettest summers ranged from 20 to 24 inches, whereas in the 10 driest summers the range was 8 to 12 inches. Given in Table 2 is the number of times on a 50-year basis rainfall during 2-, 3-, and 4-week periods totaled less than one inch, less than three-fourths of an inch, and less than one-half of an inch for three periods of the year at three locations in the State. The data are based on records for 42 years at Cullman, 56 years at Clanton, and 37 years at Robertsdale. All data have been converted to a 50-year basis. The data provide a table of odds on the probability of droughts for three sections of the State. For example, at Clanton in 50 years there were 52 times during the fall months, 27 times during the spring months, and 13 times during the summer months when rainfall was less than one inch for four consecutive weeks. EVAPORATION AMND EVAPO-PRECIPITATION RATIOS BY MONTHS In Table 1 are given by months evaporation data from a floating pan at Auburn and the calculated evapo-precipitation ratios based on these data and the average rainfall of Alabama. The evaporation data were obtained by Parsons of the Soil Conservation Service.' The ratios exceeded 1.0 from May to October. High evaporation rates are associated with high water losses from soil surfaces and plants, while high ratios are associated with periods of likely moisture deficiency in the soil. 1 Summary of principal results. Project ALR-3. Soil Cons. Serv. Report. 1947. Unpublished TABLE 2. NUMBER OF TIMES DROUGHT PERIODS OF CERTAIN LENGTHS HAVE OCCURRED AT DIFFERENT LOCATIONS IN ALABAMA' Number of continuous weeks Total accumulated rainfall less than Inches 1 3 Calculated number of times in 50 years rainfall less than indicated amounts for different periods of year Cullman Clanton Robertsdale March June September March June September March June September April July October April July October April July October August November May August November May May August November 117 98 68 54 37 18 126 102 69 49 82 18 169 144 118 87 67 48 135 115 92 56 44 31 181 101 74 40 28 20 186 164 140 89 80 57 127 101 84 47 39 24 63 51 41 16 14 7 154 189 120 84 72 55 a- Two weeks Three weeks 4 1 I- - Four weeks or more 18 28 45 27 18 52 23 8 45 3 8 12 81 19 11 44 18 7 29 /2 4 5 24 14 4 29 8 4 23 Data prepared by Montgomery office, Weather Bureau, U. S. Department of Commerce. 2 Drought frequencies calculated on a 50-year basis from actual records of 42 years at Cullman, 1907-48; 56 years at Clanton, 1893-1948; and 87 years at Robertsdale, 1912-48. 1 m ' x z -4 -I m M z IRRIGATION STUDIES with VEGETABLE CROPS 9 METHODS AND PROCEDURES The studies reported in this publication involved two phases. The first phase consisted of a study of effects of irrigation, fertilizers, and organic materials on the yield and grade of different vegetable crops. The second phase consisted of a study of production costs and returns from crops under irrigation using the best combination of treatments found in the first phase of the experiment. The first phase was conducted in concrete field bins filled with local soils thoroughly composited among all bins and within each bin (27). Phase one consisted of Series A and Series B. Series A was started in 1938 and Series B was begun in 1940. Treatments in the two series of phase one are given in the following tables: SERIES A Pounds per acre 0 500 No treatment (check). Treatment 6-10-4; fertilizer grade from 1938 through 1942 was 6-8-4; in 1943 and subsequent years the grade was 6-10-4. The quantity shown under "pounds per acre" is the amount applied to each crop in the succession. 500 500 500 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 6-10-4 + irrigation; 1 inch of water per week was applied when rainfall during previous week had not supplied that amount and plants and soil indicated need for water; measured amount equal to 1 inch of water was applied through a porous hose; water for irrigation was obtained from city supply. 6-10-4 + organic materials; organic materials consisted of 8 tons per acre of dry lespedeza sericea applied to each of three crops per year in 1938 and 1939, and after 1989, 2 tons per acre of dry lespedeza sericea applied in winter and 6 tons of green crotalaria in summer. 6-10-4 + organic materials + irrigation. 6-10-4. 6-10-4 + irrigation. 6-10-4 + organic materials. 6-10-4 + organic materials + irrigation. 6-10-4 + vetch grown and turned + irrigation. 6-10-4 + cowpeas grown and turned + irrigation. 0-10-4 + organic materials + irrigation. 10-10-4 + irrigation. 10 ALABAMA AGRICULTURAL EXPERIMENT STATION SERIES B Pounds per acre Treatment 0 No treatment (check). 1,000 6-10-4; the quantity shown under "pounds per acre" for each treatment was applied to each of two crops per year. 1,000 6-10-4 irrigation; 1 inch of water per week was applied when rainfall during previous week had not supplied that amount and plants and soil indicated need for water; a measured amount equal to 1 inch of water was applied through a porous hose; water for irrigation was pumped from a well. 1,000 6-10-4 + 12 tons manure. + 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,500 2,000 6-10-4 6-10-4 + + 12 tons manure vetch + irrigation. 6-10-4 + vetch; vetch was grown on plots and turned. + irrigation. 6-10-4 + rye; rye was grown on plots and turned. 6-10-4 + rye + irrigation. 6-10-4 6-10-4 + + 12 tons manure 12 tons manure 6-10-4 12 tons manure vetch irrigation; minor elements were applied to all treatments except this one. 6-10-4 6-10-4 6-10-4 + + + vetch. vetch ± + + irrigation. + + + 6 tons manure + vetch 6 tons manure + rye + irrigation. irrigation. + 12 tons manure + vetch + irrigation. 6-10-4 + 12 tons manure + vetch + irrigation. The economic studies were conducted on field areas large enough to measure costs of applying the several treatments and of obtaining representative data on costs, labor requirements, and returns. The water supply was a farm pond. A portable system was used to apply the water. Standard treatments consisted of 1,500 pounds per acre of a 6-8-4 fertilizer, plus a side application of 250 to 325 pounds of nitrate of soda applied to each crop, and 12 tons of manure applied annually. Two successive crops were grown each year; one-half of the cost of manure was charged to each. The irrigation system for the economic study consisted of a rebuilt auto motor, a centrifugal pump with capacity of 180 gallons per minute, 416 feet each of main and lateral pipe of light galvanized metal, and 10 overhead whirling sprinklers, each having a capacity of 18 gallons per minute. IRRIGATION STUDIES with VEGETABLE CROPS 11 PRESENTATION OF DATA CHARACTERISTICS OF THE SOILS In Table 3 are given the moisture equivalent, wilting percentage, maximum available moisture percentage, and approximate available moisture capacity of each of the first 3 feet of the soils used in the studies. The method of Briggs and McLane (5) was used in obtaining moisture equivalent, while that of Richards and Weaver (17) was used in determining wilting percentage. TABLE 3. MOISTURE EQUIVALENT, WILTING PERCENTAGE, AVAILABLE MOISTURE CAPACITY OF SOILS AND APPROXIMATE USED Source of sample Depth Moisture equivalent Wilting percentage Maximum Approximate available moisture moisture capacity Series A Series B Field area Feet 0 to 1 1 to 2 2 to 3 Percent 9.44 18.39 20.16 Per cent 8.64 10.16 11.10 Per cent 5.80 8.23 9.06 Inches 1.06 1.88 1.41 0 to 1 1 to 2 2 to 3 7.73 11.63 12.97 2.81 6.09 7.45 4.92 5.54 5.52 0.90 0.93 0.86 0 to 1 1 to 2 2 to 3 9.12 11.88 15.59 2.83 5.50 8.88 6.29 6.38 6.71 1.15 1.07 1.05 All soils were rather low in available moisture capacity. The soil used in Series A had a somewhat higher capacity than those used in Series B and in the field plots. The soil in Series B was especially low in available moisture capacity in the lower 2 feet, being able to hold only about 2.69 inches of available water in the upper 3 feet. On the other hand the soil in Series A could hold about 8.85 inches and that in field plots 3.27 inches in the upper 8 feet. RAINFALL DATA FOR YEARS OF EXPERIMENT In Appendix Table 1 are given the amounts of rainfall at Auburn by semi-monthly periods for the years covered by the irrigation experiment. To provide sufficient water at critical periods for maximum or near-maximum yields, rainfall should be approximately 2 inches or more each semi-monthly period. The data reveal how irregular 12 ALABAMA AGRICULTURAL EXPERIMENT STATION rainfall was during the investigation. Between March 16 and April 15, 1938, there was a total of 14.45 inches of rainfall, or 25 per cent of a year's supply. During the next 9 weeks, April 16 to June 15, rainfall totaled only 5.83 inches; and from August 16 to November 15, over 13 weeks, the total was only 3.42 inches. Prolonged periods of low rainfall occurred in the fall of 1939, late summer and early fall of 1940, spring of 1941, late spring and summer of 1944, fall of 1947, and spring of 1948. Shorter or less severe periods of low rainfall occurred in the spring of 1940, summer and fall of 1943, and fall of 1944. The relation of prolonged periods of drought to response to irrigation will be observed in data presented later. EFFECTS OF IRRIGATION IN DIFFERENT YEARS AND SEASONS In Figure 2 are shown the increases and decreases in yield resulting from irrigation of a number Qf crops for years of high and low response. It may be seen that in some years benefits from irrigation were very pronounced, while in other years benefits were very small or even negative. EFFECTS OF IRRIGATION AS INFLUENCED BY AMOUNT AND DISTRIBUTION OF RAINFALL Of the factors that would be expected to account for differences in response of crops to irrigation in different years, the amount and the distribution of rainfall during the growing period should be of high importance. In Appendix Tables 2 and 3 are given by years the actual and percentage increases in yield of crops and the amount and distribution of rainfall during four periods of growth. The rainfall data include the period from one week before planting to within one week of final harvest. The four periods were equal in length and corresponded roughly to: germination and establishment of stand, early growth, later rapid growth, and final growth and maturity. The data do not reveal a very close relationship between total rainfall and response to irrigation for a given period. There is a much closer relationship between distribution of rainfall and response to irrigation. Data showing response to irrigation of a few crops receiving rainfall differing in amount and distribution are given in Table 4. The average rainfall for the four growing periods of cabbage was 1.84 inches per week in 1944 and also in 1945. Yet yields in 1944 IRRIGATION STUDIES with VEGETABLE CROPS 13 IRRIGATION STUDIES withr VEGETAB~E CROPS 1 were increased 6,099 pounds, while in 1945 they were decreased 4,890 pounds per acre by irrigation. The principal difference was in the distribution- of rainfall, which was low in the fourth quarter of 1944, while low during the third period of 1945. In the case of POUNDS PER ACRE RESF INCREASE PONSE DECREASE HIGH LOW 4,000 0 4.000 8.000 t:14 CROPS * SERIES A SQUASH (SP,S)** 1947 ONIONS (F) 1939 BROCCOLI (F) 1947 SWEET CORN (SP, S) 1947 TENDERGREEN (F) 1943 CABBAGE (SP) 1944 1947 LETTUCE (F) TURNIPS (F) 1940 SERIES & SWEET CORN (SP, S) 1946 1941 1946 1946 1945 1945 1946 1941 1946 BUSHELS v9A1 PER ACRE 092$Z k9s6 DECREASE INCREASE 100 0 100 200 19~9 1948 SERIES A 1938 1938 1938 1943 BEANS, BUSH (SP) 1940 BEANSUMA (5) 1940 POTATOES (SP) 1941 SWEETPOTATO(SSF) 19 44 eY SERIES B 1940 1942 POTATOES BEANS, POLE (S,F) 1948 1947 TOMATOES (5) 1943 1941 (F) Yields per acre years of high response in LrtZJ Yields per acre in years of low response *All crops received 1,000 pounds of 6-10-4 per acre. The crops received 1 inch of water per week when rainfall the previous week had not supplied that amount and plants or soil indicated need of water. ° * (SP) = spring, (S)== summer, (F) == fall. FIGURE 2. Variations in response of crops to irrigation in different years. 14 TABLE 4. ALABAMA AGRICULTURAL EXPERIMENT STATION RELATION OF AMOUNT AND DISTRIBUTION OF RAINFALL AND RESPONSE TO IRRIGATION OF SELECTED CROPS Increase or decrease Rainfall per week Crops' Seasons Years Units from irrigation 2 Amount er cent PerAv. By 1st In. period 3rd In. 4th In. Av. In. 2nd In. Series A Beans, bush Spring 1938 1940 Bu. Bu. Lb. Lb. Bu. Bu. Lb. Lb. -34 42 6,099 -- 4,890 -6 66 11,505 679 -17 350 157 -26 8 -65 395 2 1.06 1.72 2.38 2.86 0.51 1.15 0.39 0.02 3.75 0.31 2.70 1.23 1.91 0.39 0.12 0.91 0.66 0.31 2.01 0.43 2.43 0.94 0.02 1.06 0.88 1.79 0.28 2.82 1.06 0.01 1.00 0.01 1.59 1.03 1.84 1.84 1.48 0.62 0.38 0.50 Cabbage Spring 1944 1945 Potatoes Spring 1938 1941 Turnip Fall 1940 1941 Series B Corn, sweet Spring 1946 & sum. 1948 1940 1942 Doz.' Doz. Bu. Bu. 27 413 48 25 18 103 171 32 1.24 0.32 0.92 1.65 0.60 0.32 0.27 0.22 2.40 0.47 0.08 1.36 1.53 1.76 0.95 0.28 1.44 0.72 0.56 0.88 Potatoes Sum. & fall 1 All crops received 1,000 pounds of 6-10-4 fertilizer per acre. 8One inch of water per week was applied when rainfall during previous week had not supplied that amount. SEach period was one-fourth of the time beginning one week before planting and extending to one week before final harvest. Sweet corn yields were measured in dozen ears per acre. turnips, rainfall during the four periods in 1940 averaged 0.38 inches per week and in 1941, 0.50 inches; yet yields were increased by irrigation 11,505 pounds in 1940 and only 679 in 1941. Apparently crops reacted differently to lack of water at different periods; consequently, they reacted differently to irrigation at such times. Beans, and turnips apparently suffered most from low rainfall during the second and third periods, while cabbage suffered most from low rainfall during the fourth period, and potatoes during second and fourth periods. Cabbage in 1944 with an average rainfall for the four periods of 1.84 inches per week gave an increase from irrigation of 6,099 pounds per acre, while turnips in 1941 gave practically no increase with an average rainfall of only .50 inches per week. IRRIGATION STUDIES with VEGETABLE CROPS 15 INDEPENDENT AND COMBINED EFFECTS FROM USE OF IRRIGATION, ORGANIC MATERIALS, AND DIFFERENT FERTILIZER RATES ON CROP YIELDS The data in Table 5 and Appendix Table 4 show increases in yield from irrigation, organic materials, and different fertilizer rates when used alone and in combinations. In interpreting results, it should be emphasized that the responses measured are those resulting from use of certain practices with all related effects that those practices might have on productivity of soil or on effectiveness of the other practices used. For example, some of the organic materials used probably contained relatively large amounts of nitrogen. The effects of the organic materials, therefore, are not to be considered as the effects of organic matter per se but as the combined effects of the specific organic materials including the nitrogen and minerals as well as the carbonaceous materials they contained. Since no complete analyses were made of the organic materials, the specific amounts of nitrogen and other plant nutrients added cannot be enumerated. Therefore, the term "organic materials" is used in this report as a general, over-all expression. The amount of nitrogen added in the organic materials and the effects of this nitrogen were considerable, as may be noted in the following table. Treatments Fertilizer,1000 pounds per acre 0-10-4 6-10-4 10-10-4 Organic materials* Standard None None Relative yield, average of six crops Per cent 78 100 125 6-10-4 Standard 158 * Standard organic treatment, Series A, was 2 tons per acre .of dried lespedeza sericea applied in late winter and 6 tons of green crotalaria in late summer. It may be noted in the foregoing data that the standard organic materials with no commercial nitrogen added resulted in yields 73 per cent as high as yields from 60 pounds of nitrogen in the commercial fertilizer. One hundred pounds of commercial nitrogen gave a yield of 25 per cent above the yield from the 60 pounds in the 6-10-4 application. The combination of 60 pounds per acre of commercial nitrogen and the standard organic treatment resulted in a 53 per cent higher yield than that from the 60 pounds of commercial nitrogen without added organic materials. Thus, it TABLE 5. AVERAGE YIELDS AND YIELD INCREASES BY SEASONS AND YEARS FROM USE OF IRRIGATION, ORGANIC MATERIALS, FERTILIZER RATES, SERIES A AND Treatments Fertilizer, 6-10-4 per acre Or materials Yields and increases in yields per acre by seasons Fall crops2 all years Without With Increase from irrigation irrigation' irrigation Pounds 4,136 9,516 5,380 6,936 11,497 4,561 2,800 1,981 Pounds 6,441 12,725 6,284 10,449 16,977 6,528 4,008 4,252 Pounds 2,305 3,209 904 3,513 5,480 1,967 1,208 2,271 Without irrigation Pounds 2,267 6,800 4,588 5,283 9,500 4,217 8,016 2,700 Spring crops 3 all years With Increase from irrigation irrigation Pounds 3,392 8,632 5,240 6,540 12,900 6,360 3,148 4,268 Pounds 1,125 1,832 707 1,257 8,400 2,1483 132 1,568 r* w Pounds 500 0 500 Standard Increase from organic materials 1,000 1,000 0 Standard Increase from organic materials D A C C a I- Increase from fertilizer without organic materials Increase from fertilizer with organic materials F x m 'Two 'One (Continued) z --i m 0 tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. ' Fall crops consisted of broccoli, lettuce, tendergreen, and turnip. 8 Spring crops consisted of beans, cabbage, and potatoes. inch of water per week was applied when rainfall during previous week had not supplied that amount. z 0 TABLE 5. (Continued) Treatments AVERAGE INCREASES BY SEASONS AND YEARS FROM USE OF IRRIGATION, YIELDS AND MATERIALS, AND FERTILIZER RATES, SERIES A YIELD ORGANIC z C Fertilizer, 6-10-4 per acre Organic materials 1 Yields and increases in yields per acre by seasons All crops all years Summer crops' all years With Without Increase from With s Without irrigation irrigation irrigation irrigation irrigation Pounds 4,289 8,461 4,172 6,818 10,319 3,501 Pounds 5,820 9,127 3,807 7,918 10,542 2,629 Pounds 1,031 666 -- 865 1,095 228 -872 Pounds 3,551 8,206 4,655 6,180 10,309 4,129 Pounds 4,947 9,945 4,998 8,074 13,061 4,987 m Increase from irrigation Pounds 1,896 1,739 34 1,894 2,752 858 498 1,013 0 Pounds 0 500 500 Standard Increase from organic materials 1,00 1,000 0 Standard Increase from organic materials 0 Increase from fertilizer 3,127 2,629 64 2,593 2,529 without organic materials Increase from fertilizer 3,116 2,103 ---448 1,415 1,858 with organic materials xTwo tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. SSummer crops consisted of corn, lima beans, squash, and sweetpotatoes. 8 One inch of water per week was applied when rainfall during previous week had not supplied that amount. 18 ALABAMA AGRICULTURAL EXPERIMENT STATION would appear that the nitrogen in the organic materials played a considerable role in the total effects of the organic materials. INDEPENDENT EFFECTS OF IRRIGATION, ORGANIC MATERIALS, AND FERTILIZER RATES. The comparative effects of irrigation, organic materials, and fertilizer rates as independent factors may be noted in Appendix Table 4. When the effect of each practice was measured without the presence of either of the other two practices, all 12 crops in Series A produced yield increases from use of organic materials and from increased applications of fertilizers. These yield increases were obtained in years of high response as well as the average for all years. Similarly, yield increases were obtained with all 12 crops from use of irrigation for the years of high response, while, for the average of all years, 10 of the 12 crops produced increases in yields. The relative effects of the three treatments for each season and for the average of all seasons for all years are shown in Table 5. Irrigation increased the average yield of the 12 crops for all years 1,396 pounds, organic materials increased the yield 4,655 pounds, while additional fertilizer increased the yield 2,629 pounds. For the fall crops, including all years, irrigation increased the average yield 2,305 pounds, organic materials 5,380 pounds, and extra fertilizer 2,800 pounds per acre. For the spring crops (all years), the increases were 1,125 pounds from irrigation, 4,533 pounds from the organic materials, and 3,016 pounds from the extra fertilizer. In the case of summer crops (all years), the increases were 1,031 pounds from irrigation, 4,172 from organic materials, and 2,529 pounds per acre from the extra fertilizer. In evaluating these results, it must be kept in mind that with organic materials the increases were measured from a base of zero materials added, whereas with fertilizer the increases were measured from a base application of 500 pounds per acre of a complete fertilizer and with irrigation the gains were measured from a base of the water supplied by natural rainfall. EFFECTS ON YIELDS OF IRRIGATION, ORGANIC MATERIALS, AND FERTILIZER RATES USED IN COMBINATIONS. The effects on yields of the three practices, including interaction between the treatments, when used in combination were quite different from the effects of each used separately (Table 5). When each practice was used in combination with the other two practices, the average increases in yield of all crops in Series A for all years were as follows: 2,752 pounds per acre from irrigation over no irrigation, IRRIGATION STUDIES with VEGETABLE CROPS 19 4,987 pounds from organic material over no organic applications; and 3,116 pounds from 1,000 pounds over 500 pounds per acre of fertilizer. Making the same comparisons by seasons it may be noted (Table 5) that even more pronounced gains resulted from the combined treatments on fall and spring crops. On the other hand, the increases in yields of summer crops were less when used in combination with the other two practices than when used alone. Increases from irrigation, organic materials, and extra fertilizer were as follows: Fall crops, 5,480 pounds, 6,258 pounds, and 4,252 pounds; spring crops, 3,400 pounds, 6,360 pounds, and 4,268 pounds; and summer crops 223 pounds, 2,629 pounds, and 1,415 pounds. Effects on yields from the three treatments have shown considerable interaction; that is, the effects of the two or three treatments used in combination were different from the sum of the effects of the two or three treatments used separately (Table 5). The nature of the interaction has varied among crops and especially among seasons. For example, the average increases in yields resulting from irrigation and organic materials used in combination were higher than from the sum of two practices used separately for all fall crops, for all spring crops, and for the average of all crops all seasons, but were lower for summer crops. Furthermore, where average increases in yield were larger from the combination of irrigation and organic materials than those from the two treatments used separately, the average increases were larger from the higher fertilizer rate than from the lower fertilizer rate. Irrigation and higher fertilizer rates, likewise, gave higher average increases in yield from the two practices used in combination than from the two used separately for all fall crops, all spring crops, and all crops all seasons. Yield increases of summer crops from the combination averaged lower than the sum of increases from the two practices used separately. Data for tendergreens (Appendix Table 4) illustrate the combined effects of irrigation and organic materials. Tendergreens for years of high response gave an increase of 12,006 pounds per acre from separate use of irrigation and organic materials (4,390 pounds 7,616 pounds), whereas the increase from the two practices used in combination was 13,990 pounds (18,515 pounds - 4,525 pounds). The difference in the increases was 1,984 pounds per acre. It should be noted that the same difference, 1,984 pounds, is obtained by subtracting the yield increase obtained when each + 20 ALABAMA AGRICULTURAL EXPERIMENT STATION practice is used separately from the increase obtained when each is used in combination with the other practice (6,374 pounds - 4,390 pounds = 1,984 pounds; and 9,600 pounds - 7,616 pounds 1,984 pounds). Considering all years all crops, Series A, at the 500-pound fertilizer rate, beans, lettuce, corn, potatoes, tendergreen, and turnips gave larger increases from the combination of irrigation and organic materials than from the two practices used separately; at the 1,000-pound fertilizer rate, beans, cabbage, lettuce, potatoes, tendergreen, and turnips gave higher yields from the combination. Broccoli, cabbage, lima beans, and squash at the 500-pound fertilizer rate and sweet potatoes, broccoli, onions, and squash at the 1,000-pound rate yielded smaller increases from the combination than from the two practices used separately. For all crops all years (Table 5), the increases in average yield per acre from the use of irrigation and organic materials in combination were 343 pounds per acre higher at the 500-pound fertilizer rate and 858 pounds higher at the 1,000-pound rate than the total of the increases from separate use of the two practices. The corresponding increases for fall crops in favor of the combinations were 904 pounds and 1,967 pounds, and for the spring crops 707 and 2,143 pounds per acre at the lower and higher fertilizer rates, respectively. Increases in the average yield per acre of all 12 crops for all years from the use of irrigation and extra fertilizer in combination were 498 pounds higher without the organic treatment and 1,018 pounds higher with the organic treatment than the total of the increases from use of the two practices separately. The corresponding increases for the fall crops in favor of the combination were 1,208 pounds without and 2,271 pounds per acre with the organic treatment, and for the spring crops 132 without and 1,568 pounds per acre with the organic treatment. Failure of the practices to give higher increase in yield when used in combination than when used separately occurred when one or more of the practices failed to give increases or when one or more of the practices gave excessive increases, as may be noted in the case of cabbage (Appendix Table 4, page 53). Although the increases in yield resulting from two or more of the treatments used in combination were not higher for summer crops than from the use of the treatments separately, yields continued to increase from use of each successive treatment. For example, the average yield of all summer crops for all years was IRRIGATION STUDIES with VEGETABLE CROPS 21 4,289 pounds per acre at the lower fertilizer rate without irrigation and without organic materials added, whereas the average was 10,542 pounds per acre at the higher fertilizer rate with both irrigation and organic materials added. The increase, however, from irrigation after the extra fertilizer and organic materials had been added was very low. CUMULATIVE EFFECTS OF INTENSIVE PRACTICES. Data in Appen- dix Tables 6 and 7 for certain treatments have been arranged in graphic form, Figures 3, 4, and 5, to show the cumulative effects of applying intensive practices. It may be seen from the graphs that yields continued to increase in most instances as successive treatments were added. Irish potatoes illustrate the point under discussion. Yields of potatoes by treatment were as follows: no treatment, 28 bushels; 500 pounds per acre of fertilizer, 80 bushels; 1,000 pounds of fertilizer, 115 bushels; 1,000 pounds per acre of fertilizer plus the standard organic treatment, 162 bushels; and 1,000 pounds of fertilizer, standard organic treatment, plus irrigation, 229 bushels. The yields are for all years. Data for other crops in Series A show similar increases except in the case of winter onions, which gave no increase from irrigation. In Series B, Figure 5, it will be noted that yields continued to increase as treatments became more and more intensive. In the case of some crops, however, the higher rates of fertilizers, 1,500 and 2,000 pounds, failed to increase yields to any extent. EFFECTS OF DIFFERENT RATES OF IRRIGATION Only a very limited amount of work has been done on irrigation rates. Yields from three treatments are given in Table 6. All treatments included 1,000 pounds per acre of fertilizer and the standard organic treatment for Series A. Irrigation in the three treatments consisted of 0, 1, and 2 inches per week. In each instance the yield was reduced by the higher rate of irrigation. EFFECTS OF DIFFERENT KINDS OF ORGANIC MATERIALS WITH IRRIGATION Yields from different organic materials used with irrigation are given in Tables 7 and 8. When used on crops under irrigation, the standard organic materials in Series A, Table 7, (2 tons of dry lespedeza sericea and 6 tons of green crotalaria) resulted in INJ TABLE 6. EFFECTS OF DIFFERENT AMOUNTS OF IRRIGATION ON YIELDS, SERIES A Treatments Fertilizer, per acre Lb. 1,000 1,000 1,000 Increases 6-10-4 Yields per acre of different vegetables Beans, lima Irrigation 2 total materials Standard Organic 1 per week Inches 0 1 2 summer, 1938-40 Bushels 125 133. 128 -5 Beans, bush total spring, 1938-41 Bushels 111 156 189 -- 17 Onion total winter, 1938-41 Pounds 7,949 7,957 7,345 -612 Potatoes total spring, 1938-41 Bushels 162 229 225 Turnip total fall, 1938-41 Pounds 18,432 25,516 22,240 -- 3,276 0- Standard Standard heavier over irrigation. lighter from -4 C -I C m x m 'nand Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. 2 inches of water per week were applied when rainfall during previous week had not supplied one inch. m z -{ 0 z Z z TABLE 7. EFFECTS oF DIFIERENT ORGANIC MATERIALS WITH IRRIGATION, SERIES A Treatments FertilizerrrigaBeansCorn, 6-10-4 tion Organic Yields per acre of different crops buis, otal per acre Lb. 1,000 1,000 1,000 1,000 per week= In. 1 1 1 1 materials 2 1938 41 Bug. 0 Standard Vetch Cowpeas 91' BroccoliGabbage, sweet, Lettuce, heads, heads, mkt. ears, total, fall spring Spring, fall 1946-481942-45 summer 1946-4 1946-48g1943-45 Lb. Lb. Doz. Lb. 9,091 515 7,280 2,408 4,161 2,848 3,858 20,281 10,882 15,387 809 799 666 17,050 9,542 10,637 Onion, total Potatoes, potatoes, total, Sweet- Tender winter'spring 38-41 11938-41 Lb. 3,822 7,957 4,316 5,116 Bu. 130 229 265 189 total, summertoal, green, -Turnip, total, fall m Bu. 373 415 416 372 Lb. 13,494 21,180 17,287 17,507 Lb. 18,615 25,516 23,976 22,255 0 156 196 116 1'One inch of water per week was applied when rainfall during previous week had not supplied that amount. 2 Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. Vetch and cowpeas were grown in plots and turned under. iw POUNDS BUSHELS 12000 240 160 '4'80 8000 4000 0 BROCCOLI 2 YR.AV. (LB.) BEANS 4YR.AV.(BU.) 0 A C C 4 ONIONS YR AV(LB.) POTATOES 4YR AV (BU) m x -o m Treatments same as in Figure 4 z Figure 3. Cumulative effects of intensive practices on crop yields, Series A. POUNDS BUSHELS PO z 20,000n40.0... L . 00 Li.....600L -"0i4 :C., 400 A -. F ua ivi n 0T p; c.ce on iii:l c ' ' .iedseie '-= s Aiiii .. "'= "',0 - ......... ( !i i ii ti ^ ii iiiTC :-. .. ',.M:.... ,:-.:M M i"+ ii i~iir ! ii... SL ...... . . ....... ... .. ..... 7 7 00 Ra '1 iiiihiii ~,~~~~~~~" LETTUCE CABBAGE , ii .l. iii TURNIPS TENDERGREEN SWEET POTATOES 2YR.AV.(LB.) NO 500 LB. TREATENT.-10- 4YR. AV.(LB.) 10,O00LB. 6-10-4 3YR. AV. (LB) 100O00LB. 3YR.AV. (BU.) 6-10-4 r 4YR. AV. (LB.) 1000 LB. 6-10-4 PLUS STANDARD ORGANIC AND IRRIGATION PLUS STANDARD ORGANIC Figure 4. Cumulative effects of intensive practices on crop yields, Series A. O'4 BUSHELS DOZEN EARS 480- IS57:7:: 1360 7557 360 240- 1020 680 120 0 4YR.AV. 11 OES (BU.) 1000OLB. -I c ;':::: ~ +, r :40 3/ r- m POLE BEANS 4YR.AV.(BU.) SWEET CORN 4 YR. AV. (DOZ.) TOMATOES 4 YR. AV. (BLL) 6-10-4 PLUS VETCH , 12 x m m z -4 NO TREATMENT 1000 LB, 6-10-4 6-1 -10-4 IOOOLB. 6-10-4 1000LB. 6-10-4500LB. PLUS VETCH, 12 TONS PLUS VETCJH PLUS VETOCH, 12 TONS MANURE MANURE, IRRIGATION MANURE, IRRIGATION TONS 0 Figure 5. Cumulative effects of intensive practices on crop yields, Series. B. z IRRIGATION STUDIES with VEGETABLE IRRIGATION STUDIES with VEGETABLE CROPS CROPS 27 27 most of the crops producing as high or higher yields than where either vetch or cowpeas were grown and turned under. Vetch resulted in higher yields of spring potatoes and beans. On the other hand, there was little difference between the yields of sweetpotatoes and sweet corn from the standard organic materials and from vetch. In Series A, yields of all other crops resulting from the standard organic treatment were higher than those resulting from vetch. In all instances, yields from the standard organic materials were higher than from cowpeas, although the difference was not very great in the case of turnips. In Series B, Table 8, higher yields were consistently obtained from 12 tons per acre of animal manure than from vetch or rye. Rye grown and turned under gave about the same increases as vetch. Yields from a combination of 6 tons of animal manure and vetch or of 6 tons of animal manure and rye were not quite as high as from 12 tons of manure. Twelve tons of animal manure and vetch produced higher yields of tomatoes and corn than 12 tons of animal manure alone. The yields of beans and potatoes were not increased by the addition of vetch to the animal manure. EFFECTS OF IRRIGATION AND ORGANIC MATERIALS ON GRADE OF PRODUCTS Discussions and data presented to this point have been largely confined to gross effects of treatments. No data have been presented pertaining to effects of treatments on grade. Results in Tables 9, 10, 11, and 12 relate to effects of irrigation on the grade of a few selected crops. The crops chosen were those that permitted more specific measurements of differences, and included sweet corn, potatoes, sweetpotatoes, and tomatoes. In Table 9 data are given for the number of dozen ears of marketable corn harvested, percentage of marketable ears, and average weight per dozen marketable ears from different organic treatments with and without irrigation. The data are for the year of highest response to irrigation, for the 2 years of high response, and for the 4-year average. The increases from irrigation of corn receiving different organic treatments ranged from 413 to 986 dozen ears of marketable corn in 1948; the increases ranged from 274 to 646 dozen ears for the 1944 and 1948 average; and from 117 to 256 dozen ears for the 4-year period. The increases in percentages of marketable-ears resulting from irrigation with different organic treatments varied from 15 to 36 per cent in 1948, from 11 to 24 per cent in 1944 and TABLE 8. EFFECTS OF DIFFERENT ORGANIC MATERIALS WITH IRRIGATION, SERIES B Treatments Fertilizer, 6-10-4 per acre Pounds 1,000 1,000 1,000 1,000 1,000 1,000 1,000 2Gee Yields per acre of different crops Manures Greene Beans, hole, tota, fall, 1944, 1946-48 Bushels 170 286 154 199 202 214 202 Corn, sweet, marketable ears, Irrigation per week' peAnimal Inches 1 1 1 1 1 1 1 Tons 0 12 0 0 6 6 12 Potatoes, total, Tomatoes, spring, total, 0 0 Vetch Rye Vetch Rye Vetch 1944,1946-48 Dozens 680 1,088 653 817 1,088 1,017 1,190 summer, 1940-48 Bushels 64 109 76 76 89 82 103 fall, 1940-43 Bushels 427 714 550 470 722 652 785 II- m m;m z G/) 'One inch of water per week was pSle when rainfall during previous week had not supplied that amount. manure crops were grown and turned under. a z TABLE 9. EFFECTS OF IRRIGATION ON NUMBER OF MARKETABLE EARs PRODUCED, PERCENTAGE OF MARKETABLE EARs, AND WEIGHT PER DOZEN EARs OF SWEET CORN WITH AND WITHOUT DIFFERENT ORGANIC MATERIALS, SERIES B Treatments Fertilizer, 6-10-4 Animal per per acre acre Legume Manures Marketable ears 0 E-I OIn 0 Green'Nonlegume Number marketable ears Without With Increase irriirrifrom irrigation gation gation Weight ears per dozen Percentage marketable ears Without With Increase Without With Increase irriirrifrom irriirriirrifrom irrigation gation gation' gation gation gation -1 'cU' Lb. 13,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 000 1, 1,000 Tons 0 12 0 0 12 0 12 0 0 12 0 12 0 0 12 0 0 Vetch 0 Vetch 0 0 Vetch 0 Vetch 0 0 Vetch 0 Vetch 0 0 0 Rye Doz. 0 0 0 0 Rye 0 0 0 0 Rye 0 Pct. Doz. Pct. Doz. Year of highest response, 1948 64 413 42 400 813 77 786 41 667 1,453 39 66 1,147 667 480 74 507 59 783 1,240 76 986 53 787 1,773 Average for years of high response, 1944, 1948 38 57 353 660 307 76 773 1,280 507 52 685 1,080 395 49 66 57 '68 927 274 653 940 1,586 Average for 646 63. 78 Pct. 22 36 27 15 23 16 24 17 Lb. 5.24 6.24 6.36 6.39 6.95 6.51 7.98 Lb. 6.79 8.19 7.87 7.43 8.10 7.38 9.00 8.29 Pct. 30 31 24 16 17 13 13 9 9 15 5 7 8 2 14 0 r m n 0 11 15 13 12 10 9 0 7.63- 7.27 7.76. 5.86 7.61 7.38 7.17 7.41 7.93 8.93 6.13 8.15 8.00 7.31 8.43 all 1944, 1946-48 years, 217 256 128 117 253 47 58 48 58 66 60 70 58 67 66 413 827 525 700 937 630 1,083 653 817 1,190 2'One inch of water per week was applied when rainfall during previous week had not supplied that amount. figures represent differences in percentage and not percentage difference. 'Green manure crops were grown and turned under. 'The N, 30 ALABAMA AGRICULTURAL EXPERIMENT STATION 1948, and from 0 to 13 per cent for the 4-year average. Percentage increases in the weight per dozen of marketable ears ranged from 16 to 31 per cent in 1948, from 9 to 15 per cent in 1944 and 1948, and from 2 to 14 per cent for the 4-year average. Irrigation of corn, therefore, gave differences in the percentage of marketable ears and in the average weight per dozen ears which followed closely the differences in yields. Total yields, yields of No. l's, yields of marketable (No. l's and No. 2's), percentage of No. l's, and percentage of marketable fall Irish potatoes are given in Table 10. Without organic treatment and without irrigation, the percentage of No. 1 potatoes for the years of high response was only 9 per cent of the total yield; irrigation increased the No. I's to 45 per cent. With animal manure added, irrigation increased the percentage of No. 1 potatoes from 32 to 46 per cent; with vetch added, the increase from irrigation was from 15 to 46 per cent; with rye added, from 11 to 57 per cent; and with both animal manure and vetch added, from 42 to 53 per cent. The increases in percentages of No. l's from irrigation for the 4 years were smaller but consistent. Total yield, yield of marketable, and percentage of marketable tomatoes are given in Table 11. There was not much difference between the percentages of tomatoes meeting the requirements of marketable grades produced with irrigation, and those grown without irrigation. This was true even in years of highest response. Total yields, yields of marketable grades, yields of the jumbo grade, percentage of marketable grades, and percentage of jumbo grade of sweetpotatoes are given in Table 12. Substantial increases in yield of total and of marketable grades were obtained from irrigation with all treatments. Contrary to expectations, there was no increase in the yield of jumbo grade from irrigation. Small but consistent increases in the percentage of marketable potatoes were obtained from irrigation in years of high response and for the average of all years. The percentages of the jumbo grade were somewhat less for all treatments receiving irrigation than for those not receiving irrigation. RESULTS WITH INDIVIDUAL CROPS Data on total yield and yield of the used portions, where different from the total, are given in Appendix Tables 6 and 7 for each of the 16 crops in both series for all treatments. The data are the averages of all years and for selected years of high TABLE 10. EFFECTS OF IRRIGATION ON YIELDS AND GRADES OF FALL-GROWN POTATOES WIrH AND WITHOUT DIFFERENT ORGANIC MATERIALS, SERIES B O z C Treatments FertiManures lizer, 6-10-4 Animal per Green' per acre acre Total Without irrigation Average yields per acre No. With irrigation' I's Yields in percentage Marketable No. I's Marketable m Without irrigation With irrigation Without irrigation With irrigation Without irrigation With irrigation Without irrigation With irrigation m 0I Pct. Pct. Bu. Bu. Bu. Bu. Average for years of high response, 1940-41 9 45 44 14 2 25 56 22 0 0 1,000 46 71 32 12 6 48 93 19 12 0 1,000 46 15 49 13 30 3 20 65 0 Vetch 1,000 57 11 9 50 33 2 58 18 0 Rye 1,000 53 42 83 15 51 10 24 97 12 Vetch 1,000 Average for all years, 1940-43 27 44 50 27 28 64 10 37 0 1,000 0 50 87 43 40 54 109 22 50 0 1,000 12 46 34 59 35 30 14 76 41 0 Vetch 1,000 50 30 62 28 12 38 76 40 0 Rye 1,000 47 54 87 56 39 23 49 103 12 Vetch 1,000 manure crops were grown and turned under. 1Green 2 One inch of water per week was applied when rainfall during previous week had not supplied that amount. Lb. Tons Bu. Bu. Pct. 64 63 65 50 63 78 80 73 70 80 Pct. 79 76 75 85 86 78 80 78 82 84 m A 0 N, w TABLE 11. EFFECTS OF IRRIGATION ON YIELDS AND GRADES OF TOMATOES WITH AND WITHOUT DIFFERENT ORGANIC MATERIALS, SERIES B Treatments Manures Fertilizer 6-10-4 Animal Green per acreAnimal Green Lb. 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 Tons 0 12 0 0 12 0 12 0 0 12 0 0 Vetch Rye Vetch 0 0 Vetch Rye Vetch Average yields per acre Total yields Without With igation irrigationrrgat Marketableyields Without With irrigationon Bu. Bu. Bu. Bu. Average for years of high response, 1942-43 218 466 252 815 476 869 709 467 461 697 301 582 846 871 548 427 714 550 470 785 134 338 168 195 827 246 507 822 807 485 188 405 203 247 861 284 493 854 320 538 Percentage marketable Without irrigation Pct. 61 71 67 62 69 67 72 69 67 70 With irrigation Pct. 62 70 59 67 66 67 69 64 68 69 I> w Average for all years, 1940-43 1. -I C c C P P m x *a m 'One 1Green manure crops were grown and turned under. inch of water per week was applied when rainfall during previous week had not supplied that amount. z -1 -4 0ml z: TABLE 12. EFFECTS OF IRRIGATION ON YIELDS AND GRADES OF SWEETPOTATOES FROM DIFFERENT RATES OF FERTILIZER WITH AND WrToUT ORGANIC MATERIALS, SERIEs A Average yields per acre Percentage Ttl aktbeJumbos Marketable Jumbos Without With Without With Without With Without With Without With i irri - irri - irri- i rriirriirriirriirriirrigation gation' gation gation gation gation gation gation gation gation Bu. Bu. Bu. Bu. Bu.. Bu. Pct. Pct. Pct. Pct. Average for years of high response, 1944-45 212 244 168 196 0 80 77 0 821 899 260 347 15 81 0 87 282 373 230 317 0 8285 0 387 424 831 884 1 7 86 91 TtalMaketbl C m Treatent ____________ pop FertilizerOrai 6-10-4 Oatraic per acre mtras ~ Lb. 500 500 1,000 1,000 500 500 1,000 1,000 0 Standard 0 Standard 0 Standard 0 Standard 0 m m rI m IMn Average for all years, 1943-45 229 0 5 81 83 348 8 87 9 79 320 12 7 82 86 364 Y T~~~ 80 FL~ 23 83 88 ~IYT~~rrY ~-LIPTII~T ~IY~ITP ~~ RI~~ 'Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. 2'ninch of water per week was applied when rainfall during previous week had not supplied that amount. 232 352 309 383 277 399 378 415 189 279 253 317 0 11 4 8 2 2 2 6 34 ALABAMA AGRICULTURAL EXPERIMENT STATION response. Rainfall data by semi-monthly periods for each year of the investigation are given in Appendix Table 1. Dates of planting and number of irrigations applied to each crop are given in Appendix Table 8. Data in these tables will permit detailed study of response to the treatments of any crop and the relation of response to rainfall. EcoNomic STUDIES Yield differences from treatments have been the only basis on which values have been measured in the data presented to this point. In the final analysis, the grower is concerned with dollar return for dollar outlay. Experiments were, therefore, conducted as part of this study to measure the cost of production, labor requirements, and returns obtained from crops grown under irrigation. These studies have been briefly outlined under "Methods and Materials." The data from this phase of study are used as a basis for computing the value of increased yields obtained from irrigation in the field-bin studies. COSTS, LABOR REQUIREMENTS, AND RETURNS FROM CROPS GROWN UNDER IRRIGATION. Results obtained on costs, labor requirements, and returns from crops grown under irrigation are based on experiments conducted in 1946 and 1947 on a field basis. Pole beans, sweet corn, lima beans, and fall Irish potatoes were grown both years. A number of other crops were grown one year. Several successions of pole beans and corn were grown. Each succession was treated as a separate set of data. Preparation of land was done with mules; hauling of manure was by truck; irrigation was done with a portable irrigation system; and planting, dusting, and harvesting were done by hand. The capacity of the pump was 180 gallons per minute; the main and lateral pipes were 3 inches in size; and the 10 sprinklers each had a capacity of 18 gallons per minute. Theoretically, 0.53 acre was irrigated at one setting of the system. Three men moved the sprinklers to a new setting in 20 minutes. Theoretically, 2.5 hours of continuous pumping was required to deliver one acreinch. The studies show that considering loss of time for servicing pump and engine, placing the engine and pump, priming the pump, laying the pipes, and moving the laterals and sprinklers, 3.65 hours were required to deliver one acre-inch. Three acreinches were, therefore, delivered in approximately 11 hours. Labor IRRIGATION STUDIES with VEGETABLE CROPS 35 was used for other work when not engaged in moving the pipes and sprinklers from one position to another. It should be emphasized that this phase of the work does not show the effects of irrigation; it only shows data on costs and labor requirements of producing crops under irrigation. Records from field bins necessarily were used to determine the amount of increases from irrigation and the estimated value of increases. Data on labor and equipment requirements and costs of applying one acre-inch of water for three crops of pole beans, five crops of sweet corn, and one crop each of lima beans and fall potatoes are given in Table 13. On a basis of 10 crops, the average cost per acre-inch of applying irrigation at prevailing farm wages and material costs at the time of the experiment was $5.56. This does not include a charge for upkeep and amortization of the pond. Data on costs, labor requirements, yields, and returns from production of three crops of beans, five crops of sweet corn, and one crop each of lima beans and potatoes are given in Table 14. Data on pole beans may be used to illustrate use of the table. The average yield per acre of beans was 412 bushels, the cost $825.54, and the gross sale value $1,235. The value above cost of beans was $409.46 per acre. An average of 32/3 inches of irrigation was applied at a cost of $21.43. Data for the other crops are given in the table. It will be noted that irrigation costs for beans were only 2.60 per cent of the total cost of producing and harvesting the crop, for corn 10.68 per cent, for lima beans 4.36 per cent, and for TABLE 18. LABOR REQUIREMENTS, EQUIPMENT TIME, FUEL CONSUMPTION, TOTAL COST PER ACRE-INCH OF IRRIGATION AND Items Beans, pole (3-crop av.) 5.45 3.80 7.60 0.24 Corn, Beans Weighted Potatoes average lima sweet (5-crop (1-crop) (1-crop) of av.) 10 crops 3.60 3.50 7.08 0.26 7.49 3.80 8.00 0.20 7.77 3.80 7.67 0.33 4.96 3.65 7.39 0.26 Cost Per unit Dol. 0.35 0.50 0.26 0.25 Total Dol. 1.74 1.83 1.92 0.07 5.56' Labor, hours Equipment, hours Gasoline, gallons Oil, quarts TOTAL The amount of this charge would generally range from 10 to 25 cents per acre-inch, 4 This amount does not include charge for upkeep and for amortization of pond. assuming one-half of cost is charged to fishing and recreation and one-half to irrigation. 36 ALABAMA AGRICULTURAL EXPERIMENT STATION TABLE 14. COSTS, LABOR REQUIREMENTS, YIELDS, RETURNS, IRRIGATION GIVEN AND IRRIGATION COSTS PER ACRE IN PRODUCING VEGETABLE CROPS UNDER IRRIGATION Data by crops per acre Items Beans, pole Corn, sweet Beans, lima Potatoes, 1947 (3-crop av.) 1946-1947 (5-crop av.) 1947 (1 crop) Fall, 1947 (1 crop) Labor, man hours Total Harvesting Irrigating Yields harvested, bushels 1,675 1,032 20 412 131 50 9 8571 576 499 15 153 154 44 23 204 Total costs, dollars Value of products, dollars Value above cost, dollars Irrigations, average number Cost of irrigation,2 825.54 1,235.00 409.46 3.67 119.78 296.53 176.75 2.60 304.95 459.00 154.05 2.00 239.28 428.40 189.12 3.00 average, dollars Cost of irrigation in relation to total, per cent SAverage 21.43 2.60 12.79 10.68 13.80 4.36 20.07 8.39 1 Sweet corn yields were in dozen ears per acre. amortization. cost per acre-inch of irrigation was $5.56 without charge for pond fall potatoes 8.39 per cent. The total cost of applying 29 acreinches of water to the 10 crops was $161.24. On the basis of an average of 4.89 acre-inches per crop (Appendix Table 8) and a cost of $5.56 per acre-inch (Table 13), the average cost per crop of irrigation was $27.19 per acre. RETURNS FROM USE OF IRRIGATION AND ORGANIC MATERIALS. In Appendix Tables 9 and 10 are given data on the gross value and value above cost of the practice or practices for increases obtained from irrigation with and without organic materials, from organic materials with and without irrigation, and from both practices for each of the crops in Series A and B. Data in Appendix Table 9 are for the year or years of high response, and results in Appendix Table 10 are for all years. The fertilizer rate was 1,000 pounds per acre. The standard organic treatment in Series A consisted of 2 tons of lespedeza sericea applied in late winter and 6 tons of crotalaria applied in late summer, while 12 tons of animal manure was the standard organic treatment in Series B. IRRIGATION STUDIES -with VEGETABLE CROPS 37 Cost data obtained on the field plots were used in calculating the cost of the practices. The data on increases in yields are derived directly from the bin experiments and are, therefore, basic under the conditions of the experiment. The data on gross and net values of increases are based on assumed values2 and would, therefore, vary with prices assumed. In Table 15 is given a summary of the data in Appendix Tables 9 and 10. The table gives average values for crops by seasons for all years, average values for all crops all years, and average values for all crops for the years of high response to irrigation. Considering all crops all years, the value above cost of the practices was $34.86 per acre from irrigation without organic materials, $50.79 from irrigation with organic materials, $135.19 from organic materials without irrigation, $151.12 from organic materials with irrigation, and $185.98 from use of both treatments. The returns above cost of irrigation for the increased yields from use of irrigation for fall crops were $67.22 without and $125.55 with organic materials, and for the spring crops $6.25 without and $75.81 with organic materials. Summer crops returned $36.28 above costs for the increased yields from use of irrigation without organic materials and only $16.78 with organic materials added. The average values above cost of the treatment for the increased yields resulting from irrigation with organic materials added were $125.55 for fall crops, $75.81 for spring crops, and $16.78 for summer crops, and $50.79 for all crops. The returns above cost of irrigation for the increase for all crops for years of high response to irrigation was $120.64. It has been pointed out earlier that increases in yield under certain conditions and at certain seasons were larger from use of the practices in combination than from use of the practices separately. It is pointed out that yield increases from use of practices in combination over those from practices used separately are made with no extra cost, since the cost of each practice is charged separately. The values of these yield increases are therefore net values. These increases in value amounted to $58.33 for all fall 2 In arriving at the value of increased yields, the following farm prices for products were used: beans and lima beans, $2.40 per bushel; tomatoes, $2.00 per bushel; potatoes, $2.10 per bushel for No. 1 grade and $1.05 for No. 2 grade; sweetpotatoes, $2.50 per bushel for No. 1 grade and $1.25 for No. 2 grade; sweet corn, 80 cents per dozen ears; broccoli, 10 cents per pound; cabbage, 2 cents; lettuce, 4 cents; onions, 6 cents; squash, 8 cents; tendergreen, 2 cents; and turnips, 2 cents. 38 ALABAMA AGRICULTURAL EXPERIMENT STATION crops all years, $69.56 for all spring crops all years, and $15.92 for all crops all years. Returns were $19.58 less from the combination than from the two practices used separately for all summer crops all years. Irrigation without organic materials failed to give increases in yield sufficient to justify the cost of application (average of all years) on lima beans, snap beans, sweet corn (Series A), onion, spring potatoes, and squash (Appendix Table 10). Lima beans, sweet corn (Series A), onions, squash, and tomatoes failed to TABLE 15. GROSS VALUES AND VALUES ABOVE COSTS PER ACRE OF PRACTICES FROM YIELD INCREASES RESULTING FROM DIFFERENT TREATMENTS AT DIFFERENT SEASONS Values of increases for different seasons and different treatments' Bases of values From both From From organic irrigation2 materials 3 irrigation anic With With Without Without organicorganic organic materials materials irrigation irrigation materials Dollars Dollars Dollars Dollars Dollars Fall crops,' all years Gross returns Returns above cost 91.49 67.22 149.82 125.55 156.18 131.13 214.46 189.46 305.95 256.68 Spring crops," all years Gross returns Returns above cost 33.65 6.25 103.21 75.81 112.34 87.34 181.90 156.90 215.55 163.15 Summer crops," all years Gross returns Returns above cost 63.63 36.28 44.18 16.78 165.29 140.30 145.79 120.80 209.42 157.08 All crops,' all years Gross returns Returns above cost 62.98 34.86 78.90 50.79 160.20 185.19 176.12 151.12 289.10 185.98 All crops,' years of high response Gross returns Returns above cost 126.42 98.86 148.20 120.64 170.81 145.81 192.59 167.59 319.01 266.45 SAll crops received 1,000 pounds of 6-10-4 per acre. ' One inch of water per week was applied when rainfall during previous week had not supplied that amount. ' In series A, 2 tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer; in series B, 12 tons per acre of animal manure was applied in late winter. Fall crops consisted of broccoli, lettuce, tendergreen, and turnip in series A. SSpring crops consisted of beans, cabbage, and potatoes in series A. 6 Summer crops consisted of corn, lima beans, squash, and sweetpotato in series A and pole beans, corn, potatoes, and tomatoes in series B. ' All crops included those grown in series A and series B. IRRIGATION STUDIES with VEGETABLE CROPS 39 give increases in yield from irrigation with organic materials sufficient to justify the cost of irrigation. Only lima beans failed to give returns for all years above costs from use of both practices. These comments may be made on the crops and the conditions under which irrigation failed to justify the cost of application. The lima bean responds rather indifferently to good agricultural treatments. It is drought resistant and produces well without much fertilizer and water. The onion was grown during the winter when soil moisture was adequate and moisture requirements were low. Rainfall during the growing period of sweet corn in Series A was favorable 3 of the 4 years of the experiment. Results from irrigation of tomatoes and squash were complicated by difficulties with fruit setting and decay, conditions which seemed to be more aggravated when organic materials were used with irrigation. Crops showing small increases and low returns would be eliminated in practice, while crops showing high returns would be selected. DISCUSSION In few large areas of the world is rainfall more favorable to crop production than in the southeastern United States. Of this area Israelsen (8) says, "In some parts of the Eastern United States the natural rainfall usually supplies enough water to meet all the need of growing crops." The study reported here was conducted in this area where rainfall is so favorable. It is certain that irrigation does not increase yields of all crops every year or every season. The data do show that increases in yield some years are very marked and that the average yields of most crops are increased by irrigation over a period of years. The data show rather conclusively that irrigation, high rates of fertilizer, and organic materials over a period of years accounted for increased yields when used separately. They also show that the effects of the three treatments are cumulative, and that, under certain conditions and during certain seasons, the increases in yield are generally greater when each is used in combination with the other treatments than when used separately. 40 ALABAMA AGRICULTURAL EXPERIMENT STATION RELATION OF CLIMATE TO RESPONSE FROM IRRIGATION That irrigation should not give increased yields each year or season is to be expected. Weather data show that there are great fluctuations in the amount and distribution of rainfall from year to year for the State, from area to area within the State, and from season to season in each area. Likewise, cloudiness, humidity, and wind are variable. The data in Table 4 and Appendix Tables 2 and 3 indicate that there is not a very close relationship between total rainfall during the growing season of a crop and its response to irrigation; the relationship between response to irrigation and the distribution of rainfall, especially the occurrence and length of drought periods, is more pronounced. It would seem that a closer relationship should exist between response to irrigation in a given season and rainfall during that season. When, however, the effects of other factors are considered, it is obvious that the relationship would not be very close. Factors other than available moisture in the soil affect the amount of water used by plants. Miller (14) states that differences as high as 600 per cent may occur in water losses on successive days due to weather conditions. A short period of hot, dry, windy weather may ,cause damage to plants and greatly reduce the photosynthetic efficiency of plants. Thoday (24) found, for example, that the photosynthetic rate of rigid leaves was 10 times that of plants drooping or wilted. Assume identical rainfall in two successive years for a given crop in which one inch of rain fell each week on the same day and that the full amount was absorbed by the soil. Assume, however, that there were in one year a number of periods of low humidity, high temperature, and much wind but few or no such periods in the other year. With an assumed water loss and use during critical periods twice as great one year as the other, it would be obvious that the identical amounts of rainfall might be much below the requirements for maximum production one year but adequate the other year. Irrigation, therefore, would most likely show benefits one year but little or no benefits the other year, even though rainfall were identical and normally adequate. RELATION OF SOIL CHARACTERISTICS TO IRRIGATION NEEDS With other factors favorable, satisfactory growth depends to a considerable extent upon adequate soil moisture. Many factors IRRIGATION STUDIES with VEGETABLE CROPS 41 enter into the complex that determine whether a soil has or will have adequate quantities of available moisture to enable plants to make maximum yields. The water reservoir for growing crops is the capillary moisture of the soil. Soils of a given texture and organic matter content can retain only a certain amount of water. Soils vary greatly in moisture-holding capacity and in availability of moisture they hold. Soils of light texture will normally hold, in available form, water equivalent to about 11/3 inches of rainfall, or about 36,000 gallons per acre in the top 2 feet of soil, those of medium texture about 22/3 inches, and those of fine texture about 4 inches. While young crops draw on the soil for only a limited amount of water, crops at the time of maximum growth draw on the soil for great quantities. For heavy users, this will often amount to as much as 1 inches or about 40,000 gallons of water per acre per week. The moisture reserves of the soil thus may be exhausted within a period of 2 or 3 weeks. The water supply therefore, must be replenished if crops are not to suffer. Rapidly growing crops on light soils usually begin to suffer for water if rain does not fall within 2 or 3 weeks. A study of drought frequencies in Table 2 will reveal the odds that drought periods of 2, 3, or 4 weeks will occur at different seasons of the year at different locations in Alabama. It is during these periods that irrigation serves its purpose of providing water. Since soil moisture held as capillary moisture is lost by evaporation and by transpiration of plants, it may be assumed that three-fourths to one inch per week of water should be available or provided during the early period of growth and from 1 to 11 inches per week during the period of rapid growth if rain has not supplied those amounts. The data show that nothing is gained by irrigation if rainfall supplied such amounts. On the other hand the data show that, when rainfall fails to provide the required amounts, irrigation increases yields and gives higher gross and net returns. EFFECTS FROM USE OF PRACTICES IN COMBINATIONS It has been shown that the effects of successively adding the treatments are cumulative. It has also been shown that, under certain conditions and with certain crops, the effects of one practice are increased when used in combination with other practices. Although the increased yields obtained from the use of two 42 ALABAMA AGRICULTURAL EXPERIMENT STATION practices in combination above those obtained from the two practices used separately is correctly a mutual effect, in practical application the amount of this mutual effect may be attributed to the use of one practice alone if the other is normally used. For example, the value above cost from the use of irrigation was only $6.25 per acre for the average of all spring crops for all years without organic materials; the value above cost was $75.81 from irrigation with organic materials. If a grower generally adds organic materials but not irrigation, irrigation might, therefore, be credited with an increase of $75.81; or if irrigation was planned without organic materials, the addition of organic materials might be given credit for the amount of the mutual effect. While results obtained under the condition of this experiment show, in general, that use of two or more practices in combination gave higher yield increases than use of the practices separately for fall and spring crops, the reverse was generally true with summer crops. More research is needed to determine: (1) whether the particular summer crops used responded differently to treatments than did fall and spring crops; (2) whether there were basic differences in effects of the treatments on the soil during the summer as compared to those during the spring and fall; and (3) whether drought periods during the summer were sufficiently different from those in the spring and fall to account for response differences. IRRIGATION STUDIES with VEGETABLE CROPS 43 SUMMARY The results of irrigation studies with vegetable crops extending over 11 years are reported in this bulletin. The investigation consisted of two phases. One was to measure the effects of irrigation with and without use of other good agricultural practices. The other was to obtain data on costs, labor requirements, and returns from production of crops under irrigation. The basic treatments consisted of applications of irrigation, organic materials, and different fertilizer rates. The following results were obtained: Irrigation gave marked increases some years and little or no increase other years, yields some years being less with than without irrigation. Response to irrigation was more closely related to distribution of rainfall than to the total amount of rainfall during the life of a crop. The average increases in yield of all crops for all years resulting from the use of each practice without either of the other two practices was 1,396 pounds per acre from irrigation, 4,655 pounds from organic materials, and 2,629 pounds per acre from additional fertilizer. When each practice was used in combination with the other two practices, the average increases of all crops all years were 2,752 pounds per acre from irrigation, 4,987 pounds from organic materials, and 3,127 pounds from the higher fertilizer rate. The average increases in yield were higher from use of irrigation and organic materials used in combination than from use of the two practices separately for fall crops, for spring crops and for all crops all seasons, but not for summer crops. Where the increases were higher, the amounts of the increases resulting from the use of irrigation and organic materials in combination over those resulting from the use of the two practices separately were higher at the higher fertilizer rate than at the lower fertilizer rate. The average increases in yield of fall crops, spring crops, and all crops all years were higher from irrigation and extra fertilizer used in combination than from separate use of the two practices. 44 ALABAMA AGRICULTURAL EXPERIMENT STATION Where average increases were higher, the resulting increases from use of irrigation and higher fertilizer rates in combination over those from the use of the two separately were higher with than without organic materials. Effects of treatments were cumulative. Yields, in general, continued to increase as fertilizer rates were increased, organic materials added, and irrigation applied. Limits were approached when 1,000 pounds per acre of a 6-10-4 fertilizer, 12 tons of stable manure, a crop of vetch, and 1 inch of water per week were added. Increasing the fertilizer from 1,000 to 1,500 pounds per acre after all other treatments were given usually resulted in little or no further increase in yield. Irrigation improved the grade and quality and gave higher yields of marketable products. Effects were generally more pronounced in seasons of high response and when organic materials were used with irrigation. The yield of marketable sweet corn (Series B), for the 2 years of high response was increased 307 dozen ears per acre, the percentage of marketable ears was increased from 38 to 57 per cent, and the weight of marketable ears was increased from 6.51 to 7.38 pounds per dozen from irrigation without organic materials. Irrigation when used with 12 tons of animal manure for the same years increased the yield 507 dozen ears, the percentage of marketable ears from 52 to 76, and the weight from 7.98 to 9.00 pounds per dozen ears. Effects of irrigation on the percentage of marketable crop were more pronounced on fall potatoes but less pronounced on sweetpotatoes and tomatoes than on corn. An average of approximately 5 inches (4.89) of irrigation per crop was applied in this study. The number ranged from 3 inches for short-season crops to 9 inches for long-season crops. The cost of applying irrigation under the conditions of the larger field experiment was $5.56 per acre-inch, not including an amortization charge against cost of the pond. For the years of high response to irrigation, the average value of the increased yields above cost of the practices for all crops was $98.86 from irrigation without organic materials, $120.64 from irrigation with organic materials, $145.81 from organic materials without irrigation, $167.59 from organic materials with irrigation, and $266.45 from both irrigation and organic materials. IRRIGATION STUDIES with VEGETABLE CROPS 45 For all crops all years, the average value of the increased yield above cost of the practices was $34.86 from irrigation without organic materials, $50.79 from irrigation with organic materials, $135.19 from organic materials without irrigation, $151.12 from organic materials with irrigation, and $185.98 from both irrigation and organic materials. The average values of the increased yields from irrigation above cost of the practice for all years for fall crops were $67.22 without and $125.55 with organic materials; for spring crops, $6.25 without and $75.81 with organic materials; and for summer crops, $36.28 without and $16.78 with organic materials. LITERATURE (1) (2) C-131. 1948. (3) (4) (5) (6) Irrigation Rpt. 58, p. 104. 1946. Irrigation Rpt. 59, p. 119. 1947. (Horticulture). (Horticulture). Ga. Agr. Expt. Sta. Ann. Ga. Agr. Expt. Sta. Ann. ANONYMOUS. N. Y. 1945. Supplemental irrigation. Irrigation for Oklahoma. Johns-Manville, New York, Okla. Agr. Expt. Sta. Cir. BRIGGS, L. J., AND McLANE, J. W. The moisture equivalents of soils. U. S. Dept. of Agr., Bur. Soils Bul. 45. 1907. CORDNER, H. B. The influence of irrigation water on the yield and quality of sweet corn and tomatoes with special reference to time and number of applications. Proc. Amer. Soc. Hort. Sci. 40: 475481. 1942. GAINES, STANLEY H. et al. Bibliography on soil erosion and soil and (7) (8) water conservation. U. S. Dept, of Agr. Misc. Pub. 812. 1938. ISRAELSEN, O. W. Irrigation principles and practices. and Sons, Inc. New York. 1932. John Wiley (9) JANES, B. E. The effects of varying amounts of irrigation on the composition of two varieties of snap beans. Proc. Amer. Soc. Hort. Sci. 51: 457-462. 1948. (10) KINCER, J. B. Climate and weather data for the United States. U. S. Dept. of Agr. Yearbook : 685-1210. 1941. (11) KING, F. H. Irrigation and drainage. The Macmillan Co., New York. 1922. (12) KRAMER, PAUL J. Plant and soil water relationships. Book Co., Inc., New York. 1949. McGraw-Hill 46 ALABAMA AGRICULTURAL EXPERIMENT STATION (13) LEWIs, M. R. Practical Irrigation. U. S. Dept. of Agr. Farmers' Bul. 1922. 1943. (14) MILLER, E. C. Plant Physiology. McGraw-Hill Book Co., Inc., New York. 1938. (15) NETTLES, V. F. Two years results of the effect of several irrigation treatments on the yield of cabbage and snap beans. Proc. Amer. Soc. Hort. Sci. 51 : 463-467. 1948. (16) , JAMISON, F. S., AND JANES, B. E. Irrigation studies with sweet corn, cabbage, and snap beans at Gainesville. Fla. State Hort. Soc. : 155-160. 1947. (17) PRICHARDS, L. A. AND WEAVER, L. R. Fifteen-atmosphere percentage as related to the permanent wilting percentage. Soil Sci. 56 : 331339. 1943. (18) STAEBNER, F. E. Supplemental irrigation. Farmers' Bul. 1846. 1940. U. S. Dept. of Agr. (19) STALLINGS, J. H. Research summaries and abstracts of recently published material on soil and water conservation. U. S. Dept. of Agr., Soil Cons. Serv. 1945-47. (20) STRAND, A. B. Truck crop investigations in the Douglas Reservoir Area. Tenn. Agr. Expt. Sta. Rpt. 57. pp. 102-103. 1944. (21) (22) (23) (24) Truck crop investigations in the Douglas Reservoir Area. Tenn. Agr. Expt. Sta. Rpt. 58. pp. 149-152. 1945. Horticulture in the Douglas Reservoir Area. Tenn. Agr. Expt. Sta. Rpt. 59. pp. 109-111. 1946. Horticulture in the Douglas Reservoir Area. Tenn. Agr. Expt. Rpt. 60. pp. 121-122. 1947. THODAY, D. Experimental researches on vegetable assimilation and respiration. Proc. Royal Soc. B-82. pp. 421-450. 1910. (25) THORNE, W. D., AND PETERSON, H. B. Irrigated soils. The Blakiston Co., Philadelphia. 1949. (26) TURNBULL, JAMES, et al. Report of the Steering Committee on supplemental irrigation. Mimeog. S. E. Sect. Amer. Soc. Agr. Engin. 1949. (27) WARE, L. M., AND JOHNSON, W. A. Use of field bins for experimental studies with vegetable crops. Proc. Auburn. Conf. on Statistics Applied to Research. pp. 54-60. 1948. (28) WARE, L. M. The effects of fertilizers, organic material, and irrigation on the yield of certain truck crops. Proc. Amer. Soc. Hort. Sci. 89 : 863-366. 1941. (29) The value of organic matter and irrigation in the production of potatoes in Alabama. Amer. Pot. Jour. 20 : 12-28. 1948. APPENDIX APPENDIX TABLE 1. March RAINFALL DATA BY SEMI-MONTHLY PERIODS FOR YEARS OF EXPERIMENT, AUN, April May June July August September ALABAMA, 1938-48' November October 1-15 16-31 In. In. 1-15 16-30 In. In. 1-15 16-31 In. In. 1-15 16-30 In. 0.73 1.77 5.39 1.77 4.87 0.59 1.03 1.14 3.79 0.38 2.18 In. 1-15 16-31 In. 2.05 0.35 6.68 2.43 1.65 2.91 1.76 2.37 2.45 0.00 9.07 In. 5.71 3.73 0.73 2.54 1.75 2.07 4.21 6.19 2.47 2.40 1.55 1-15 16-31 In. 2.41 2.55 0.76 3.84 3.20 3.80 6.15 1.54 2.14 2.30 5.50 In. 0.87 6.78 2.57 1.37 2.85 0.22 4.88 0.27 0.40 1.23 0.18 1-15 16-30 In. 1.93 0.60 0.17 1.41 0.72 2.04 4.10 1.86 2.01 2.95 2.48 In. 0.09 3.40 0.73 1.51 3.08 1.02 2.12 0.65 2.08 0.03 2.77 1-15 16-31 In. 1-15 16-30 In. In. 0.22 1.82 0.33 0.10 2.45 0.35 1.28 0.96 0.72 1.12 3.77 0.67 0.04 3.33 0.59 2.73 1.04 2.81 6.97 2.52 2.86 14.91 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 0.18 4.69 1.43 5.64 5.07 2.83 2.86 1.16 3.94 4.90 4.70 11.10 0.69 11.75 2.54 1.52 2.51 4.25 3.44 2.64 8.11 3.78 9.76 0.69 1.63 0.63 2.22 0.76 2.12 1.32 0.51 4.30 1.63 0.97 3.61 0.90 2.41 0.00 1.82 9.46 9.13 1.86 1.56 0.00 2.73 0.74 0.07 0.83 1.67 3.24 1.10 4.30 4.01 1.13 0.97 1.40 2.12 1.80 0.01 2.33 1.22 0.51 1.26 4.10 3.74 1.23 2.49 1.96 2.93 2.69 1.34 1.14 0.80 6.52 3.20 2.45 3.63 0.17 0.01 0.23 1.02 1.38 0.69 0.36 1.05 0.77 0.32 1.19 In. 0.14 0.09 0.94 1.60 0.92 0.03 0.00 2.43 1.04 0.85 0.17 0 c '- c rm M ' Data from local weather station.X z -I -I z IRRIGATION STUDIES with VEGETABLE CROPS 49 IRRIGATION SUDIES with EGEABE ROPS 49 APPENDIX TABLE 2. INCREASES IN YIELDS FROM IRRIGATION AS INFLUENCED BY AMOUNT AND DISTRIBUTION OF RAINFALL BY YEARS WITHOUTr ORGANIC MATERIALS Crops and seasons 1 Series A Beans, bush, total spring Broccoli, heads, fall Cabbage, heads, spring Lettuce, total fall Potatoes, total spring Units Incr ase SBushels r ct-23 Increases in yields by years and amount and distribution of rainfall by periods 1939 -24 1940 42 1941 4-yr. av. 53 9 589 350 11 2 CDDB Amount ____ aheb accb bcdb Rainfall( ZDistribution3 _.AACB ADAA ADDA cddb Year_---------------_________1938 - 3 1947 1948 -------------340 18 -11 103 Rainfall 2Amount ---. BCCA CAAA CBCA Distribution bcca ccbb cccb Year--Increase WPounds- ----.cent------- (Per 1946 3-yr. av. 176 1,824 663 38 1945 4-yr. av. -4,890 1,553 12 Year---------------------- 1942 Increase 4Wounds 1943 ---Percen------- .5,868 34 Amount-Rainfall amaDistribution _.codb ACDA 157 -26 -8 ABBC AAAD AACA babc aacb cccc 1947 6,388 -864 1944 6,099 Year-Rainfall Pounds -8,194 Increase S cent--------- -38 Per 946 2-yr. av. S---------------------- ~Distribution_ SBushels Amount 217 BDAA bdba 1,597 28 ---- ACCB bccb Year--------- Increase RainfallDistribution SweetNotatoes, Year--------------Increase S Prcent -----(anfl Amount -- 1938 6g CACBI cacb 1941 4-yr. av 66 15 65 13 18 -10 CAAC ABDA BDBD cbcc abda bdod 1944 1945 98 85 31 34 DCAA BAAC ccaa babc 3-yr. av. 1939 -11 1940 13 1943 summer and fall 10 Bushels -----BCBC-3 ccbb 64 21 Ranal Distribution_ 'll (Continued) = crops received 1,000 pounds of 6-104 fertilizer per acre. Rainfall by periods : A rainfall above 1.2 inches per week; B rainfall of .8 to 1.2 inches; C= rainfall of .4 to .8 inch; D= rainfall of 0 to .4 inch. Order of symbols corresponds to four equal periods beginning one week before planting and extending to one week before final harvest. and amount of rainfall within each period :a excellent; b = good; c = fair; and d =d or. Symbols from left to right correspond to periods from first to fourth perio. 'Distribution 5m ALABAMA AGRICULTURAL EXPERIMENT STATION 50D AILSABAA ARICULTUA XEIMN TTO APPENDIX TABLE 2. (Continued) INCREASES IN YIELDS FROM IRRIGATION AS INFLUENCED BY THE AMOUNT AND DISTRIBUTION OF RAINFALL BY YEARS WITHOUT ORGANIC MATERIALS Crops andUnt Increases in yields by years and amount nt seasons 1 Series A Tendergreen, and distribution of rainfall by periods 3-yr. av. 6,136 83 total fall Year__-_ 1944 1945 7,412 5,433 63 215 55 Per cent2_____ Rainfall 2 Amount _____DDAD ACDD BCCD ccdd bccd Distribution ddcd Increase Pond----- 5,561 ~Pounds-1943 _ Trip, total fall Year---Increase 1941 679 2 395 50 49 2 er cent----__________. DDDB BDDD DDDB cccc Rainfall SAmount Distribution dddc cddd cddb cccc _---_----- 1938 1939 1940 5 Pounds------ 3,349 7,080 11,505 4-yr. av. 5,653 44 Series B Beans, pole, total summer and fall Corn, sweet, marketable, spring and summer Potatoes, total summer and 1946 1947 1948 4-yr. av. 44 67 127 62 76 57 cent-300 24 93 Amount-__--.AAAC Rainfall ?Distribution.-..abbc BCDA BBDD ACBC ccdd bccd bcdb Year ---- ----------------------- 1944 1946 1947 1948 4-yr. av. 413 217 227 27 200 Increase sDozen ears-RPer cent --103 65 53 18 28 Rainfall SAmount --- _ADCC BCAA BCCB DDCA bccc cddb Distribution- bddc bcaa Year---- Increase (Per ---- cBushels ----12 - 1944 Z fall Tomatoes, total, 1942 1943 4-yr. av. 1940 1941 25 15 27 21 48 InraeBuhl--__-131 72 InraePer centL---171 32 56 BDDB ACCD ADAC BCDD - --Rainfall ~Distribution -. cddb bccc bdbc bbcc Year---SAmount spring and summer 1'All 2f Year___--------------_______1940 1941 1942 1943 160 6 23 44 Increase SBushels--114 2 9 4 Pe et---Amount --- ADAA BDCA DAAC ACBA Rainfall cdcb dbbd bcba lDistribution adab 4-yr. av. 58 15 crops received 1,000 pounds of 6-10-4 fertilizer per acre. Rainfall by periods: A = rainfall above 1.2 inches per week; B rainfall of .8 to 1.2 inches; C = rainfall of .4 to .8 inch; D = rainfall of 0 to..4 inch. Order of symbols corresponds' to four equal periods beginning one week before planting and extending to one week before final harvest. ~' Distribution and amount of rainfall within each period: a= excellent; b good; c = fair- and d --- oor. Symbols from left to right correspond to periods fro'm first to Ifourth period = IRRIGATION STUDIES with VEGETABLE CROPS 51 IRRIIGATION STUDES with VEGETBLE ROPS 5 APPENDIX TABLE 3. INCREASES IN YIELDS FROM IRRIGATION AS INFLUENCED BY THE AMOUNT AND DISTRIBUTION OF RAINFALL BY YEARS WITH ORGANIC MATERIALS ADDED Crops and seasons' Series A Beans, bush, total Units Increases in yields by years and amount and distribution of rainfall by periods spring Broccoli, heads, fall Year------------------- 1939 _-__ ---- 1938 1940 1941 4-yr. av. Incr ase Bushels --21 106 130 45 nea Per cent.. -20 -13 129 382 41 2 AACB ADAA ADDA CDDB Rinfal Amount ______ aa Distribution'_. abcb aCcb bcdb cddb Year---------------------------- 1946 1947 1948 3-yr. av. I crease 5Pounds.. .124 1,619 76 606 ncresePer 35 cent ----4 .45 2 17 Cabbage, heads, spring BCCA Rainfall $Amount 2Distribution_. bcca Year 1942 Wounds ------ 8,794 _IncreasePer cent--38 Rainfall SAmount-______ ACDA ~Disibution_ccdb --------------------------- CAAA CBCA ccbb cccb 1943 1944 1945 2,829 12,084 -3,187 18 212 4-yr. av. -11 5,129 27 ABBC AAAD AACA cccc babc aacb 2-yr. av. 562 49 Lettuce, totalcrease fall Year ---- -------1946 1947 Pounds 1,031 10,208 n Per cent ------7 117 ACCB BDAA Rainfall iAmount ----Distribution_ bccb bdba _-------- --------21 59 100 92 Potatoes, totalS Year spring ------------------------1938 1939 1940 1941 4-yr. av. Bushels ----Increase Per cent -----12 49 60' 48 41 67 -Amount ___ cacb Rainfall ZDistribution__ CACB CAAC ABDA BDBD cbcc abda bdcd Sweetpotatoes, Year-----------------nraeS total summer and falRifall Inras Bushels -----_----- 1943 1944 1945 3-yr. av. 27 53 22 Per cent_._-_ 32 Rifl Distribution Amount ----BCBC ccbb 7 13 DCAA 6 BAAC 8 (Continued) ccaa babc 2Rainfall by periods: A = rainfall above 1.2 inches per week; B= rainfall of .8 to 1.2 inches; C = rainfall of .4 to .8 inch; D = rainfall of 0 to .4 inch. Order of symbols corresponds to four equal periods beginning one week before planting and extending to one week before final harvest. 1All crops received 1,000 pounds of 6-10-4 fertilizer per acre. b= penid 'Distribution good; c rainfall within each period : a= excellent; poor. Symbols from left to right correspond to from fist to fourth period. = and amount of fair; and d = 52 ALABAMA AGRICULTURAL EXPERIMENT STATION 5;2 AL~BAA ARCULTUA XEiMN TTO APPENDIX TABLE 8. (Continued) INCREASES IN YIELDS FROM IRRIGATION AS INFLUENCED BY THE AMOUNT AND DISTRIBUTION OF RAINFALL BY YEARS WITH ORGANIC MATERIALS ADDED Crops andUnt 1 seasons is Year--Increase Rainfall Increases in yields by years and amount and distribution of rainfall by periods 1944 3-yr. av. 8,610 68 Series A Tendergreen, total fall Turnip, total fall Series B Beans, pole, total summer and fall Coin, sweet, 1945 5,241 86 Amount 2 ------ DDAD ACDD BCCD JDistribution-. ddcd ccdd bccd SPounds 1948 ----- 10,578 10,010 (Per cent ----- 62 147 ------------- Year--------- - -- --- 19 38 - -- -Increase SPounds------.1,740 cent-----15 Amount---.DDDB Rainfall SDistribution dddc (Per 1941 4-yr. av. 1989 1940 18,565 11,117 1,914 7,084 38 6 81 100 BDDD DDDB cccc oddd cddb marketable, spring and summer Potatoes, 1944 1946 1947 1948 4-yr. av. 142 41 60 -21 -16 InraePer cent - -_ 21 49 45 -27 -7 AAAC BCDA BBDD ACBC Rainfall Amountbccd SDistribution abbe bcdb ccdd 1946 1947 1948 4-yr. av. Year-- -------- - -- --- 1944 227 160 786 256 5Dozen ears -147 Increase 118 31 14 -24 Per cent ----26 DDCA Rainfall SAmount---- - ADCC BCAA BCCB cddb bccc bcaa ZDistribution. .bddc Yncease SBushels ----usYearh------ --97 ------462 1941 1942 1948 4-yr. av. 59 52 88 49 116 38 272 118 Inras Per cent Rainfall 5ZAmount--_--- BDDB ACCD ADAC BCDD bccc bdbc bbcc Distribution cddb 1942 1943 4-yr. av. Year ---------- h-ls - -1940 1941 Tomatoes, --117 5 116 -71 -142 total Per cent ------Icae -18 -8 22 30 1 spring and BDCA DAAC ACBA summer Rainfall SAmount -- ADAA adab cdcb dbbc bcba ' All crops received 1,000 pounds of 6-10-4 fertilizer per acre. rainfall above 1.2 inches per week; B = rainfall 2 Rainfall by periods : A rainfall of 0 to .4 inch. of .8 to 1.2 inches; C = rainfall of .4 to .8 inch; D Order of symbols corresponds to four equal periods beginning one week before planting and extending to one week before final harvest. 3 Distribution and amount of rainfall within each period: a= excellent; b = good; c = fair; and d = poor. Symbols from left to right correspond to to fourth period. periods from total summer and fall 1940 first APPENDIX TABLE 4. YIELDS AND INCREASES IN YIELDS FROM IRRIGATION, FERTILIZERS, AND ORGANIC MATERIALS, OF HIGH RESPONSE) SEMES A (YEARS z -I C m Treatments Fertilizer per acre Yields and increases in yields per acre for years of high response Lettuce, Broccoli, Cabbage, Beans, bush, total, heads, heads, total, fall, 1947 spring, 1942 fall, 1947 spring, 1940 With- WithIncrease WithWithIncrease With- With Increase WithWith Increase fro out from o ut rom out irriirri-i irriirri-rriirriirrirri-rriirrigation gation gation gation gation gation gation gation Bu. Bu. 29 135 106 54 188 184 25 53 Bu. 24 59 35 42 106 64 18 47 Lb. 1,453 4,384 2,931 1,779 8,597 1,818 326 -787 Lb. 2,035 5,446 3,411 3,603 5,216 1,613 1,568 -230 Lb. 582 1,062 480 1,824 1,619 -205 1,242 557 Lb. Lb. Lb. 8,588 2,541 Lb. Lb. Lb. 4,249 4,947 698 6,388 10,208 3,820 2,139 5,261 5 76 71 12 82 70 7 6 0 8,538 13,920 16,461 13,920 461 4,710 7,264 12,211 6,803 7,501 6-10-4 Organic materials 6-10-4 m sacreirt I Lb. 500 500 0 Standard Increase from organic materials 0 Standard Increase from organic materials a I- 7,923 -5,997 14,324 10,867 0 1,000 1,000 8,122 22,446 20,339 31,206 12,217 2,950 9,338 8,710 18,918 5,760 2,489 1,446 9,580 4,628 6,707 8,760 -3,457 5,786 8,326 Increase from fertilizer without organic materials Increase from fertilizer with organic materials 8,122 13,908 6,419 14,745 ''OTwo inch per water of dryweek was applied was applied in during previoustons of greennot suppliedinthat amount. ne tons of acre per lespedeza sericea when rainfall winter and 6 week had crotalaria summer. (Continued) W U' APPENDIX TABLE 4. (Continued) YIELDS AND INCREASES IN YIELDS FROM IRRIGATION, FERTILIZERS, AND ORGANIC MATERIALS, SERIES A (FOR ALL YEARS) Treatments Fertilizer S per Organic materials' acre Yields and increases in yields per acre for all years Lettuce, Cabbage, Broccoli, total, heads, heads, total, fall, 1946-47 spring, 1942-45 fall, 1946-48 spring, 1988-41 With Increase With- With Increase With- With Increase With Increase WithWithout With from out from out Wt from out from irrigaion irrirrirri-i -irri- irriirri- irrii irrigation gation gation gation o gati gatio ogati gati gati gation gatin2 gation Beans, bush, i w !1: Lb. 500 500 0 Standard Increase from organic materials 0 Standard Increase from organic materials Bu. 45 85 40 82 111 29 37 26 YCI Bu. 64 120 56 91 156 65 27 86 ~I Bu. 19 35 16 9 45 86 -10 10 Lb. 1,298 3,244 1,946 1,745 3,555 1,810 447 ~ 811 \Iln Lb. 1,606 8,370 1,764 2,408 4,161 1,758 802 .I 791 .I-r Lb. 808 126 -182 663 606 -57 855 480 I li Lb. Lb. 651 3,336 9,630 11,786 8,979 8,400 Lb. 2,685 2,106 -579 2,603 4,832 2,229 -82 2,726 Lb. Lb. 1,610 8,078 6,890 10,845 5,280 5,683 11,480 5,747 4,073 4,540 7,767 7,280 17,050 9,770 4,202 6,205 Lb. 1,468 3,955 2,487 1,597 5,620 4,023 129 1,665 C 1,000 1,000 6,488 9,091 15,449 20,281 8,961 5,837 6,470 11,190 5,755 8,545 x X m Increase from fertilizer without organic materials Increase from fertilizer with organic materials ~ ( Continued) z -4 -4 -4 crotalaria in summer. 'Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of greennot supplied that amount. 2 One inch of water per week was applied when rainfall during previous week had o z X APPENDIX TABLE 4. (Continued) Y I . Y I I~ YIELDS AND INCREASES IN YIELDS FROM IRRIGATION, FERTILIZERS, AND SERIES A (YEARS OF HIGH RESPONSE) ORGANIC MATERIALS, z C TIWI Treatments L ~- ~ n~ nY I~ - I ~ r\ L 1~ \ Yields and increases in~ ~I ~ yields per acre for years of high response U~rI L L l r IL~l\L 1r~l L 1 Ferti- lizer 6-10-4 per acre Lb. 500 500 Organic materials' Squash, Onion, Corn, sweet, Beans, lima, totaltotal, marketable, total, fall, winter, 1939-40 spring, summer, 1946-47 summer, 1940 spring, summer, 1948 With- With Increase With- With Increase With- With Increase With- With Increase out from out from out from out from irriirri--iri-iirr ri gatriongion-ir-iri gationgion gation gation gation gation gation gation gation gaion irri-gat rri gatio an Bu. 60 180 120 m 1,000 1,000 0 Standard Increase from organic materials 0 Standard Increase from organic materials Bu. 170 148 -32 Bu. 110 Lb. 102 1,600 1,498 Lb. 1,197 2,784 1,587 Lb. 1,095 1,184 Lb. 1,305 5,538 Lb. 1,534 4,836 -702 -931 Lb. 229 Lb. 1,048 6,995 Lb. 1,360 6,742 Lb. 817 -253 m a -I >u0 rrU) 0 -22 -142 187 196 9 17 89 1,779 979 -800 684 4,233 2,631 7,577 4,946 1,326 3,302 3,653 6,730 5,952 3,840 10,845 7,005 2,797 5,382 -570 143 201 58 83 44 -5 1,357 3,834 2,477 1,255 3,136 4,813 1,677 1,939 1,022 -847 3,789 -51 9,619 -1,226 5,830 -1,175 2,429 -49 -66 3,077 -- 1,869 Increase from fertilizer. without organic materials Increase from fertilizer 2,119 1,894 793 -368 -973 with organic materials 21 48 27 2,234 2,029 -205 2,039 -145 3,850 2,877 'On (Continued) 'Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. inch of water per week was applied when rainfall during previous week had not supplied that amount. IU' on APPENDIX TABLE 4. (Continued) YIELDS AND INCREASES IN YIELDS FROM IRRIGATION, FERTILIZERS, AND ORGANIC MATERIALS, SERIES A (FOR ALL YEARS) Yields and increases in yields per acre for all years Beans, lima, Corn, sweet, Onion, Squash, total, marketable, total, total, summer, 1938-40 spring, summer, 1946-48 fall, winter, 1988-41 spring, summer, 1946-47 With- With Increase WithWith Increase WithWith Increase With- With Increase from out fro outfrom out Wifrom out irri- gation i irirriirriirriirrimirrigation gation gation gation gation gatiogatn gation gation gation Bu. 90 118 28 126 125 -1 36 7 Bu. 123 111 -12 131 133 2 8 22 -28 15 Bu. 33 Treatments Fertilizer Organic materials 6-10-4 per acre Lb. 500 500 Iw Irrir 0 Standard Increase from organic materials 0 Standard Increase from organic materials -7 -40 5 8 3 Lb. 653 8,951 8,298 2,656 5,617 2,961 2,003 1,666 Lb. 994 4,489 8,495 8,416 5,734 2,818 2,422 1,245 Lb. 341 538 197 760 117 -643 419 -421 Lb. 2,106 6,171 4,065 3,295 7,949 4,654 1,189 Lb. 2,147 6,040 8,893 8,822 7,957 4,135 1,675 Lb. 41 -131 -172 527 8 -519 486 Lb. 1,043 6,995 5,952 8,840 10,845 7,005 2,797 Lb. 1,360 6,742 5,882 Lb. 317 -253 -570 -I C 1,000 1,000 3,789 -51 9,619 -1,226 5,830 -1,175 C L-I m Increase from fertilizer without organic materials Increase from fertilizer with organic materials --- 2,429 -3868 in 1 m -Il I z 1,778 1,917 139 3,850 2,877 -973 ( Continued) STwo inch of acre per week was sericea when rainfall winter and 6 green SOne tons per waterof dry lespedeza applied was applied induring previoustons of had notcrotalaria in summer. week supplied that amount. y z APPENDIX TABLE 4. (Continued) YIELDS AND INCREASES IN YIELDS FROM IRRIGATION, FERTILIZERS, AND ORGANIC MATERIALS, SERIES A (YEARS OF HIGH RESPONSE) -1 z O Treatments Fertilizer 6-10-4 per acre Organic 1 materials Yields and increases in yields per acre for years of high response Potatoes, Sweetpotatoes, Tendergreen, Turnip, total, total, spring, 1941 summer, fall, 1944 fall, 1948 fall, 1989 With- With Increase WithWith Increase WithWith Increase WithWith Increase out from from out out from out . irriirri-irrgation2 irriirriirriirriirriiirrigation gation gation gation gation gation gationga gation Bu. 51 157 106 101 191 90 50 Bu. 88 195 107 167 288 116 79 Bu. 37 88 1 66 92 26 29 Bu. 230 828 93 287 395 108 57 Bu. 265 409 144 885 448 63 120 Lb. Lb. Bu. 35 4,525 8,915 86 12,141 18,515 51 98 53 -45 63 7,616 9,600 Lb. 4,390 6,874 1,984 Lb. Lb. 10,573 15,956 16,218 24,597 5,645 8,641 Lb. 5,888 8,379 2,996 7,080 13,565 6,485 1,697 m .I. Lb. 500 0 500 Standard Increase from organic materials 1,000 0 1,000 Standard Increase from organic materials Increase from fertilizer without organic materials Increase from fertilizer with organic materials 1 Two SOne ~uA rr0 r n- 8,781 14,842 5,561 16,108 26,118 10,010 7,327 11,776 4,256 5,427 4,449 1,171 14,153 21,233 16,798 30,863 2,645 8,580 9,130 5,277 34 88 54 72 39 -33 38,967 7,603 3,686 580 5,766 5,186 (Continued) tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. inch of water per week was applied when rainfall during previous week had not supplied that amount. UI V4 UG 0O APPENDIX TABLE 4. (Continued) YIELDS AND INCREASES IN YIELDS FROM IRRIGATION, SERIES A (FOR ALL YEARS) FERTILIZERS, AND ORGANIC MATERIALS, Treatments Fertilizer per acre acre Lb. 500 500 0 Standard Increase from organic materials 0 Standard Increase from organic materials Organic materials' Yields and increases in yields per acre for all years Potatoes, Sweetpotatoes, Tendergreen, Turnip, total, total, total, total, fall, 1938-41 fall, 1943-45 summer, fall, 1943-45 spring, 1938-41 With Increase With Increase With- With Increase WithWith- WithIncrease Without from out out from irri- out from lrrirri-from irriot i i 2 irri- gation irriirrii irriirriirri- irriirrigation gation gation gation gation gation gation gation gation gation Bu. 80 137 57 115 162 47 35 25 Bu. 82 176 94 130 229 99 48 53 Bu. 2 39 87 15 67 52 18 28 Bu. 232 352 120 309 383 74 77 31 Bu. 277 399 122 873 415 42 96 16 Bu. 45 47 2 64 82 -382 19 -15 Lb. Lb. 4,139 8,098 9,783 14,701 5,644 6,603 Lb. 3,959 4,918 959 6,136 8,610 2,474 2,177 3,692 Lb. Lb. 9,498 12,981 18,145 21,983 8,647 9,002 Lb. 3,483 3,838 355 5,653 7,084 1,481 2,170 Ir c- 1,000 1,000 7,358 13,494 12,570 21,180 5,212 3,219 2,787 7,686 5,896 6,479 12,962 18,615 18,432 25,516 5,470 8,464 287 6,901 5,634 rm Increase from fertilizer without organic materials Increase from fertilizer with organic materials 1 Two 8,533 83,246 Z -4 tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. 2One inch of water per week was applied when rainfall during previous week had not supplied that amount. z APPENDIX TABLE 5. YIELDS AND INCREASES IN YIELDS FROM IRRIGATION AND DIFFERENT ORGANIC MATERIALS FOR YEARS OF HIGH RESPONSE AND FOR ALL YEARS, SERIES B R-I Treatments Ferti6-10-4 per acre lizer Manures' Yields and increases in yields per acre Beans, pole, Corn, sweet, Potatoes, total, marketable ears, total summer, fall spring, summer summer, fall WithWt Increase WithIncrease WithW Ith ras out 0 Tomatoes, total, spring, summer WithWt Increase out .. z C irriBut. 0 Animal manure Increase from animal manure 0 Rye Increase from rye 168 287 119 With gaion' ga02gation from out gation n With r i from gir-ation gation gation tn- irr out mn gationgn . .h from With irni- from gation gation But. 48 97 49 gation gation Bu. 160 117 in. m Lb. 1,000 1,000 1,000 1,000 Bu. 1948 295 429 134 Bu. 127 142 15 Doz. 400 667 267 Doz. Doz. Bu. Bu. For years of high response 1948 1940 813 413 28 76 1,453 786 21 118 640 378 -7 42 Bu. 140 396 256 Bu. 1943 800 518 213 rrin In ~~w "v HI -43 160 22 0 168 206 38 295 320 25 127 114 -13 400 733 333 813 1,240 427 413 507 94 28 11 -17 76 82 6 48 71 23 140 258 118 800 280 -20 -138 58 5 1,000 1,000 0 Animal manure Increase from animal manure 1,000 0 1,000 Rye Increase from rye 1 Animal manure was applied at 1944, 1946-48 108 170 62 195 236 41 87 66 -21 1944, 1946-48 413 630 217 827 1,083 256 414 453 Average for all years 37 50 13 1940-43 64 109 45 27 59 32 369 709 340 1940-43 427 714 287 108 145 170 199 62 54 413 700 630 817 39 217 117 -53 58 9 -49 U' 37 40 64 76 27 36 369 461 92 427 470 43 'One 37 29 -8 287 187 -100 3 12 9 the rate of 12 tons per acre per year. Rye was grown and turned under. inch of water per week was applied when rainfall during previous week had not supplied that amount. o APPENDIX TABLE 6. YIELDS OF DIFFERENT VEGETABLE CROPS FROM USE OF IRRIGATION, FERTILIZER, SERIES A ORGANIC MATERIALS, AND RATES OF Treatments Fertilizer 6-10-4 per acre Lb. 0 500 500 500 500 1,000 1,000 1,000 1,000 1,000 1,000 1,0003 1,000 0 0 0 Standard Standard 0 0 Standard Standard Vetch Cowpeas Standard 0 Irrigation per week 2 In. 0 0 1 0 1 0 1 0 1 1 1 1 1 Yields per acre for years of high response and average yields for all years Beans, lima Beans, snap Broccoli Cabbage (4-yr. av.) (4-. 1942-45 Heads Total Lb. 0 651 8,836 9,630 11,736 6,488 9,091 15,449 20,281 10,882 15,387 2,865 18,252 Lb. 898 6,735 9,222 14,841 17,495 12,666 14,219 18,728 23,857 16,719 20,285 10,048 17,179 > D ¢ o Omaterials 1940 (3-yr. av.) (2-yr.av.) (4-yr.av.) 1 1947 1938-40 1 1 Total1938-40 1940-41 1938-41 Head Total Total Total Bu. 60 170 180 148 143 187 201 196 258 ... 128 __ Lb. 122 90 123 118 111 126 131 125 133 162 ... 126 _83,642 Bu. 0 2 40 53 128 11 58 58 176 214 78 88 Bu. 19 45 64 85 120 82 91 111 156 196 116 87 Bu. 307 1,453 2,035 4,384 5,446 1,779 8,603 8,597 5,216 4,038 5,267 8,526 (3-yr.av.) (2-yr. a) av.) r2yr 19421944 1946-48 Heads Heads Total Lb. 160 1,298 1,606 3,244 8,370 1,745 2,408 3,555 4,161 2,848 8,358 2,078 8,189 Lb. 0 0 4,682 6,960 12,467 4,061 12,816 10,196 21,824 15,174 17,998 896 5,862 Lb. 826 6,083 11,453 12,678 18,820 10,601 16,585 14,358 24,797 18,867 22,630 9,273 13,984 C -I c r 0 x M -I (Continued ) 1Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. 2One inch of water per week was applied when rainfall during previous week had not supplied that amount. SNitrogen was not included in the fertilizer for this treatment. ' Extra nitrogen, 40 pounds per acre, was applied to this treatment. z APPENDIX TABLE 6. (Continued) YIELDS OF DIFFERENT VEGETABLE CROPS FROM USE OF RATES OF FERTILIZER, SERIES A IRRIGATION, ORGANIC MATERIALS, AND A Treatments Fertilizer Organic Yields per acre for years of high response and average yields for all years IrriSweet corn 1948 Mkt. Lb. 0 102 1,197 1,600 2,784 1,857 8,1386 8,884 4,818 4,000 8,814 1,274 4,864 Total Lb. 1,549 3,725 4,090 4,902 6,010 4,442 6,797 7,782 7,866 8,147 7,296 8,942 9,254 (3-yr. av.) 1946-1948 Total Mkt. Lb. 0 653 994 3,951 4,489 2,656 3,416 5,617 5,784 5,722 4,514 2,112 5,227 Lb. 692 8,245 3,292 6,547 7,365 5,427 6,003 8,881 9,016 9,320 7,287 4,220 8,748 1947 Heads Lb. 0 0 269 723 2,470 0 1,670 1,427 6,016 1,779 1,728 2,598 1,606 Total Lb. 13 461 4,710 7,264 12,211 2,950 9,338 8,710 18,918 11,942 10,680 10,682 9,722 Lettuce (2-yr. av.) 1946-1947 Total Heads Lb. 0 0 185 467 1,402 848 992 1,146 8,868 1,081 1,290 1,895 1,146 Lb. 7 1,610 8,078 6,890 10,845 5,688 7,280 11,480 17,050 9,542 10,687 8,045 11,744-Onion (2-yr.av.) (4-yr. av.) 1989-40 1988-41 Total Total Lb. 248 1,305 1,534 5,588 4,886 2,631 8,658 7,577 6,780 8,055 4,818 8,195 Lb. 406 2,106 2,147 6,171 6,040 8,295 8,822 7,949 7,957 4,816 5,116 4,252 ga- z 4 -g C m 6-10-4 per acre Lb. 0 500 500 500 500 1,000 1,000 1,000 1,000 1,000 1,000 1,0003 1,0004 0 0 0 materials tion per week 2 In. 0 0 1 0 1 0 1 0 1 1 1 1 1 0 m, m I Standard Standard 0 0 Standard Standard Vetch Cowpeas Standard 0 w R- o 0 A 'Two (Continued) tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. 2One inch of water per week was applied when rainfall during previous week had not supplied that amount. 3 Nitrogen was not included in the fertilizer for this treatment. 4 Extra nitrogen, 40 pounds per acre, was applied to this treatment. 0% APPENDIX TABLE 6. (Continued) YIELDS OF DIFFERENT VEGETABLE CROPS FROM USE OF IRRIGATION, ORGANIC MATERIALS, AND RATES OF FERTILIZER, SERIES A Treatments Fertilizer 6-10-4 per acre Lb. 0 500 500 500 500 1,000 1,000 1,000 1,000 1,000 1,000 1,000' 1,0004 0 0 0 Standard Standard 0 0 Standard Standard Vetch Cowpeas Standard 0 Irrigation per week' In. 0 0 1 0 1 0 1 0 1 1 1 1 1 Yields per acre for years of high response and average yields for all years Potatoes (2-yr. av.) 1940-1941 Total Mkt. Bu. 0 23 46 115 166 57 96 147 242 247 144 94 -_ Squash (2-yr. av.) 1946-1947 Total Lb. 0 1,043 1,360 6,995 6,742 3,840 3,789 10,845 9,619 5,411 3,533 2,327 9,568 Sweetpotatoes (2-yr. av.) 1944-1945 Total Mkt. Bu. 40 162 195 260 346 280 316 331 883 875 342 238 342 Bu. 69 212 248 321 898 281 373 386 424 441 384 276 889 (3-yr. av.) 1943-1945 Total Mkt. Bu. 57 189 229 279 348 253 320 317 364 345 322 262 Bu. 94 232 277 352 399 809 373 3883 415 416 372 317 > , a G C -4 Organicls (4-yr. av.) 1938-1941 Total Mkt. Bu. 18 49 50 100 134 75 90 125 186 247 150 90 Bu. 28 80 82 137 176 115 130 162 229 265 189 121 Bu. 1 44 66 147 197 86 125 178 274 265 176 123 c r m * m Z - 873 329 (Continued ) Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. ' One inch of water per week was applied when rainfall during previous week had not supplied that amount. 8 Nitrogen was not included in the fertilizer for this treatment. SExtra nitrogen, 40 pounds per acre, was applied to this treatment. -4 O Z APPENDIX TABLE 6. (Continued) YIELDS OF DIFFERENT VEGETABLE CROPS FROM USE OF IRRIGATION, ORGANIC MATERIALS, AND RATES OF FERTILIZER, SERIES A Yields per acre for years of high response and average yields for all years Irria ga-tion perals 0 ..1. Treatments Fertilizer 6-10-4 acre z C v Tendergreen (2-yr. av.) 1943-1944 Turnip (2-yr. av.) 193-9019814 6-10-4 per Organic materials (3-yr. avRo 1943-1945 (4-yr. av.) Lb. 0 6,438 12,166 13,451 21,630 8,531 17,824 13,967 26,308 22,193 21,113 13,271 Lb. 98 5,293 7,538 9,446 12,023 6,608 9,588 8,647 12,441 11,872 10,452 7,438 ----- week' Total Total RootsToaRotTtl Lb. 0 500 500 500 500 1,000 1,000 1,000 1,000 1,000 1,000 1,0003 1,000k 1 2 In. 0 0 0 Standard Standard 0 0 Standard Standard Vetch Cowpeas Standard 0 Lb. 52 3,194 '7,242 9,309 15,149 6,112 12,599 11,648 21,942 16,557 19,236 4,874 19,027 Lb. 69 4,139 8,098 9,783 14,701 7,358 13,494 12,570 21,180 17,287 17,507 5,025 18,827 Lb. 0 3,108 6,737 6,230 11,016 3,954 8,346 5,908 12,408 10,340 10,087 6,593 Lb. 368 9,498 12,981 18,145 21,983 12,962 18,615 18,432 25,516 23,976 22,255 13,888 _ --- 0 0 1 0 1 0 1 0 1 1 1 1 1 m 0 a m A 0 y) ------- Two tons per acre of dry lespedeza sericea was applied in winter and 6 tons of green crotalaria in summer. One inch of water per week was applied when rainfall during previous week had not supplied that amount. Nitrogen was not included in the fertilizer for this treatment. 4'Extra nitrogen, 40 pounds per acre, was applied to this treatment. I0% W APPENDIX TABLE 7. YIELDS OF DIFFERENT VEGETABLE CROPS FROM USE OF IRRIGATION, ORGANIC MATERIALS, AND RATES OF FERTILIZER, SERIES B Treatments Fertilizer Animal per6-10-4 per acer acre Manure Green Legume Yields per acre for years of high response and average of all years Tomatoes Potatoes Corn, sweet Beans, pole rri Irrigation (2-yr. av.) (4-yr. av.) (2-yr. av.) (4-av. (2-yr. av.) (4-yr. av.) (2-yr. av.) (4-yr. av.) per 1946, 1948 1944-48 1944,19481946-48 1940, 1941 1940-4 1942, 1943 1940-48 week2 Total Total Mkt. ears Mkt. ears Mkt. Total Mkt. Total Mkt. Total Mkt. Total Mkt. ears Inches Bu. 0 120 217 210 311 122 202 151 265 192 268 295 253 285 305 812 Bu. 10 108 170 195 236 128 154 145 199 147 202 216 202 214 202 204 Doz. 0 353 660 773 1,280 685 1,080 658 927 940 1,586 1,520 1,407 1,247 1,493 1,486 Doz. 0 413 630 827 1,083 525 653 700 817 987 1,190 1,220 1,083 1,017 1,876 1,333 Bu. 2 14 43 12 71 13 49 9 49 15 83 81 56 60 99 96 Bu. 7 22 56 19 92 20 65 18 58 24 97 97 71 71 113 109 Bu. 3 27 50 40 87 80 59 28 62 39 87 86 69 68 101 95 Bu. 10 37 64 50 109 41 76 40 76 49 103 104 89 82 118 112 Bu. 11 184 187 333 405 167 203 195 247 326 361 407 350 838 867 880 Bu. 20 218 301 465 582 252 846 315 370 476 543 616 509 472 566 554 Bu. 49 246 284 507 493 322 354 807 320 485 538 571 509 481 513 521 Bu. 76 369 427 709 714 467 550 461 470 697 785 814 722 652 777 764 > 7A r* rm m ? : Z acacr Pounds 0 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,0003 1,000 1,000 1,500 2,000 2 a Tons 0 0 0 12 12 0 0 0 0 12 12 12 6 6 12 12 e legume on- 0 0 0 0 0 Vetch Vetch 0 0 Vetch Vetch Vetch Vetch 0 Vetch Vetch 0 0 0 0 0 0 0 Rye Rye 0 0 0 0 Rye 0 0 0 0 1 0 1 0 1 0 1 0 1 1 1 1 1 1 1 Green manure crops were grown and turned under. One inch of water per week was applied when rainfall during previous week had not supplied that amount. Minor elements were applied to all treatments except this one. -I O Z APPENDIX TABLE 8. PLANTING AND HARVESTING DATES AND AVERAGE AMOUNT OF IRRIGATION PER YEAR GIVEN EACH CROP FOR -I THE SELECTED YEARS OF HIGH RESPONSE AND FOR ALL YEARS Years and acre inches of water applied Crops Seasons Planting dates Harvesting dates Years of high response YearsYearsAcre inches applied All years Acre inches Years Years applied -I C Series A Beans, lima Beans, bush Broccoli Cabbage Corn, sweet Lettuce Onion Potatoes Squash Sweetpotatoes Tendergreen Turnip Series B Beans, pole Corn, sweet Potatoes Tomatoes Average Summer, fall Spring, summer Summer, fall Spring, summer Summer Spring Fall Spring Spring, summer Fall Fall, winter Spring Spring, summer Summer, fall Fall Fall June 19 to 24 Mar. 20 to May 9 Aug. 20 to 30 Feb. 20 to Mar. 10 Apr. 5 to May 22 Sept. 12 to 18 Sept. 4 to Oct. 14 Feb. 22 to Mar. 13 Apr. 21 to May 17 Apr. 30 to May 16 Sept. 12 to 21 Sept. 12 to Oct. 8 Aug. 16 to Sept. 18 May 23 to July 1 Nov. 20 to Feb. 20 June 1 to 20 June Nov. Feb. June 26 to July 13 15 to Dec. 18 7 to May 2 7 to 24 1940 1939-41 1947 1942, 1944 1948 1947 1939-40 1940-41 1946-47 1944-45 1943-44 1939-40 1946, 1948 1944, 1948 1940-41 1942-43 5.00 2.50 4.00 6.00 6.00 8.00 8.50 5.00 8.00 7.50 5.50 5.50 5.00 6.75 4.50 8.50 5.08 1988-40 1938-41 1946-48 1942-45 1946-48 1946-47 1938-41 1938-41 1946-47 1943-45 1943-45 1938-41 1944, 1946-48 1944, 1946-48 1940-43 1940-43 8.67 3.50 8.83 5.50 5.00 8.00 9.25 4.25 3.00 8.67 4.33 6.00 4.25 6.50 4.50 3.50 4.89 Us mo w Im~ 0 June 10 to July 22 Oct. 1 to 10 Oct. 19 to Dec. 10 Nov. 6 to Dec. 1 Sept. 12 to Nov. 10 June 18 to July 21 Oct. 81 to Nov. 19 June 26 to Aug. 9 July 14 to Aug. 10 Apr. 2 to May 2 Aug. 11 to 20 Mar. 28 to Apr. 24 APPENDIX TABLE 9. GROSS VALUES AND VALUES ABOVE COST OF PRACTICES FROM YIELD INCREASES RESULTING FROM USE IRRIGATION AND ORGANIC MATERIALS SEPARATELY AND IN COMBINATION, SERIES A AND B, YEARS OF HIGH RESPONSE OF Gross values of increases per acre' Crops' Values of increases above cost of practices per acre From irrigation 3 Crops Without organic materials' With organic materials From organic materials Without irrigation Dollars irrigation From both From irrigation Without organic materials Dollars With organic materials Dollars From organic materials Without irrgation Dollars irrigation From both Dollars Dollars Series A 21.60 127.20 77.60 -40.00 114.20 -3.40 74.20 Beans, lima 105.60 -12.00 189.20 258.20 857.00 98.80 269.20 87.80 283.20 112.80 283.20 396.00 112.80 Beans, snap 296.30 139.50 156.80 136.80 181.80 161.30 343.70 160.00 182.40 161.90 Broccoli 165.16 296.66 355.26 131.50 198.96 97.70 165.10 232.56 122.70 190.16 Cabbage Corn, sweet 80.10 24.00 120.00 63.90 144.00 46.50 -9.60 95.00 88.90 85.40 283.20 638.72 288.72 891.52 205.40 858.20 596.92 Lettuce 255.52 408.32 230.40 159.62 173.34 245.94 13.72 -98.42 271.76 61.32 ---50.82 296.76 184.62 Onion 174.80 156.45 260.40 330.75 42.35 146.30 181.45 285.40 277.75 Potatoes 70.35 -36.78 210.15 174.90 173.37 -18.3 ---5.58 185.15 149.90 181.57 Squash -1.53 149.25 99.25 203.75 153.75 803.00 141.25 228.75 178.75 870.00 Sweetpotatoes 191.25 58.08 87.82 199.48 241.28 111.66 141.40 128.46 158.20 88.08 112.82 Tendergreen 83.72 144.68 299.74 155.06 216.02 108.72 169.68 855.54 185.86 246.82 Turnip Series B 214.40 191.00 200.60 405.40 225.60 458.40 204.80 232.80 242.40 216.00 Beans, pole 54.30 114.30 101.00 161.00 215.30 152.10 126.00 186.00 278.10 Corn, sweet 92.10 24.35 53.75 2.10 49.85 103.95 29.40 76.65 -22.90 Potatoes 54.60 101.85 873.00 411.00 497.40 898.00 486.00 542.00 86.40 124.40 Tomatoes 106.00 144.00 145.81 167.59 266.45 148.20 170.81 192.59 819.01 98.86 120.64 Average 126.42 All crops received 1,000 pounds of 6-10-4 per acre. 2 Values were based on estimated prices considered reasonably conservative. The value of No. 2 grade potatoes and sweetpotatoes was at one-half that of No. 1 grade. One inch of water per week was applied when rainfall during previous week had not supplied that amount. series A, 2 tons per acre of dry lespedeza was applied in winter and 6 tons of green crotalaria in summer; in series B, 12 tons per acre of animal manure was applied in late winter. With and irriorganic gation materials Dollars Dollars With and irri- organic gation materials Dollars Dollars a C rC x m m z -I -4 ' 'In -I z APPENDIX TABLE 10. GROSS VALUES AND VALUES ABOVE COST OF PRACTICES FROM YIELD INCREASES RESULTING FROM USE OF AND ORGANIC MATERIALS SEPARATELY AND IN COMBINATION, SERIES A AND B, ALL YEARS IRRIGATION Gross values of increases per acre' Values of increases above cost of practices per acre Crops From irrigation oCropsmaterials With Without organic 4 organic materials materials Dollars Dollars 8 From organic Without irrigation Dollars irrigation and With irriorganic gation materials Dollars Dollars From both Dollars Dollars Dollars Series A -28.70 -27.40 -20.20 16.80 -8.50 -1.30 -2.40 4.80 12.00 19.20 Beans, lima Beans, snap 21.60 108.00 69.60 156.00 177.60 2.00 88.40 44.60 181.00 133.00 197.95 156.00 150.80 47.65 41.95 175.30 241.60 66.30 60.60 181.00 Broccoli 212.06 154.22 198.80 57.84 275.86 13.26 223.80 96.64 179.22 52.06 Cabbage Corn, sweet 29.40 8.00 114.60 88.20 117.60 1.40 -25.00 89.60 63.20 64.60 365.80 412.88 208.00 204.88 47.08 390.80 454.68 229.88 63.88 224.80 Lettuce 223.10 202.92 -51.82 254.24 279.72 -20.18 .48 279.24 248.10 31.62 Onion 144.40 68.20 140.90 8.50 81.20 193.80 88.80 165.90 27.30 105.00 Potatoes 181.57 185.15 149.90 -18.83 -58.58 174.90 173.87 210.15 -1.53 -36.78 Squash 95.00 182.75 93.75 87.75 89.00 256.25 118.75 120.00 186.25 187.50 Sweetpotatoes 128.72 223.44 144.20 79.24 276.44 94.72 104.24 158.72 122.72 172.20 Tendergreen 192.48 84.40 118.02 79.46 108.08 188.02 251.08 141.68 109.40 118.06 Turnip Series B 258.40 183.80 133.40 125.00 74.60 807.20 208.80 158.40 148.80 98.40 Beans, pole 110.90 189.60 40.40 99.20 28.70 185.90 201.00 124.20 65.10 76.80 Corn, sweet 59.00 41.15 1.25 17.85 57.75 109.20 26.25 66.15 82.95 48.05 Potatoes 449.40 497.00 898.00 56.40 -47.60 418.00 494.00 -28.00 522.00 76.00 Tomatoes 151.12 185.98 50.79 185.19 289.10 84.86 160.20 176.12 62.98 78.90 Average 1 All crops received 1,000 pounds of 6-10-4 per acre. 2 Values were based on estimated prices considered reasonably conservative. The value of No. 2 grade potatoes and sweetpotatoes was at one-half that of No. 1 grade. One inch of water per week was applied when rainfall during the previous week had not supplied that amount. ' In series A, 2 tons per acre of dry lespedeza was applied in winter and 6 tons of green crotalaria in summer; in series B, 12 tons per acre of animal manure was applied in late winter. Fromirrigation Foigamaterials With Without organic organic materials materials Dollars Dollars From organic Without irrigation With irrigation From both irrigation and organic materials Z o c D 0 w r m O 1 APPENDIX TABLE 11. YIELDS OF DIFFERENT COVER CROPS GROWN AND TURNED, SERIES A Treatments FertiOrNo. er acre' Lb. maerials' Yields per acre by years Irrigation 199 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 r3*I A In. Lb. Lb. Lb. Lb. Lb. Lb. Lb. Lb. Lb. Lb. Lb. 12,000' 12,000' 10 1,000 Vetch 1 3 10,208 6,470 11,661 6,400 10,507 8,677 14,413 12,000' 12,000' 11 1,000 Cowpeas 1 8,269 9,600 19,750 21,098 18,090 17,860 12,000' 12,000' 12,000' 1 Irrigation and fertilizer were applied to vegetable crops and not to cover crops. 2 Vetch and cowpeas were grown in plots and turned. SCover crops were grown and turned without record of weights being taken. ' Tonnage low due to short growing period between truck crops, enough green manure added to give 6 tons. m 0 -I -4 z I -1 Hm APPENDIX TABLE 12. YIELDS OF DIFFERENT COVER CROPS GROWN AND TURNED, SERIES B Z C Treatments FertiManure lizer Yields per acre by years Irri- No. per Lb. Ani a acret Green' gation1 19403 Lb. 20,000 20,000 6,000 6,000 20,000 20,000 20,000 20,000 6,000 20,000 20,000 1941 Lb. 10,016 12,352 6,950 6,969 12,448 16,681 14,166 15,638 7,232 16,156 14,105 1942 Lb. 8,800 3,680 8,684 14,432 17,840 11,843 13,440 10,000 12,378 1948 Lb. 9,360 8,480 11,680 9,520 11,360 9,600 10,960 8,240 10,640 9,440 10,640 1944 1945 19464 1947 1948 (6-10-4) Tons 0 0 0 0 12 12 12 6 6 12 12 Vetch Vetch Rye Rye Vetch Vetch Vetch Vetch Rye Vetch Vetch In. 0 1 0 1 0 1 1 1 1 1 1 Lb. 8,960 9,920 10,720 9,040 14,880 10,160 14,960 13,360 11,440 16,400 16,160 Lb. 4,829 4,144 14,016 11,722 8,528 8,846 8,077 5,850 14,720 7,805 6,806 Lb. 8,944 6,256 17,200 14,804 10,512 12,144 18,680 12,688 21,856 14,832 12,672 Lb. 11,616 10,464 12,800 9,184 19,872 23,498 19,923 15,536 15,232 21,146 22,768 Lb. 5,082 6,762 18,680 12,640 13,562 14,522 12,320 11,882 17,040 14,858 14,042 -4 6 7 8 9 10 11 12' 13 14 15 16 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,500 2,000 L.0 I-° Mn 18,840 12,800 'Irrigation and fertilizer were applied to vegetable crops and not to cover crops. ' Vetch and rye were grown in plots and turned. 1940 green manures were introduced. 'I 4'In 'Mno 1946 blue lupine was grown instead of vetch. elements were applied to all treatments except this one.