Pt .*. lP 7[ 3tX f i*~ . .- * p A .. t' 4 < r, .... ./ ! -' . "' w .y - 0ATO C: DIECO 3* 41# AUUR UNVRST LBM 0 BUHNN AUUNUIESIY CONTENTS Page ORIGIN AND DISTRIBUTION SEED GERMINATION .............. SEEDING RATE .................. VARIETY ADAPTATION PESTS . ................ .......... ................. ................................ .................. ........... ........... .................................. 3 3 ........... ........... ........... ........... 4 5 6 10 DESCRIPTION AND CHARACTERISTICS .......................... ............ ............ ........... TREFOIL-GRASS MIXTURES MANAGEMENT FOR PRODUCTION AND PERSISTENCE ............... FORAGE QUALITY AND ANIMAL PERFORMANCE SEED PRODUCTION .............. SUMM ARY ................ ACKNOWLEDGMENT ............ ............ 10 12 13 13 14 15 16 ....................................... LITERATURE CITED ............................................... FIRST PRINTING 4M, MAY 1982 Information contained herein is available to all without regard to race, color, sex, or national origin. Birdsfoot Trefoil in Alabama C.S. HOVELAND, R.L. HAALAND, R.R. HARRIS, and JA. McGUIRE* BORIGIN AND DISTRIBUTION IRDSFOOT TREFOIL (Lotus corniculatus) is a perennial forage legume that originated in the Mediterranean area of Europe (5). It occurred naturally in many pastures but was not cultivated in Europe until after 1900. Since then, it has also been grown in southern Brazil, Chile, Uruguay, Australia, and New Zealand. It is not known when trefoil was introduced to the United States, but during the 1930's and 1940's it became recognized as a valuable legume in New York State. At present, trefoil is mainly grown in the Northeast, Upper Midwest, and Pacific Northwest. DESCRIPTION AND CHARACTERISTICS Birdsfoot trefoil is a broad-leaved, tap-rooted, perennial legume which grows to a height of 12 to 30 inches, figure 1. It is finer stemmed and leafier than alfalfa (Medicago sativa). Trefoil leaves differ from alfalfa leaves in that the latter are always in groups of three, but trefoil has an additional two leaves at the base of the leaf branch. Flowers, resembling those of peas, are yellow and may have faint orange or red stripes. The slender brown to purple seed pods are 1 to 11/2 inches long and radiate from the stem branch similar to toes on a bird's foot; hence the name of this legume, figure 2. As the seed pods mature and dry they snap open and scatter the seed. Seeds are light to dark brown, oval to spherical in shape, and larger than seed of ladino clover *Respectively, former Professor and former Associate Professor, Department of Agronomy and Soils; Professor, Department of Animal and Dairy Sciences; and Associate Professor, Department of Research Data Analysis. 4 ALABAMA AGRICULTURAL EXPERIMENT STATION (Trifolium repens) but smaller than seed of alfalfa and red clover (Trifolium pratense). Birdsfoot trefoil seed must be inoculated with a special inoculum before planting. Bacteria that inoculate alfalfa, arrowleaf clover, or white clover are not effective on trefoil. Trefoil has several advantages: (1) tolerant of soil acidity, (2) drought tolerant, (3) not damaged by alfalfa weevil, (4) reseeds well from hard seed, (5) high quality forage, and (6) does not cause bloat in cattle or sheep. Disadvantages are:.(1) indeterminate flowering and seed shattering, generally resulting in low seed yields, and (2) susceptibility to crown and root-rotting diseases in the Southern United States. In addition, northern trefoil varieties generally have poor seedling vigor and are slow to establish. New varieties and experimental lines developed from Mediterranean germplasm at the Alabama Agricultural Experiment Station and other institutions offer promise that trefoil may have a place in the South. This publication summarizes research with birdsfoot trefoil in Alabama. Research was conducted with the following trefoil varieties and lines: AT-U-Erect-growing, hay type selected for persistence from Italian and Yugoslavian plant introductions at Auburn University. Not released. AT-i--Semi-erect type selected at Auburn University from superior plants of the San Gabriel variety brought from Brazil. Not released. AT-P-Semi-prostrate type with stolons, selected at Auburn University from Italian and Yugoslavian plant introductions. Not released. Fergus--Naturalized semi-prostrate strain from a 15-year-old Kentucky pasture planted to a mixture of Empire and imported French germplasm. Dawn-Semi-erect variety selected in Missouri for resistance to root rots and to leaf and stem diseases. Empire-Prostrate, late-maturing variety selected for persistence in New York State. Viking-Erect, broad-leaved variety developed in New York State from Danish and New York strains. San Gabriel-Naturalized erect strain from Rio Grande do Sul in southern Brazil. Vega II-Erect type selected from San Gabriel trefoil by Northrup King Co. in California. Carroll-Semi-prostrate, pasture type developed in Iowa. Georgia--Seed increase of erect-type Mediterranean germplasm that had persisted for many years at Griffin, Georgia. Not released. SEED GERMINATION Trefoil is normally seeded during autumn in the South when soil temperatures are often high and moisture is limited. In laboratory seed germination BIRDSFOOT TREFOIL IN ALABAMA 5 TABLE 1. SEED GERMINATION OF TREFOIL VARIETIES AT TWO TEMPERATURES AFTER 16 DAYS Variety Seed germination 68F Pct. 86 0F Pct. AT-U ........................ AT-1 ......................... 85ab* 90a 81a 79a AT-P ........................ Fergus ..................... .. 90a 92a 79a 73ab Viking ....................... 8lab 63bc Dawn ........................ 79ab 56c Empire ...................... 74b 40d *Any two means within a column marked with the same letterare not significantlydifferent at 5 percent level of probability. trials, trefoils of Mediterranean or Brazilian origin (AT-U, AT-1, and AT-P) germinated better at high temperature than trefoils of northern origin (Viking, Dawn, and Empire), table 1. Fergus was intermediate in germination at high temperature. Seed germination in the laboratory under simulated drought was highest for Fergus and trefoils of Mediterranean or Brazilian origin, table 2. According to these results, varieties such as Fergus should result in better stands than varieties such as Dawn or Empire when soil moisture is not optimum. TABLE 2. SEED GERMINATION OF TREFOIL VARIETIES AFTER 12 DAYS AS AFFECTED BY 0 SIMULATED DROUGHT USING A POLYETHYLENE GLYCOL SOLUTION AT 68 F Seed germination Variety Pure water, Simulated drought, Obars Pct. Fergus ....................... AT-U ........................ 98a* 97a -3 bars Pct. 98a 90a AT-1 ......................... AT-P ........................ Viking ....................... 94ab 95ab 82bc 88ab 85ab 75bc Dawn ........................ Empire ...................... 5 percent level of probability. 82bc 76c 70c 45d * Any two means within acolumn marked with the same letter are not significantly different at SEEDING RATE Broadcast seeding of trefoil varieties was made at the Plant Breeding Unit on a well-prepared fine sandy loam seedbed. The first year, AT-P yielded more at 6 pounds than 4 pounds seed per acre while Fergus required 8 pounds per acre for highest yields, table 3. Dawn yielded more at 10 pounds per acre than at 6 pounds. By the second year, seeding rate had no effect on yield ofAT-P and only a small effect with Fergus and Dawn. Considering the 6 ALABAMA AGRICULTURAL EXPERIMENT STATION TABLE 3. FORAGE YIELD OF TREFOIL VARIETIES AS AFFECTED BY SEEDING YEARS RATE AT PLANT BREEDING UNIT, TALLASSEE, OVER TWO Dry forage yield per acre Variety 1980 1981 Lb. Lb. Lb. 10 6,180a* 8,730ab AT-P................... 6,180a 9,340a 8 8,700a5 6 6,140a 9,lO0ab 4,990bc 4 10 5,350b 8,980ab Fergus ................. 8,590ab 8 4,900bcd 6 4,090e 9,250a 4 4,170de 8,530b 8,680ab 10 5,270b Dawn................... 8,380bc 8 4,660bcde 4,28Scde 8,220bc 6 7,840c 4 4,21de *Any two yield entries within a column marked with the same letter are not significantly different at 5 percent level of probability. Seeding rate/acre cost oftrefoil seed, 4 pounds per acre should be a practical seeding rate when planting on a good seedbed. VARIETY ADAPTATION The performance ofSan Gabriel trefoilwas excellentwhen compared with alfalfa and red clover, at the Sand Mountain Substation over a 4-year period, table 4. Average forage yield for trefoil was similar to that for alfalfa, just under 4 tons per acre. The productive seasons extended from April through July and again during September to mid-October. Red clover yield declined each year of the test as stands thinned. Stands of trefoil were still good after 5 years, figure 3. Natural reseeding of the trefoil into adjacent areas was common. In the first series of trefoil variety trials, good stands were obtained at each location except at the Sand Mountain Substation where rains delayed planting and many seedlings were lost due to soil heaving. Three-year average forage yields were similar for all varieties except AT-i and Vega LI at TABLE 4. FORAGE YIELD OF TREFOIL, ALFALFA, AND RED CLOVER OVER 4-YEAR PERIOD AT SAND MOUNTAIN SUBSTATION Dry forage yield per acre Average 1978 1977 1976 Lb. Lb. Lb. Lb. 7,,020a 7,780a Gladiator alfalfa.........5,600a* 10,410a 7,470a San Gabriel trefoil.......6,330a 10,270a 7,450a 5,830b Oc 4,830b Kenstar red clover...5,400a 8, 960b 4, 970b evi. s 1975 Lb. 8,10a Legume stand 1976 1978 Pct. Pct. 78 92 89 71 95 0 *Any two yield entries within a column marked with the same letter are not significantly different at 5 percent level of probability. BIRDSFOOT TREFOIL IN ALABAMA TABLE 5. FORAGE YIELD OF TREFOIL VARIETIES AT FOUR ALABAMA LOCATIONS 7 Dry forage yield per acre Variety Tennessee Valley Sub. 1978-80 Lb. 6,130a* 5,870a AT-P ... AT-U ... Sand Mountain Sub. 1977-78 Lb. 3,860a -- Upper Coastal Plain Sub. 1978-80 Lb. 5,090a 4,870a Black Belt Sub. 1978-79 Lb. 5,000a 4,220ab Average all locations Lb. 5,020 -- Fergus .. AT-1 .... Vega II . 5,670ab 5,550b 5,490b 3,550a -- 5,080a 4,650ab 4,230b 4,430ab 3,360c 3,630bc 4,680 --- -- Dawn ... Viking .. Carroll .. Empire . 5,860a 6,050a -- 2,780b 2,520b 2,660b 1,120c 4,560ab 4,500ab -- 4,160b 2,610d -- 4,340 3,920 -- -- -- -- -- *Any two yield entries within a column marked with the same letter are not significantly different at 5 percent level of probability. the Tennessee Valley Substation, table 5. At the Sand Mountain Substation, the advantage of excellent seedling vigor in AT-P and Fergus resulted in less loss of plants by soil heaving in winter so yields were higher than for northern types. Yields were generally similar for most trefoils over a 3-year period at the Upper Coastal Plain Substation. At the Black Belt Substation, however, AT-P, Fergus, and AT-U were more productive than AT-1 and Viking. When yields at all locations were averaged, AT-P and Fergus were most productive. In the second series of trefoil variety trials, forage yields of about 2 to over 4 tons per acre annually were obtained over 2 years at five locations, table 6. Good stands were obtained at all locations. At the Tennessee Valley and Piedmont substations, forage yields were similar for all trefoil entries. At the Plant Breeding Unit, Georgia-i, AT-P, and AT-U outyielded Fergus and Dawn. AT-P was the highest yielding and Dawn the lowest yielding variety TABLE 6. FORAGE YIELD OF TREFOIL VARIETIES AT FIVE ALABAMA LOCATIONS, 2-YEAR AVERAGE, 1980-81 Variety Tennessee Valley Sub. Lb. -- Dry forage yield per acre Prattville Plant Piedmont Breeding Exp. Field Unit Lb. Lb. Lb. -7,350a -- Gulf Coast Sub. Lb. 8,820a Average all locations Lb. Georgia-1 .. -- 7,240a 4,100a AT-P ...... 5,410a* 5,610b 4,070a Fergus ..... 5,360a 7,040a 4,190a 5,570a AT-U ...... 6,580ab 3,870a Vega II .... 4,650a 6,620ab 4,360a 4,770a AT-1 ....... 5,750b 3,650a 5,020a Dawn ...... *Any two yield entries within a column marked with the different at 5 percent level of probability. 7,020a 5,930b 6,550b 6,150b 6,370b 5,670c same letter 6,080 6,620b 5,510 6,580b 5,460 3,950d 5,140 4,440d 5,130 3,520d 5,050 5,170c are not significantly $ 1 'as- Al- V.' a.,7&. - V r ~ .:/ ' 2 L. Y 4 fr. r A AA, t over much of late spring and summer inAlabama. FIG. 2 (top right). Birdsfoot trefoil gets its name from the five or six seed pods attached to the end of a flower stem, which give the appearance of a bird's foot. FIG. 3(bottom left). Excellent stand of trefoil (left) is contrasted with poor survival of red clover (right) after 5 years at the Sand Mountain Substation (photo made June 21, 1979). FIG. 4 (bottom right). Seedling vigor of some trefoil varieties such as Fergus (left, labeled Kentucky) is much better than most northern varieties, such as Dawn (right). FIG.1 (top left). Birdsfoat tref oil is aleafy legume with bright yellow flowers that bloom at Prattville. Surprisingly, the highest trefoil y ieldl in the State xwas Made at the Ciif Coast Substation. First-y ear production dfali entries at this location was good, hot by the second year only Georgia-1, AT-P, and Fergus had good stands. Poor persistence was a serious prolblem wxith the other-entries. Other obserxvationis indicate that trefoil v arieties cutrrentlx axvailahie are not adapted and will not persist in central or sontitern Alabama. Seedling vigor is important in trefoil establishment. Weed competitio)t can be' severe and seedllings of northern trefoil varieties grow mttch sioxwer -j i "ir .,,,.*' , .. sp. r. . Fnudi e e y o r F ( . r o $j n s o ( etlyanginofro temreFG8 na. tura rsen. Smalln seeings are shw diler tine rost Fegu (riht) Thsce-rfi potgrah ereto eprimntal Geftergihavi (le tocethen tTennessee Valley SubstationG (ottmf)To ma inai aul stan of9reoilan than those of Mediterranean or Brazilian origin, figure 4. Often, northern trefoil varieties, such as Dawn or Empire, fail to become estab~lishedl in Alabama because they are poor competitors. The growth habits of trefoil varieties (liffer greatly, figure 5. The most prostrate types, such as Fergus, are likely to persist better than erect ty pes under grazing. It is also likely that yield trials under clipping do not properly assess the worth of prostrate trefoil types wh ich hav e more leaf tissue near the ground than the erect types 10 ALABAMA AGRICULTURAL EXPERIMENT STATION PESTS Crown and root rots are important diseases of trefoil, often resulting in serious stand losses. These problems are much more severe in central and southern Alabama than in the northern part of the State. Nematodes are a major problem in trefoil persistence on sandy soils of central and southern Alabama. In a 3-year field trial in central Alabama, trefoil stands and forage yields were good the first year but declined drastically the second year on untreated soil, table 7. Trefoil on soil previously treated with methyl bromide maintained fair stands and a low level of forage production during the second and third years. Parasitic nematode numbers were higher on red clover than on alfalfa or trefoil, table 8. Rootknot was the major nematode species on trefoil. TABLE 7. FORAGE YIELD OF TREFOIL, RED CLOVER, AND ALFALFA AS AFFECTED BY NEMATODE CONTROL, PLANT BREEDING UNIT, OVER 3 YEARS Dry forage yield per acre 1980 1979 1978 Treated Untreated Treated Untreated Treated Untreated soil soil soil soil soil soil Lb. Lb. Lb. Lb. Lb. Lb. Gladiator alfalfa ......... 14,790a* 12,380b 9,470a 7,960a 6,040a 2,410b Redland red clover ...... 9,690c 8,190cd 4,680b 460c Oc Oc AT-1 trefoil ............. 7,550cde 6,390e 3,120b 500c 3,090b Oc *Any two yield entries for a particular year marked with the same letter are not significantly different at 5 percent level of probability. Legume TABLE 8. PARASITIC NEMATODE POPULATIONS IN SOIL AND ROOTS OF ALFALFA, RED CLOVER, AND TREFOIL AS AFFECTED BY NEMATODE CONTROL Legume Gladiator alfalfa ............... Redland red clover ............ AT-1 trefoil ................... . Nematodes per 50 cc soil and roots 1979 1978 Treated Untreated Treated Untreated soil soil soil soil No. No. No. No. 0 28 18 37 34 86 86 103 0 49 13 46 TREFOIL-GRASS MIXTURES Trefoil grows well in association with a cool season perennial grass. In a trial planted in September 1976 at the Sand Mountain Substation, autumn drought caused late establishment of trefoil seedlings, resulting in severe stand loss due to soil heaving during winter. With natural reseeding, however, trefoil stands increased each year over the 3-year period so that by the third year the grass-trefoil yield equalled that of grass-red clover, table 9. BIRDSFOOT TREFOIL IN ALABAMA 11 TABLE 9. FORAGE YIELD OF TREFOIL AND RED CLOVER IN MIXTURES WITH KENTUCKY 31 TALL FESCUE AND BOONE ORCHARDGRASS AT SAND MOUNTAIN SUBSTATION Dry forage per acre 1978 1979 Average Lb. Lb. Lb. Lb. 7,980a 7,260a Ky. 31 tall fescue-none (120 lb. N/acre) ..... 8,200a* 5,600ab 5,660ab 4,230b 6,080b Ky. 31 tall fescue-Redland red clover ....... 8,344a 5,020b 5,190b 5,860b 4,690bc Ky. 31 tall fescue-AT-1 trefoil .............. 5,250b 5,880b 5,550ab Boone orchardgrass-None (120 lb. N/acre) ... 6,840b 6,100b 6,300a 4,050b Boone orchardgrass-Redland red clover ..... 7,940a 5,460b 5,030b 4,430c 5,200b Boone orchardgrass-AT-1 trefoil ............ *Any two yield entries within a column marked with the same letter are not significantly different at 5 percent level of probability. Grass-legume 1977 TABLE 10. FORAGE YIELD OF TREFOIL AND CLOVER IN MIXTURES WITH KENTUCKY 31 AND TRIUMPH TALL FESCUE AT SAND MOUNTAIN SUBSTATION, 2-YEAR AVERAGE Dry forage yield per acre Lb. 8,260ab* Ky. 31 tall fescue-none (150 lb. N/acre) ........................ 8,950a Ky. 31 tall fescue-Redland red clover .......................... 7,360bc Ky. 31 tall fescue-Regal ladino clover ................. 6,640c Ky. 31 tall fescue- Fergus trefoil .............................. 8,170ab Triumph tall fescue-none (150 lb. N/acre) ....................... 8,000ab Triumph tall fescue-Redland red clover ........................ 6,690c Triumph tall fescue-Regal ladino clover ....................... 6,540c Triumph tall fescue-Fergus trefoil ................. *Any two yield entries within a column marked with the same letter are not significantly different at 5 percent level of probability. Grass-legume Trefoil with tall fescue (Festucaarundinacea)did not produce as much dry forage as tall fescue that received 120 pounds of N per acre. However, trefoil with orchardgrass (Dactylis glomerata) yielded nearly as much as orchardgrass with nitrogen fertilizer. Since orchardgrass is less competitive than tall fescue, it is an ideal companion grass with trefoil, figure 6. In another 2-year trial at the Sand Mountain Substation, trefoil with Kentucky 31 or Triumph tall fescue yielded about the same as ladino clover but less than red clover or tall fescue with 150 pounds of N per acre, table 10. Had this experiment been continued another year, red clover stand and production probably would have declined while trefoil would have remained productive. 1 Sod-seeding Fergus trefoil in tall fescue using Paraquat M as a growth suppressant was successful (1). By the third year, trefoil stands and productivity were superior to both red clover and ladino clover. 'Paraquat is a product of Chevron Chemical Co. 12 ALABAMA AGRICULTURAL EXPERIMENT STATION MANAGEMENT FOR PRODUCTION AND PERSISTENCE Reseeding is important for persistence of trefoil in pastures. In areas where the perennial nature of trefoil is shortened by diseases, natural reseeding is essential for maintaining stands and productivity (7). This is demonstrated by a 3-year experiment at the Sand Mountain Substation, table 11. Clipping frequently to simulate grazing sharply reduced trefoil stands and production by the third year as compared to clipping frequently but allowing seed production each year. New seedlings arise from natural reseeding from existing trefoil plants, figure 7. Rotational grazing with cattle or sheep resulted in better persistence and higher animal productivity than under continuous grazing in Ohio research (8, 9). This was due to the unfavorable effect of continuous grazing on maintenance of carbohydrate root reserves, which are normally low for trefoil during the growing season (6). Vigorous trefoil stands can best be maintained by long intervals between harvests, cutting at a high stubble height, and leaving some leaf tissue on plants. Thus, prostrate trefoil types, such as Fergus, can be grazed more frequently and will maintain productivity much better than erect-growing types since many leaves remain on the plants. Practical grazing management of trefoil should allow considerable leaf tissue to assure vigorous regrowth throughout the season. Management becomes even more critical under high temperature conditions in Alabama because carbohydrate root reserves are lower under warm than cool temperatures (4). TABLE 11. TOTAL FORAGE YIELD AND BOTANICAL COMPOSITION OF AT-1 TREFOIL WITH TALL FESCUE AND ORCHARDGRASS AS AFFECTED BY MANAGEMENT, SAND MOUNTAIN SUBSTATION OVER 3-YEAR PERIOD Cutting treatment' Dry forage yield per acre 1978-79 1979-80 1980-81 Lb. Lb. Lb. Average trefoil content of forage 1978-79 1979-80 1980-81 Pct. Pct. Pct. Trefoil alone 7,850bc* 3,480a 3,550bc 100 100 100 Hay-reseeding .......... Pasture-reseeding ....... .7,710bc 2,470bc 4,790a 100 100 100 100 100 Pasture-no reseeding .....6,760cd 2,680bc 3,010bc 100 Trefoil-Ky. 31 fescue 28 8,500ab 3,100ab 3,480bc 25 17 Hay-reseeding .......... 2,490bc 3,980ab 34 24 28 Pasture-reseeding ....... 9,270a 2,210d 33 17 2 Pasture-no reseeding ..... 9,060a 2,160c Trefoil-Boone orchardgrass 70 31 30 Hay-reseeding .......... 7,280cd 3,630a 3,560bc Pasture-reseeding ....... 7,130cd 2,780bc 3,960ab 72 38 33 22 21 Pasture-no reseeding ..... 6,160d 2,710bc 2,550d 54 *Any two yield entries within a column marked with the same letter are not significantly different at 5 percent level of probability. 'No nitrogen fertilizer applied. BIRDSFOOT TREFOIL IN ALABAMA 13 FORAGE QUALITY AND ANIMAL PERFORMANCE Crude protein and dry matter digestibility of trefoil is at least equal to that of alfalfa. In a Minnesota study (3), substitution of birdsfoot trefoil for alfalfa-grass as one-third of total seasonal pasture resulted in 22 to 24 percent increases in lamb average daily gains (ADG) over a 3-year period. In a 2-year grazing study at the Sand Mountain Substation in northern Alabama, ADG of beef steers on Fergus trefoil-tall fescue pasture was equal to that on ladino clover even though stands of trefoil were thin and average legume composition of the pasture was only 13 percent as compared to 24 percent for ladino clover (2). At the Tennessee Valley Substation in northern Alabama, the experimental AT-P trefoil was planted in mixtures with two tall fescue varieties and orchardgrass in 2.5-acre paddocks with three replications. Beef steers were grazed during two seasons on the trefoil-grass and tall fescue-nitrogen pastures. Drought seriously reduced production during both years. Stocking rate and gain per acre were highest on the tall fescue-nitrogen pastures, but ADG was much higher on the trefoil grass pastures, table 12. Tall fescue-nitrogen furnished twice the normal ADG, probably a result of the low level of Acremonium coenophialum, a fungus that has been associated with poor animal gains on tall fescue. Even so, the trefoil sharply increased ADG to levels well above those normally obtained on small grain pasture. Natural reseeding of trefoil occurred during the 2 years. Steers on trefoilgrass pastures were in excellent condition, figure 8. The outstanding ADG of steers on trefoil suggests that, with this legume, good gains can be maintained on stocker steers in the summer after small grain-ryegrass pastures are mature. TABLE 12. PERFORMANCE OF BEEF STEERS ON AT-P TREFOIL-GRASS PASTURES AT TENNESSEE VALLEY SUBSTATION, 2-YEAR AVERAGE, 1980-81 Pasture species' Stocking rate, steers/acre Gain per acre Average daily gain of steers Hallmark orchardgrass + trefoil ....... Triumph tall fescue + trefoil .......... Ky. 31 tall fescue + trefoil ........... . Ky. 31 tall fescue + 200 lb. N/acre .... No. 1.32 1.44 1.35 2.00 Lb. 357 375 336 425 Lb. 2.94 2.50 2.36 2.14 'Planted September 1979; no nitrogen fertilizer applied to trefoil pastures. SEED PRODUCTION Seed yields of trefoil are much lower than other legumes, due primarily to the tendency of pods to dehisce as they mature, scattering seed on the 14 ALABAMA AGRICULTURAL EXPERIMENT STATION ground. Seed harvesting is further complicated by the fact that mature and green pods occur throughout the seed production period since plants flower over a long period. Considerable experience is required to determine when to harvest the seed crop. Trefoil seed production is not recommended for farmers in Alabama. SUMMARY Birdsfoot trefoil is a productive perennial forage legume with several desirable qualities: (1) tolerant of soil acidity, (2) drought tolerant, (3) resistant to alfalfa weevil, (4) reseeds well from hard seed, (5) non-bloating, and (6) furnishes excellent animal performance. Undesirable qualities are: (1) low seed yields because of shattering, (2) susceptibility to crown and root rot diseases, and (3) poor seedling vigor of northern varieties. Dry forage yields of trefoil have averaged from 4,000 to over 8,000 pounds per acre. Once established, most varieties have yielded well for several years in northern Alabama. The productive season in northern Alabama extends from April through July and during September to mid-October. Trefoil shows promise only for northern Alabama. Root rots and nematodes reduce stand persistence in central and southern Alabama. Poor seedling vigor and slow establishment are serious problems with northern varieties of trefoil, making them poor competitors with weeds and associated grasses. Trefoil varieties of Mediterranean origin germinate better at high temperature, have much better seedling vigor, and provide more rapid establishment than northern varieties. Prostrate types of trefoil are better suited to grazing than erect-growing types since some leaf tissue must be kept on plants to maintain productivity and stands. At this time, Fergus is the only commercially available trefoil variety with good seedling vigor, prostrate growth habit, and disease tolerance that appears to be adapted to northern Alabama. Trefoil grows well in association with orchardgrass or tall fescue if the grasses are planted in 12- to 14-inch rows. Natural reseeding is important for persistence of trefoil in pastures. Grazing should be light enough to permit some seed production each year. Steer gains on trefoil have been high in Alabama, averaging over 2.5 pounds per day for the grazing season. Seed production oftrefoil should not be attempted in Alabama since yields will be low because of shattering. BIRDSFOOT TREFOIL IN ALABAMA BIRDSFOOT TREFOIL IN ALABAMA 15 1 Trefoil is a promising legume for northern Alabama. Some suggestions are offered for growing trefoil on a limited basis: (1) Soil test to be sure fertilizer and lime needs are met. (2) Plant 4 to 5 pounds per acre of inoculated Fergus trefoil seed in September on a well-prepared seedbed with a cultipacker-seeder. Plant orchardgrass or tall fescue in 12- to 14-inch rows. (3) Do not graze until trefoil is 6 inches tall. Graze lightly the first year to permit some seed production. (4) In succeeding years, do not overgraze. Allow some seed production each year. ACKNOWLEDGMENT Technical assistance for these studies was supplied by M. W. Alison, Jr., D.H. Sides, C.F. Weaver, and Judy B. Hill. Assistance ofthe following substation and experiment field personnel who cared for field plots and grazing experiments is gratefully acknowledged: W.B. Webster and V.H. Calvert II, Tennessee Valley Substation; J.T. Eason and M.E. Ruf, Sand Mountain Substation; R.A. Moore, Jr., Upper Coastal Plain Substation; W.A. Griffey and H. E. Burgess, Piedmont Substation; L. L. Walker and H. C. Hoyle, Plant Breeding Unit; F.T. Glaze, Prattville Experiment Field; L.A. Smith and H.W. Grimes, Jr., Black Belt Substation; and E.L. Carden and F.B. Selman, Gulf Coast Substation. LITERATURE CITED (I) C.S., M.W. ALISON, JR., R.F. MCCORMICK, JR., W.B. WEBS.TER,'V:H... CALVERT II, J.T. EASON, ME. RUF, WA. GRIFFEY, HE. BURGE S, L.,A. SMITH, AND H.W. GRIMES, JR. 1981. Seeding Legumes in Tall. Fescue So& Ala. Agr. Exp. Sta. Bull. 531. (RR. HARRIS, E.E. THOMAS, EM. CLARK, JA. MCGUIRE, J.T. EASON,,AND M.E. RUF. 1981. Tall Fescue with Ladino Clover or HOVELAND, Birdsfoot Trefoil as Pasture for Steers in Northern Alabama. Ala. Agr. Exp. ,(3) (4) (5) Sta. Bull. 530. MARTEN, G.C. AND R. M. JORDAN. 1979. Substitution Value of Birdsfoot Trefoil for Alfalfa-grass in Pasture Systems. Agron. J. 71:55-59. NELS.UN, C. J;.AND DALE SMITH. 1969. Growth of Birdsfoot Trefoil and Alfalfa. IV. Carbohydrate Reserve Levels and Growth Analysis Under Two Temperature Regimes. Crop Sci. 9:589-591. SEANEY, R.R. 1973. Birdsfoot Trefoil. pp. 177-188. In M.E. Heath, D.S. Metcalfe, and R.F. Barnes (ed.), Forages, the Science of Grassland Agriculture (3rd ed.). Iowa State Univ. Press, Ames, Iowa. (6) (7) SMITH, DALE. 1962. Carbohydrate Root Reserves in Alfalfa, Red Clover, and BirdsfootTrefoil Under Several Management Schedules. Crop Sci. 2:75-78. TAYLOR, T. H., W.C. TEMPLETON, JR., AND J. W. Effects on Persistence and Productivity of Birdsfoot Trefoil (Lotus corniculatus Agron. J. 65:646-648. WYLER. 1973. Management (8) (9) L.). VAN KEUREN, R.W. AND (Lotus corniculatus L.) as Influenced by Plant Growth Habit and Grazing Management. Agron. J. 60:92-95. , R.R. DAVIS, D.S. BELL, AND E.W. KLOSTERMAN. 1969. Effect of Grazing Management on the Animal Production from Birdsfoot Trefoil Pastures. Agron. J. 61:422-425. R. R. DAVIS. 1968. Persistence of Birdsfoot Trefoil