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also increases the density of residue covering the vetch stubble to prevent regrowth. Much quicker and more energy-efficient than mowing is use of a modified Buffalo rolling stalk chopper, an implement designed to shatter standing corn stubble. The chopper’s rolling blades break over, crimp and cut crop stems at ground level, and handle thick residue of hairy vetch or foxtail millet at 8 to 10 mph (131). No-till vegetable transplanting. Vetch that is suppressed or killed without disturbing the soil maintains moisture well for transplanted vegetables. No-till innovator Steve Groff of Lancaster County, Pa., uses the rolling stalk chopper to create a killed organic mulch. His favorite mix is 25 lb. hairy vetch, 30 lb. rye and 10 lb. crimson clover/A (132). No-till, delayed kill. Jeff Moyer of the Rodale Institute in Kutztown, Pa., no-tills corn into standing hairy vetch in late May or early June, waits several more days, then flail-chops the vetch before corn emergence. This method allows the vetch to produce maximum N and is late enough to allow soil warming even with the vetch in place (230). Also useful in killing hairy vetch on raised beds for vegetables and cotton is the improved prototype of an undercutter that leaves severed residue virtually undisturbed on the surface (70). The undercutter tool includes a flat roller attachment, which, by itself, usually provides only partial suppression unless used after flowering. Herbicides used to kill hairy vetch include glyphosate (only somewhat effective), paraquat, 2,4-D, dicamba and triazines including atrazine, cyanazine and metribuzin.Vetch will die in three to 30 days (338), depending on the material used and crop conditions. Vetch incorporation. As a rule, to gauge the optimum hairy vetch kill date, credit vetch with adding two to three pounds of N per acre per Winter hardy through the warmer parts of Zone 4, few legumes can rival hairy vetch’s N contributions. sunny day after full spring growth begins. Usually, N contribution by early bloom (10-25 percent) stage warrants killing the legume, rather than accepting yield loss due to late planting to get marginally more N at seed set or natural dry down after seed set. Cutting hairy vetch close to the ground at full bloom stage usually will kill it. However, waiting this long means it will have maximum top growth,and the tangled mass of mature vetch can overwhelm many smaller mowers or disks. Flail mowing before tillage helps,but that is a time- and horsepower-intensive process. Sickle-bar mowers should only be used when the vetch is well supported by a cereal companion crop and the material is dry (351). Heavy disk harrows, rotovators and power spaders can incorporate heavy, unmowed vetch stands. A moldboard plow can turn under large amounts of mowed vetch. Chisel plows and lighter disks can handle vetch killed earlier with herbicides. Harvesting seed. Plant hairy vetch with grains if you intend to harvest the vetch for seed. Use a moderate seeding rate of 10-20 lb./A to keep the stand from getting too rank (132). Vetch seedpods will grow above the twining vetch vines and use the grain as a trellis, allowing you to run the cutter bar higher to reduce plugging of the combine. Direct combine at midbloom to minimize shattering, or swath up to a week later. Seed is viable for at least five years (302). If you want to save dollars by growing your own seed, be aware that the mature pods shatter easily, increasing the risk of volunteer weeds. To keep vetch with its nurse crop, harvest vetch with a winter cereal and keep seed co-mingled for planting. Check the mix carefully for weed seeds. Management Cautions • About 10 to 20 percent of vetch seed is “hard” seed that lays ungerminated in the soil for one or more seasons. This can cause a weed problem, 116 MANAGING COVER CROPS PROFITABLY
especially in winter grains. With wheat, you can use 2,4-D for control. After a corn crop that can utilize the vetch-produced N, you could establish a hay or pasture crop for several years. • Don’t plant hairy vetch with a winter grain if you want to harvest grain for feed or sale. Production is difficult because vetch vines will pull down all but the strongest stalks. Grain contamination also is likely if the vetch goes to seed before grain harvest.Vetch seed is about the same size as wheat and barley kernels, making it hard and expensive to separate during seed cleaning (302). Grain price can be markedly reduced by only a few vetch seeds per bushel (82). • A severe freeze with temperatures less than 5 F may kill hairy vetch if there is no snow cover, reducing or eliminating the stand and most of its N value. If winterkill is possible in your area, planting vetch with a hardy grain such as rye ensures spring soil protection. Pest Management In legume comparison trials, hairy vetch usually hosts numerous small insects and soil organisms (162). Many are beneficial to crop production, (see below) but others are pests. Soybean cyst nematode (Heterodera glycines) and root-knot nematode (Meliodogyne spp.) sometimes increase under hairy vetch. If you suspect that a field has nematodes, carefully sample the soil after hairy vetch.If the pests reach an economic threshold, plant nematode-resistant crops and consider using another cover crop. Other pests include cutworms (302) and southern corn rootworm (47), which can be problems in no-till corn; tarnished plant bug— noted in coastal Massachusetts (38)—which readily disperses to other crops; and two-spotted spider mites in Oregon pear orchards (107). Leaving unmowed remnant strips can lessen movement of disruptive pests while still allowing you to kill most of the cover crop (38). Prominent among predator beneficials associated with hairy vetch are lady beetles,seven-spotted ladybeetles (38) and bigeyed bugs (Geocaris spp.). Vetch harbors pea aphids (Acyrthosiphon pisum) and blue alfalfa aphids (Acyrthosiphon kondoi) that do not attack pecans but provide a food source for aphid-eating insects that can disperse into pecans. (40). Similarly, hairy vetch blossoms harbor flower thrips (Frankliniella spp.), which in turn attract important thrip predators such as insidious flower bugs (Orius insidiosus) and minute pirate bugs (Orius tristicolor). Two insects may reduce hairy vetch seed yield in heavy infestations: the vetch weevil or vetch bruchid.Rotate crops to alleviate buildup of these pests (302). CROP SYSTEMS Mix hairy vetch with cereal grains to reduce the risk of N leaching. Killed hairy vetch creates a short-term but effective spring/summer mulch, especially for transplants. The mulch retains moisture, allowing plants to use mineralized nutrients better than unmulched fields. The management challenge is that the mulch also lowers soil temperature, which may delay early season growth (302). One option is to capitalize on high quality, low-cost tomatoes that capture the late-season market premiums. See Vetch Beats Plastic (p. 118). How you kill hairy vetch influences its ability to suppress weeds.Durability and effectiveness as a light-blocking mulch are highest where the stalks are left whole. Hairy vetch severed at the roots or sickle-bar mowed last longer and blocks more light than flailed vetch, preventing more weed seeds from germinating (70, 340). While there is evidence that hairy vetch exudes weak natural herbicides that may inhibit development of small onion, carrot and tomato seedlings (26), these compounds do not affect transplants (132). Southern farmers can use an overwintering hairy vetch crop in continuous no-till cotton. Vetch mixed with rye has provided similar or even increased yields compared with systems that Note: An unmown rye/hairy vetch mix sustained a population of aphid-eating predators that was six times that of the unmowed volunteer weeds and 87 times that of mown grass and weeds (39). HAIRY VETCH 117
Page 1 and 2:
$19.00 Managing Cover Crops Profita
Page 3 and 4:
SUSTAINABLE AGRICULTURE NETWORK THE
Page 5 and 6:
ACKNOWLEDGMENTS This book represent
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FOREWORD Cover crops slow erosion,
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HOW TO USE THIS BOOK Think of this
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BENEFITS OF COVER CROPS Cover crops
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decompose quickly, especially in wa
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Expect excessive field traffic arou
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5. Settle for the Best Available Co
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ORGANIC MATTER ADDITIONS The benefi
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Cover Crops Can Stabilize Your Soil
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generally a good idea to kill a leg
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• For perennial legumes that have
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MANAGING PESTS WITH COVER CROPS By
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The farmers get weed control by fla
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insects. This approach has been use
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• Subterranean Clover (Trifolium
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does no direct tillage, but aggress
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eplace the cover crop before beans,
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as buckwheat, cowpeas, sorghum-suda
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the couple harrows every two to thr
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Start Where You Are In many instanc
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INTRODUCTION TO CHARTS The four com
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pH Preferred. The pH range in which
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Chart 1 TOP REGIONAL COVER CROP SPE
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Chart 2 PERFORMANCE AND ROLES conti
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Chart 3B PLANTING Cost Cost/A Inoc.
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Chart 4B POTENTIAL DISADVANTAGES Sp
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ANNUAL RYEGRASS Lolium multiflorum
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prolonged heat, cold or drought.Tha
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crop for establishing a forage or l
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arley plants from fungus, armyworm
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can increase the fertilizer replace
Page 67 and 68: cultural and local considerations t
Page 69 and 70: (339), and by 99 percent in a Calif
Page 71 and 72: Killing & Controlling Nutrient avai
Page 73 and 74: ye/vetch/crimson clover,for example
Page 75 and 76: • In the Corn Belt and northern U
Page 77 and 78: Wheat Offers High-Value Weed Contro
Page 79 and 80: BUCKWHEAT Fagopyrum esculentum Type
Page 81 and 82: Rotations Buckwheat is used most co
Page 83 and 84: plants fractured subsoil compaction
Page 85 and 86: press some species of nematodes. Sp
Page 87 and 88: Incorporated sorghum-sudangrass res
Page 89 and 90: lodge soil particles. Sunlight is u
Page 91 and 92: Crimson-Berseem Clover Combo Works
Page 93 and 94: in water-use efficiency in the tria
Page 95 and 96: Microorganisms mineralize, or conve
Page 97 and 98: COWPEAS Vigna unguiculata Also call
Page 99 and 100: control if you go with rows, using
Page 101 and 102: drought-tolerant sorghum-sudangrass
Page 103 and 104: several winter annual legumes that
Page 105 and 106: In Ohio, crimson clover mixed with
Page 107 and 108: FIELD PEAS Pisum sativum subsp. arv
Page 109 and 110: Chill tolerant. Austrian winter pea
Page 111 and 112: In a “Flexible Green Manure” cr
Page 113 and 114: values from 13 to 34,but were gener
Page 115 and 116: year Maryland study that also inclu
Page 117: possible, but remember that hairy v
Page 121 and 122: less biomass than overwintering sta
Page 123 and 124: Jess Counts on GEORGE for N and Org
Page 125 and 126: after mid-April planting in souther
Page 127 and 128: second cutting. Regrowth comes from
Page 129 and 130: RED CLOVER Trifolium pratense Also
Page 131 and 132: MANAGEMENT Establishment & Fieldwor
Page 133 and 134: it function more like a biennial th
Page 135 and 136: Subclover cultivars often are descr
Page 137 and 138: trample in the seed. Subclover ofte
Page 139 and 140: Crop Systems Interseeded with wheat
Page 141 and 142: SWEETCLOVERS Yellow sweetclover (Me
Page 143 and 144: difficult to establish annual cover
Page 145 and 146: Spring seeding provides yellow swee
Page 147 and 148: enhances soil fertility, texture an
Page 149 and 150: WHITE CLOVER Trifolium repens Also
Page 151 and 152: for several freeze-thaw cycles. Mak
Page 153 and 154: COMPARATIVE NOTES • White clover
Page 155 and 156: Fall planting. Most growers seed at
Page 157 and 158: combining with a belt-type rubber p
Page 159 and 160: Then seed the remainder while walki
Page 161 and 162: screening, a number of farmers have
Page 163 and 164: the seed is relatively expensive. B
Page 165 and 166: Dyer, David A. 1998. Conservation L
Page 167 and 168: OTHER RESOURCES Cover Crops On The
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Cal/West Seeds Box 1428 Woodland, C
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Pick Seed Canada P.O. Box 304 1 Gre
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SARE Northeast Region Office Univer
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APPENDIX F REGIONAL EXPERTS These i
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David W. Wolfe Cornell University 1
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Bob Burdette Southern Seed Certific
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Shiou Kuo Washington State Universi
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20 Bird, George. 1997. Personal com
Page 185 and 186:
59 Clark,A.J. 1993. Managing hairy
Page 187 and 188:
102 Fernholz, Carmen. 1997. Persona
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141 Helm, J.L. and Dwain Meyer. 199
Page 191 and 192:
186 Koume, C.N. et al. 1988. Screen
Page 193 and 194:
226 Mohler, Charles L. 1994.A livin
Page 195 and 196:
267 Plumer, Mike. 1997. Personal co
Page 197 and 198:
309 Shrestha,A. et al. 1996.“Annu
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352 Varco, J.J., J.O. Sanford and J
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Bulk Discounts: Except as indicated
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INDEX A Alfalfa, 10, 42, 84, 88, 94
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performance and roles, 48-49 planti
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sorghum-sudangrass hybrids, 85 subt
Page 209 and 210:
subterranean clovers, 133, 137 swee
Page 211 and 212:
comparative notes, 71 crop systems,
Page 213 and 214:
crimson clover for, 102, 103 crop r
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