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Red Clover . . . . . . . . . . . . . . . . . . . . . . . . . . . 159Subterranean Clovers . . . . . . . . . . . . . . . . . . 164Sweetclovers . . . . . . . . . . . . . . . . . . . . . . . . . 171 Sweetclover: Good Grazing, GreatGreen Manure. . . . . . . . . . . . . . . . . . . . . 174White Clover . . . . . . . . . . . . . . . . . . . . . . . . . 179 Clovers Build Soil, BlueberryProduction . . . . . . . . . . . . . . . . . . . . . . . . 182Woollypod Vetch . . . . . . . . . . . . . . . . . . . . . . 185APPENDICESA.Testing Cover Crops on Your Farm . . . . . . 189B. Up-and-Coming Cover Crops. . . . . . . . . . . 191C. Seed Suppliers . . . . . . . . . . . . . . . . . . . . . . 195D. Farming Organizations withCover Crop Expertise . . . . . . . . . . . . . . . . 200E. Regional Experts . . . . . . . . . . . . . . . . . . . . 202F. Citations Bibliography . . . . . . . . . . . . . . . . 280G. Resources from SARE . . . . . . . . . . . . . . . . 230H. Reader Response Form . . . . . . . . . . . . . . . 232INDEX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233ACKNOWLEDGMENTShis 3rd edition could not have been written without the help of many cover crop experts. It isbased in large part on the content of the 2nd edition, researched and written by Greg Bowman,Craig Cramer and Christopher Shirley. The following people reviewed the 2nd edition, suggestedrevisions and updates and contributed new content.TAref Abdul-Baki, retired, USDA-ARSWesley Adams, Ladonia, TXKenneth A. Albrecht, Univ. of WisconsinJess Alger, Stanford, MTRobert G. Bailey, USDA Forest ServiceKipling Balkcom, USDA-ARSRonnie Barentine, Univ. of GeorgiaPhil Bauer, USDA-ARSR. Louis Baumhardt, USDA-ARSRich and Nancy Bennett, Napoleon, OHValerie Berton, SARERobert Blackshaw, Agriculture and Agri-Food CanadaGreg Bowman, NewFarmRick Boydston, USDA-ARSLois Braun, Univ. of MinnesotaEric B. Brennan, USDA-ARSPat Carr, North Dakota State Univ.Max Carter, Douglas, GAACKNOWLEDGMENTSGuihua Chen, Univ. of MarylandAneeqa Chowdhury, SAREHal Collins, USDA-ARSCraig Cramer, Cornell Univ.Nancy Creamer, North Carolina State Univ.William S. Curran, The Pennsylvania State Univ.Seth Dabney, USDA-ARSBryan Davis, Grinnell, IAJorge Delgado, USDA-ARSJuan Carlos Diaz-Perez, Univ. of GeorgiaRichard Dick, Ohio State Univ.Sjoerd W. Duiker, The Pennsylvania State Univ.Gerald W. Evers, Texas A&M Univ.Rick Exner, Iowa State Univ. ExtensionRichard Fasching, NRCSJim French, Partridge, KSEric Gallandt, Univ. of MaineHelen Garst, SARE5

Dale Gies, Moses Lake, WABill Granzow, Herington, KSStephen Green, Arkansas State Univ.Tim Griffin, USDA-ARSSteve Groff, Holtwood, PAGary Guthrie, Nevada, IAMatthew Harbur, Univ. of MinnesotaTimothy M. Harrigan, Michigan State Univ.Andy Hart, Elgin, MNZane Helsel, Rutgers Univ.Paul Hepperly, The Rodale InstituteMichelle Infante-Casella, Rutgers Univ.Chuck Ingels, Univ. of CaliforniaLouise E. Jackson, Univ. of CaliforniaPeter Jeranyama, South Dakota State Univ.Nan Johnson, Univ. of MississippiHans Kandel, Univ. of Minnesota ExtensionTom Kaspar, USDA-ARSAlina Kelman, SARERose Koenig, Gainesville, FLJames Krall, Univ. of WyomingAmy Kremen, Univ. of MarylandRoger Lansink, Odebolt, IAYvonne Lawley, Univ. of MarylandFrank Lessiter, No-Till FarmerJohn Luna, Oregon State Univ.Barry Martin, Hawkinsville, GATodd Martin, MSU Kellogg Biological StationMilt McGiffen, Univ. of CaliforniaAndy McGuire, Washington State Univ.George McManus, Benton Harbor, MIJohn J. Meisinger, USDA/ARSHenry Miller, Constantin, MIJeffrey Mitchell, Univ. of CaliforniaHassan Mojtahedi, USDA-ARSGaylon Morgan, Texas A&M Univ.Matthew J. Morra, Univ. of Idaho6Vicki Morrone, Michigan State Univ.Jeff Moyer, The Rodale InstitutePaul Mugge, Sutherland, IADale Mutch, MSU Kellogg Biological StationRob Myers, Jefferson InstituteLloyd Nelson, Texas Agric. Experiment StationMathieu Ngouajio, Michigan State Univ.Eric and Anne Nordell, Trout Run, PASharad Phatak, Univ. of GeorgiaDavid Podoll, Fullerton, NDPaul Porter, Univ. of MinnesotaAndrew Price, USDA-ARSEd Quigley, Spruce Creek, PARJ Rant, Grand Haven, MIBob Rawlins, Rebecca, GAWayne Reeves, USDA-ARSEkaterini Riga, Washington State Univ.Lee Rinehart, ATTRAAmanda Rodrigues, SARERon Ross, No-Till FarmerMarianne Sarrantonio, Univ. of MaineHarry H. Schomberg, USDA-ARSPat Sheridan, Fairgrove, Mich.Jeremy Singer, USDA-ARSRichard Smith, Univ. of CaliforniaSieglinde Snapp, Kellogg Biological StationLisa Stocking, Univ. of MarylandJames Stute, Univ. of Wisconsin ExtensionAlan Sundermeier, Ohio State Univ. ExtensionJohn Teasdale, USDA-ARSLee and Noreen Thomas, Moorhead, MNDick and Sharon Thompson, Boone, IAEdzard van Santen, Auburn Univ.Ray Weil, Univ. of MarylandCharlie White, Univ. of MarylandDave Wilson, The Rodale InstituteDavid Wolfe, Cornell Univ.MANAGING COVER CROPS PROFITABLY

HOW TO USE THIS BOOKhink of this book as a tool chest, not a cookbook.You won’t find the one simple recipeto meet your farming goals. You will findthe tools to select and manage the best covercrops for the unique needs of your farm.In this tool chest you will find helpful maps andcharts, detailed narratives about individual covercrop species, chapters about specific aspects ofcover cropping and extensive appendices thatwill lead you to even more information.T1. Start with Top Regional Cover Crop Species(p. 66). This chart will help you narrow yoursearch by listing the benefits you can expect fromthe top cover crops adapted to your region.You’lldiscover which are the best nitrogen (N) sources,soil builders, erosion fighters, subsoil looseners,weed fighters and pest fighters.2. Next, find out more about the performance andmanagement of the cover crops that look likegood candidates for your farm. You’ll find twostreams of information: Charts quickly provide you with details tohelp you compare cover crops. Performance andRoles (p. 67) lists ranges for N and dry matter production and ranks each cover crop’s potential forproviding 11 benefits. Cultural Traits (p. 69) andPlanting (p. 70) explains the growth, environmental tolerances, seeding preferences and establishment costs for each crop. Narratives. The Table of Contents (p. 4)and the page numbers accompanying eachspecies in Charts 2, 3 and 4 direct you to the heartof the book, the chapters on each cover crop.Thechapters offer even more practical descriptions ofhow to plant, manage, kill and make the best useof each species. Don’t overlook Up-and-ComingCover Crops (p. 191) that briefly describespromising but lesser known cover crops. One ofthem may be right for your farm.HOW TO USE THIS BOOK3. With some particular cover crops in mind, stepback and look at the big picture of how you canfit cover crops into your farming operations. Sitdown with a highlighter and explore thesechapters: Benefits of Cover Crops (p. 9) explains important cover crop roles such as reducing costs,improving soil and managing pests. Selecting the Best Cover Crops (p. 12) helpsyou evaluate your operation’s needs and niches(seasonal, cash-crop related, and profit potential).Several examples show how to fit crops todetailed situations. Building Soil Fertility and Tilth (p. 16) showshow cover crops add organic matter and greaterproductivity to the biological, chemical and physical components of soil.SORGHUM-SUDANGRASS is a tall, warm-season grassthat stifles weeds and decomposes to build soil organicmatter.7

Managing Pests withCover Crops (p. 25)explores how covercrops change fieldenvironmentstoprotect cash cropsfrom insects, disease, weeds andnematodes. New this edition:Managing Cover Cropsin Conservation TillageSystems (p. 44) provides management details for cover crops inreduced tillage systems. Crop Rotations (p. 34) explains how to integrate cover crops and cash crops in sequencefrom year to year for optimum productivity fromon-farm resources. Citations Bibliography (p. 208) lists many ofthe publications and specialists cited in the book.Citations within the book are numbered in parentheses. Refer to the numbered citation in the bibliography if you want to dig deeper into a topic. Climatic Zone Maps inside the front andback covers help you understand differences incover crop performance from location to location. You may find that some cover crops haveperformed well in tests far from where you farm,but under comparable climatic conditions.The USDA Plant Hardiness Zone Map (insidefront cover) shows whether a crop will survivethe average winter in your area.We refer to theUSDA hardiness zones throughout the book.Readers’ note: A new version of the map isincluded in this reprint of the book (2012).The U.S. Forest Service map, Ecoregions ofthe United States (inside back cover), served inpart as the basis for the adaptation maps includedat the beginning of each cover crop chapter. Thisecosystem map, while designed to classify forestgrowth, shows localized climate differences, suchas rainfall and elevation, within a region. SeeBailey (citation #17 in Appendix F, p. 209) formore information about ecoregions.8Cultivars of SUBTERRANEANCLOVER, a low-growing,reseeding annual legume, areadapted to many climates.4. Now that you’vetried out most of thetools, revisit thecharts and narrativesto zero in on the covercrops you want to try.The Appendices include information to help you run reliable onfarm cover crop comparison trials.You’ll alsofind contact information for cover crop expertsin your region, seed and inoculant suppliers, references to books and academic papers cited inthis book and websites with more cover cropinformation.5. Finally, share your cover crop plans with farmers in your area who have experience with covercrops.Your local Extension staff, regional IPM specialist or a sustainable farming group in your areamay be able to provide contacts. Be sure to taplocal wisdom. You can find out the cover croppractices that have worked traditionally, and thenew wrinkles or crops that innovative practitioners have discovered.Abbreviations used in this bookA acre or acresbu. bushel or bushelsDM dry matter, or dry weight of plant materialF (degrees) Fahrenheit in. inch or inchesK potassium lb. pound or poundsN nitrogenOM organic matterP phosphorusp. pagepp. pagesT ton or tons progression to another crop/ a mixture of crops growing togetherMANAGING COVER CROPS PROFITABLY

BENEFITS OF COVER CROPSover crops can boost your profits the firstyear you plant them. They can improveyour bottom line even more over the yearsas their soil-improving effects accumulate. Otherbenefits—reducing pollution, erosion and weedand insect pressure—may be difficult to quantifyor may not appear in your financial statements.Identifying these benefits, however, can help youmake sound, long-term decisions for your wholefarm.What follows are some important ways to evaluate the economic and ecological aspects ofcover crops. These significant benefits (detailedbelow) vary by location and season, but at leasttwo or three usually occur with any cover crop.Consult local farming groups and agencies withcover crop experience to figure more precisecrop budgets. Cut fertilizer costs Reduce the need for herbicides and otherpesticides Improve yields by enhancing soil health Prevent soil erosion Conserve soil moisture Protect water quality Help safeguard personal healthCEvaluate a cover crop’s impact as you would anyother crop, balancing costs against returns in allforms. Don’t limit your calculations, however, tothe target cover crop benefit. A cover often hasseveral benefits. Many cover crops offer harvestpossibilities as forage, grazing or seed that workwell in systems with multiple crop enterprisesand livestock.SPELLING IT OUTHere’s a quick overview of benefits you can growon your farm. Cover crops can:Cut fertilizer costs by contributing N to cashcrops and by scavenging and mining soil nutrients.BENEFITS OF COVER CROPSRED CLOVER is an annual or multi-year legume thatimproves topsoil. It is easily overseeded into standingcrops or frostseeded into grains in early spring.Legume cover crops convert nitrogen gas inthe atmosphere into soil nitrogen that plants canuse. See Nodulation: Match Inoculant toMaximize N (p. 122). Crops grown in fields afterlegumes can take up at least 30 to 60 percent ofthe N that the legume produced. You can reduceN fertilizer applications accordingly. For moreinformation on nitrogen dynamics and how tocalculate fertilizer reductions, see Building SoilFertility and Tilth with Cover Crops (p. 16). TheN value of legumes is the easiest cover cropbenefit to evaluate, both agronomically and economically. This natural fertility input alone canjustify cover crop use. Hairy vetch boosted yield for no-till cornmore than enough to cover its establishmentcosts, a three-year study in Maryland showed.Further, the vetch can reduce economic risk andusually will be more profitable than no-till cornafter a winter wheat cover crop (1993 data). Theresult held true even if corn were priced as low as 1.80 per bushel, or N fertilizer ( 0.30/lb.) wasapplied at the rate of 180 lb. N/A (173). Medium red clover companion seeded withoats and hairy vetch had estimated fertilizerreplacement value of 65 to 103 lb. N/A in a fouryear study in Wisconsin, based on a two year rotation of oats/legume corn. Mean corn grain yieldfollowing these legumes was 163 bu./A for red9

clover and 167 bu./A for hairy vetch, comparedwith a no legume/no N fertilizer yield of 134bu./A (400). Austrian winter peas, hairy vetch andNITRO alfalfa can provide 80 to 100 percent of asubsequent potato crop’s nitrogen requirement, astudy in the Pacific Northwest showed (394). Fibrous-rooted cereal grains or grasses areparticularly good at scavenging excess nutrients—especially N—left in the soil after cash cropharvest. Much of the N is held within the plantsuntil they decompose. Fall-seeded grains or grasses can absorb up to 71 lb. N/A within threemonths of planting, a Maryland study showed(46). Addition of cover crops to corn soybeanand corn peanut cotton rotations and appropriate timing of fertilizer application usually reducetotal N losses, without causing yield losses in subsequent crops, a USDA-ARS computer modelingstudy confirms (354).Reduce the Need for HerbicidesCover crops suppress weeds and reduce damageby diseases, insects and nematodes. Many covercrops effectively suppress weeds as: A smother crop that outcompetes weeds forwater and nutrients Residue or growing leaf canopy that blockslight, alters the frequency of light waves andchanges soil surface temperature A source of root exudates or compounds thatprovide natural herbicidal effectsManaging Pests with Cover Crops (p. 25)describes how cover crops can: Host beneficial microbial life that discouragesdisease Create an inhospitable soil environment formany soilborne diseases Encourage beneficial insect predators and parasitoids that can reduce insect damage beloweconomic thresholds Produce compounds that reduce nematodepest populations Encourage beneficial nematode species10Using a rotation of To estimatemalting barley covercropradish sugar your potential Nbeets has successfully fertilizer savingsreduced sugar beetcyst nematodes to from a coverincrease yield of sugarcrop, see thebeets in a Wyomingtest. Using this brassi- sidebar, Howca cover crop aftermalting barley or Much N? (p. 22).silage corn substituted profitably forchemical nematicides when nematode levelswere moderate (231). A corn rye soybeans wheat hairy vetch rotation that has reducedpesticide costs is at least as profitable as conventional grain rotations without cover crops, a studyin southeastern Pennsylvania shows (174). Fallplanted brassica cover crops coupled withmechanical cultivation help potato growers witha long growing season maintain marketable yieldand reduce herbicide applications by 25 percentor more, a study in the inland Pacific Northwestshowed (394).Improve Yields by Enhancing Soil HealthCover crops improve soil by: Speeding infiltration of excess surface water Relieving compaction and improving structure of overtilled soil Adding organic matter that encouragesbeneficial soil microbial life Enhancing nutrient cyclingBuilding Soil Fertility and Tilth with CoverCrops (p. 16) details the biological and chemicalprocesses of how cover crops improve soil healthand nutrient cycling. Leading soil-building cropsinclude rye (residue adds organic matter and conserves moisture); sorghum-sudangrass (deep penetrating roots can break compaction); andryegrass (stabilizes field roads, inter-row areas andborders when soil is wet).MANAGING COVER CROPS PROFITABLY

Prevent Soil ErosionQuick-growing cover crops hold soil in place,reduce crusting and protect against erosion dueto wind and rain.The aboveground portion of covers also helps protect soil from the impact of raindrops. Long-term use of cover crops increaseswater infiltration and reduces runoff that cancarry away soil. The key is to have enough stalkand leaf growth to guard against soil loss.Succulent legumes decompose quickly, especiallyin warm weather. Winter cereals andmany brassicas have a better chanceof overwintering in colder climates.These late-summer or fall-plantedcrops often put on significant growtheven when temperatures drop intothe 50s, and often are more winterhardy than legumes (361). In a notill cotton system, use of covercrops such as winter wheat, crimsonclover and hairy vetch can reduce soilerosion while maintaining high cotton yields, a Mississippi study shows(35).Conserve Soil MoistureResidue from killed cover crops increaseswater infiltration and reduces evaporation, resulting in less moisture stressduring drought. Lightly incorporatedcover crops serve dual roles. Theytrap surface water and add organicmatter to increase infiltration to theroot zone. Especially effective atcovering the soil surface are grasstype cover crops such as rye,wheat, and sorghum-sudangrasshybrid. Some water-efficientlegumes such as medic andINDIANHEAD lentils provide covercrop benefits in dryland areaswhile conserving more moisturethan conventional bare fallow (383). Timelyspring termination of a cover crop avoids the negative impact of opposite water condition

Copy editing: Andy Clark Proofreading: Aneeqa Chowdhury Indexing: Claire Brannen Printing: United Book Press, Inc. Library of Congress Cataloging-in-Publication Data Managing cover crops profitably / project manager and editor,Andy Clark.—3rd ed. p.cm.-- (Sustainable Agriculture Res