Crops Including Grasses, Legumes and Forbs for Seasonal Cover and Other Conservation Purposes

Cover Crop 340-3 Use deep-rooted species to maximize nutrient recovery. USDA NATURAL RESOURCES Use grasses to utilize more soil nitrogen, and CONSERVATION SERVICE legumes utilize both nitrogen and phosphorus. DELAWARE CONSERVATION Avoid cover crop species that harbor or PRACTICE STANDARD carryover potentially damaging diseases or insects. COVER CROP For most purposes for which cover crops are CODE 340 established, the combined canopy and (Reported by Acre) surface cover is at nearly 90 percent or greater, and the above ground (dry weight) biomass production is at least 4,000 lbs/acre. DEFINITION Cover crops may be used to improve site Crops including grasses, legumes and forbs for conditions for establishment of perennial seasonal cover and other conservation purposes. species.

PURPOSES Use plant species that enhance bio fuels opportunities. 1. Reduce erosion from wind and water. Use plant species that enhance forage 2. Increase soil organic matter content. opportunities for pollinators.

3. Capture and recycle or distribute nutrients in CRITERIA the soil profile. General Criteria Applicable to All Purposes 4. Promote biological nitrogen fixation. Plant species, seedbed preparation, seedling 5. Increase biodiversity. rates, seeding dates, seeding depths, fertility requirements, and planting methods will be 6. Weed suppression. consistent with approved local criteria and site conditions. 7. Provide supplemental forage. Drilling or planting with a cultipacker-seeder or 8. Soil moisture management. no-till drill are preferred seeding methods because they optimize seed-soil contact. Other CONDITIONS WHERE PRACTICE methods may be used, such as broadcasting seed APPLIES by hand, cyclone seeder, or aerial, but these methods usually result in poorer seed On all lands requiring vegetative cover for distribution and germination, and require higher natural resource protection and or improvement. seeding rates to compensate and provide good coverage. Plant cover crops as early as feasible CONSIDERATIONS within the time period indicated in Table 1.

Plant cover crop in a timely matter to Apply lime and fertilizer only if needed based establish a good stand. on recent soil test results. Any use of plant nutrients must be in compliance with Delaware Maintain an actively growing cover crop as nutrient management regulations, as applicable. late as feasible to maximize plant growth, allowing time to prepare the field for the The species selected will be compatible with next crop and moisture depletion. other components of the cropping system. Conservation practice standards are reviewed periodically, and updated if needed. To obtain the current version of this standard, contact the Natural Resources Conservation Service.

NRCS - DELAWARE May 2008 Cover Crop 340-2 Cover crops will be terminated by harvest, frost, crop will be killed in relation to the planting date mowing, tillage, crimping, and/or herbicides in of the following crop. If the objective is to best preparation for the following crop. synchronize the use of cover crop as a green manure to cycle nutrients, factors such as the Avoid using plants that are on the state’s carbon/nitrogen ratios may be considered to kill noxious weed or invasive species lists. early and have a faster mineralization of nutrients to match release of nutrient with Cover crop residue will not be burned. uptake by the following cash crop. A late kill may be used if the objectives are to use as a Additional Criteria to reduce erosion from biocontrol and maximize the addition of organic wind and water matter. The right moment to kill the cover crop will depend on the specific rotation, weather and Cover crop establishment, in conjunction with objectives other practices, will be timed so that the soil will be adequately protected during the critical Additional Criteria to promote biological erosion period(s). nitrogen fixation.

Plants selected for cover crops will have the Only legumes or legume-grass mixtures will be physical characteristics necessary to provide established as cover crops. adequate protection. The specific Rhizobium bacteria for the selected The amount of surface and/or canopy cover legume will either be present in the soil or the needed from the cover crop shall be determined seed will be inoculated at the time of planting. using the current erosion prediction technology. Additional Criteria to Increase Biodiversity Additional Criteria to Increase soil organic matter content Cover crop species shall be selected that have different maturity dates, attract beneficial Cover crop species will be selected on the basis insects, increase soil biological diversity, serve of producing high volumes of organic material as a trap crop for damaging insects, and/or and or root mass to maintain or improve soil provide food and cover for wildlife habitat organic matter. management.

The NRCS Soil Conditioning Index (SCI) Additional Criteria for Weed Suppression procedure will be used to determine the amount of biomass required to have a positive trend in Species for the cover crop will be selected for the soil organic matter subfactor. their chemical or physical characteristics to suppress or compete with weeds. The cover crop will be terminated as late as feasible to maximize plant biomass production, Cover crops residues will be left on the soil considering the time needed to prepare the field surface to maximize alleopathic (chemical) and for planting the next crop and soil moisture mulching (physical) effects. depletion. For long-term weed suppression, reseeding Additional Criteria to capture and recycle annuals and/or biennial species can be used. excess nutrients in the soil profile Additional Criteria to Provide Supplemental Cover crops will be established and actively Forage growing before the expected period(s) of nutrient leaching. Species selected will have desired forage traits, be palatable to livestock, and not interfere with Cover crop species will be selected for their the production of the subsequent crop. ability to take up large amounts of nutrients from the rooting profile of the soil. Forage provided by the cover crop may be hayed or grazed as long as sufficient biomass is let for When used to redistribute nutrients from deeper resource protection. in the profile up to the surface layer, the cover

NRCS - DELAWARE May 2008 Cover Crop 340-3 Additional Criteria for Soil Moisture 4. Establishment method (i.e. aerial, no-till drill) Management SUPPORTING DATA AND Terminate growth of the cover crop sufficiently DOCUMENTATION . early to conserve soil moisture for the subsequent crop. Cover crops established for The following is a list of the minimum data and moisture conservation shall be left on the soil documentation to be recorded in the case file: surface. 1. Location the practice on the conservation In areas of potential excess soil moisture, allow map. the cover crop to grow as long as possible to maximize soil moisture removal. 2. Assistance notes. The notes shall include dates of site visits, name or PLANS AND SPECIFICATIONS initials of the person who made the visit, specifics as to alternatives discussed, Plans and specifications for this practice shall be decisions made, and by whom. prepared in accordance with the previously listed criteria. Plans and specifications shall 3. Completed copy of the appropriate job contain sufficient detail to ensure successful sheet (s) or other specifications, and implementation of this practice. Documentation management plans. Specify the shall be in accordance with the section following for each field, or groups of "Supporting Data and Documentation" in this fields: standard. a. Purpose of the planting OPERATION AND MAINTENANCE b. Soil loss calculation when erosion is The producer/client is responsible for the a purpose operation and maintenance of the practice. Operation and maintenance activities address the c. Plant species, varieties, method and following: rate of planting, and planting dates: Refer to table 1. 1. Describe the extent of management needed to maintain the cover crop for the desired period of d. Kill/destroy methods and dates time. Management may consist of mowing, haying, grazing, harvesting grain, and/or surface e. Other management requirements, residue. as appropriate.

2. Describe the acceptable uses, including REFERENCES grazing, haying and time of year/frequency of use restrictions. Bowman, G., C. Cramer, and C. Shirley. A. Clark (ed.). 1998. Managing cover crops 2. When the cover crop will be used for forage profitably. 2nd ed. Sustainable Agriculture or hay, harvest when optimal nutritional content Network Handbook Series: bk 3. National and yield is available. Agriculture Library. Beltsville, MD.

Record Keeping Hargrove, W.L., ed. Cover crops for clean water. SWCS, 1991. Participating producer must maintain records to allow the certifying individual to document plan Magdoff, F. and H. van Es. Cover Crops. 2000. implementation. As applicable, records include: p. 87-96 In Building soils for better crops. 2nd ed. Sustainable Agriculture Network Handbook 1. Species or species of plants planted. Series: bk4. National Agriculture Library. Beltsville, MD. 2. Seeding rates. Reeves, D.W. 1994. Cover crops and erosion. P. 3. Seeding dates. 125-172 In J.L. Hatfield and B.A. Stewart (eds)

NRCS - DELAWARE May 2008 Cover Crop 340-2 Crops Residue Management. CRC Press, Boca Raton, FL.

NRCS - DELAWARE May 2008