Summer and winter cover crops for spring planted vegetables

Authors: Webber Iii, Charles; WALTON, DOUG - WALTON'S FAMILY FARM; Russo, Vincent; ROBERTS, B.W. - OSU, WWAREC; KAHN, B.A. - OSU, STILLWATER

Submitted to: Proceedings of Horticultural Industry Show
Publication Type: Proceedings
Publication Acceptance Date: 1/10/2004
Publication Date: 1/15/2004
Citation: Webber III, C.L., Walton, D., Russo, V.M., Roberts, B., Kahn, B. 2004. Summer and winter cover crops for spring planted vegetables. Proceedings of Oklahoma and Arkansas Horticultural Industry Show. 23:181-184.

Interpretive Summary: Although it's been over 200 years since George Washington, who was justly called "America's first scientific farmer," worked with crop rotations and cover crops, the present U.S. vegetable producers often face the same challenges and potential benefits of selecting the optimum crop rotations and cover crops. Legume and cereal cover crop combinations can provide numerous benefits to the soil environment and the following vegetable crops. The objective of this research was to evaluate the performance of twenty-four cover crop combinations for potential use prior to spring planted, no-tillage, organic, vegetable production systems. The research was conducted at Walton's Family Farm (Muskogee, OK) on a Parsons silt loam soil. The research included both summer and winter cereals and legumes. The summer annual cover crops compared two planting dates (late July or mid August) for eight cover crop combinations, four legumes each combined with one of two cereal crops. The summer cover crops grew until the first hard frost in the fall. The winter cover crops, which were planted in mid September, compared sixteen winter cover crop combinations, eight legumes each combined with one of two cereal crops. Low summer soil moisture levels often adversely affected the summer cover crops. The earliest summer cover crop planting produced greater growth and dry matter than the late summer cover crop planting. The summer cover crops established protective crop canopies and root systems sooner than the winter cover crops. The woolypod vetches usually initiated flowering 2-3 weeks prior to the standard winter legume, hairy vetch, but they also tended to produce less dry matter. Although it may be more ideal to cut hairy vetch at mid to late bloom to maximize dry matter production, it may be more advantageous to cut hairy vetch sooner to provide for an earlier, more timely planting date for spring vegetables. Subterranean clover's very dense, tight-knit, rug-like growth on the soil surface created a very competitive environment for reducing weed establishment and growth. Crimson and berseem clover provided an intermediate plant architecture, producing ample dry matter, but with a lower dry matter density at the soil surface compared to subterranean clover, and more dry matter in the mid range than the taller and more spindly hairy vetch. Crimson and berseem clover's intermediate growth also produce a more balanced cereal and legume mix than the other winter legumes. The research demonstrated the advantages and disadvantages involved with each cover crop combination and will provide important management information for selecting the optimum cover crop for specific producer requirements.

Technical Abstract: Legume and cereal cover crop combinations can provide numerous benefits to the soil environment and the following vegetable crops. The objective of this research was to evaluate the performance of twenty-four cover crop combinations for potential use prior to spring planted, no-tillage, organic, vegetable production systems. The research was conducted at Walton's Family Farm (Muskogee, OK) on a Parsons silt loam soil. The research included both summer and winter cereals and legumes. Each cover crop combination (legume and cereal) was planted on 30-in wide 7-in high raised beds. The summer annual cover crops compared two planting dates (late July or mid August) for eight cover crop combinations, four legumes each combined with one of two cereal crops. The four legumes used for the summer annual cover crops included cowpea, soybean, sunn hemp and lablab. Each of these legumes was combined with either foxtail millet or sorghum Sudan. The summer cover crops grew until the first hard frost in the fall. The winter cover crops, which were planted in mid September, compared sixteen winter cover crop combinations, eight legumes each combined with one of two cereal crops. The eight winter legumes included hairy vetch, crimson clover, field peas, berseem clover, common vetch, subterranean clover, and two woolypod vetches. Each of these legumes was combined with either rye or barley. The winter cover crop combinations were cut just above the soil surface when the legume portion reached 50' 70% flowering. Low summer soil moisture levels often adversely affected the summer cover crops. The earliest summer cover crop planting produced greater growth and dry matter than the late summer cover crop planting. The summer cover crops established protective crop canopies and root systems sooner than the winter cover crops. The woolypod vetches usually initiated flowering 2-3 weeks prior to the standard winter legume, hairy vetch, but they also tended to produce less dry matter. Although it may be more ideal to cut hairy vetch at mid to late bloom to maximize dry matter production, it may be more advantageous to cut hairy vetch sooner to provide for an earlier, more timely planting date for spring vegetables. Subterranean clover's very dense, tight-knit, rug-like growth on the soil surface created a very competitive environment for reducing weed establishment and growth. Crimson and berseem clover provided an intermediate plant architecture, producing ample dry matter, but with a lower dry matter density at the soil surface compared to subterranean clover, and more dry matter in the mid range than the taller and more spindly hairy vetch. Crimson and berseem clover's intermediate growth also produce a more balanced cereal and legume mix than the other winter legumes. The research demonstrated the advantages and disadvantages involved with each cover crop combination and will provide important management information for selecting the optimum cover crop for specific producer requirements.