Harvest Management of a Crimson Clover Cover Crop For No-Tillage Corn Production

Legume cover crops are valuable N sources for no-tillage corn (Zea mays L.). However, little research has been done in assessing the management options for legume cover crops. Field studies were conducted on a Coastal Plain Matapeake silt loam soil (fine-silt), mixed, mesic Typic Hapludult) from 1983 through 1986 to determine the effects of various harvest management schedules on total N contribution of legume cover crops, subsequent corn grain and silage yields, and total forage (combined cover crop and corn herbage) production. A crimson clover (Trifolium incarnatum L.) cover crop was subjected to no harvest; spring silage harvest with clippings removed (spring silage); and simulated pasture harvests with clippings from multiple harvests removed (pasture removed) or returned (pasture returned). A no-cover control treatment was also included. No-tillage corn was grown in the cover crop residues and two fertilizer N (FN) rates (0 and 90 kg ha⁻¹) were applied in a split-block design to each harvest management treatment. Averaged over 3 yr, multiple harvests of the cover crop vs. a spring silage harvest resulted in lower cover crop herbage yields (3.0 vs. 4.7 Mg ha⁻¹) and total N content (114 vs. 146 kg N ha⁻¹) for the multiple harvests. Corn grain and silage yields and corn N uptake were consistently higher following crimson clover cover than for no cover, regardless of harvest management, and were generally higher when the cover was left in place than following removal of the cover. There were FN responses regardless of harvest management treatment. The reduction in corn silage yield when the cover crop was harvested and removed was less than the cover crop herbage dry matter yield, resulting in greater total forage production when the cover crop was harvested as forage. Results suggest that harvest management options of a crimson clover cover crop offer flexibility in either optimizing subsequent corn grain yields or total forage production for no-tillage cropping systems and provide control over how cover crop N is utilized in the overall cropping system. Contribution no. 8008. Scientific article A-4964 of the Maryland Agric. Exp. Stn., Dep. of Agronomy.