Reseeding of Crimson Clover and Corn Grain Yield in a Living Mulch System

A major drawback to the use of crimson clover Trifolium incarnatum L.) as a winter legume cover with corn (Zea mays L.) is the cost of new seed each fall. Planting corn into a living mulch and allowing the clover to reseed could reduce these costs. This study was conducted for 3 yr (1989–1990) at Plains and Griffin, GA, to determine the feasibility of planting corn into various widths of chemically killed strips of crimson clover and allowing a living clover mulch between corn rows to mature and reseed naturally. Each fall, ‘Tihbee’ crimson clover was planted on a new strip and the previous year's plots were continued for reseeding studies in 1989 and 1990. Treatment included chemically killing 0, 25, 60, 80, 95, and 100% of the total area with paraquat (1.1-dimethyl-4,4″-bipyridinium ion) Killing the clover was accomplished 2 week before or at corn planting, except the 25% kill, which was killed at planting only. ‘Pioneer 3165’ corn was no-till planted on all of the plots in late March to early April at Plains and in mid April to early May at Griffin. Reseeding was satisfactory (>70% groundcover) for killed strips of 80% or less. Corn grain yields when clover was completely killed were 6 to 10 Mg ha⁻¹ at Griffin and 3 to 6 Mg ha⁻¹ at Plains, where rainfall was less. Corn grain yield was not depressed by the presence of a living clover mulch, as long as the clover was killed in strips of 60% or greater, compared with the conventional practice of completely killing clover. Time of killing clover was not important in most instances, but in 1989 killing early significantly reduced corn grain yields in the reseeded plots at Griffin and, to a lesser extent, in the fall-seeded plots at Plains. Based on corn yield and reseeding of clover, planting corn into clover killed in strips of 60 to 80% appears to be the optimum.