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 s eed each fall. Planting corn into a living mulch and allowing the clov er 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 c rimson clover and allowing a living clover mulch between corn rows to mature and reseed naturally. Each fall, 'Tibbee' crimson clover was pl anted on a new strip and the previous year's plots were continued for reseeding studies in 1989 and 1990. Treatment included chemically kill ing 0, 25, 60, 80, 95, and 100% of the total area with paraquat (1.1-d imethyl-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 t he plots in late March to early April at Plains and in mid April to ea rly May at Griffin. Reseeding was satisfactory (> 70% groundcover) for killed strips of 80% or less. Corn grain yields when clover was compl etely killed were 6 to 10 Mg ha-1 at Griffin and 3 to 6 Mg ha-1 at Pla ins, where rainfall was less. Corn grain yield was not depressed by th e presence of a living clover mulch, as long as the clover was killed in strips of 60% or greater, compared with the conventional practice o f completely killing clover. Time of killing clover was not important in most instances, but in 1989 killing early significantly reduced cor n grain yields in the reseeded plots at Griffin and, to a lesser exten t, in the fall-seeded plots at Plains. Based on corn yield and reseedi ng of clover, planting corn into clover killed in strips of 60 to 80% appears to be the optimum.