Herbicide and Rye Cover Crop Residue Integration Affect Weed Control and Yield in Strip-Tillage Peanut

Abstract

ABSTRACTReduced-tillage peanut production is increasing due to reduced production costs and increased environmental and economic benefits compared to conventional systems. Experiments were conducted in Alabama and Georgia between 2005 and 2007 to evaluate a strip-tillage system utilizing a high-residue cereal rye cover crop, in comparison to a conventional tillage system. Six weed management schemes were evaluated including a preemergence (PRE) application of pendimethalin alone at 1.12 kg ai/ha or in combination with S-metolachlor at 1.36 kg ai/ha. Both PRE applications were applied alone or followed by (fb) a postemergence (POST) application consisting of a mixture of paraquat at 0.140 kg ai/ha plus bentazon at 0.56 kg ai/ha plus 2,4-DB at 0.224 kg ae/ha. The remaining two treatments consisted of a no-herbicide control and aforementioned POST-only application. In 2005 at the Alabama location, pendimethalin plus metolachlor with or without a POST application controlled all weeds >91% in the strip tillage treatment and controlled tall morningglory, yellow nutsedge, and common bermudagrass >83% in the conventional tillage system. Pendimethalin fb a POST application controlled all weeds > 97%, except large crabgrass (75%) and common bermudagrass (≤ 58%) regardless of tillage system. In 2007, pendimethalin and pendimethalin plus S-metolachlor followed by (fb) a POST application controlled smooth pigweed, tall morningglory, large crabgrass, Florida beggarweed, and sicklepod 70 to 99%, across tillage systems. In 2005 at the Georgia location, large crabgrass control was consistently reduced in strip-tillage compared to conventional tillage regardless of herbicide treatment. In 2006, pendimethalin plus S-metolachlor fb POST controlled common bermudagrass and yellow nutsedge 74 to 99%. Herbicide treatment effect on peanut yield varied with environment. Peanut yield was equivalent or greater by 25% or more in 3 of 4 site years utilizing strip-tillage indicating a yield advantage compared to conventional tillage. Peanut market grade was not affected by any herbicide treatments or tillage methods evaluated. Results show that producers can maintain weed control, equivalent grade and yield in reduced-tillage systems when utilizing a high-residue conservation agriculture system integrated with a PRE plus POST herbicide system.