CONSERVATION TILLAGE FOR BETTER IRRIGATION AND WATER MANAGEMENT IN CORN PRODUCTION

In order to take advantage of the increasing demand for and price of corn related to the unprecedented growth of the corn-based ethanol industry, growers in the Southeast need to alleviate weather and soil limitations that have hindered corn production in the region. We present two years of preliminary results from an ongoing research with objectives to demonstrate the potential of high residue conservation tillage to enhance water conservation and improve irrigation and water use efficiency in corn production. The research is being conducted within two irrigated corn-cotton- peanut rotation studies at University of Georgia research stations at Camilla and Tifton, GA. All crops in the rotation are present each year but this research focuses only on each year's corn crop. At each location treatments are assigned to nine 30 ft x 70 ft plots in four complete blocks in a factorial arrangement consisting of 2 tillage (conventional (CT) without a rye cover crop on 4 plots and strip- tillage (ST) with a rye cover of high residue on 4 and low residue on 1 plot) by 4 irrigations (spanning the zero to full irrigation scale). Strip-tillage enhanced infiltration. While still within statistical margin of error, this led to slightly taller plants with more biomass (stalks and leaves) at tasselling. Corn grain yield differentials arising from tillage treatments have not yet materialized. In non-irrigated plots, grain yield remained 40 to 50 bu ac-1 at Camilla and 40 to 100 bu ac-1 at Tifton, while fully irrigated plots produced 200 to 250 bu ac-1. Improvement in residue management (raising high residue and being able to plant into it) and developing the irrigation schedule strategies that would capture the advantages of the enhanced infiltration under strip-tillage continue to be areas of research.