TILLAGE DEPTH, TILLAGE TIMING, AND COVER CROP EFFECTS ON COTTON YIELD, SOIL STRENGTH, AND TILLAGE ENERGY REQUIREMENTS

Abstract

During the early 1990s, declining cotton (Gossypium hirsutum L.) yields plagued farmers in the TennesseeValley Region of North Alabama who tried to eliminate moldboard and/or chisel plowing from their conventional farmingsystems to meet conservation compliance programs. The severely reduced yields were possibly due to inadequate rootingsystems caused by excessive soil compaction. A study was conducted from 1995-1998 to investigate conservation tillagesystems which incorporated a rye (Secale cereale L.) cover crop to maintain surface cover and in-row tillage to disruptroot-impeding soil layers. Energy requirements for shallow tillage (0.18 m) and deep tillage (0.33 m) performed in theautumn and spring were also assessed. Factors investigated included time of tillage, depth of tillage, and use of a covercrop. A rye cover crop was found to be the largest single factor in increasing seed cotton yield, with positive results seenin three of four years. Of somewhat lesser importance, autumn tillage and shallow tillage increased seed cotton yield inthose years containing more typical growing seasons. The conservation tillage practice of shallow, autumn, in-rowsubsoiling in conjunction with a cover crop may offer the best alternative for farmers trying to reduce the negative effectsof soil compaction, maintain adequate residue cover, and improve seed cotton yield.