Tillage depth, tillage timing, and cover crop effects on cotton yield, soil strength, and tillage energy requirements

During the early 1990s, declining cotton (Gossypium hirsutum L.) fields pla gued farmers in the Tennessee Valley Region of North Alabama who tried to e liminate moldboard and/or chisel plowing from their conventional farming sy stems to meet conservation compliance programs. The severely reduced yields were possibly due to inadequate rooting systems caused by excessive soil c ompaction. A study was conducted from 1995-1998 to investigate conservation tillage systems which incorporated a rye (Secale cereale L.) cover crop to maintain surface cover and in-row tillage to disrupt root-impeding soil la yers. Energy requirements for shallow tillage (0.18 m) and deep tillage (0. 33 m) performed in the autumn and spring were also assessed. Factors invest igated included time of tillage, depth of tillage, and use of a cover crop. A rye cover crop was found to be the largest single factor in increasing s eed cotton yield, with positive results seen in three of four years. Of som ewhat lesser importance, autumn tillage and shallow tillage increased seed cotton yield in those years containing more typical growing seasons. The co nservation tillage practice of shallow, autumn, in-row subsoiling in conjun ction with a cover crop may offer the best alternative for farmers trying t o reduce the negative effects of soil compaction maintain adequate residue cover, and improve seed cotton yield.