Conservation Tillage, Double Cropping and Cover Crops in a Semi-Arid Subtropical Environment.
Robert Wiedenfeld, Texas Agric. Exp. Station, 2415 E Hwy 83, Weslaco, TX 78596-8399
Conservation tillage offers the advantage of reduced field operations compared to conventional tillage which should result in several benefits. Water loss and degradation of soil structure due to tillage is reduced, and oxidation of organic residues is slowed down. Hopefully this will result more efficient water use as well as lower costs. Double cropping and cover crops offer the potential to increase organic matter accumulation, but will increase initial water requirements. Planting and weed control are major challenges for implementing conservation tillage. In a biannual cotton/sorghum rotation, water infiltration following heavy rainfall has been improved by conservation tillage, and irrigation water requirements have been reduced slightly. Conservation tillage has resulted in comparable grain sorghum yields but lower cotton yields compared to conventional tillage. Tillage, double cropping and fall cover crops have resulted in very little difference in soil properties after four years. Stand establishment is difficult into crop residues. The potential soil improvements and water savings of conservation tillage are difficult to achieve in a subtropical environment, however the reduction in field operations will result in a substantial reduction in costs.