As a means to increase profitability and reduce soil erosion, conservation tillage systems have gained increased interest, especially in sandyland areas of the Texas Southern High Plains. Experiments were established in 1986 to evaluate effects of tillage and cropping systems on cotton yields and profitability under both irrigated and dryland conditions. Plots were established at three locations which are typical of sandyland, mixedland, and hard-land areas. Systems evaluated included conventional, reduced, and no-till continuous cotton and conservation tillage rotations including wheat-cotton, terminated wheat-cotton, and sorghum-cotton. Cotton lint yields and fiber quality were determined to calculate income levels and all inputs and tillage operations were used to calculate production costs. Net returns for each system were determined.

An early freeze reduced irrigated yields at Lubbock in 1989. No difference in per acre yields or net returns were observed. Highly significant differences in dryland yields and net returns did exist. Due to dry weather, conventional tillage continuous cotton produced only 160 lb/A with net returns of $18/A. Yields with the wheat-cotton rotational system were 471 lb/A and net returns were $210/A. Higher yields resulted from increased soil moisture storage in the conservation tillage plots. In continuous cotton, higher yields and net returns were achieved with both reduced and no-till systems as compared to conventional tillage. Yields and net returns with the terminated wheat-cotton system were equal to conventional tillage cotton.

Average dryland yields were higher at the sandyloam site at Wellman. Highest yields and net returns resulted with the cotton-wheat system, again due to increased soil water storage. In continuous cotton, slightly greater net returns were achieved with the reduced tillage system.

Over a three-year period at Lubbock, dryland cotton yields were highest with the wheat-cotton conservation tillage system. Net returns with the wheat-cotton system averaged $258/A compared to $97/A for continuous cotton with conventional tillage. In continuous cotton, net returns with the reduced tillage system were $161/A or 66% higher than conventional tillage. At Wellman, net returns with the wheat-cotton system averaged $262/A compared to $173/A for conventional tillage continuous cotton. The terminated wheat-cotton system produced average net returns of $215/A, an increase of 24% over conventional tillage. These results indicate that conservation tillage systems can offer economic benefits in a addition to reduced soil erosion.