Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2006
Publication Date: 11/17/2006
Citation: Acosta Martinez, V., Upchurch, D.R., Zobeck, T.M. 2006. Managing Soil Properties through Dryland Cropping System Intensities[absstract]. International Center for Arid and Semiarid Land Studies Conference. Lubbock, Texas. November 15-17, 2006. Interpretive Summary:
Technical Abstract: Modification of soil functioning/quality parameters (i.e., organic matter content) is important to improve the capacity of soil as a water storage-reservoir for crop production in dryland. A long-term dryland cropping research study was established at the USDA-ARS farm near Lubbock, Texas in 2003, to investigate changes in soil properties as a function of cropping intensity. The project is currently in its fourth growing season. This study is designed to evaluate the potential to modify the properties of the low organic matter content soils of semi-arid regions in dryland conditions using a range of cropping intensities. From less cropping intensity to maximum cropping intensity the study evaluates: continuous cotton (Gossypium hirsutum), cotton-sorghum (Sorghum bicolor), cotton-rye (Secale cereale)-sorghum, and haygrazer (alfalfa-sorghum hybrid, Sorghum bicolor L.)-rye rotations. All crop rotations are split plots with conventional tillage and no-tillage or minimum tillage, except for continuous cotton, which is under conventional tillage. After completing the first rotation cycle, a rotation with winter cover crops had an enhanced soil microbial populations and enzyme activities (0-5 cm) compared to continuous cotton or cotton-sorghum rotations. There were no effect of tillage on the soil microbial populations or any of the enzyme activities evaluated. Preliminary results show that a management including a winter cover crop and a diversity of crops in a rotation positively impacts soil microbial functioning, compared to continuous cotton. In addition, significant differences in water infiltration rates were found among cropping systems. The no tillage systems had consistently greater water infiltration than conventionally tilled cropping systems. These trends suggest that changes in soil organic matter content may occur. Continuation of this study is vitally important for a long-term evaluation and confirmation of these trends, and their implications in water management and crop productivity in dryland. However, management (treatments) cannot be guaranteed under dryland conditions due to the impact of rainfall variability on crop establishment. For example, last winter (2005), the winter cover crops did not germinate due to lack of timely fall rains and we experience another record drought in the current fourth (summer) growing season. This is the reality of dryland crop production, however, it delays our ability to test measure the impact of our treatments.