Cover Crop Effects on Soil Moisture in Transitioning Organic Cropping Systems.

Maintaining soil fertility has been another major concern of most organic farmers. A well-planned legume-based crop rotation along with manure and compost application has been shown to improve soil fertility in long-term organic systems. However, cover crops can reduce the available soil moisture for the subsequent crop. This study investigated soil moisture depletion by cover crops in organic grain/soybean systems in Texas. The experimental design was a randomized split-plot design with four replications. The rotation for main crops was soybeans-corn-sorghum. All three main crops were in rotation each year. Treatments included current practice (no cover crop and conventional tillage , summer cowpea cover crop (no-tillage), and summer cover crop + fall rye/vetch mixture (no-tillage and conventional tillage). Continuous soil temperature and soil moisture measurements were made using multi-parameter CS-655 soil water content reflectometer probes (Campbell Scientific, Logan, UT, USA). Site-specific calibration equations were developed for these sensors prior to their installation. Final results from this study will be presented at the meeting.