Semi-Arid Dryland Cover Cropping: Panacea Or Fallacy?.

Cover crops are widely touted for their purported benefits in cropping.  These benefits include reduced soil erosion, increasing soil biological diversity, improved nutrient cycling, and water conservation.  Separating fact from fiction is a challenge, however, as cover cropping is often promoted as the end-all for rainfed cropping systems sometimes with little regard to differences in evaporative demand across different regions in the U.S., Australia, Africa, or Asia.  But research in many semi-arid dryland cropping systems is lacking to document whether indeed cover cropping helps the overall system--especially when moisture is limiting, and whether other means such as reduction in tillage, residue management of existing crops, etc. may in fact accomplish the same goal.  On one hand moisture use is a critical concern of cover crops, but on the other hand potential net moisture conservation may be possible.  Extension of research findings and practices from more humid cropping regions to semi-arid regions is not advised without field research.  This presentation will present an overview and summary of the Symposium cover crop topic in general and outline potential areas of needed research based on current research findings.