Cover Crops: Opportunities and Challenges to Realizing Ecosystem Services in Organic Agriculture.

Cover crops are essential in organic systems because they can provide a multitude of crop production and environmental benefits (e.g. soil fertility, pest suppression, water infiltration and retention, increased soil carbon sequestration and reduced surface water pollution). However, management, soil fertility status, drainage, climate, and pests drive the magnitude and duration of cover crop services and result in variable performance across years and locations. In organic systems, consistent performance of cover crops is important because underperforming cover crops can cause 1) a low return of nitrogen for the cover crop input costs (seed, fuel, labor); 2) poor yield of succeeding crops due to low fertility or weeds, and 3) excessive phosphorous inputs when animal byproducts are used to meet crop nitrogen needs. Combining cover crop species that target multiple services is gaining interest by researchers and growers. However, managing mixtures to target specific production needs can be challenging and require extensive decision support. Increased performance and adoption of cover crops will require a comprehensive approach to improve machinery, germplasm, cultural knowledge, and communication of research findings to farmers. This paper will briefly review the benefits of cover crops, and focus on their variability in performance, approaches being evaluated to improve their performance consistency, and recommendations for future research and development. We will draw from research on integrating cover crops into organic cropping systems for agronomic and high-value horticultural crops in the U.S.