Within-field variation of crop yield loss from cover crops

Abstract

The amount of high-resolution agricultural data has increased rapidly in the current decade. Integration of satellite multispectral imagery, combine harvester yield monitoring data, and soil moisture mapping allows managing for within-field variation and better interpreting on-farm experimentation. In this study, we investigated the effect of cover crops on yield in Finland by integrating Sentinel-2 satellite imagery (normalized difference vegetation index), topographic soil moisture indexes, and high-resolution yield data. The experiment was run by three farmers over 4 years and serves as an example for low-cost on-farm experimentation. Our results confirmed earlier findings that undersown cover crops result in approximately 5% yield loss. We also found that the effect is highly variable across farms and within fields. The highest yield losses were found in areas of the field, which were wetter in the spring seeding time. The competition between crop and cover crop could be observed in the vegetation maps for autumn and early summer. Combining NDVI and soil moisture maps allows delineating field zones, which require extra management to reduce the risk of yield loss from cover crop resource competition. Evaluating the overall effect of cover crops on yield would require replication on more farms. The within-field variation results and workflow investigated in this study can guide placement of sampling areas within those fields.