Effect of Multispecies Cover Crop Mixture on Soil Properties and Crop Yield

Abstract

Core Ideas: After 3 yr, soybean yield was higher from multispecies than from single- and double-species cover cropping. Multispecies cover cropping had higher soil water and inorganic N content than less-diverse treatments. Soil organic C was unaffected by cover crop species diversity. Several years of cover cropping are needed to achieve ecosystem benefits. Multispecies cover cropping has become popular in recent years because of the multiple ecosystem benefits compared with single- or double- species cover cropping. However, scientific studies on the effects of multispecies cover cropping—especially in the southern United States—are limited. A field study was initiated in 2013 at the University of Tennessee's Research and Education Center in Milan, TN, to assess the agronomic and soil responses from single-, double-, and multispecies cover cropping in corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] systems. After 3 yr, we found that a multispecies mixture of legumes, grasses, and Brassica spp. significantly increased soybean yield, gravimetric soil water content, and soil inorganic nitrogen as compared to the less-diverse treatments and a no-cover control. However, after 3 yr, cover cropping did not increase soil organic carbon. Although multispecies cover cropping exhibited a positive effect on yield and some soil properties after 3 yr, we plan to continue collecting multiple years of data from this field trial.