Location: Agricultural Systems ResearchTitle: Relating soil organic carbon fractions to crop yield and quality with cover crops
|GHIMIRE, RAJAN - New Mexico State University|
|WANG, JUN - Northwest University|
Submitted to: Advances in Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2021
Publication Date: N/A
Interpretive Summary: Cover crops provide numerous agronomical and environmental benefits compared to no cover crop, but little is known about how soil organic carbon fractions due to cover cropping relate to succeeding crop yields and quality. Researchers from ARS, Sidney, MT, New Mexico State University, and Northwest University found that a mixture of legume and nonlegume cover crops enhanced increased soil organic carbon and labile carbon fractions compared to nonlegume or no cover crop and sustained succeeding crop yields and quality similar to legume cover crop. Soil organic carbon and labile carbon fractions due to cover crops were nonlinearly related to crop yields, with opposite trends. Producers can enhance crop yields and quality when soil organic carbon due to cover cropping exceeds 12 g C/kg soil. A mixture of legume and nonlegume cover crops is preferable to enhance soil organic C and crop yield and nutritional quality compared to either species alone.
Technical Abstract: Cover crops provide many soil and environmental benefits, such as reducing soil erosion, increasing soil organic matter, decreasing nitrogen (N) leaching, and enhancing biodiversity compared to no cover crop or bare fallow. There is little information about how soil organic C fractions relate to crop yield and nutritional quality as influenced by cover crops. This study analyzed the effect of cover crop species on cover crop biomass yield and N accumulation, soil labile and nonlabile C fractions, and their relationship with succeeding crop yields and N uptake from data collected around the globe. The results showed that a mixture of legume and nonlegume cover crops increased cover crop biomass yield and soil organic C compared to legume or no cover crop. The mixture also increased cover cop biomass N accumulation compared to nonlegume or no cover crop and produced similar or greater succeeding crop yields and N uptake than nonlegume or no cover crop. Soil organic C and labile C fractions nonlinearly related to crop yield, except KMnO4-extractable C, which was linear. However, the relationships showed opposing trends. A mixture of legume and nonlegume cover crops can enhance soil organic C fractions and sustain succeeding crop yields and quality compared to either species alone or the control without cover crop. Succeeding crop yields due to cover crops increased when soil organic C was =12 g C kg-1, but crop yields varied with labile C fractions.