Structural Equation Modeling of Cover Crop Effects on Soil Nitrogen and Dry Bean

Abstract

Core Ideas Structural equation modeling is utilized to explore how cover crops influence dry beans. Cover crop C/N ratio and incorporation timing can indirectly affect dry bean yield. Cover crops quality needs to be managed to benefit cash crops. The direct impact of cover crops on nutrient cycling and yield has been studied in many different systems, however limited datasets have prevented larger scale modeling of the complex relationships among these variables. The reduced model generated from this analysis demonstrated that in an organic dry bean system, both higher cover crop C/N ratio and shorter time from cover crop incorporation until dry bean planting could negatively affect yield through lower soil inorganic N availability at the time of bean planting (mid‐ to late June). Days between cover crop incorporation and dry bean planting ranged from 1 to 64, with the model showing that less time also reduced yield through reduced dry bean population. These findings support the premise that cover crop quality and time for decomposition are important parameters to manage to benefit the subsequent cash crop.