PNNL

Abstract

Successful incorporation of cover crops within agricultural rotations requires the ability to objectively evaluate their effects on agroecosystem functions. In this study, we compiled data from a set of soil health measurements collected across the globe. We then used t-tests and unbalanced analysis of variation (UANOVA) tests to analyze cover crop effects on 38 soil health indicators. The t-test analysis indicated that cover crop use during fallow seasons caused significant changes in 28 of 38 indicators, with differences seen for all physical parameters and most indicators associated with biological and environmental measurements. Our UANOVA analysis allowed us to identify a hierarchy of most to least important environment and management factors for each indicator. Using this hierarchy, we developed a calculator for soil health evaluation. The soil health calculator requires only four inputs – climatic region, soil texture group, cash crop rotation, and cover crop type – and as output reports mean percent change for 13 soil health indicators. The analyses produced in this study provide new information on cover crop effects on soil health, and the corresponding web-based calculator will help to ensure that soil health measurements from the field and laboratory are useful to farmers, planners, and regulators. Further, as more data becomes integrated into the calculator, results will continue to improve in accuracy and realism, ultimately making soil health evaluation a practical outcome across the globe.