PNNL

Abstract

Conservation management practices – including agroforestry, cover cropping, no-till, reduced tillage, and residue return – have been applied for decades to control surface runoff and soil erosion, yet results have not been integrated and evaluated across cropping systems. Using a global soil health database (SoilHealthDB), this study collected data comparing agricultural production with and without conservation management strategies, and then used a non- parametric bootstrap resampling analysis to explore interactions between practice type, soil texture, surface runoff, and soil erosion. We further analyzed the relationships between surface runoff and erosion response ratios (RR), along with the RR of other 13 soil health and agronomic indicators, including soil organic carbon, soil aggregation, infiltration, porosity, subsurface leaching, and cash crop yield. Across all conservation management practices, surface runoff and erosion had respective mean decreases of 67% and 80% compared with controls. Use of cover cropping provided the largest decreases in erosion and surface runoff. Coarse- and medium-textured soils had greater decreases in both erosion and runoff than fine-textured soils. Changes in surface runoff and soil erosion under conservation management were highly correlated with soil organic carbon (R 2 =0.09 and 0.25), aggregation (R 2 =0.57 and 0.03), porosity (R 2 =0.42 and 0.51), infiltration (R 2 =0.34 and 0.31), leaching (R 2 =0.70 and 0.54), and yield (R 2 =0.13 and 0.00), showing that conservation practices help drive important interactions between these different facets of soil health. In conclusion, this study demonstrated that introducing conservation management into croplands significantly decrease surface runoff and soil erosion, and therefore plays an important role in subsequent soil health improvement.