Agricultural Management Practices Impact Soil Properties More than Soil Microarthropods

Soil biology is a fundamental aspect of soil quality; thus, it is imperative to understand how agricultural management impacts soil organisms. Among soil biota, microarthropods such as mites (Acari) and springtails (Collembola) act at multiple trophic levels, influencing soil microbial communities and nutrient dynamics. We investigated how agricultural management influences soil microarthropods at the U.S. Department of Agriculture (USDA) Agricultural Research Service Farming Systems Project (FSP), a long-term study comparing the sustainability and productivity of conventional and organic agriculture, in Beltsville, Maryland. We sampled soil and soil microarthropods from plots under conventional management—tilled and no till—and under organic management. Though soils managed using organic practices had significantly higher values for organic matter and several key nutrients, we found no significant differences in microarthropod abundance and QBS-ar score among agricultural systems. All agricultural plots scored lower in both metrics than undisturbed areas evaluated for comparison. Thus, differences in abiotic soil factors do not necessarily translate into differences in the biotic community; these differences may only be apparent with greater taxonomic resolution than used in this study. These results demonstrate the utility of the QBS-ar index in evaluating impacts of agricultural management on biological components of soil quality, specifically soil arthropod communities.