Conservation management and ecosystem services in midwestern United States agricultural systems

Abstract

The recognition that agricultural systems provide services beyond food production has motivated federal legislation and associated programs that promote sustainable management and conservation of productive working lands. This study evaluates the ability of the USDA Natural Resources Conservation Service's (NRCS) Conservation Measurement Tool (CMT), which has been used to determine eligibility for enrollment in the Conservation Stewardship Program, to reflect changes in ecosystem services resulting from the use of conservation management practices on croplands. This work evaluates four macroconcerns or outcomes (soil erosion, soil quality, water quality, and air quality) that are quantified within the tool by comparing CMT scores tabulated according to practices reported by farmers involved in grain producing operations in the US Midwest with soil health measures (dynamic soil properties [DSPs]) determined on 72 Illinois farm fields. Three management practice categories—Conventional, Conservation, and Organic—were evaluated. The CMT identified significant differences among management categories, and scores ranked consistently higher for Organic than Conventional or Conservation systems. Direct analysis of DSPs suggested that there were relatively small differences among soil health indicators measured on farms under varied management; this implies that the CMT might be overemphasizing the influence of selected management practices. The evaluation of multivariate relationships between the practices scored in the CMT and DSPs revealed that soil properties like soil pH and particulate organic matter-carbon (POM-C) can be used to improve the accuracy of the tool. They also show how relationships between questions (practices) and outcomes suggested by DSPs vary among farming categories and suggest this type of practice-based tool should be adapted by embedding factors to scale farming systems or, preferably, by adding questions that better describe important factors (e.g., plant productivity and fertilizer timing, rate, and form of application) and their interactions with other factors known to influence specific outcomes. This work shows how field data describing practices, properties, and outcomes can be used to statistically evaluate and refine conservation scoring tools.