- Production Systems: agroecosystems, organic agriculture
- Soil Management: nutrient mineralization, organic matter, soil quality/health
Impact of management practices on soil health in organic grain systems
Assessing and managing organic agricultural systems for biological soil health is essential to sustaining these systems as their fertility relies on the microbial processing of organic amendments, such as manure and compost. In Wisconsin, organic field crop production represents over 50% of all organic production acres (USDA-NASS, 2017). Identifying the most influential soil properties and management practices for biological soil health in these systems is critical to the development of soil health assessments and best management practice (BMP) recommendations. Overall, improvements in these areas would optimally inform farm decision making for better soil health.
To determine the key factors affecting soil carbon (C) and nitrogen (N) pools as well as biological soil health, publicly accessible soil property information from the United States Department of Agriculture – Natural Resources Conservation Service (NRCS) along with farmer-obtained management histories for 124 fields from 16 certified organic grain farms in the Driftless Area of Wisconsin were analyzed for significant effects. The main pools of C and N were measured via soil organic matter (SOM), total organic C (TOC), and total N (TN), while biological soil health was measured via permanganate oxidizable C (POXC), mineralizable C (minC), potentially mineralizable N (PMN), and autoclaved-citrate extractable protein (ACE).
Results indicate that publicly accessible NRCS soil information is useful for benchmarking soil health at the regional level. In particular, soil taxonomy, soil moisture, the fragile soil index, susceptibility to soil surface sealing, and susceptibility to SOM depletion should be considered as potential co-variates in soil health assessments. Disparate responses of biological soil health indicators to management practices suggest that multiple shifts in management may be required to support both healthy C and N cycling in agricultural systems. The outcomes of this study have and will continue to be disseminated to our participating farmers, other farmers, and stakeholders through farm-specific reports, conferences, field days, Extension events, and at least one peer-reviewed publication. From these sources, farmers will gain knowledge of currently recommended measurements for biological soil health and first indications of BMPs to consider in their operation's goals.
The expected learning outcomes for this research are as follows: 1) researchers will learn which management practices and inherent soil properties contribute the most to biological aspects of soil health on organic grain farms; 2) researchers will learn whether the duration cropland has been in certified organic management has an effect on biological aspects of soil health; 3) farmers will have increased knowledge of the current measurements for the biological component of soil health and best management practices for improving this component of their soil’s health. The expected action outcomes are that: 1) farmers will incorporate identified best management practices for soil health in their operations; 2) farmers that incorporate such practices will improve biological aspects of soil health, which may result in long-term crop productivity and ecosystem services.