Which management practices influence soil health in Midwest organic corn systems?

Fostering and maintaining soil health via holistic management is a central goal for most organic farmers. However, many questions remain regarding how different management practices influence soil health in farm fields. In this study, we used a mail-in soil survey to assess how organic management practices such as crop diversity, perennials in rotation, tillage, manure use, and subscription to soil cation balancing influence soil biochemical health indicators in certified organic corn (Zea mays L.) fields. Organic farmers (n = 195) from the eastern Corn Belt mailed in soil along with a completed management survey to a research lab for analysis. Soils were analyzed for mineralizable carbon (C), permanganate oxidizable carbon (POXC), soil protein, texture, and routine soil nutrient analyses. Soil texture had the largest influence on soil biochemical health indicators, underscoring the need to consider soil type with soil health assessments. Crop diversity was negatively correlated with mineralizable C, soil C, and soil nitrogen (N) (r = -.19 to -.24) at p < .05 when perennials were in the rotation. This was attributed to tillage frequency increasing with crop diversity across all soil types. The presence of a perennial in rotation influenced soil biochemical health indicators, except for total C. Additionally, mineralizable C significantly increased when perennials were left in rotation for longer periods of time. This study demonstrates the effectiveness of incorporating management survey data with soil biochemical health analyses. We conclude that a main management driver for improved soil biochemical health in organic corn production systems is to reduce tillage intensity and incorporate perennials.