Crop Rotational Diversity Impacts on Soil Health in Organic Corn Production
While there are many definitions, our lab views soil health as a holistic approach to soil management that strives to reach optional biological, chemical, and physical function for enhanced crop production and ecosystem health. There is an increasing amount of enthusiasm for soil health testing, which consists of indicators that are sensitive to management and have the ability to predict agronomic performance. The most common soil health indicators measured in our lab include soil respiration and permanganate oxidizable carbon, which measures the labile pool of carbon, and soil protein, which is an indicator of the organically bound pool of nitrogen.
Despite these new advances in soil health testing, several questions remain on how management practices influence different soil health indicators and how this, in turn, influences important ecosystem services. For example, the most commonly asked questions we are asked by farmers include:
(1) What is the average value for a given soil health indicator?
(2) How do my soil health test values compare to others?
(3) What crops should I include in my rotation to improve my soil health?
To address these questions, we teamed up with Dr. Steve Culman's Soil Fertility Lab to build a soil health database for the Great Lakes Region:
Soils were collected from over 200 farms consisting mostly of organic corn producers. Our primary objectives were to :
(1) Develop distributions of soil health indicators across the Great Lakes Region
(2) Assess the extent to which various management practices influence soil health
We collaborated with department social scientists who were conducting a survey of organic farmers in the region. We created an additional short survey and offered a free soil health test to any farmer who returned a completed survey. We received over 200 soil samples across four states and are in the process of analyzing the data. We plan to prepare the results for manuscript publication aimed at the scientific community and for outreach materials aimed at the farming community and the extension agents who work with them.
We found that organic farm crop rotational diversity has a complex relationship with soil health indicators, which we believe is correlated to increased tillage frequency:
INCREASED crop rotational diversity -> INCREASED tillage -> DECREASED soil health
INCREASED perennials in rotation -> DECREASED tillage -> INCREASED soil health