On June 26, a diverse group of companies with an interest in the long-term resilience of US corn and soy production journeyed together to hear the latest science and see first hand from farmers where the opportunities and challenges lie. Our shared goal is to maintain and improve soils and productivity as new knowledge is gained about how to do so through cover crops, extended rotation, and edge of field practices, such as grassed waterways and bioreactors.
We spent the morning with Dr. Matt Liebman and Dr. Mike Castellano at the ISU research farm, seeing the results of long-term trials. The Marsden Farm Trials compare three systems: a 2-year corn/soybean rotation, a 3-year corn/soybean/oat + red clover rotation, and a 4-year corn/soybean/oat + alfalfa/alfalfa rotation.
For many of us it was surprising when Dr. Castellano shared that fertilizer is not the problem when it comes to water quality issues in the corn belt when farmers use practices
that keep living roots in the ground year round, such as cover crops and extended rotation with small grains. The cover crops keep the ground full of living roots that take up and hold Nitrogen in place so that it can’t be washed into the water table. The Marsden trial reveals that “diversification of conventional corn soybean systems with small grains and forage legumes can allow for large reductions in the use of mineral fertilizers and herbicides and lead to less environmental damage, equivalent profitability, improved soil quality, and higher crop productivity.”
Read Liebman’s paper on the Marsden Farm Experiment and the data on farm economics and environmental impact. data on farm economics and environmental impact.
Details on the water quality and GHG benefits of these practices using data from the Iowa Nutrient Reduction Strategy and the Fieldprint Calculator can be found here.
Following the ISU research trials we visited Jeremy Gustafson’s farm, where we heard from Jeremy about the risks farmers face for adopting cover crops and rotating with a small grain (in this case oats). Jeremy outlined the recipe for giving farmers like him the confidence to experiment with cover crops and extended rotation and listed the barriers:
- cost-share per acre of cover crops or small grain
- make it easy to get cover crop seed and support by:
- coordinating groups of farmers around aerial seeding of cover crops in the fall
- purchase cover crop seed from input suppliers
- Pay farmers to mentor other farmers and encourage knowledge share and support in expert facilitated farmer network groups (i.e. PFI)
- Create market pull for small grains as inclusion in a sustainable feed ration
At Jeremy’s farm we also had an opportunity to view the rainfall simulator with NRCS representative Neil Sass. The rainfall simulator visually represents the differences in water runoff and soil erosion between different types of tillage systems with and without cover crops or an extended rotation with a small grain.