What type of return on investment do farmers realize when they make a long-term commitment to planting cover crops on their farm?
That question can be tough to answer. In many cases, the payback can’t be calculated using only dollars and cents; better soil heath, the benefits of increased water-holding capacity, and a soil’s ability to feed a crop, while withstanding the punishing effects of drought can be difficult to measure.
But more research is emerging to help farmers better calculate the benefits of cover crops. On this episode of Soil School, Laura Van Eerd, professor of sustainable soil management at University of Guelph, discusses results from long-term cover crop trials she’s been conducting at the Ridgetown campus.
In the video, Van Eerd shares an economic analysis conducted by her Guelph colleague, associate professor Richard Vyn, on cover crops in a vegetable system (two years of tomatoes followed by sweet corn and squash) and a grain system (two years of wheat followed by corn and soybeans).
For vegetables, Vyn’s economic analysis shows that the addition of cover crops over the eight-year period improved vegetable profit margins by five to nine per cent. Van Eerd attributes much of the increase to a tomato crop’s ability to respond to intensive management and a noticeable improvement in soil health. (Story continues after the video.)
Economically, cover crops did not have the same impact on the grain system, showing a negative margin of about five per cent. However, Van Eerd notes that it’s difficult for a rotation including two years of wheat to be compared economically to a rotation featuring two years of a vegetable crop like tomatoes. Added cost for spring burndown of cover crops in the grain system is another cost factor to be considered.
Overall, Van Eerd notes that the research indicates significant improvements for organic matter levels and soil health. Over eight years, comparing cover crop and non-cover crop systems, cover crops consistently showed higher soil organic matter, 11 per cent, and scored 17 per cent higher when assessed for soil health.
“That means better water-holding capacity and in years when we get really dry in August, that shows up in our yield,” she adds.
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