We’ve talked in this space before about the state of soils in western Texas and the need for conservation measures to battle severe erosion in cotton fields.
Something I read the other today really blew my mind, and put this into perspective: It takes about 500 years to replace 1 inch of topsoil that is lost through erosion, according to Katie Lewis, a soil scientist at Texas A&M AgriLife Research.
Lewis says the university has been studying the potential of seeding winter cover crops after cotton harvest to help hold soil in place during high winds, as well as dust storms that can carry away up to half an inch of topsoil.
For 18 years, the university has been studying no-till practices with either rye as a cover or a mix of covers including rye, hairy vetch, radish and winter pea and comparing the results to conventional tillage cotton.
You can read the rest of the article below, but in short, they aren’t finding a yield advantage with no-tilled, cover cropped cotton fields. But they did find that soil organic matter levels have doubled, and improved plant diversity and crop rotation reduced insect pressure.
If you read between the lines, this also seems to refute arguments I’ve heard many times that cover crops will steal too much moisture for the cash crop and hurt yields. Proper termination timing to manage moisture profiles is key, and that’s something Lewis and colleagues are studying.
Lewis says one issue they’re dealing with is having to terminate covers in mid-March to allow for timely rains and moisture storage ahead of May cotton planting — which doesn’t allow cover crops to nodulate enough to fix nitrogen (N), she says.
I think if Texas A&M continues this work they’re going to find the answers eventually. Watching topsoil blow away doesn’t help profitability now, and waiting 250-500 years for soil to regenerate won’t help farmers in the future.