Since 1969, select farm plots at the University of Illinois have been in continuous no-till. In that time, the measure of organic matter has been boosted three-fold – from about 1 percent to 3.2 percent, without cover crops, according to Mike Plumer, the natural resources management educator at the university Extension. He said that in the same period, rotating between corn and soybean crops, the stored carbon in that soil has risen from 25,200 lbs per acre to 99,300 lbs.
“Cover crops essentially speed the recapture of organic matter and carbon in the soil,” Plumer said. He points to annual ryegrass as an example. “Its network of deep roots sequester carbon over the winter while increasing organic matter, rebuilding soil structure more quickly than by no-till alone.” Cover crops also reduce erosion, store nitrogen, mine deeper minerals and, particularly in the case of annual ryegrass, produce channels for subsequent corn and soybean crops to follow, allowing them access to deeper moisture in dry years.
In a 2 year, replicated study on a southern Illinois farm where corn yields were compared with conventional, no-till and no-till with annual ryegrass, Plumer found that crop productivity increased substantially with annual ryegrass. Moreover, the yield increased as the years in no-till and cover crops increased. Here’s a brief look at the data, collected during 2006 and 2007 seasons. Note that the weather was very dry and the soil features a signature fragipan layer.
Type of tillage Ave. yield in bushels/acre
Conventional 52.5
Conventional (1st yr), No-till (2nd) 61.5
No-till 79.0
No-till w/annual ryegrass cover crop 121.0
Tags: Annual ryegrass, annual ryegrass as a cover crop, carbon sequestration, crop yield, deep rooting, fragipan soil, macropores, Mike Plumer, No-Till farming, University of Illinois
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