Having planted your cover crop…yeah, those of you lucky enough to have gotten to it with a late harvest and wet conditions…you might be wondering what’s going on below that snow right now.
Well, for starters, what’s not happening above ground is erosion. Even if that snow cover melts off, the annual ryegrass fall growth will keep the soil in the field, as well as the soil nutrients.That means clean runoff next spring, no pollutants.
Even if the top growth of annual ryegrass is 4 to 6 inches going into dormancy before winter, the roots will continue to grow all winter. Presuming there’s no winter kill – when no snow, frigid temps and a wind chill create a hostile climate for cover crops…perhaps killing them – then the roots can grow to more than FIVE FEET DEEP.
Of course, deep rooting breaks through plow pan, hard pan and other compacted soils. This allow more water infiltration and gradually increases friability…that crumbly condition ideal for plant growth. The following growing season, corn and soybean roots follow the pathways established by the cover crop, allowing cash crops to grow deeper roots and withstand dryer summers.
After years of growing annual ryegrass and other cover crops, the decaying root matter begins to increase organic matter in the soil. Additionally, cover crops increase the carbon in the soil…a good thing. Worms and a host of microorganisms find the untilled soil attractive and add further composting below the surface. Plus the growth of mycorrihizal fungus increases the cash crop’s ability to uptake water and nutrients.
Annual ryegrass and other cover crops also sequester nitrogen and other resident nutrients in the soil. When corn needs a boost in June and July, the decaying cover crop residue gives up its nitrogen for use by the corn or beans.
The key with bringing health back to overtaxed soil is to quit plowing and go no till, then plant cover crops year after year. The net benefit, besides cleaner water, healthier soil and fewer inputs of fertilizer is a boost in production. Consistent testing of cover crop lands versus conventionally tilled soil proves that those with cover crops are better producers.