Soils in the Midwest have been through the ringer in the last few years. A good cover crop can offer some real benefits to soil quality and act as a hedge against increases in fertilizer prices. Left to fallow, productivity and soil health can decline dramatically. A number of fields we have observed have exhibited a dry crust with gummy soil underneath. Others are simply slippery mud.
As the window closes for replant, some growers will choose a prevented plant option and what happens to those acres in that scenario can impact yields in following years. The biggest concern this year is with excessive precipitation and the resulting nitrogen loss. N loss, of course, can be combated using conventional fertilizers on planted crops, but the right cover crop on fallow ground can replace some of that nitrogen, or at least keep the last of it from trailing away.
No-tillfarmer.com offers ten tips on seed selection for cover crops here. A good rule of thumb is legumes before corn and grasses before beans. Radishes may go before either.
A lot of folks have recently touted the benefits of radishes as a cover crop or as part of a cover crop mixture. Tubers in the soil will help keep the ground from compaction. If forecasters are correct, July and August could see a return to the hot, dry conditions of summer 2012 and that could turn soils into something like dried concrete.
Roots in fallow ground, tubers in particular, can help salvage applied nitrogen, break up the substrata and return some organic nitrogen to the soil. Options for different varieties are wider the earlier a cover crop goes in. As fall approaches, the array of possibilities narrows, so it is wise to begin thinking this through.
- Do you plan to harvest or graze the crop?
- Do you want the soil covered through the winter?
- What seeds are available? -- shortages have already been suggested so the sooner the better.
- Do you want a live or dead cover crop in the spring?
- What works for neighboring growers?
For specifics on exactly what you can and cannot do with your fallow prevented plant ground consult your insurance agent. Soils are at their best when they do what they are intended to do -- nourish root systems and encourage robust yields. If prevented plant ground is left to stand, uncovered, little progress toward improved soil health can be expected.