Your soil health questions answered
Questions abound about soil health practices and principles, from why reducing tillage is necessary to which cover crops are best to adopt. In this regular feature of the Soil Health Digest, we try to answer them.
What changes can I expect after reducing tillage?
Four thousand years of tillage and land degradation “is a cost we cannot pay any longer,” says Roberto Peiretti, Argentina scientist and farmer. Reduced tillage and adoption of cover crops is essential to keeping productive soil in place.
The good news is that no-till can not only boost productivity and help farmers be more sustainable, but it can also repair past mistakes. Farms that have suffered erosion can rebuild soil. Organic matter can be restored. “That makes no-till beyond sustainable,” Peiretti says.
That message comes not a minute too soon. Peiretti cites farms in Argentina that lose more tons of soil each year to erosion than they produce in grain. “That’s a price humanity cannot pay any longer,” he says.
Which cover crop is essential to building soil health?
Not a crop, but a species, says Caley Gasch, soil scientist at North Dakota State University. Cereal grains such as oats, rye, or wheat feature fine root systems, rather than a single large taproot, that die and regenerate. “The architecture of these root systems is more efficient at putting biomass below ground. The roots actually alter the arrangement of soil particles and create pore space so the soil holds water more effectively,” Gasch explains.
“If you want to improve soil faster, you tend to see physical property benefits if we have a small grain in rotation, or we use them as cover crops,” she says.
What new cover crop species are available for 2020?
Field pennycress and hybrid rye are two new options. As a winter annual oilseed, field pennycress is similar to camelina in producing oil for industrial uses. It helps reduce soil erosion and nutrient leaching plus offers weed suppression properties. Also, it makes a good pollinator crop, says Scott Wohltman, cover crop lead for La Crosse Seed.
Hybrid rye has robust stands and improved yield over varietal cereal rye, yet it retains the same soil health benefits. It is more expensive, but growers wanting to produce grain or feed may find the extra cost worth it. Keep in mind that farmers cannot save back and replant hybrid rye seed, he adds.
How can I jump-start soil biology?
Once you become comfortable with cover crops and reduced till, boost soil health by “intercropping” or “bio-strip-till,” says Lana Shaw, manager of the South East Research Farm at Redvers, Saskatchewan. Why not? The synergistic effect of the intercropping often leads
to more overall revenue
Nick Toussaint, who farms with his father, Doug, and brother Brad near Wahpeton, North Dakota, has shifted to bio-strip-till. After small grain harvest in the summer, they plant 60 pounds of cereal rye and 2.5 pounds each of rapeseed, radish, and flax in 30-inch rows; they plant sunflowers into the strip the following spring. The plan is to put starter fertilizer on in the strip at planting, reducing the need for broadcast fertilizer and building soil health at a more budget-friendly rate.
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