If you’re not already including small grains and pasture in your crop-rotation practices, you should reconsider. According to a joint Purdue-U.S. Department of Agriculture study, your soil will thank you.
Reducing tillage is another factor that can help soil health, the findings, reported in Soil Science Society of America Journal, highlighted.
Diane Stott, national soil health specialist for USDA’s Natural Resources Conservation Service and a Purdue adjunct professor of soil science, and Ashley Hammac, a postdoctoral research associate for USDA Agricultural Research, looked at soil samples from the Cedar Creek Watershed, which drains into the Western Lake Erie Basin in northeastern Indiana and is one of 17 study areas around the country. The soil in the study area is healthy, with scores on the Soil Management Assessment Framework — which grades soil using 10 quality indicators — quite high. Physical, chemical and nutrient component indices averaged 90 percent, 93 percent, and 98 percent of optimum, respectively.
There was no difference in soil health when comparing tilled vs. no-till fields, except when looking at hills. Toe slopes, the areas at the bottom of a hill, had higher physical, biological and overall scores than the soil at the summit of a hill. That’s likely because loosened soil at the summit runs downhill, taking nutrients and microbes with it.
The highest-rated soils were in land converted to perennial grasses. In many cases, these were agricultural fields in which farmers have gotten government payments to convert them to grassland because of erosion issues. While growing fields have nitrogen and phosphorus applied to improve crop growth, grasslands that aren’t fertilized had the same nutrient profiles as agricultural land.
“A lot of soil health is really about being able to deal with weather extremes, and a lot of it boils down to water,” Stott said. “Usually, having wheat or other small grains one in three years improves the structural stability of the soil.”