Greg Andrews/Leon Morrison column: Soil conservation and soil health
Soil conservation has been around since 1934, when the first contour strips were laid out near Coon Valley, Wis. Since then, most of the highly erodible land (HEL) eventually had some contour strips with hay in the crop rotation. The goal was to reduce erosion and conserve the soil. In recent years, some farmers have removed contour strips from their land, creating larger fields that are more efficient to farm with big equipment. This change has increased soil erosion on farm land, especially where conventional tillage is used on HEL.
Within the last five years, soil scientists have focused on soil health. Agronomists and soil scientists now look for living organisms such as earthworms in the soil. They also advocate higher soil organic matter levels, especially where half of the original topsoil and organic matter has been lost over time. Soil organic matter in a forest that has never been farmed or grazed is around 6 percent. Organic matter in many farm fields today is often less than 3 percent. Soil scientists and others now know that tillage destroys organic matter in the soil. Soil dwelling organisms beneficial to soil health are also adversely affected by tillage. Soil degradation is now a major problem.
So what can be done to stop or even reverse soil degradation?
The most practical method used to improve soil health is no-till combined with use of cover crops, which is practiced by an increasing number of farmers today. The combination of no-till and cover crops can reverse soil degradation by increasing organic matter and reducing soil erosion. Rain water infiltrates soil with high organic matter much faster, reducing runoff and erosion.
A four-year study, sponsored by the Salford equipment company, found water infiltration from heavy rainfall events was four times faster on no-tilled cropland than on conventionally tilled fields. High organic matter soils also retain more water and nutrients, which is critical for attaining higher yields. High organic matter and improved water retention also provide a better environment for earthworms. The presence of earthworms is an indicator of healthy soil, and earthworm tunnels can further improve water infiltration.
There are steps that should be considered before transitioning to no-till.
The soil should be tested. The soil pH level needs to be increased if tested below 6.2. Correcting the P and K soil nutrients to optimal levels should also be considered. Good planting equipment is needed, and should be setup for no-till. Finally, contacting the conservation staff in the Land Conservation Department (LCD) at the local Natural Resources Conservation Service (NRCS) office is very important. Rod Webb is a Soil Conservationist with the Pierce County LCD/NRCS, and a local farmer who has several years of no-till experience. We are also willing to talk with anyone about soil conservation, soil health, and no-till farming.