Monday, December 15, 2014

Protect your soil to reduce erosion

As I’m sure we all recognize, soils are an important part of our agricultural systems, but they to far more than just provide a place for plants to grow roots and anchor themselves. Soils are really an ideal growth medium, they maintain spaces that are filled with oxygen to help, others that are filled with water, they hold nutrients in a place where plants can get them, and they insulate roots from drastic daily changes in temperature. As such, it acts as an ideal growth medium. That means protecting it an making sure it remains in the field for years to come is vital for maintaining our agricultural productivity.

Have you seen this video of raindrops hitting a sand surface that was captured a team of scientists in the Chemical Engineering and Material Science department at the University of Minnesota. Their video shows the impact of water drops on the surface of sand particle. The high-speed photography reveals the detailed liquid-drop impact dynamics at various impact velocities. As you watch the video look at how the soil particles are struck and scatter when the drop hits; drops can be up to 6 mm in diameter and hit the soil at up to 20 miles per hour. As you can see this force from the raindrops can dislodge soil particles and splash them up to three feet away. If there is no residue coverage left, then our soil is exposed to these pounding forces that breaks apart our soil aggregates and facilitate the formation of a crust that seals the soil from taking in additional moisture as quickly as it otherwise would. However, if we keep crop residue on the surface or grow cover crops, we can reduce the impact this raindrop impact has. Residue provides a cushioning effect that absorbs the impact of the rainfall, and helps protect your soil.

So what are some ways that you can help protect your soil resources by leaving more residue? Here are three tips:
1. Try to follow a crop rotation sequence where a high-residue producing crop is grown every couple years. Or if you have need for a forage, consider planting a perennial like alfalfa that will maintain surface residue coverage for several years.
2. Wait until spring for tillage operations.
3. Try planting a cover crop, especially in fields where low residue crops where grown. For example, focus on fields where your corn was harvested as corn silage and lots of the residue removed.