By Brad Ross
“The top six inches of the earth’s surface is what keeps our population from starvation!” stated my professor. He was referring to the depth of the topsoil of our earth’s crust and the fact that the human population would not survive if we lost this topsoil. Most of us take for granted the important role soil plays in our lives. We build our basements in it; we pave over it for our roads; we grow our trees and flowers in it; we play soccer and hike on it; and most importantly we use it to grow our food and fiber. During my nearly 40 year career in soil conservation, I have never forgotten that statement by my soils professor. It made a huge impression on how I have looked at our soil and the importance of protecting and improving it.
If not adequately protected, it can be easily damaged or destroyed. Soil erosion is the number one cause of soil degradation, and by weight, that eroded soil is the most common pollutant in Ohio streams. While soil is a resource that can recreate itself, the process is extremely slow. How slow? Think about this - it takes 500 years to create a layer of soil one inch thick! The surface layer of soil contains organic matter which is plant and animal residue in various stages of decomposition. Only half the original organic matter remains in most modern cultivated soils - in general, the levels have fallen from five to six percent of the soil to less than three percent on most cropland. Organic matter is extremely important because it provides a carbon and energy source for beneficial soil microbes. These microbes need food and cover to survive, just like other living creatures, and as a group they cycle nutrients, build the soil, and give it structure.
So how do we protect our soil, including that valuable organic matter? Take a lesson from Mother Nature — keep your soil covered. No-till and cover crops are two excellent management tools for not only protecting your soil, but improving it. No-till is a method that keeps the soil covered with crop residue and reduces soil disturbance to almost zero. Long term research has demonstrated there are many benefits to a no-till systems approach to crop production. First and foremost, the soil is kept covered with the previous year’s crop residue which protects the soil from erosion by raindrop impact. This residue also makes the soil much less susceptible to the effects of wind erosion. The residue also shields the soil from the heat of the summer sun, conserving soil moisture for growing plants. The residue shades weed seeds, suppressing them and giving desirable plants the opportunity to absorb water and nutrients and outcompete the weeds.
Another way to emulate Mother Nature is through the use of cover crops. Cover crops are plants seeded into the soil, usually in late summer or fall, with the primary purpose of improving soil health. These plants are not harvested for their seed, fruit, or forage. Cover crops provide some of the same benefits as no-till by reducing wind and water erosion, improving soil water holding capacity, combating weeds, and adding organic matter. They also reduce soil compaction, provide nitrogen for plant use, and increase nutrient cycling.
Continuous no-till with cover crops imitates Mother Nature by keeping soil covered most, if not all, of the year. This two part system results in improved soil structure and soil health and myriad other benefits. Whether you are a farmer or gardener, no-till and cover crops are great conservation practices that help you help your land. For more information on Delaware County’s soils, no-till, or cover crops visit www.delwareswcd.org and www.nrcs.usda.gov or call 740-368-1921.
Brad Ross is a Communications Specialist at the Delaware SWCD.