The United Nations has declared 2015 the “ International Year of Soils.” Well, that does not sound very interesting. But let’s look at some statistics and information that indicate just how vital a healthy soil condition is to our food supply, general health, national economy and the environment.
Soil is the earth’s living skin. It supports our daily lives and provides us with the resources we all need to survive. It is absolutely critical to our food supply. Without it human life would be impossible. Soil provides plants with the necessary nutrients to grow, filters storm water runoff and filters seepage into our ground water through their chemical, biological and physical properties.
Soil is a living dynamic resource that covers most of the planet. It is complicated mix of mineral particles, (sand, silt and clay), water and air voids, decomposing organic material and living organisms. In a healthy tablespoon of soil you would find about: 100 million to 1 billion bacteria, thousands of protozoans, dozens of soil nematodes, (tiny worms) plus other larger worms and invertebrates. Soil professionals have stated that in handful of soil, there could be more living organisms than there are people on earth. The life cycle of all of these organisms contribute to the top most fertile layer of the soil that is, the top soil. By capturing these decaying organisms, vast amounts of organic carbon is stored. Worldwide, soils serve as a critical reservoir to maintain a balance of carbon dioxide in the atmosphere.
Much of the land use worldwide has been devoted to agriculture for thousands of years. Intensive row crop agriculture that is prevalent in most of the Midwest is incredibly successful. Modern agricultural technology has been responsible for feeding much of the world and a critical factor in our balance of trade. Modern equipment, GPS technology, crop hybrids, pesticides and integrated pest management have all contributed to the highest crop yields in the world.
However, there has been a downside. Continuous row-crop agriculture has led to a significant degradation of the soil base. Modern U.S. Department of Agriculture (USDA) soil surveys indicate that many of the sloping fields in the Midwest, under continuous corn and soybean systems, have lost anywhere from 50 to 100 percent of the original top soil that was present when the land was settled. Soil erosion, soil compaction, destroying beneficial fungi and earthworms and an increase in storm water runoff are all results continuous tillage. We have measured soil erosion rates in excess of 10 tons of soil per acre per year on crop fields.
But there are encouraging trends. Soil conservation farming techniques are gaining much wider acceptance then in the past. No-til farming is a method where the current crop is planted directly into the residue from the previous year’s crop with no ground disturbance. No-til crop systems will drastically reduce the rate of soil erosion, add to the top soil and reduce tillage trips over the field.
An increase in interest and use of cover crops is also an encouraging trend. Cover crops are plants that are sown late in the crop year into growing or recently harvested row crops. When the corn or soybean crop is harvested, the cover crop will germinate and grow until it is goes dormant by winter cold. Some cover crops will start to grow again in the spring. With cover crops, the soil is providing growing plants for nine months of the year, not just the 4 months when the cash crop is growing. The cover crop will reduce erosion, add organic matter and increase the soil’s ability to absorb rain. It is like having a solar energy power plant producing healthy organic matter for most of the year. It has been estimated that for every one percent increase in soil organic matter, (top soil) an extra 200,000 gallons of rain water can be held in the soil per acre. Water that is used by the plant, seeping into the ground and not running off into water bodies.
So, next time you are in the yard, take a good look down and realize what you are standing on is of vital importance to our health and our environment.
Rick Macho is a resource conservationist with the Madison County Soil and Water Conservation District in Edwardsville.