BIOLOGICAL IMPACT Living organisms impact soil structure. Organic matter attracts earthworms that drill channels deep into the subsoil. These channels provide needed space for plant roots, air and water. Worms leave behind castings as they they tunnel, which improve nutrient levels in the soil. In addition to earthworms, microbes live in soil. Microbes break down some nutrients and organic matter into simper units that plants can use. The organic remains of microbes improve soil structure. Some plants roots and microbes have a Symbiotic relationship. These microbes depend on plant roots to provide them with food. In exchange, microbes make nutrients available to the roots. Some microbes attach themselves to the root and form extensions called Nodules. These extensions increase the root’s surface. Microbes chemically change nutrients, transforming them into usable forms for the plant. An example of these microbes is nitrogen- fixing bacteria on the roots of beans and peas. Even growing plants change soil structure as they send their root down into the soil. Roots enlarge openings in the soil and provide organic matter when they die and decay. Improving soil structure is an ongoing goal of gardeners. Soil structure cannot be changed easily. However, the addition of organic matter and working the soil at the proper moisture levels improve soil structure. Correct soil moisture level exist when soil crumbles easily when turned over with a fork or spade. Soil should not stick to the fork or spade. Working wet soil compacts structure and reduces air and water space.
Posted on: Sat, 21 Sep 2013 20:15:26 +0000