Tuesday, September 15, 2009
Organic matter is the basis of any sustainable agricultural operation. Broadly speaking organic matter is anything in the soil derived from living or once living creatures. The rest of the soil is minerals from broken down rock.
Organic material in the soil works wonders. It mediates chemical, physical, and biological processes and creates a more stable soil structure. Each tiny piece of organic matter is actually not solid at all, but filled with pores. The tremendous surface area acts a sponge for plant nutrients and water. During dry periods it holds moisture for plants. In wet periods it better retains and releases water to prevent surface runoff-in other words it helps in both flood and drought. Likewise, the sponge holds all kinds of plant nutrients.
Perhaps the most amazing component of soil organic matter is the living component. In a tablespoon of healthy soil the organic matter holds more than 7 billion organisms, as many creatures as there are people on the entire planet. This living soil literally builds more soil by breaking down dead plant matter, manure, and minerals. As minerals and dead matter are broken down nutrients are released for crops.
Some soil organisms form beneficial relationships with plants. For example, fungi in the soil can extend the effective root area of a plant by several orders of magnitude. This allows the plant to absorb water and nutrients more effectively.
The best part is that we can make this soil organic matter! Perhaps you know it as compost. Compost is the foundation of sustainable crop growing. To make compost we combine fresh plant matter and manure with dry matter like straw or leaves. Within a few days a properly built pile will become warm to the touch as microorganisms whip into a feeding frenzy. After only a few weeks or months (depending on season, ingredients, and pile management) what was once a pile of horse poop, straw, and cucumbers will turn into a rich, dark, sweet smelling, crumbly substance.
Fresh compost on the garden
Unfortunately, we can also destroy soil organic matter. The excessive use of synthetic plant nutrients, excessive tillage, and the use of poisons for both insects and weeds will kill soil life. Without the living component of the soil organic matter no new dead plant matter is ever incorporated. Leaves will stay leaves and corn stalks will stay corn stalks, for many months. Eventually, the soil will be reduced to a hard, lifeless medium used to hold plants up and receive the chemical fertilizers the producer sprays. Additionally, without the structural support of organic matter soil easily erodes with excess water. Soil becomes highly susceptible to compaction by machinery. As the soil is degraded crops require more and more inputs to produce. The additional use of fertilizers and machinery generally speeds the process of soil degradation. In the end soils can be turned into lifeless dirt. One that is extremely difficult to grow anything in.
At Bluebird Farm we strive to build our soil organic matter through the use of compost and rotational grazing techniques. As organic matter improves we will see a decrease in our water needs and an increase in yields. As the process continues our land will only improve in its food production ability and the food will be of higher quality.
For more information on compost read
For information on organic soil management check out