It' s Our Garden The Importance Of Soil/Part 3

By Elkabeth and Crow Miller

Composting, Building Healthy Soil

One of the great beauties of the organic approach is that it enables a person to grow beautiful, healthy plants without much of anything special. In Nature the soil is built by a very efficient recycling of nutrients. Things that die and fall to the ground begin to rot almost immediately. Little is lost. The organic approach feeds plants by feeding the myriad organisms of decay that live in the soil. Wonderful gardens are built on wastes, trash and castoffs.

Basic composting is an easy to arrange process. True, transformation of a mass of undecomposed organic materials into life-giving fertilizer is one of Nature's almost unbelievable miracles. But the elementary steps which set off this transformation are simple, and easy to follow.

Sheet Composting is one good example of low temperature decomposition. It involves tilling under plant refuse, manure and other wastes, leaving them to decay in the soil. Since there's no pile to turn, sheet composting means less work. But the problem with it, as with other methods of anaerobic decomposition like trench or pit composting, is that high carbon residues rely on the nitrogen (N) reserves of the soil for their break down. High-nitrogen materials, on the other hand, release their (N) too quickly or in the wrong form for plants to use when decomposed anaerohically Sheet composting is slow. What can be accomplished in a well managed heap in a few weeks may take a full season in the soil.

Hot compost means fast compost, but hot, aerobic compost pile, too, has its disadvantages. Building a pile takes plenty of time, energy and sweat. Nutrient-rich liquids can leach into the ground beneath the pile where they are of little help to plants.

Rapid decomposition burns up oxygen fast. A well made pile will heat up in 2-days. But to keep it rotting as quickly as it is able requires a turning for aeration every third day. Without it, the bacteria and fungi that are digesting the pile run out of oxygen and the decomposition slows.

Active composting has some compelling advantages. One is that it is an easier way to apply large amounts of organic matter to the soil. Especially in small gardens where vegetables are spaced closely.

The process of composting reduces the bulk of whatever material you have roughly in half, with minimal losses of nutrients. Some of the nutrients in the original material are rendered readily availahle to roots. the continuing action of soil microbes on digested compost releases more.

Behind every successful compost pile are well fed microbes. They acquire essential energy by oxidizing the carbon and nitrogen (N) contained in those materials, using carbon for growth and (N) for protein synthesis. The heat in a compost pile is a direct result of this oxidation for biological burning. For a pile to heat up properly, it needs the right blend of organic wastes, air, moisture and sufficient size, in that order.

To start building a compost pile, all you need to know is a rough estimate of the carbon/nitrogen content of the materials you have to work with. The carbon content is a gauge of the food energy, that is available for the microbes. The microbes also use nitrogen (N) as building blocks for protein as they multiply.

To work at peak efficiency, the bacteria and fungi in a compost pile need 25 to 30-parts of carhon to one part (N). If there is too much (N), that is, less than 25-parts of carbon to one part (N), the excess will he wasted. You will smell it escaping as ammonia gas when you turn the pile.

When the balance is right (carbon level between 25 to 30), heat loving microbes thrive. The temperature raises, which makes the microbes work even faster. As a bonus to you, the high heat also kills many weed seeds and disease-causing organisms. Nearly all the (N) is incorporated into the bodies of the micro-organisms. And they consume carbon energy in the process until the carbon level drops to roughly 10-parts to each part (N). That's the same carhon to nitrogen ratio (C/N ratio) as a humus-rich soil. The compost then cools to about 110· F. and is ready to go on the garden beds immediately.

Feeding a compost pile is simple. The micro-organisms require only a special blend of protein and carbohydrate sources. Vitamins, minerals, and other nutrients, these they seem to either manufacture for themselves or forage for just fine. High-protein wastes are usually succulent, green

vegetation (kitchen wastes and grass clippings), and many animal by-products including manure and urine. Note: Urine is not a source of protein, but of (N) containing compounds from which some microbes can build their own protein.

Energy-rich materials are almost exclusively dry, tough, fibrous former plant parts; autumn leaves, straw, sawdust and the like. these contain complex carbohydrates, which the microbes digest for the energy they contain.

Adding organic matter triggers a complex soil system into action. When plant and animal wastes are worked into the soil, the most soluble components, sugars and starches, decompose first. They're a good source of energy for the micro-organisms in the soil. The micro-organisms feed on some of the carbon and (N) in the organic matter and convert them into their own cellular material. In the process, many nutrients are released in a form accessible to plants. Later, when the micro-organisms die, their cells decompose, and the nutrients in their cells become available for plants.

A yearly application of 10 to 20-tons of organic matter per acre, 240 to 450-pounds per 100-square feet, would certainly provide all the (N), nitrogen, (P) phosphorus and (K) potassium you'd need in most garden situations. After about 5-years, you might want to cut back, and you'll still find the nutrient level increasing.(Note:) have your soil tested.

An ideal soil profile contains about 5 to 10% organic matter. Getting the level up that high isn't difficult. Since a 6-inch layer of mineral soil in a 100-square foot plot weighs about 47,000 pounds, adding 235-lbs. of compost will give you an instant 5% organic matter. Even in soil that has only 1% organic matter initially, 20-tons per acre (460-lbs. per 100-square feet) will make a big difference.

Finally, a few review points for successful composting:

1) Make sure the nitrogen content of your pile is high enough.

2) Try to mix together more kinds of raw materials, primarily to provide

proper physical condition.

3) Shred all fibrous materials.

4) Keep your compost moist, not soggy.

5) Turn it with a spading fork, as often as you can. (at lest 3-times/Wk.

6) Test your soil, if your soil is acid, mix in Dolomitic limestone (54% Ca.

Calcium/42% Mg. Magmesium). No matter what kind of soil you have, mix in

some kelp meal to increase the trace mineral content.

If you haven't been composting, now is the time to start. Your garden will love you for it!

Copyright · 1996/Crow Miller,Syndication/Magazine/The Soil/#76/ On line/