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  MG Manual Reference
Ch. 2, pp. 38 - 42
[Fertilizers: fertilizers | analysis | types | organic | applying | application | improving | compost ]


In special cases, coarse sand, vermiculite, and perlite are added to heavy clays to help improve the soil texture or structure. However, these inert materials can be expensive and large quantities are needed to do any good. In some cases, they can make the situation worse by causing clays to "set up" similar to concrete. Compost, manures, and other organic amendments are more effective and economical for modifying the soil structure, while leaving soil texture unchanged..
Organic matter is a great soil improver for both clay and sandy soils. Good sources of organic matter include manures, leaf mold, sawdust, and straw. These materials are decomposed by soil organisms. Various factors such as moisture, temperature, and nitrogen availability determine the rate of decomposition through their effects on these organisms. Adequate water must be present, and warm temperatures will increase the rate at which the microbes work. The proper balance of carbon and nitrogen is needed for rapid decomposition. The addition of nitrogen may be necessary if large amounts of undecomposed high-carbon substances such as dried leaves, straw, or sawdust are used. In the process of breaking down the organic matter, nitrogen is used by the microbes and, therefore, may become deficient in the plants. Fresh green wastes, such as grass clippings, are higher in nitrogen than dry material.
Building a Compost Pile Top
The use of compost is one way avoid tying up nitrogen during decomposition. Compost is usually made by the gardener from plant wastes. Correct composting can result in a valuable nutrient and humus source for any garden. The basis of the process is the microbial decomposition of mixed raw organic materials to humus, a dark, fluffy product resembling rich soil, which is then spread and incorporated into the garden soil.
Recipe for Composting

Recipe for Composting
When you layer materials in a compost pile in this order, you will ensure the proportions of carbon and nitrogen that decay organisms need to work efficiently. You can repeat these layers to a total height of about 5 feet. The depression helps retain needed moisture.

3 Step
Start the compost pile with a 3-inch layer of coarse plant material such as small twigs or chopped corn stalks. This will aid in aeration and drainage. On top of this, put a layer of plant and kitchen refuse-leaves, straw, weeds, waste from garden plants, husks, coffee grounds, crushed egg shells, canning wastes, etc. It is not a good idea to use animal products except manure because they will attract digging animals and unwanted insects. Next, add a layer of nitrogen-rich material. This can be fresh manure if available, fresh grass clippings (not too thick a layer, as they will mat) or fresh hay. If you don't have enough nitrogenous material, there will not be enough nitrogen for the microorganisms to make proteins. Add more in the form of synthetic nitrogen fertilizer (1 cup 10-10-10 per 6-inch layer will do), blood meal (1 cup per 6-inch layer), or cottonseed meal (1 cup per 6-inch layer). The latter two are expensive when purchased in the typical 5 pound bags available in garden centers, but cottonseed meal can be found at a very reasonable price in bulk at farm supply stores. It has formerly been recommended that a 1-inch layer of soil be added for each 6 inches of plant wastes to supply microorganisms for the composting process, but research has shown that this is not always necessary. Enough soil is generally included on roots of plants and in manure to inoculate the compost pile. Compost starters are also unnecessary. If the wastes are free of soil for the most part, however, a sprinkling of soil at each layering may be beneficial. Repeat the layers of plant material and nitrogenous material as many times as needed to use all the plant refuse available. To generate the needed internal heat, a 3x3x3 foot pile is needed. If you are using a ready-made composter, follow the manufacturer’s instructions.
Water the pile as often as necessary to keep the contents as moist as a well wrung out sponge, but not soaking wet. The top of the pile should be low in the center to cause water to move into the pile rather than to run off. Within a few days, the pile should heat up significantly, to about 160 degrees F. This is a necessary stage in composting, as the temperature will kill many weed seeds and harmful organisms. If the pile fails to heat, there is insufficient nitrogen, volume of material, or water in the pile, and more should be added. The pile will decrease in size after a few weeks if it is composting properly. If the compost pile smells like ammonia, it may mean that the materials in the pile are too tightly packed or that the pile is too wet; i.e., there is not enough air. Turn the heap, adding some coarser material, and start over.
Rotating Barrel
The pile should be turned over after about a month (2 weeks if the material is shredded), putting the outside materials on the inside and vice versa to make sure everything gets broken down. Turn again 5 to 6 weeks later. The plant materials should decompose into good compost in about 4 or 5 months in warm weather, but may take longer under cool or dry conditions. Composting may be completed in 1 or 2 months if the materials are shredded, kept moist, and turned several times to provide good aeration.
Squeeze Test
The squeeze test, used to estimate the moisture content of the compost pile.
When compost is finished it will be black and crumbly, like good soil, with a pleasant, earthy smell. Only a few leftover corncobs or stalks will remain undecayed. These can be sifted out and added to the next batch. For use in potting mixtures, a relatively fine sieve ( 3 / 8 to 1 / 2 inch hardware cloth) will take out the larger chunks. Otherwise, the compost can be spread in the garden as it is and dug or tilled under.
If you need only a small amount of compost, you can use a plastic trash bag to compost relatively fine material such as leaves, lawn clippings, or chopped garden refuse. Make layers as in a compost pile, or mix all materials together. Add 2 quarts of water to dry material (one quart if it is quite moist or succulent). Tie the bag and turn it over every few weeks to aerate the material and distribute the moisture.
Cover CropsTop
Another source of inexpensive soil improvement that should not be underestimated is the cover crop. Green manures, or cover crops are planted in the garden in the fall for incorporation in the spring. Any fast growing annual plant that is easily killed will make a good green manure crop. Choices include annual ryegrass, wheat, barley, vetch, or field peas. For best results, seed should be sown as soon as possible after the main crop has been harvested. In a fall garden, plant cover crops between the rows and in any cleared areas. Cover cropping provides additional organic matter, holds nutrients that might have been lost over the winter, and helps reduce erosion and loss of topsoil. Legume cover crops can increase the amount of nitrogen in the soil and reduce fertilizer needs. A deep-rooted cover crop allowed to grow for a season in problem soil can help break up a hardpan and greatly improve tilth. Incorporate green manures at least two weeks before planting vegetables. They should not be allowed to go to seed.
Carbon to Nitrogen Ratios
for Selected Materials

(by Weight)
Materials with High Nitrogen Values
Vegetable Wastes
Coffee Grounds
Grass Clippings
Cow Manure
Horse Manure
Horse Manure (with Litter)
Poultry Manure (Fresh)
Poultry Manure (with Litter)
Pig Manure

Materials with High Carbon Value
Foliage (Leaves)
Corn Stalks
Wood Chips and Sawdust

12-20 : 1
20 : 1
12-25 : 1
20 : 1
25 : 1
30-60 : 1
10 : 1
13-18 : 1
5-7 : 1

30-80 : 1
60 : 1
40-100 : 1
100-130 : 1
150-200 : 1
100-500 : 1

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