COMPOSTS Are Good Means of Improving Soil of Small Farms

Composts offer a practical means of maintaining the soil fertility which is the most important factor in the successful operation of a subsistence farm.

The subsistence farm is usually small in area, which implies the necessity of having every square foot of it as fertile as possible in order to obtain maximum crops. Where there is an ample labor supply in the family, the preparation of composts and the securing of material for them may well be worked into periods which would not otherwise be fully employed.

There is need here for intensive gardening, and the basis of building up the soil for this purpose is in most cases an adequate supply of humus. Because the area is too small to permit profitable use of green-manure crops, the homestead farmer must rely on manure and composts. As the question of cash involved is also important, it is advisable so far as possible to utilize materials which are at hand or easily secured. In most cases these materials have no cash value, but when properly composted contribute to the building up of the soil and bring increased crop yields.

There are available on practically all farms and gardens many materials which are useful for composts, although the farmer or gardener often fails to appreciate their value. Some of the common materials which are often wasted are leaves, straw, muck, vegetable tops, grass clippings, and garbage material which is inedible for chickens or pigs.  Where stock is kept, the manure from the cows, chickens, and pigs may well be worked into the compost heap, because, unless something of this character is put in, fertilizer chemicals will be needed to break down the compost, and these require an outlay of cash. With this in mind, the treatment of the farm animals may be modified to give greater amounts of material for composts. Larger amounts of bedding than are absolutely required may be used, and the use of superphosphate as a part of the absorbent of the manure is helpful. Superphosphate not only acts as a preservative of the nitrogen in the manure, but also builds up the phosphoric acid content of the mixture, and ultimately that of the compost.

Methods of Making Composts

There are a number of methods of making composts and the one chosen will depend on the materials available, the location, and the time which can be allowed for the compost to mature. An ordinary pile of leaves without treatment, if kept moist, will ultimately break down into humus, as in the case of forest litter and forest soils.  Although this process may take several years in a forest, the breaking down of the compost may be hastened by methods which also improve its character. A small amount of lime added to the compost materials, together with a little manure, will speed up the breaking down of the inert material. The greater the amount of manure which may be put in, the better. If manure is not available, fertilizer chemicals may be added. These may be either a complete fertilizer mixture, high in nitrogen, such as one containing 7 percent nitrogen, 6 percent phosphoric acid, and 5 percent potash, or the separate materials may be added. A mixture recommended by the New York Agricultural Experiment Station at Geneva, N. Y., is sulphate of ammonia, 60 pounds; ground limestone, 50 pounds; superphosphate, 30 pounds; muriate of potash, 25 pounds; total, 165 pounds. This is sufficient to mix with a ton of straw or other waste material.

The straw or organic matter is spread out in 6-inch layers and treated layer by layer with the chemicals until the pile is 4 feet high.  Each layer is wet as placed, and finally the pile is kept moist as decomposition occurs. In the warm part of the year decomposition may be thoroughly completed within 3 months. Other satisfactory mixtures are recommended by Missouri, Iowa, and other State experiment stations. Use of the mixtures recommended by the nearest experiment station is advised. In making up a compost pile it is customary to have the pile 5 or 6 feet wide and at least 4 feet high, with the length corresponding to the amount of material available.  In this way the ideal condition of allowing the pile to be damp and not wet, will usually operate in humid climates. It is not advisable to apply so much moisture that it runs through the pile as this will leach out soluble fertilizer compounds. On the other hand, if the compost is too dry, proper decomposition will not take place.  In some cases it has been found convenient to make the compost in a concrete-lined pit or on a concrete floor. Where running water is available in ample amounts, a covered pit may be used effectively, as the moisture can be controlled under these conditions. However, the compost pile may be on the ground without any other protection than proper care in seeing that the sides are more or less vertical and that the top is depressed in the center to hold the water.

When the compost is thoroughly broken down into a homogeneous mixture, and no undecomposed leaves or other material may be seen, it is ready for use. It may be broadcast and worked into the entire topsoil, if large enough amounts are available. With smaller amounts it is often better to put it in individual hills.

   The use of composts will vary somewhat with the soils involved.  They are very necessary in sandy soils and are also efficient in improving the mechanical condition of clay soils. On good loams, and on peaty soils, they are not so necessary, though useful. They are a substitutue for manure, when manure is not available, and extend the use of manure when small amounts are on hand. In fact, a mixture of manure and compost is almost as good as manure and will cover a much larger area. Composts also save part of the expense of chemical fertilizers and so improve the soil that the fertilizers give more efficient results.

Table 2 gives the analyses of some of the common materials which may be put into composts:

TABLE 2.—Percentage composition of some standard commercial fertilizing materials and other materials
Ammonium sulfate19.0-20.5
Calcium cyanamid19.0-22.0
Nitrate of soda15.5-16.25
Treble superphosphate44
Ammonium phosphate1346
Raw ground phosphate rock26.0-35.0
Ground bone (raw)2.5-4.520.0-25.0
Steamed bone meal2.523.0
Potassium sulfate48.0-52.0
Potassium chloride (muriate)48.0-60.0
Apple leaves1.00.150.35
Apple pomace 0.2 0.02 0.15
Banana skins (ash)
3.25 41.76
Cantaloup rinds (ash)
9.77 12.21
Castor bean pomace 5.0-6.0 2.0-2.5 1.0- 1.25
Cattail reed and stems of waterlily 2.02 0.81 3.43
Coal ash (anthracite)
0.1-0.15 0.1-0.15
Coal ash (bituminous)
0.4-0.5 0.4- 0.5
Coffee grounds 2.08 0.32 0.28
Corncob ash

Corn (green forage) 0.30 0.13 0.33
Crabgrass (green) 0.66 0.19 0.71
Duck manure (fresh) 1.12 1.44 0.49
Eggs 2.25 0.40 0.15
Eggshells 1.19 0.38 0.14
Feathers 15.30

Fish scrap (fresh) 2.0-7.5 1.5-6
Grapefruit skins (ash)
3.58 30.60
Lemon culls (California) 0.15 0.06 0.26
Oak leaves 0.80 0.35 0.15
Orange culls 0.20 0.13 0.21
Peanut shells 0.80 0.15 0.50
Peat 0.5-4.00

Pigeon manure (fresh) 4.19 2.24 1.41
Pigweed, rough 0.60 0.16
Pine needles 0.46 0.12 0.03
Potatoes, leaves and stalks 0.60 0.15 0.45
Ragweed, great 0.76 0.26
Salt marsh hay 1.10 0.25 0.75
Sewage sludge from filter beds 0.74 0.33 0.24
Soot from chimney flues 0.5- .11 1.05 0.35
Stringbean strings and stems (ash)
4.99 18.03
Sweetpotato skins, boiled (ash)
3.29 13.89
Tea grounds 4.15 0.62 0.40
Tobacco leaves 4.00 0.50 6.00
Tobacco stalks 3.70 0.65 4.50
Tobacco stem 2.50 0.90 7.00
Tomato leaves 0.35 0.10 0.40
Wheat straw 0.50 0.15 0.60
Wood ashes (leached)
1.0- 1.5 1.0- 3.00
Wood ashes (unleached)
1.0- 2.00 4.0- 10.00


The use of composts is one of the safest and most economical methods of building up soil productivity in small areas. This is shown by the fact that their use is world-wide and dates back many centuries.  The agriculture of China, in spite of outstanding faults, has been kept going for centuries essentially by the proper use of composts. In almost any location there are materials available for the hauling which make useful soil amendments. This is especially true if the landholder is located near an industrial area or any large city.

C. C. FLETCHER, Bureau of Chemistry and Soils.