Compost
Compost is the decayed remnants of plant materials and animal manure. But not just any old rubbish just thrown together will produce the essential ingredient in compost -- humus. The best compost is made from roughly one third by volume of materials from the following three groups:
- Wilted green material
- Dry, straw-type material
- Animal manures
Usually, the wilted green material is provided by crop residues, or plants mowed for the purpose. The dry material provides the cellulose needed by the composting bacteria for conversion to sugars and heat. Cereal straws are best. Animal manures tend to consist of whatever you can get locally, but a mixture is best. While poultry manure provides the most concentrated protein (what we are after to allow the compost bacteria to thrive), it contains little fibre. Horse manure provides both. Sheep and cattle manure don't drive the compost heap to as high a temperature as poultry or horse manure, so the heap takes longer to produce the finished product.
The materials are placed in alternating layers approximately 3 cm (an inch) thick, 1-1.5 m (3-4 ft) wide and as long as is practible. As the heap is built, it is wetted to the consistency of a well wrung-out sponge. Providing the weather is suitable (not too hot, or too cold), the centre of the heap will begin to warm up. If this fails to happen, it's nearly always because the heap is too wet, thus excluding the oxygen required by the compost bacteria, or because there is insufficient protein (animal manure).
Depending on how quickly the compost is required, the heap can be turned one or more times to bring the outer layers to the inside of the heap and vice versa. Once all the material has become barely recognisable from the original ingredients, it's ready to use. Some practitioners like to leave the compost to mature further for up to a year as this seems to make the benefits of compost last longer.
Some like to put special materials and activators into their compost. Most of them (in the writer's opinion) are unnecessary. A light dusting of agricultural lime (not on the animal manure layers) can curb excessive acidity that can slow down the fermentation. Seaweed meal can provide a ready source of trace elements. Finely pulverised rock dust can also provide needed minerals, but watch out for rock dust that consists mostly of clay.
The following text is taken from the Household Cyclopedia of 1881:
The use of manure, in the shape of compost, or ingredients of various qualities, mixed together in certain proportions, has long been a favorite practice with many farmers: though it is only in particular situations that the practice can be extensively or profitably executed. The ingredients used in these composts are chiefly earth and lime, sometimes dung, where the earth is poor; but lime may be regarded as the main agent of the process, acting as a stimulus for bringing the powers of the heap into action; lime, in this view, may be considered as a kind of yeast, operating upon a heap of earth as yeast does upon flour or meal. It is obvious, therefore, that unless a sufficient quantity is given, the heap may remain unfermented, in which case little benefit will be derived from it as a manure.
The best kind of earth for compost is that of the alluvial sort, which is always of a rich greasy susbstance, often mixed with marl, and in every respect calculated to enrich and invigorate barren soils, especially if they are of a light and open texture. Old yards, deep headlands, and scourings of ditches, offer themselves as the basis of compost-middens; but it is proper to summer-fallow them before hand, so that they may be entirely free of weeds. When the lime is mixed with the soil of these middens, repeated turnings are necessary, that the whole may be suitably fermented, and some care is required to apply the fermented mass at a proper time to the field on which it is to be used.
The benefit of such a compost in nourishing soils is even greater than what is gained by dressing them with dung.
Composting systems