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. Compost is used in gardening and agriculture, mixed to the soil to improve its structure (by increasing its organic content[?] amount) and fertilizing quality. 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. 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.

Composting systems

• Container composting
• German mound
• Leaf mold
• High fibre composting
• Worm compost
• Spent mushroom compost
• Sheet composting