Trench composting is a method of Cold Composting (where the compost temperatures do not rise to 140 degrees). It can be used for gardens or small farms.
Dig a long trench 6" - 8" deep between crop rows. Place disease-free, organic litter not treated with pesticides in the bottom of the trench. Cover with a few inches of soil. Do not add more than a few inches of soil because more biological activity occurs closer to the soil surface. Decomposition takes one season. Even very fibrous garden waste such as tough stalks, decompose in one year with this method.
Peas and beans can be planted directly in the trench. These two vegetables are able to fix nitrogen in their roots. The action of decomposition will not disturb their nitrogen requirements.