The amount of nitrogen in compost is low compared to organic materials, such as manure. Since nitrogen in the plant waste is lost during the composting process, some nitrogen is also incorporated into organic compounds and released slowly after the compost is applied to the soil. Humus lessens the need for chemical fertilizers and helps prevent leaching of nitrogen into groundwater. Humus-rich soil also promotes healthy plants which are less susceptible to diseases and insect pests. This can reduce the need for chemical pesticides.
Compost reduces erosion by improving soil structure.
Better drainage allows water to flow into lower soil layers, rather than puddle on top and run off. Improved soil structure also helps the growth of roots which hold soil in place. Finally, compost recycles garden wastes to benefit the enviroment. First, strain the compost through a sieve to eliminate large particles. Then mix two parts compost, one part garden loam, and one part perlite or sand.