Effect of the application of town refuse compost on the soil-plant system: A review

This paper reviews the currently available information concerning the use of town refuse compost as a potential fertilizer. Many studies have generally shown that the application of this material has promoted a positive influence on a wide variety of craps. Nevertheless, contradictory results of crop yields have been obtained when the fertilizing capacity of compost has been contrasted with those of organic and mineral fertilizers. It has been demonstrated that the application of compost to soil improves some physical properties such as porosity, water-holding capacity and bulk density. It also promotes buffering capacity of soil and increases the percentage of organic matter and cation exchange capacity. Occasionally, negative aspects can emerge from compost incorporation, such as an increase in organic pollutants and electrical conductivity of soils. In general, compost application to soil has a positive effect on the microbial population and rhizosphere microorganisms and also contributes to the reduction of nemotode populations in plants. However, when big doses of compost are used, an inhibitory effect on seed germination may appear. The nitrogen availability of the municipal compost is closely related to the maturity of this material. A wide range of results has been obtained from different studies performed to evaluate the efficiency of compost as a source of phosphorus, sulphur, calcium and magnesium for plants. The incorporation of municipal compost constitutes a valuable resource for supplying potassium and some micronutrients (i.e. boron and zinc), but also presents potential pollution hazards associated with some heavy metals.