ABSTRACT
The use of chemical fertilizers to replenish nutrient losses and raise crop productivity in intensive farming systems is well known, but there has been growing concern about the widespread use of chemical fertilizers as a means to restore, maintain or build up soil fertility, as some are coming to the conclusion that this does more harm than good and that such farming systems cannot be sustained in the long run. Ways of restoring the drained plant nutrients, which are healthy for the soil as well as the environment, are being increasingly emphasized.
