Soil Depletion

Soil Depletion 

a sharp decrease in crop yields after continual cultivation of the same crops or frequent use of the same field. It is most pronounced after the growing of clover (clover sickness), flax (flax sickness), and sugar beets (beet sickness).

The main causes of soil depletion are the accumulation of pathogenic microorganisms (fungi, bacteria, viruses) that inhibit the growth of certain plants by their secretions or by infesting the roots; the development of pests and weeds; and soil exhaustion. Control measures include crop rotation (clover can be grown on the same field after five years, flax after six or seven years, and sugar beets after three years), growing resistant varieties, and applying pesticides to the soil.