Soil sickness and its control

Allelopathic soil sickness is a major factor for poor growth and yield decline in crops. Allelochemicals in the soil play an important role in determining biodiversity of plants and soil microorganisms. Numerous examples have shown that autotoxicity can occur in crops grown in continuous monoculture, causing stunted growth of plants and severe outbreaks of soil-borne diseases. Problems of soil sickness can be minimized by exploitation of allelopathy for production of crops and control of soil-borne diseases. Methods for alleviation of soil sickness include crop rotation, soil amendment, use of disease resistant cultivars, biological control and chemical control for management of soil-borne diseases and improvement of crop production. Biological control of plant diseases is ecologically sound and environmentally safe. It can be achieved by modification of soil physical and chemical properties that are not only inhibitory to soil-borne pathogens, but also stimulatory to biological control agents and other beneficial microorganisms. The success of a biological control strategy for managing risks of soil sickness depends on a thorough ecological understanding of survival and activity of biological control agents in various cropping systems and agro-environments.