Soil management for sustainable crop disease control: a review

Excessive use of agrochemicals in conventional crop management has caused serious environmental and health problems including loss of biodiversity and human disorders. A number of chemical biocides have shown complex chronic effects such as change in endocrine functions and immune systems. Application of different chemical biocides to the soil and plants have increased substantially over the last five decades. Total consumption of chemical fertilizers worldwide increased tenfold from 1950 to 2000. This is also true for chemical biocides with its annual current use of 3 billion l and a value of 30 billion dollars. There are ample evidences indicating that plants which grow in rich soil associated with N-P-K availability are prone to pests and diseases. Managing and exploiting soil environmental conditions as part of an integrated control strategy can make a significant contribution to agricultural sustainability and environmental quality. Application of organic matter and practises which increase the total microbial activity in the soil might enhance general suppression of pathogens by increasing competition for nutrients. Choice of crops in rotation with plants less susceptible to specific pathogens causes a decline in population due to natural mortality and the antagonistic activities of co-existent root zone microorganisms. Plants growing in disease-suppressive soil resist diseases much better than in soils with low biological diversity. Understanding the effect of soil environmental factors on plant disease incidence and the best crop management strategies to prevent, avoid, escape and control diseases were the aims of this literature review. This article comprises the main topics on soil fertility associated with N-P-K and other macro- and micro nutrients, and also soil pH, structure and texture, organic matter and microbial reserves, describes the use of various crop management practises which reduce the incidence of plant diseases.