Different cover promote sandy soil suppressiveness to root rot disease of cassava caused by Fusarium solani

Sandy soils of 19 arable fields were analyzed for disease suppressiveness against root rot disease of cassava, caused by Fusarium solani CFF109. Analysis of chemical, physical, biochemical, microbial population and activity, and soil characteristics were assessed. Soils with different management histories and covers most commonly found in the region were collected to build a greenhouse experiment, to evaluate the natural suppressiveness of soils against cassava root rot. The severity was submitted with all data across correlation and multivariate analyses to find correlation between disease suppressiveness and abiotic or biotic soils attributes. Differences in disease suppressiveness were found between the treatments for cassava root rot. Significant disease suppression was found in 37% of the soils. The sandy soil covered with consortium of Zea mays + Vigna unguiculata was the most efficient in suppressiveness against disease caused by F. solani. The data indicated significant correlation between soil characteristics and suppressiveness cassava root rot. The soil supressiveness against cassava root rot was favored by increase by total bacteria, fluorescent group bacteria populations and activity of acid and alkaline phosphatase and β-glucosidase.   Key words: Disease suppression, soil characteristics, enzyme activity, soil communities, abiotic factor, biotic factor.