Cultivation management of common bean and its effect on the suppressive potential of brown calcareous soils on Rhizoctonia solani

Abstract

For assessing the effect of management on the suppressive potential of the brown calcareous soils on the lesion length caused by Rhizoctonia solani Kühn in the bean crop it was conducted this experiment under semicontrolled conditions. It was used a complete random design with two types of fertilization (urea: 225 kg ha-1 and compost: 7 t ha-1) and soils from two fields with different agricultural management (conventional and organic). Soil were used in natural state and sterile through autoclaved and 4 replicates by treatment. The bean cultivar selected was CC 25-9N and the strain of R. solani was AG-4-HGCuLT-Rs-36. The lesion length was superior in the non-sterilized soils from the conventional management. Fertilization used in the studied did not influence on the obtained results. The multiple regression analysis demonstrated that the lesion leght will decrease by increments in permeability and organic matter content for both managements, but in the conventional will do the same by auments in pH-KCl. Besides, the lesion length showed significant simple regressions for both managements with stable aggregates and pH-KCl, but with the content of organic matter is significant only for the organic management, meanwhile in the conventional management were significant with permeability and P Olsen. The soil under organic management showed a higher suppressive potential with lower lesion length and 28 % of dependence of the evaluated soil properties status.

Keywords

• conventional and organic management
• rhizoctonia
• disease supressiveness
• supressive soils