Assessment of compost for suppression of Fusarium oxysporum and impoving Zea mays and Hibiscus sabdarriffa resistance to wilt diseases

The present research has been conducted to evaluate the compost effectiveness on Zea mays and Hibiscus sabdarriffa under Fusarium wilt disease. Compost physical, chemical and biological characters were monitored weekly during the ripening process. Both coliform and nematode were tested. Finally, the effect of compost on pathogenic Fusarium, was examined within Zea mays and Hibiscus sabdarriffa in soil amended with 10 % compost. Biochemical tests and antioxidallt enzyme activities were determined for all the treated plants. The compost structure is homogeneous, the pH is neutral to slightly alkaline and the temperature was within 41 to 45 °C during ripening. The values of organic carbon recorded a pereentage of 3.8 %, while N, P and K values recorded 1.7, 4.6 and 5.6 % higher than the commercial compost. The concentrations of Ni, Cu, Zn, Mn, Co, Cd and Pb in compost were below the threshold standard values. The compost are free of nematodes and coliform bacteria at maturity stage. Microbial population densities were usually high for Bacillus sp compared to other microorganisms. In infected Zea mays with compost, shoot height, fresh and dry weight increased significantly (62, 248 and 130 %) and Hibiscus sabdarriffa also recorded increase in the same plant criteria. In infected Zea mays, a significant increase in CAT and APX activities was recorded (162 and 150 %). For Hibiscus sabdarriffa there was a significant decrease in APX activity (35 %) with compost, while no significant differences in PODs activity for both plants. In case of infection, a significant decrease was observed for both Zea mays and Hibiscus sabdarriffa compared to infected plants without compost, The observed disease suppression in compost-amended soil was associated with the reduction in soil pathogen population and increase in microbial activity of composts. Moreover, diversification of different organic materials in compost enhanced the activation of the microbial population in soil that eventually increases disease suppressiveness and effectively controlling Fusarium wilt.