Biochar and vermicompost soil amendments reduce root rot disease of common bean (Phaseolous Vulgaris L.)

Abstract

Common bean production is constrained by root rot complexes resulting to as much as 70% losses in Kenya. This study sought to establish the effect of soil amendments biochar and vermicompost on root rot fungal pathogens of commonbean in Western Kenya. Application of biochar, vermicompost and fertilizer were done in farmer fields in four agro ecological zones of Western Kenya prior to planting during the long rains of 2013 and 2014. No applications were done in the shot rains seasons of 2013 and 2014. Plant emergence and disease incidence was recorded in the field and disease severity determined in the laboratory. Isolation and identification of pathogens was done from treatment plots following a two weeks and six weeks sampling after planting. Pathogens isolated were identified using morphological characteristics. Soil amendments positively influenced plant emergence. Root rot disease incidence and severity was greatly reduced up to 40% and 60% every season respectively. Biochar and vermicompost treatments reduced the population of fungal pathogens and also influenced the populations of beneficial microorganisms such as Trichoderma and Paecilomyces lilacinus. Application of soil amendments increased yield by 46% and also soil pH and nutrients were increased. In conclusion treatment application of vermicompost and biochar reduce root rot disease and improve bean productivity.