Biodiversity of Soil Microorganisms and their Effects on Disease Management at Black Pepper Farms in Gia Lai Province

Research on soil ecological systems, such as the soil characteristics and properties of the soil micro-flora system, is essential in the sustainable production of black pepper (Piper nigrum L.).The role of using beneficial microorganisms in the sustainable production of black pepper is in increase because many people are being aware of the hazards associated with consuming products with chemical substances. Twenty-seven soil samples were collected from Chu Se, Chu Prong and Duc Co district of Gia Lai province to determine the relationships between the ecological system, pathogenic fungi and nematodes in black pepper farms. The obtained results showed that the soil micro flora community was quite diverse. The average total density microorganism in Duc Co district, Chu Prong district and Chu Se district was of 8.41x106 CFU/g, 6.76x106 CFU/g and 8.91x106 CFU/g, respectively. The density of average total beneficial microorganisms in Duc Co district, Chu Prong district and Chu Se district was of 20.03x104 CFU/g, 14.25x104 CFU/g and 17.62x104 CFU/g, respectively. The use of organic fertilizers is common to the farms where high microbial densities were recorded. The relationship between the density of beneficial microorganisms (Nitrogen fixing bacteria, Phosphorus soluble bacteria, Cellulose degradation bacteria) and the density of fungal pathogens and nematodes was negatively correlated with R = - 0.84 and R = - 0.81 respectively. The results of correlation analysis showed that the density of beneficial microorganisms in the soil and the incidence of diseases in orchards were negatively correlated (R = - 0.69). This study proposes that the correlation between the basic factor of soil ecological system with pathogenic fungi and nematodes plays a very important role in biological control and the sustainable production of black pepper.