Tea leaves biochar as a carrier of Bacillus cereus improves the soil function and crop productivity

Abstract

The application of biochar for plant growth and yield is of great importance. A combination of biochar and potent plant growth-promoting rhizobacteria (PGPR) may contribute extensively to crop production. The present investigation revealed the role of phosphate solubilizing bacteria and different biochars produced from tea leaves (Camellia sinensis L.). Biochar was prepared at 350 °C (B1) and 600 °C (B2) temperatures by using the pyrolysis tank. Seven bacterial strains were isolated from various types of soil collected from Mansehra, Pakistan. On the basis of phosphate solubilization and indole acetic acid production, one strain (Bacillus cereus) was applied with biochar. A greenhouse experiment was carried out to evaluate biochar as carriers for inoculant on mung bean (Vigna mungo) plant by comparing it with peat moss. Plastic pots of 15 × 18 cm2 were filled with 1:3 of sand and autoclaved garden soil. Results revealed that biochar produced at a higher temperature (B2) showed greater shelf life as compared to peat. Among bacterial inoculation of Bacillus cereus with biochar at 600 °C improved soil properties i.e., soil organic carbon (14%), dissolved organic carbon (17%), total nitrogen (39%), Olsen phosphorus (36%) with enhanced microbial biomass (Cmic (17%), Nmic (36%), and Pmic (56%)), enzyme activity (urease (12%), dehydrogenase (40%), and phosphatase (49%)), crop growth and N2-fixation (54%) over control (peat). Additionally, high-temperature biochar inoculated with Bacillus cereus (B2 + BC) significantly (P ≤ .05) enhanced the Proteobacteria (11%), Firmicutes (46%), Actinobacteria (20%), and Cyanobacteria (33%) community as compared to peat alone. It is concluded that biochar formulated at high temperature and its co-inoculation with bacteria (Bacillus cereus) may enhance soil fertility, growth, and yield of mung bean.