Impacts of rice-husk biochar on soil microbial biomass and agronomic performances of tomato (Solanum lycopersicum L.)

Tomato is beneficial to human health because it contains valuable vitamins such as vitamins A, C and several minerals. However, to meet up with the demands of the ever increasing population, there is need to improve tomato production. This research, thus, investigated the impact of rice-husk biochar on the agronomic performances of tomato plant and microbial biomass of carbon, nitrogen and phosphorus in different tomato growth stages. The rice husk biochar pyrolyzed at 350 °C was amended with soil at four different application rates: 0, 2.5, 5.0 and 7.5 t/ha. Physicochemical property of soil was conducted using Mid Infrared Reflectance Spectroscopy method. Impact of biochar on Microbial Biomass Carbon, Microbial Biomass Nitrogen and Microbial Biomass Phosphorous was conducted using fumigation extraction method and monitored at three functional stages. Biochar application appreciably increase the soil physicochemical properties such as pH, Ca, Na, H(+), S, P, B, C, Zn and cation exchangeable capacity in comparison with the control. Biochar amended soil significantly enhanced tomato height, stem girth, leaf area, flowers, fruit yields and weight. Although, B3 recorded the lowest leaf area, it possessed the highest number of fruits and fruit weight of 3 and 40%, respectively. The ratio of Microbial biomass C:N:P for biochar amended soil at 7.5 t/ha (B3) was 302.30:18.81:11.75 µg/g, compared to control, which was 242.12:18.30:11.49 µg/g. This study revealed that biochar amendments significantly (p < 0.05) increased the yields and microbial biomass of tomato plants. Conclusively, the application of rice-husk biochar (7.5 t/ha) to soil is considered as a suitable approach to improve tomato growth and yield.