Response of soil microbial biomass and enzymatic activity to biochar amendment in the organic carbon deficient arid soil: a 2-year field study

The application of pyrolyzed organic carbon (C) to soils has been assessed worldwide to play a vital role in improving the physical-chemical characteristics of the soil. However, the effects of co-use of biochar and nitrogen (N) fertilizer on soil biological process in an arid region are not well understood. For this, a 2-year field experiment was conducted in an arid region to assess the co-use of biochar and nitrogen (N) fertilizer on soil microbial biomass and enzyme activity in the rhizosphere of the wheat crop. Sugarcane bagasse was used as biochar feedstock and applied with three levels of biochar (0, 0.5, and 1% C ha−1) on carbon equivalent basis in the presence and absence of N fertilization (46 kg N ha−1). Biochar was incorporated in the soil before sowing of wheat, and the soil samples were taken from each treatment at crop maturity. Findings of the study indicated that biochar amendments enhance the soil organic carbon, DOC, inorganic N, and soil moisture contents, while reducing the bulk density and salinity of soil in both wheat growing season. Microbial biomass carbon and nitrogen increased by 18% and 63% with biochar amended at 1% C ha−1 with nitrogenous fertilizer and the same trend was observed in the following year. Urease and dehydrogenase activities also significantly increased with biochar applied at 1% C ha−1 with N fertilization illustrating 15% and 19%, respectively. During the second year of wheat trial, the enzymatic activity also boosted up as the first year. The results revealed that sugarcane bagasse-derived biochar addition can be utilized in improving the soil health, nutrient status, and soil biological functions in the calcareous soil of the arid region.