Effect of biochar on microorganisms quantity and soil physicochemical property in rhizosphere of spinach (Spinacia oleracea L.)

To investigate the effects of biochar on greenhouse soil, three biochar treatments, i.e. 0 t ha(-1) (C0), 12.5 t ha(-1) (Cl) and 25 t ha(-1) (C2), were applied to the rhizosphere of spinach (Spinacia oleracea L.). And the microbial biomass C (MBC), the quantities of the bacteria, fungi, actinomyces, ammonifying bacteria, azotobacter and denitrifying bacteria, pH, oxidation-reduction potential (Eh), and mineral nutrient content were studied. The results indicated that MBC contents with C2 and C1 treatments were significantly (P < 0.01) higher than those with C0 treatment, and the quantities of bacteria, fungi, actinomyces, ammonifying bacteria, azotobacter, and denitrifying bacteria under C1 treatment were 1.06 fold, 2.18 fold, 1.17 fold, 1.47 fold, 2.94 fold and 0.38 fold of those with C0 treatment in rhizosphere of spinach, while those with C2 treatment were 1.25 fold, 2.08 fold, 1.24 fold, 1.41 fold, 4.92 fold and 1.76 fold of those with C0 treatment. The total phosphorus, total carbon, total sulphur, total potassium content, carbon/nitrogen, and Eh with C2 and C1 treatments were higher than in those with C0 treatment. Our results suggest that biochar can be used as ameliorant to improve quantity of microorganisms and physical and chemical properties of greenhouse soil.