Soil amelioration with biochars pyrolyzed from different feedstocks of an acidic bamboo ( Phyllostachys violascens ) plantation

Abstract

To evaluate the effects of biochars pyrolyzed from different feedstocks (bamboo, maize straw, and peels of Carya cathayensis) on the soil properties, acidity, microbial abundance, and soil enzyme activity in an acidic soil collected from a bamboo (Phyllostachys violascens) plantation in Lin'an, Zhejiang Province, a 90-day pot experiment was conducted in a completely randomized design with treatments of above three biochars and a non-amended control in three replicates. The biochars were added to the soil at a rate of 2% (weight of biochar to soil) with ryegrasses being planted during the experiment. Fungal 18S rRNA and bacterial 16S rRNA gene abundances were assessed via quantitative real-time (qRT) polymerase chain reaction (PCR). Significant differences between treatment means were tested with one-way analysis of variance (ANOVA) followed by Duncan's test at P < 0.05. Results indicated that biochars derived from maize and peels of C. cathayensis significantly (P < 0.05) increased the biomass of ryegrass, soil organic carbon, total nitrogen, and pH, but decreased (P < 0.05) exchangeable H+ and exchangeable Al3+. Also bamboo biochar significantly increased (P < 0.05) soil organic carbon and decreased (P < 0.05) exchangeable H+. The qRT-PCR showed that compared with the control only additions of maize biochar significantly increased (P < 0.05) fungal community abundance by 53%; whereas, peels of Carya cathayensis biochar and bamboo biochar significantly increased (P < 0.05) bacterial community abundance by 71% (C. cathayensis biochar) and 66% (bamboo biochar). In comparison with maize straw biochar and bamboo biochar, the addition of peels of C. cathayensis biochar resulted in higher (P < 0.05) enzymatic activities of dehydrogenase, β-glucosidase, β-D-cellobiosidase, and acid phosphatase. Enhancement of ryegrass growth was noted with peels of C. cathayensis biochar and maize straw biochar. In summary, results indicated that biochars pyrolyzed from maize straw and peels of C. cathayensis showed better amelioration effects in terms of chemical and biological ability than bamboo biochar.