The Impact Of Peanut Shell Biochar Amendment On Agricultural Soil Nitrogen Bioavailability

Biochar is a stable, highly aromatized carbon material that biomass produced under low oxygen or no oxygen condition. Because it owns wide pore distribution, large surface area, functional groups and mineral, it shows good prospect on reducing greenhouse gas emission, carbon sequestration and soil amendment. Thus biochar received science researchers’attention. This paper using common agriculture by-product-peanut shell as material and produced biochar at 350 ℃, and made biochar amendment by mixing other fertilizer with it. Agricultural soil was selected and researched the impact of biochar and amendment on crop growth, crop making use of nitrogen fertilizer under four seasons crop rotation and soil nutrient. Besides, nitrogen bioavailability was evaluated. This study set six treatments (CK, NF, BC, BCNF, AD and ADNF), and used urea as nitrogen fertilizer. The result of this study offers theoretical basis for biochar application on agriculture and effective use of nitrogen fertilizer. The main result of this paper as follow:(1) Biochar has not asignificant effect on crop dry weight, but when nitrogen fertilizer used, the biomass of crop increased by seasons. Amendment and nitrogen fertilizer used together also increased crop biomass. Compared first season with last season, BCNF and ADNF treatment improved biomass by 102.00% and 63.00%.(2) The addition of biochar enhanced soil pH. For rhizosphere soil, the forth season soil pH increased 0.09 unit, which compared to control. While all treatments had no effect on soil ammonia content. Biochar had no effect on soil nitrate nitrogen content, but others increased soil nitrate nitrogen and total nitrogen content. Biochar increased soil organic matter content (SOM). In last season, compared to control, the SOM of rhizosphere soil and non-rhizosphere soil of BC treatment enhanced by 6.79 g/kg and 7.20 g/kg, respectively.(3) Compared to control, biochar and amendment not significantly increased nitrogen fertilizer accumulation efficiency and utilization efficiency, while the addition of nitrogen fertilizer improved crop’s NAE. In first season, the NAE of ADNF treatment was 59.1 mg/m. Through forth season rotation, NAE was increased to 84.2 mg/m. NUE in first season was between 0.011～0.012 g/mg, while in forth season, the NUE rised to 0.02-0.05 g/mg.(4) The addition of BC improved NAE change rate, while NAE change rate in AD treatment was 103.8%, which had a max value in third season. BCNF and ADNF treatments all made NUE chage rate get to the peak in second season.