Effects of application of inhibitors and biochar to fertilizer on gaseous nitrogen emissions from an intensively managed wheat field

• Published in: The Science of the total environment 2018-07, Vol.628-629, p.121-130
• Main Authors: He, Tiehu, Liu, Deyan, Yuan, Junji, Luo, Jiafa, Lindsey, Stuart, Bolan, Nanthi, Ding, Weixin
• Format: Article
• Language: English
• Subjects: Agriculture - methods; Air Pollutants - analysis; Biochar; Charcoal; China; Fertilizers; Gaseous N emissions; Gases; Inhibitor; Mitigation; Nitrogen - analysis; Nitrous Oxide; Paddy soil; Soil; Triticum
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.02.048

•Optimal N fertilizer application rate decreased N2O, NO and NH3 emissions.•Biochar application increased SOC, total N and pH, and also NH3 and N2O emissions.•Addition of urease and nitrification inhibitors decreased N2O, NO and NH3 emissions.•Combined application of biochar and inhibitors reduced N2O, NO and biochar-induced NH3 emissions.•Wheat yield was increased by biochar; NUE was increased by biochar and inhibitors. [Display omitted] The effects of biochar combined with the urease inhibitor, hydroquinone, and nitrification inhibitor, dicyandiamide, on gaseous nitrogen (N2O, NO and NH3) emissions and wheat yield were examined in a wheat crop cultivated in a rice-wheat rotation system in the Taihu Lake region of China. Eight treatments comprised N fertilizer at a conventional application rate of 150kgNha−1 (CN); N fertilizer at an optimal application rate of 125kgNha−1 (ON); ON+wheat-derived biochar at rates of 7.5 (ONB1) and 15tha−1 (ONB2); ON+nitrification and urease inhibitors (ONI); ONI+wheat-derived biochar at rates of 7.5 (ONIB1) and 15tha−1 (ONIB2); and, a control. The reduced N fertilizer application rate in the ON treatment decreased N2O, NO, and NH3 emissions by 45.7%, 17.1%, and 12.3%, respectively, compared with the CN treatment. Biochar application increased soil organic carbon, total N, and pH, and also increased NH3 and N2O emissions by 32.4–68.2% and 9.4–35.2%, respectively, compared with the ON treatment. In contrast, addition of urease and nitrification inhibitors decreased N2O, NO, and NH3 emissions by 11.3%, 37.9%, and 38.5%, respectively. The combined application of biochar and inhibitors more effectively reduced N2O and NO emissions by 49.1–49.7% and 51.7–55.2%, respectively, compared with ON and decreased NH3 emission by 33.4–35.2% compared with the ONB1 and ONB2 treatments. Compared with the ON treatment, biochar amendment, either alone or in combination with inhibitors, increased wheat yield and N use efficiency (NUE), while addition of inhibitors alone increased NUE but not wheat yield. We suggest that an optimal N fertilizer rate and combined application of inhibitors+biochar at a low application rate, instead of biochar application alone, could increase soil fertility and wheat yields, and mitigate gaseous N emissions.