减氮配施生物炭对北疆小麦产量品质及固碳减排的影响

    Effects of reducing nitrogen ferilizer combined with biochar on the yield and quality of wheat and carbon sequestration and emission reduction in Northern Xinjiang of China

    • 摘要: 为研究生物炭在北疆灌区农田应用的稳产增产及固碳减排综合潜力,探索农田氮肥优化施用途径,该研究于2021年4月—2022年7月在新疆奇台设置常规施氮(N1:300 kg/hm2)、氮肥减量15%(N2:255 kg/hm2)、氮肥减量30%(N3:210 kg/hm2)、单施生物炭(B:20 t/hm2)、常规施氮+生物炭(N1B)、氮肥减量15%+生物炭(N2B)、氮肥减量30%+生物炭(N3B)7个处理,分析两季小麦(春小麦、冬小麦)种植期间不同处理下麦田土壤有机碳含量、土壤呼吸速率、小麦品质及产量变化。结果表明,与单施常规氮肥相比,施用生物炭后土壤总有机碳(soil total organic carbon,SOC)、活性有机碳(active organic carbon,AOC)、碳库管理指数(carbon pool management index,CPMI)和小麦产量、籽粒水分及蛋白(干基)含量均呈提高趋势。综合表现以氮肥减量15%配施生物炭(N2B)处理最优,较氮肥常规单施(N1)相比,AOC、SOC均有显著提高,2 a产量分别显著提高22.12%、36.17%(P<0.05)。与常规施氮相比,氮肥减量15%配施生物炭(N2B)处理下,2022年冬小麦蛋白(干基)、面筋(湿基)、Zeleny沉降值均有提高,而2021年各处理间差异不显著(P>0.05)。同时,除单施生物炭(B)处理(2021年)和除单施生物炭(B)及减氮15%(N2)处理外(2022年),其他处理下土壤CO2累积排放量较单施常规氮肥均有所升高。综上,氮肥减量15%(255 kg/hm2)配施20 t/hm2生物炭时其农田土壤固碳减排效果及小麦产量品质综合表现较好,建议作为北疆灌区麦田氮肥优化配施生物炭的理想施肥方案。

       

      Abstract: Numerous research endeavours have been conducted to explore the application of biochar as a means to enhance soil fertility and augment crop productivity in agricultural regions, but there is a lack of quantitative research and in-depth analysis on whether the application of biochar in farmland of irrigation area of Northern Xinjiang can increase production, sequester carbon and reduce emission. Hence, this study aimed to conduct a thorough assessment to ascertain the possible applicability of biochars in the ecosystems of agriculture irrigated in oasis regions. A field experiment was herein conducted in a spring and winter wheat rotation system from April 2021 to July 2022 with 7 treatments: the conventional application of nitrogen (N1: 300 kg/hm2), the reduction of nitrogen fertilizer by 15% (N2: 255 kg/hm2), the reduction of nitrogen fertilizer by 30% (N3: 210 kg/hm2), a single application of biochar (B: 20 t/hm2), the conventional application of nitrogen combined with biochar (N1B), the reduction of nitrogen fertilizer by 15% combined with biochar (N2B), and the reduction of nitrogen fertilizer by 30% combined with biochar (N3B). The effects of nitrogen fertilizer and biochar on soil organic carbon pool, soil respiration, wheat quality and yield were studied, with the aim to explore the potentiality of stable yield, carbon fixation and emission reduction of biochar application in the farmland of the Northern Xinjiang irrigation area. The results showed that compared with applying conventional nitrogen fertilizer alone (N1), the application of biochar resulted in an increase in soil total organic carbon (SOC), active organic carbon (AOC), carbon pool management index (CPMI), wheat yield, wheat quality as well. The soil AOC content was 1.44 g/kg in the treatment that 15% nitrogen fertilizer reduction combined with biochar(N2B), which was 30.91% higher than that in N1. Meanwhile, the SOC content was higher than that in N1. When it comes to the wheat yield, the spring wheat yield was 8 301.35 kg/hm2, and the winter wheat yield was 10 784.76 kg/hm2 in N2B, with an increase of 22.12% and 36.17%, respectively when compared with N1. As it for the wheat quality, the sedimentation value of protein (dry base) , gluten (wet base) and Zeleny increased under the treatment of 15% reduction of nitrogen fertilizer combined with biochar (N2B) in 2022, while there was no significant difference among the 2021 treatments. The cumulative soil CO2 emission under other treatments was higher, except for biochar treatment in 2021 and 2022, and nitrogen reduction by 15% (N2) treatment alone in 2022. In a word, the effect of carbon sequestration and emission reduction in farmland soil and the yield and quality of wheat were better, when applied with 255 kg/hm2 nitrogen fertilizer and 20 t/hm2 biochar, which could be suggested as an ideal fertilization scheme to optimize the combination of nitrogen fertilizer and biochar in the wheat field of irrigation area in the northern Xinjiang.

       

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