Shi Deng-Lin, Wang Xiao-Li, Duan Jian-Jun, Liu An-Kai, Luo An-Huan, Li Rui-Dong, Hou Zai-Fen
College of Agriculture, Guizhou University, Guiyang 550025, China.
College of Tobacco Science, Guizhou University, Guiyang 550025, China.
Ying Yong Sheng Tai Xue Bao. 2020 Dec;31(12):4117-4124. doi: 10.13287/j.1001-9332.202012.027.
Reducing the application of chemical fertilizer and increasing fertilizer efficiency can contribute to the sustainable development of agriculture. To evaluate the impacts of N fertilizer reduction and biochar application on soil organic carbon active components and mineralization in yellow soil, an experiment was carried out with five different substitution rates of chemical N fertilizer by biochar under the same rate of N input, ., 0, 10%, 20%, 30%, 40% (CK, T-T). The results showed that chemical N fertilizer reduction combined with biochar application could significantly improve soil organic carbon (SOC), the magnitude of which was proportional to the amount of biochar application. Under the condition of 20% substitution rate (T), soil microbial biomass carbon (MBC) and readily oxidized carbon (ROC) were the highest with 293.68 mg·kg and 250.00 mg·kg, respectively, but the concentration of soil dissolved organic carbon (DOC) was the lowest. SOC mineralization rate reached the highest on the third day of incubation. Then, it decreased rapidly in the early period (day 3 of incubation to day 6), decreased slowly in the middle period (day 6 of incubation to day 18), and stabilized in the later period (day 18 of incubation to day 30). There was a logarithmic relationship between mineralization rate of soil organic carbon and incubation time. SOC cumulative mineralization amount and cumulative mineralization rate were the lowest in the T treatment with 0.66-0.86 g·kg and 2.9%-4.0%, respectively. As the substitution rate of chemical N fertilizer by biochar increased, rice yield increased firstly and then decreased. Rice yield in the T treatment was the highest, which increased by 13.4% compared with the CK. The substitution of 20% chemical N fertilizer with biochar (5 t·hm) could effectively improve the contents of SOC, MBC, ROC, and rice yield, reduce the cumulative mineralization amount of organic carbon and cumulative mineralization rate, and enhance the capacity of soil carbon sequestration. Hence, it could be the most effective fertilizer practice for improving soil fertility and rice yield in paddy field of yellow soil in Guizhou Province.
减少化肥施用量并提高肥料效率有助于农业的可持续发展。为了评估氮肥减量和生物炭施用对黄壤土壤有机碳活性组分及矿化的影响，在相同氮输入量下进行了生物炭替代不同比例化学氮肥的试验，即0、10%、20%、30%、40%（CK，T1-T4）。结果表明，氮肥减量与生物炭施用相结合能显著提高土壤有机碳（SOC），其增幅与生物炭施用量成正比。在20%替代率（T2）条件下，土壤微生物生物量碳（MBC）和易氧化有机碳（ROC）最高，分别为293.68 mg·kg和250.00 mg·kg，但土壤溶解性有机碳（DOC）浓度最低。SOC矿化率在培养第3天达到最高，随后在前期（培养第3天至第6天）迅速下降，中期（培养第6天至第18天）缓慢下降，后期（培养第18天至第30天）趋于稳定。土壤有机碳矿化率与培养时间呈对数关系。T2处理的SOC累积矿化量和累积矿化率最低，分别为0.66-0.86 g·kg和2.9%-4.0%。随着生物炭替代化学氮肥比例的增加，水稻产量先增加后降低。T2处理的水稻产量最高，与CK相比增产13.4%。用生物炭（5 t·hm）替代20%的化学氮肥能有效提高SOC、MBC、ROC含量及水稻产量，降低有机碳累积矿化量和累积矿化率，增强土壤固碳能力。因此，这可能是提高贵州省黄壤稻田土壤肥力和水稻产量最有效的施肥措施。
