摘要:探索长期施肥下黑土有机肥替代率与土壤肥力提升的关系，可为农田土壤培肥和有机替代提供理论依据。对吉林省公主岭黑土32年的长期肥力试验定位观测数据进行系统分析，基于作物氮素吸收量和土壤氮素供需方程探讨高产条件下施用不同量有机肥的黑土有机肥替代率的变化特征。研究表明，作物产量随着有机肥施用年限增加逐渐提高，32年的持续施肥，施用有机肥的作物产量趋同甚至高于NPK化肥处理的作物产量。基于作物氮素吸收量，高产条件下有机肥替代率与施肥年限呈极显著线性正相关（P < 0.01），高量有机肥处理（M2）的有机肥替代率高于常量有机肥处理（M1）；且有机肥施用29年后，高量有机肥处理（M2）的有机肥替代率达到100%，并保持稳定不变。基于土壤氮素供需方程估测的常量和高量有机肥处理（M1和M2）的有机肥替代率与基于作物氮素吸收量得到的有机肥替代率相关系数（R2）达到0.78和0.84（P < 0.01），相对均方根误差（RMSE）均小于15%（分别为10.4%和14.6%），表明土壤氮素供需方程可以较好地估测土壤有机肥替代率。基于作物氮素吸收量和土壤氮素供需方程能够准确反映长期有机培肥下黑土有机肥替代率的变化规律。本研究结果表明，基于作物氮素吸收量和土壤氮素供需方程两种方法验证，高产条件下有机肥替代率是土壤肥力的函数；随着有机肥施肥年限的增加，土壤肥力提升，有机肥替代率逐渐增加。
Abstract:This study explored the relationship between the substitution rate of organic fertilizer (SROF) and soil fertility under long-term fertilizer application in black soils and thereby laid the basis of theoretical guidance for optimal fertilization in black soils. A 32-year dataset on black soil fertilization from Gongzhuling in Jilin Province experimental site was analyzed to determine the changes in SROF under different rates of organic fertilizer application based on crop removal of nitrogen (N) and soil N supply-demand balance. Results showed that crop yield increased gradually with increasing application years of organic fertilizer, which was slightly higher than for NPK fertilization after 32 years. A significant positive correlation existed between SROF and fertilization years as driven by crop removal of N (P < 0.01). Furthermore, SROF reached 100% and was stable after 29 years of high quantity manure (M2) application, higher than that of the application of conventional manure quality (M1). The correlation coefficients (R2) between SROFs of conventional and high quantity manure (M1 and M2) applications between based on crop N absorption (RN) and soil N supply-demand balance (RN') were 0.78 and 0.84 (P < 0.01), respectively. The corresponding root mean square errors (RMSE) were 10.4% and 14.6%, validating the method of calculation of SROF based on soil N supply-demand balance. The results suggested that SROF under high crop yield could be used as a fertility index under current intensive fertilization. Longer applications of organic fertilizers led to higher soil fertility and crop productivity and a gradual increase in SROF.
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