农业化肥减量及生物肥料替代可行性研究——来自新疆棉区调查数据的实证

推进化肥减施增效是实现中国农业绿色高质量发展的关键途径。本文以新疆棉花为例,基于2000—2020年棉花化肥施用量及技术、资本、劳动力投入时序数据,构建生产函数考察了新疆棉花单位面积化肥施用强度变化及其对棉花单产提升的贡献作用,并利用2015—2020年不同植棉区化肥和生物肥料施肥区的微观定位调查数据,采用熵权法构建肥料应用效益评价指标体系,对两种肥料的综合效益做出总体评判,并对经济效益（棉花产量、黄萎病害发生率）和生态效益（土壤有机质、微生物数量）及两种肥料施用成本进行具体比较,探讨了生物肥替代化肥的可行性及其实现机制。研究表明：① 2000—2020年间新疆棉花单位面积化肥施用强度呈不断上升态势,高于同期国内大部分植棉省份,自2016年起趋于减缓和平稳,施肥量浮动在585 kgN/hm²左右。② 2000—2010年随着单位面积化肥施用强度的增加,对棉花单产增加呈正向促进作用;而2010—2020年,单位面积化肥施用强度增加对棉花单产提高的贡献率为-21.29%,表明持续增加化肥用量对棉花单产提高已呈现负效应。③ 生物肥料施肥区生态效益优势更突出,但经济效益低于化肥区,两种肥料的综合效益随使用年限增加差距趋于缩小;较化肥组,研究期内不同植棉区生物肥组棉花单产降低3%~8%,黄萎病害发病率降幅27.75%~58.20%,土壤有机质含量提高了14.59%~28.54%,土壤微生物数量显著增加;生物肥单位施用成本高于化肥14%~19%。根据生物肥生态属性及作用机理,结合农户经济理性及传统的化肥依赖,建议在生物肥推广初期,实行一定的政策激励或生态补偿,同时积极引导和培育农户亲环境意识,农业化肥逐步减量及生物肥替代具有理论与实践可行性。

Feasibility study on reduction of agricultural chemical fertilizer and substitution of bio-fertilizer: An empirical study of cotton survey data in Xinjiang

Reducing chemical fertilizer and increasing biofertilizer are important ways to achieve green agricultural development in China. This paper used production function to investigate the evolution of cotton chemical fertilizer application intensity and its effect on cotton yield per unit area in Xinjiang from 2000 to 2020. Based on the survey data from 2015 to 2020, an evaluation index system was constructed using entropy weight method to evaluate the comprehensive benefits of two types of fertilizers. Furthermore, the feasibility and realization mechanism of using biofertilizer to replace chemical fertilizer were discussed. The results showed that: (1) The total amount of chemical fertilizer per unit area of cotton in Xinjiang increased continuously, and it was higher than the level in most provinces. Since 2016, the amount of cotton fertilizer in Xinjiang tended to slow down and stabilize, and the amount of cotton fertilizer fluctuated around 585 kg N/hm². (2) From 2000 to 2010, the increase of fertilizer application per unit area positively promoted the increase cotton yield per unit area. While the contribution rate of increasing fertilizer application per unit area to the increase of cotton yield per unit area was -21.29% from 2010 to 2020, indicating that a continuous increase of chemical fertilizer had a negative effect on the increase of cotton yield per unit area. (3) The ecological benefits of the biofertilizer were more prominent, but the economic benefits of the biofertilizer fertilization area were slightly lower than that of the chemical fertilizer area, and the comprehensive benefits of the two fertilizers tended to narrow down with the increase of use years. The average yield per unit area of cotton in the biofertilizer group was 3%-8% lower than that in the chemical fertilizer group, but the incidence of verticillium wilt was significantly reduced in the biofertilizer group and the average decrease in different cotton planting areas was 27.75%-58.20%, soil organic matter content increased by 14.59%-28.54%, and soil microbial quantity increased significantly. The fertilizer cost per acre of biofertilizer was 14%-19% higher than that of chemical fertilizer. The characteristics of biofertilizer require some incentive or ecological compensation policies to guide and raise farmers' environmental awareness at the beginning of the promotion of biofertilizer. It is feasible to reduce the amount of agricultural chemical fertilizer and gradually replace agricultural chemical fertilizer with biofertilizer.