旱地土壤硝态氮的产生、淋洗迁移及调控措施

Review of soil nitrate formation, leaching transport and their control measures in upland farming systems

  • 摘要: 如何在保证作物高产的前提下,提高氮肥利用率、减少氮肥损失及其对环境的影响已经成为一个世界性研究课题。硝态氮淋洗是旱地土壤氮素损失去向的重要途径之一,是导致区域性地下水硝酸盐污染的重要原因,已成为全球集约农区重大农业和生态环境问题。明确不同农作系统土壤硝态氮的产生、淋洗过程及影响因素,并进一步提出阻控措施,具有重要的农学和环境意义。在这一方面国内外学者已经开展了长期、大量的研究,并积累了丰富的资料。本文简要综述了旱地土壤硝化作用的微生物驱动过程,比较了当前最为常用的田间原位监测硝态氮淋洗方法的优缺点,分析了影响硝态氮累积和淋洗的各种因素,总结了相应的调控措施,并对今后的研究工作进行展望:加强旱地土壤硝化作用的关键微生物过程、机理以及相关驱动因子调控作用的研究,有助于增加对土壤氮素循环的认识,而这些认识是旱地农作系统进行氮素优化管理和制定硝态氮淋洗阻控技术的重要基础;继续寻找和建立一种扰动更少、维护简单、样品污染更低、尤其适合长期监测的田间原位研究方法,对于准确地揭示旱地土壤硝态氮的淋洗规律和实时通量尤为重要;系统地开展不同旱地农作系统硝态氮淋洗的综合性研究,阐明影响硝态氮累积和淋洗的主要因素,并提出针对性的阻控措施,更符合田间实际,对于降低区域硝态氮淋洗风险意义重大。

     

    Abstract: Figuring out how to improve nitrogen use efficiency and reduce nitrogen loss to abate its impact on environment in order to ensuring high crop yield production are of leading global research interest today. The leaching of nitrate is the main pathway of nitrogen loss and the main mode of regional groundwater nitrate pollution. It has become a severe agricultural and ecological environmental problem in intensive agricultural regions around the world. Thus it is important to understand nitrate formation, leaching process, influencing factors and to put forward effective control measures. A great number of studies have been carried out by both local and foreign scholars in this area that has led to the generation of abundant information over the years. In this paper, soil nitrification process driven by micro-organisms was briefly reviewed. The advantages and disadvantages of in situ nitrate leaching monitoring methods were compared. The factors that affected nitrate accumulation and leaching were also analyzed. On the basis of the above parameters, effective control measures were summed up and future research directions were suggested strengthening researches on key micro-organism processes, mechanisms and functions of relevant driving factors of nitrification of upland soils. These clear understanding on soil nitrogen would contribute to the critical basis for the optimization of nitrogen management and the development of technologies to control nitrate leaching in upland farming systems. The exploration and establishment of methods of reducing soil disturbance, simple maintenance, less sample pollution and suitable long-term in situ field monitoring was particularly crucial to accurately reveal the soil nitrate leaching and real-time flux. The systematic development of comprehensive studies on nitrate leaching in different upland farming systems, the clarification of various factors that affected nitrate accumulation and leaching, and then the putting forward of effective control measures based on actual field conditions were required to reduce the risk of nitrate leaching at regional scale.

     

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