Based upon the review of the status of nitrogen use efficiency in salinized farmland in China, we summarized the effect of salinization on key processes of nitrogen transformation in farmland soil, analyzed the microbial mechanism underlying nitrogen transformation, and summed up the main ways for high efficient utilization of nitrogen in salinized farmland. Salinization had thre-shold effects on mineralization, nitrification, and denitrification of nitrogen from farmland soil, with the influence varying greatly in different scopes. Salinity and secondary barriers had different effects on microorganisms, with threshold in their effects. The most widely used methods for nitrogen synergism regulation in salinized farmland include soil conditioner, biomass material, growing salt-tole-rant plants, optimizing the ratio of different nitrogen forms, and biological inhibitor. We proposed current research shortcomings and future research directions of nitrogen cycle processes in salinized farmland. This study was of great significance for reducing nitrogen loss, enhancing utilization of nutrient from fertilizers, and controlling agricultural non-point source pollution in salinized farmland.
本文在回顾我国盐渍化农田氮肥利用现状的基础上,总结了盐渍化对农田土壤氮素转化关键过程的影响规律,剖析了其对参与氮素转化的微生物的作用机制,归纳了盐渍化农田氮素养分增效调控的主要途径。盐渍化对农田土壤氮素矿化、硝化和反硝化过程存在阈值效应,不同范围内影响差别较大。盐分以及次生障碍对相关微生物也具有不同的影响,且同样存在阈值效应。目前盐渍化农田氮素增效调控的途径主要包括土壤改良剂改良、生物质材料改良、种植耐盐植物、优化氮素形态配比和生物抑制剂改良,最后提出盐渍化农田氮素循环过程研究目前存在的不足以及未来的研究方向。本文对盐渍化农田氮素减损增效、化肥养分高效利用与农业面源污染阻控具有重要指导意义。.
Keywords: efficiency improving; nitrification; nitrogen transformation; salinized farmland; soil microorganism.