应重视硝态氮同化过程在降低土壤硝酸盐浓度中的作用

发布时间：2018-07-13 09:30

【摘要】：在保证生产力条件下,采取合理的氮肥管理措施降低土壤硝态氮浓度对降低氮污染至关重要。当前,应用硝化抑制剂能够有效延缓铵态氮的硝化速率,进而降低土壤硝态氮淋溶损失和氮氧化物排放,但是其缺点显而易见:促进氨挥发并引起硝化抑制剂污染。好氧条件下,土壤硝态氮净变化量取决于产生(硝化)和消耗(硝态氮同化)的量。但是,一直以来,受微生物优先利用铵态氮这一传统观点的影响,人们普遍认为农田土壤微生物较少利用硝态氮,很大程度上忽视了对硝态氮同化过程的研究。该过程独具优势,它将硝态氮转变为微生物生物量氮进行短期储存并发生再矿化,具有保氮功能且环境友好。加入特定的碳源可以提高硝态氮同化这已是不争的事实,未来应加强硝态氮同化降低土壤硝酸盐累积方面的研究:(1)外源碳影响硝态氮同化的微生物驱动机制是什么?(2)怎样才能操控硝态氮同化和再矿化过程,使得作物氮需求和土壤氮供应相匹配,进而降低氮损失?(3)在碳源充足的条件下,反硝化作用亦会增强,如何才能做到在提高硝态氮同化的同时避免反硝化氮损失?
[Abstract]:Under the condition of guaranteed productivity, it is very important to reduce the nitrate concentration in soil by adopting reasonable nitrogen management measures. At present, nitrification inhibitors can effectively delay the nitrification rate of ammonium nitrogen, and then reduce soil nitrate leaching loss and nitrogen oxide emissions, but its disadvantages are obvious: promote ammonia volatilization and cause nitrification inhibitor pollution. Under aerobic conditions, the net change of nitrate in soil depends on the amount of production (nitrification) and consumption (nitrate assimilation). However, under the influence of the traditional view that microbes preferentially utilize ammonium nitrogen, it is generally believed that the soil microbes in farmland make less use of nitrate nitrogen, which largely neglects the study of the assimilation process of nitrate nitrogen. This process has unique advantages. It converts nitrate nitrogen to microbial biomass nitrogen for short-term storage and mineralization. It has the function of nitrogen conservation and is environmentally friendly. It is an indisputable fact that adding specific carbon sources can improve nitrate assimilation. In the future, the study of nitrate assimilation and reduction of nitrate accumulation in soil should be strengthened: (1) what is the microorganism driving mechanism of exogenous carbon affecting nitrate assimilation? (2) how to control the nitrate assimilation and mineralization process? Make crop nitrogen demand and soil nitrogen supply to match, and then reduce nitrogen loss? (3) denitrification will be enhanced under the condition of sufficient carbon source, how to improve nitrate assimilation while avoiding denitrification loss?
【作者单位】：土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所);江苏省农业委员会;
【基金】：国家自然科学基金项目(41671231,41571294) 国家重点研发计划项目(2017YFD0200106,2017YFD0800103)资助~~
【分类号】：S153

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