节水灌溉条件下冬小麦生长期田间氮素迁移转化试验

Nitrogen translation and transformexperiments in winter wheat field under watersaving irrigation

在节水灌溉的条件下，通过田间现场试验测定了冬小麦生长期田间土壤中铵氮、硝态氮含量的动态分布，分析了田间土壤中氮素的迁移转化规律，为合理施肥提供科学依据。试验结果表明，冬小麦耕层中的营养氮素含量以硝态氮为主，约占８５％多，除用施肥的方法为植物生长提供一定的氮素以外，土壤本底的含量，特别是土壤中有机氮矿化后的无机氮也是植物营养氮素的一个重要来源，在节水灌溉的条件下，冬小麦生长季节硝态氮的深层渗漏微乎其微，但是冬小麦收割后根层中仍有大量的硝态氮，如不合理利用会在汛期因大量降水造成肥料的大量流失，并对地下水构成潜在的威胁。

Under watersaving irrigation condition, the ammonium N and nitrate N content dynamic distributions in the soil protile are measured during winter wheat growing period, the transportation and transformation of nitrogen in the wheat root zone take nitrate N as dominant, being about 85% of the total nitrogen. Besides applying fertilizer, the inorganic N transformed from mineralization of organic N is also an important source for crop growing. Under watersaving irrigation, seepage of nitrate N out of root zone can be neglected. However, there is a large amount of nitrate N in the root zone after wheat harvest, they will leach and contaminate groundwater during flood season if they can not be utilized rationally.