ABSTRACT

Nitrogen fertiliser application can effectively increase the net primary productivity (NPP) of agriculture and grassland ecosystems. There is some long-term retention of nitrogen applied to soils, but much is lost to runoff, to in situ denitrification and to gaseous forms of nitrogen (such as NH₃ and NO_X). So it is particularly important to improve nitrogen-use efficiency through various ways. Therefore, the effects of the urea with urease inhibitor N-(n-butyl)thiophosphoric triamide (NBPT) or/and nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on the NPP, NH₃ and ¹⁵N recovery were researched on the alpine grassland ecosystem. The results showed that the addition NBPT to urea can significantly reduce the cumulative NH₃ emission of urea-N compared with urea alone. The NBPT or DMPP addition to urea significantly increased the above-ground NPP and the economic efficiency. Urea added to NBPT or NBPT+DMPP could increase the ¹⁵N recovery rate of plant and soil (0-40 cm) by nearly 20%. The results indicated that urea combined with DMPP may be a good way to nitrogen fertiliser retention and reduction of NH₃ emission for the alpine grassland of the northeast of the Qinghai-Tibet Plateau.

摘要

施氮肥可有效提高农业和草地生态系统的净初级生产力（NPP）。施用于土壤的氮有一些长期保留，但大部分因径流、原位反硝化和气态氮（如 NH ₃和 NO _X）而损失。因此，通过多种方式提高氮素利用效率显得尤为重要。因此，尿素与脲酶抑制剂N -（正丁基）硫代磷酰三胺 (NBPT) 或/和硝化抑制剂 3,4-二甲基吡唑磷酸酯 (DMPP) 对 NPP、NH ₃和^{15 的影响}对高寒草地生态系统的氮回收进行了研究。结果表明，与单独使用尿素相比，向尿素中添加NBPT可以显着降低尿素-N的累积NH ₃排放。在尿素中添加NBPT或DMPP显着提高了地上NPP和经济效益。在NBPT或NBPT+DMPP中添加尿素可使植物和土壤（0-40 cm）的¹⁵ N回收率提高近20%。结果表明，尿素联合DMPP可能是青藏高原东北部高寒草原氮肥滞留和减少NH ₃排放的良好途径。