氮肥施用时期及基追比例对土壤矿质氮含量时空变化及小麦产量和品质的影响

采用田间试验方法，研究了不同氮肥施用时期和基追比例对土壤硝态氮和铵态氮含量变化及小麦产量和品质的影响.结果表明：土壤硝态氮和铵态氮含量随着土层深度的增加而降低，不同氮肥施用时期和基追比例对0～20 cm土层土壤硝态氮和铵态氮含量均有显著影响；与氮肥全部基施处理相比，氮肥施用时期后移和基追比例的增加，明显提高了氮肥吸收利用率，减少了小麦全生育期土壤氮素的表观盈余量，同时显著改善了小麦籽粒品质；但对籽粒产量影响不显著，孕穗期追施比例过大导致产量显著降低.在本试验条件下，综合考虑产量、品质和生态效益，以基肥∶拔节肥∶孕穗肥为5∶3∶2为最佳氮肥运筹方式.

Effects of application time and basal/topdressing ratio of nitrogen fertilizer on the spatiotemporal variation of soil NO3--N and NH4+-N contents and the grain yield and its quality of wheat.

Field trials were conducted to study the effects of different application time and basal / topdressing ratio of nitrogen fertilizer on the spatiotemporal variation of soil NO₃^--N and NH₄⁺-N contents and the grain yield and its quality of wheat. The results showed that soil NO₃^--N and NH₄⁺-N contents decreased with increasing soil depth. Both the application time and the basal / topdressing ratio of nitrogen fertilizer had significant effects on the NO₃^--N and NH₄⁺-N contents in 0-20 cm soil layer. Compared with basal application, later fertilization and higher topdressing ratio could promote the nitrogen uptake by wheat plant and increase the plant nitrogen recovery significantly, decrease the soil nitrogen recovery during wheat growth, and improve the grain quality significantly, while had less effects on the grain yield. Topdressing too much nitrogen fertilizer at booting stage could result in a significant decrease of grain yield. Under the condition of this experiment, the optimal nitrogen fertilization mode for good wheat grain yield and its quality and good ecological benefits was 5 ∶3∶2 of basal application ∶topdressing at jointing stage ∶topdressing at booting stage.