旱区土壤无机氮素与春玉米根系时空分布对控释尿素输入的响应

以先玉698为供试材料，在等氮量(225 kg/hm²)条件下，以不施氮为对照(CK)，设置UR (100%普通尿素，2/3基施，1/3小喇叭口期追施)、CRU1(1/3控释尿素+1/3普通尿素基施，1/3普通尿素小喇叭口期追施)，CRU2(2/3控释尿素+1/3普通尿素一次基施)、CRU3(100%控释尿素基施)4种施氮模式，探究控释尿素输入对土壤氮素、玉米根系特性、氮素吸收及产量的影响。结果表明，相对于UR处理，CRU处理显著提升了春玉米生育中后期土壤硝态氮和铵态氮的含量，其中CRU2效果最明显。UR和CRU处理在不同时期对根系参数的影响不同，前期UR处理有利于根系的生长，花后CRU处理对0～80 cm土层根系长度及0～20 cm根重密度影响更大。通径分析进一步表明，玉米根长及根重密度的变化是增产的重要原因之一。CRU处理显著提升了玉米整个生育期内植株氮素含量及最终子粒产量。花后15 d，CRU处理较UR提高了子粒氮素含量，CRU处理间以CRU2最佳。CRU2处理子粒产量为14.65 t/hm²，分别较CK、UR、CRU1、CRU3提高32.70%、5.78%、1.52%、5.17%。在宁南山区CRU2处理能实现春玉米高产高效。

Response of Spatiotemporal Distribution of Soil Inorganic Nitrogen and Spring Maize Roots to Controlled Urea Input in Arid Area

In this research, the cultivar Xianyu698 was applied as research material. Five nitrogen application regimes:No nitrogen was applied as the control(CK), Conventional urea(U) supply UR:100% U, 1/3 U base application, 1/3 U flare opening period application, CRU1:1/3 CRU+1/3 U base application, 1/3 U flare opening period application, CRU2:2/3 CRU+1/3 U base application, CRU3:100% CRU base application were set to analyze the effects of CRU on the spatial and temporal distribution of soil inorganic nitrogen and root growth distribution, nitrogen uptake efficiency and grain yield of maize. The results indicated that the content of soil nitrate nitrogen and ammonium nitrogen in CRU significantly increased at late stage of spring maize compared with UR, CRU2 is the most obvious. UR and CRU have different effects on root system parameters in different periods. UR in the early stage is beneficial to root growth, while CRU after anthesis has a greater impact on root length and root weight density of whole soil layer. It showed that the change of maize root length and root weight density is one of the important reasons for increasing yield. CRU input significantly increased the nitrogen content of the plant and the grain yield during the whole growth period. At 15 days after flowering, CRU increased grain nitrogen content compared with UR. The outstanding one is CRU2, which is not only the grain has a high nitrogen content, but high yield. CRU2 grain yield was 14.65 t/ha, which was 32.70%, 5.78%, 1.52% and 5.17% higher than other. Consequently, through CRU2 can realized to high yield and high efficiency cultivation of spring maize.