中文摘要：

针对设施蔬菜生产中化肥氮高强度投入造成的肥料资源浪费和土壤质量下降等突出问题，以我国设施蔬菜生产典型区山东寿光为研究基地，在该区域 3 年减施氮肥模式对农学、肥力和环境效应影响的定位试验基础上，应用15N示踪技术，对筛选出的氮肥优化模式进行验证，并定量化地研究氮肥基于C/N 调控和基于水分调控的优化模式下氮素的吸收、利用及去向，以期为设施菜地合理的氮素管理提供理论和技术支持。试验设2个处理，1）农民习惯施氮模式（FP）； 2）优化施氮模式（OPT）。研究结果表明， OPT处理的番茄地上部产量和氮素吸收量均高于FP，作物吸收氮只有 20% 左右来自化肥氮；与FP相比，OPT处理的化肥氮素农学效率和氮素利用率显著提高（P〈0.05）；土壤中残留氮主要以硝态氮的形式存在，FP和OPT处理在0—100 cm土层中的残留量分别为N 536.9 和340.3 kg/hm2，主要分布在0—40 cm 土层，随着深度的增加，累积量有所减少，OPT处理显著降低了各土层硝态氮的累积（P〈0.05）；除了作物吸收和土壤残留的氮，FP和OPT处理中分别有32.4%和8.2%的化肥氮以各种途径损失，OPT处理氮素损失率比FP低24.2个百分点。综合以上研究结果，优化施氮模式对化肥氮的吸收、利用及减少化肥氮的损失方面均优于农民习惯施氮模式。

英文摘要：

Excessive nitrogen （N） fertilization input has resulted in fertilizer waste and soil quality degeneration, etc. Based on the last 3-year results of the effects of different N fertilizer management models on soil agronomy, fertilizer and environment efficiency, an optimum N fertilizer management model was selected. To indentify the model and investigate the fate and utilization of the chemical N fertilizer, a microplot experiment with 15N tracing technique was carried out in Shouguang, Shandong Province, which is the famous greenhouse vegetable production base in Northern China. The experiment included the conventional N fertilizer model （FP） and optimized N fertilizer model （OPT）. The main findings are that the higher dry matter production and N content are obtained in the OPT model and only about 20% of N uptake of plants comes from chemical N fertilizer. Compared with the FP model, the agronomic efficiency and N recovery efficiency of chemical fertilizer N are significantly increased in the OPT model. NO-3-N is the main chemical N residue form, and the NO-3-N accumulation amounts in 0-100 cm soil layer of the two models are N 536.9 and 340.3 kg/ha respectively.NO-3-N is mainly accumulated in 0-40 cm soil layer, and NO-3-N accumulation amounts are decreased with the increase of soil depth. Compared with the FP model, soil NO-3-N accumulation amounts in each soil layer of the OPT model are significantly decreased. 32.4% and 8.2% of 15N loss are from the chemical N fertilizer, respectively in the FP and OPT models, and the N loss rate of the OPT model is 24.2% lower than that of the FP model. The present study shows that the OPT model can improve chemical N fertilizer uptake and utilization, reduce chemical N fertilizer loss and maintain the sustainability of greenhousebased intensive vegetable systems.