Abstract: 【Objective】A field experiment was conducted in an arid region to investigate the effects of nitrogen form and drip irrigation placement on nitrogen transformation dynamics in rice rhizosphere and yield formation, aiming to address low nitrogen use efficiency in drip-irrigated rice and provide theoretical and technical support for improving nitrogen management in these systems. 【Method】A three-factor randomized complete block design was adopted. The experimental factors included nitrogen application methods under drip irrigation, i.e., surface drip irrigation (Su) and subsurface drip irrigation at a depth of 10 cm (Sh); nitrogen forms, including no nitrogen application (N0), nitrate nitrogen (NN, calcium nitrate), and ammonium nitrogen combined with a nitrification inhibitor (AN, ammonium sulfate + DMPP, where DMPP is a nitrification inhibitor); and rice cultivars, namely Liangxiang 3 (LX3) and Ningjing 48 (NJ48). The three factors were fully crossed, resulting in 12 treatment combinations with three replicates for each combination. We conducted a comparative analysis of the following parameters across the different treatment combinations: rhizosphere soil pH, NH₄⁺-N and NO₃⁻-N content, nitrification rate and denitrification potential, aboveground nitrogen accumulation, and yield components. 【Result】Dry matter accumulation, nitrogen accumulation, and yield differed significantly among the treatment combinations. Overall, the AN treatment outperformed the NN and N0 treatments, with the Sh+AN combination yielding the highest results.The rhizosphere soil pH was significantly lower in the AN treatment than in the NN treatment. At both the tillering and heading stages, the soil NH₄⁺-N content differed significantly among nitrogen forms, with the AN treatment being significantly higher than the N0 and NN treatments. The highest values were observed in the Sh+AN combination (LX3: 20.39 mg/kg; NJ48: 21.05 mg/kg). Similarly, soil NO₃⁻-N content varied significantly among nitrogen forms, with the NN treatment significantly exceeding the N0 and AN treatments. The Su+NN combination showed the highest levels (LX3: 61.71 mg/kg; NJ48: 59.97 mg/kg). The soil potential nitrification rate and denitrification potential were significantly higher in the NN treatment than in the N0 and AN treatments. While these rates were slightly higher under Su irrigation compared to Sh, the difference was not statistically significant. 【Conclusion】Shallow subsurface drip irrigation at 10 cm depth combined with ammonium nitrogen stabilization management (Sh + AN) better maintained NH₄⁺-N levels in the rice rhizosphere and suppressed nitrification-related nitrogen loss. Consequently, this practice enhanced nitrogen uptake and increased grain yield. Therefore, the Sh+AN strategy can be recommended as an optimized nitrogen and irrigation management practice for drip-irrigated rice in the arid region of Xinjiang, effectively balancing yield enhancement with the mitigation of nitrogen loss.

Key words: drip-irrigated rice, irrigation method, nitrogen form, nitrogen transformation, nitrogen use efficiency, yield

摘要： 【目的】针对干旱区滴灌水稻氮素利用率低的问题，探究不同形态氮肥结合滴灌施肥位置对水稻根际土壤氮转化动力学特征及产量形成的影响机制，为滴灌水稻氮肥高效利用提供理论依据和技术参考。【方法】采用三因素完全随机区组试验设计。试验因素包括滴灌施肥方式，分为地表滴灌施肥(Su)和地下埋深10 cm滴灌施 肥(Sh)；氮肥分为不施氮(N0)、施硝态氮肥(NN，硝酸钙)和施铵态氮肥配施硝化抑制剂(AN，硫酸铵+DMPP，DMPP为硝化抑制剂3,4-二甲基吡唑磷酸盐)；水稻品种选用粮香3号(LX3)和宁粳48号(NJ48)。三因素完全随机组合，共设12个处理，每处理设置3个重复。对比分析不同处理组合下水稻根际土壤pH、NH₄⁺-N和NO₃⁻-N含量、硝化速率和反硝化势，水稻地上部氮积累量及产量构成。【结果】两个水稻品种的干物质积累量、氮积累量和产量在不同处理组合间差异显著，总体表现为AN处理高于NN和N0处理，其中，以Sh+AN处理组合最高。AN处理的根际土壤pH值显著低于NN处理。在两个水稻品种的分蘖期和孕穗期，不同氮肥形态间土壤NH₄⁺-N含量表现为AN处理显著高于N0和NN处理，其中以Sh+AN处理组合的含量最高(LX3: 20.39 mg/kg；NJ48: 21.05 mg/kg)。不同氮肥形态管理间土壤NO₃⁻-N含量则表现为NN处理显著高于N0和AN处理，其中以Su+NN处理组合最高(LX3: 61.71 mg/kg；NJ48: 59.97 mg/kg)。两个品种的土壤氮初级硝化速率和反硝化势均表现为NN处理显著高于N0和AN，Su处理略高于Sh，但两者无显著性差异。【结论】地下10 cm滴灌结合铵态氮稳定化管理(Sh+AN)有利于维持水稻根际NH₄⁺-N水平，抑制根际氮硝化损失，进而提高水稻氮吸收量和促进产量增加。该方法可以推荐为新疆干旱区兼顾滴灌水稻产量提升和减少氮素损失的优化施肥选择。

关键词: 滴灌水稻, 施肥方式, 氮肥形态, 氮转化, 氮素利用率, 产量