测墒补灌条件下施氮量对小麦干物质积累转运和产量的影响

为筛选测墒补灌节水条件下实现小麦高产和氮素高效利用的最优施氮量，以小麦品种烟农1212为材料，在拔节期和开花期将0~40 cm土层土壤相对含水量补灌至70%条件下，设置0、120、180和240 kg·hm^-2施氮量处理（分别用N0、N1、N2和N3代表），分析施氮量对测墒补灌小麦旗叶光合特性、干物质积累与转运和氮素利用率的影响。结果表明，N2处理下小麦花后7~28 d旗叶光合性能显著高于N0和N1处理，但施氮量增至N3时光合性能无显著变化。N2处理的营养器官花前贮藏干物质在花后向籽粒的转运量显著高于其他处理；花后光合同化物积累量显著高于N0和N1处理，但与N3处理无显著差异。成熟期N2处理干物质在籽粒中的分配比例较N0和N1处理分别高5.00和2.86个百分点。N2处理的籽粒灌浆持续时间和活跃灌浆期长，最大灌浆速率下粒重高，籽粒产量较N0和N1处理分别高41.01%和22.44%，且氮肥农学效率最高，氮肥偏生产力较高。综合考虑，180 kg·hm^-2施氮量为测墒补灌节水条件下最佳施氮量。

Effect of Nitrogen Application Rates on Dry Matter Accumulation, Transportation and Yield of Wheat under the Conditions of Soil Moisture Measurement and Supplementary Irrigation

To explore the optimal amount of nitrogen application to synergistically improve wheat yield and nitrogen utilization efficiency under the conditions of water-saving irrigation by measuring soil moisture,the wheat variety Yannong 1212 was used as the material.Under the conditions of supplementing the soil relative water content of 0-40 cm soil layer under each treatment to 70% at the jointing stage and flowering stage, four nitrogen application treatments of no nitrogen application 0 kg·hm^-2(N0) and 120 kg·hm^-2(N1), 180 kg·hm^-2(N2), and 240 kg·hm^-2(N3) were conducted to study the effect of nitrogen application on the photosynthetic characteristics of flag leaves,dry matter accumulation and transport, and nitrogen use efficiency of wheat by measuring soil moisture and supplementing irrigation. The results showed that the photosynthetic capacity of flag leaves at 7-28 days after anthesis under N2 treatment was significantly higher than that under N0 and N1 treatments. On this basis, increasing the amount of nitrogen application to N3 did not significantly increase the above parameters. The transport amount of dry matter stored in vegetative organs to grains before flowering under N2 treatment was significantly higher than that under other treatments. The accumulation of photosynthates after flowering under N2 treatment was significantly higher than that of N0 and N1 treatments, yet there was no significant difference compared with that under N3 treatment. The distribution ratio of dry matter in grains under N2 treatment was 5.00 and 2.86 percentage points higher than that under N0 and N1 treatments, respectively. The duration of grain filling and active filling period of N2 treatment were longer; the grain weight was higher at the maximum filling rate; and the grain yield was 41.01% and 22.44% higher than that of N0 and N1 treatments, respectively. N2 treatment performed the highest agronomic efficiency of nitrogen fertilizer and higher partial productivity of nitrogen fertilizer. Considering the grain yield and nitrogen use efficiency of wheat, the treatment of 180 kg·hm^-2 nitrogen application rate is the best nitrogen application rate under the conditions of measuring soil moisture, supplementary irrigation and water saving.