氮磷配施条件下作物产量及水肥利用效率

Crop yield and water-fertilizer utilization efficiency under combined application of nitrogen and phosphorous

农田退水过程中氮、磷等污染物对黄河造成较严重的污染，需要合理调控农业生产过程中氮、磷配施水平，进一步削减氮、磷用量，从源头上解决农业面源污染问题。本研究分析了不同氮、磷配施条件下小麦玉米套作的产量及水肥利用效率。结果表明：随着施氮（磷）量的增加，小麦玉米套作的产量、百粒重（千粒重）、耗水量及水分利用效率表现为先增加后减少的规律，氮、磷合理配施能够显著增加土壤贮水量的消耗，提高作物对土壤水分的利用；氮（磷）肥的偏生产力及农学效率表现为随着施氮（磷）量的增加而降低，施氮（磷）量恒定时，在一定范围内增施磷（氮）肥能够有效提高作物的氮肥偏生产力及农学效率，施磷（氮）过量，则表现为降低趋势；小麦玉米套作达到最高产量的最佳施肥量为，小麦施氮191.7～216 kg·hm-2，施磷165.38～186.64 kg·hm-2，玉米施氮243～299.14 kg·hm-2，施磷168.38～189 kg·hm-2；氮、磷合理配施能够在保证产量的前提下，适量削减氮、磷施量，提高作物对水肥的利用，减轻农业面源污染。

The pollutants such as nitrogen （N） and phosphorus （P） caused serious pollution to the Yellow River in the process of agricultural water withdrawal. It is necessary to reduce the application amounts of N and P by further controlling the combined application levels of N and P reasonably in the process of agricultural production, thereby solving the problem of agricultural nonpoint source pollution from the source. The yield and waterfertilizer utilization efficiency of wheatmaize intercropping were analyzed under different combined applications of N and P. The yield, hundredkernel weight （or thousandkernel weight）, water consumption and water utilization efficiency were increased first and then decreased with increasing the application amounts of N and P. The reasonable application of N and P significantly increased the water consumption stored in the soil and thus enhanced soil water utilization by crop. The PFP-N, PFP-P and agronomic efficiency were decreased with increasing the application amounts of N and P. The PFP-N and agronomic efficiency of crop were improved when increasing P fertilization within a certain range but keeping the application amount of N constant or vice versa. The PFP-N and agronomic efficiency of crop would be reduced when the P or N application was excessive. The best fertilization amounts of N and P which could make the maximum yield of wheatmaize intercropping were 191.70-216 kg·hm-2 and 165.38-186.64 kg·hm-2 for wheat, and 243-299.14 kg·hm-2 and 168.38-189 kg·hm-2 for maize, respectively. On the premise of guaranteeing production, the reasonable application amount of N and P could reduce fertilization and improve the waterfertilizer utilization efficiency, reducing agricultural non-point source pollution.