冬小麦不同生育阶段水分利用对保水剂与氮肥的响应

为探明保水剂和氮肥及其配施后对冬小麦不同生育阶段水分利用的作用机理,通过大田试验,以不施保水剂和氮肥为对照,研究了保水剂(60 kg.hm 2)与氮肥0、225 kg(N).hm 2、450 kg(N).hm 2]单施及其配施后对冬小麦不同生育阶段的土壤水分、干物质积累及水分利用的作用特征。结果表明:保水剂和氮肥的施用均提高了土壤剖面各层次的含水量及冬小麦干物质积累量、产量和水分利用效率。各处理中以单施450kg(N).hm 2氮肥、单施保水剂及保水剂与450 kg(N).hm 2氮肥配施处理土壤含水量较高。不施保水剂时,随施氮量的增加,冬小麦地上部干物质积累量显著提高。施用保水剂时,氮肥用量过高,干物质积累有所降低。拔节—收获期,保水剂与225 kg(N).hm 2氮肥配施处理冬小麦干物质积累量均较高,且到生育后期效果更明显。在播种—拔节期和孕穗—灌浆期,随氮肥用量的增加水分利用效率提高,且保水剂与氮肥配施处理增加幅度更大。而灌浆—收获期,高氮450 kg(N).hm 2]和保水剂与225 kg(N).hm 2氮肥配施处理的水分利用效率提高幅度最大,分别较对照增加53.8%和57.8%。而最终产量与水分生产效率以60 kg.hm 2保水剂与225 kg(N).hm 2氮肥配施处理最高。说明氮肥用量适宜时,施用保水剂冬小麦产量和水分利用效率的提高幅度更大。

Response of water use of winter wheat at different growth stages tonitrogen fertilizer and water-retaining agent

A field experiment was conducted to determine the water use characteristics of winter wheat at different growth stages under application of water-retaining agent (60 kg·hm ^-2) and nitrogen fertilizer 0, 225 kg(N)·hm^-2, and 450 kg(N)·hm ^-2]. The field experiment investigated soil moisture, winter wheat biomass accumulation, water use at different growth stages as affected by wa-ter-retaining agent and nitrogen fertilizer. The results indicated that soil moisture, biomass accumulation, yield and water use effi-ciency (WUE) of winter wheat increased after water-retaining agent and nitrogen fertilizer application. Compared with other treat-ments, soil moisture under treatments of 450 kg(N)·hm ^-2 of nitrogen fertilizer, 60 kg·hm ^-2 of water-retaining agent, and 60 kg·hm^-2 of water-retaining agent plus 450 kg(N)·hm ^-2 nitrogen fertilizer increased. There was a significant increase in the accumulation of above-ground winter wheat dry-matter with increasing nitrogen application rate without water-retaining agent. However, winter wheat dry-matter accumulation decreased under water-retaining agent plus excessive nitrogen fertilizer treatment. Winter wheat dry-matter biomass increased from jointing to harvest and the increase was more obvious at the later growth stage under wa-ter-retaining agent with 225 kg(N)·hm^-2 nitrogen fertilizer treatment. From sowing through jointing, booting and grain-filling stages, WUE was boosted by increased nitrogen fertilizer application rate. WUE increased significantly under water-retaining agent plus nitrogen fertilizer treatment. Also from grain-filling to harvest, WUE increased by 53.8% and 57.8% over the control (CK) under 450 kg(N)·hm^-2 nitrogen fertilizer and water-retaining agent plus 225 kg(N)·hm^-2 nitrogen fertilizer treatments, respectively. In conclu-sion therefore, the yield and WUE of winter wheat increased and with the best effect under 60 kg·hm^-2 water-retaining agent plus 225 kg(N)·hm^-2-2 nitrogen fertilizer application.