推迟拔节水及其灌水量对小麦耗水量和耗水来源及农田蒸散量的影响

Effects of Delayed Irrigation at Jointing Stage and Irrigation Level on Consumption Amount and Resources of Water in Wheat and Farmland Evapotranspiration

于2007—2008和2008—2009小麦生长季,以高产中筋冬小麦品种济麦22为材料,采用测墒补灌的方法,研究推迟拔节水及不同灌水水平对冬小麦耗水量、耗水来源、单位土地面积上旗叶叶面积和蒸腾速率、株间蒸发量、籽粒产量及水分利用效率的影响。结果表明,测墒补灌后0～140cm土层能够达到目标含水量。相同补灌时期,随补灌水平的提高,拔节至开花阶段日耗水量增大,0～120cm土层贮水消耗量减小,生育期总灌水量和田间耗水量增加,土壤贮水消耗量先增加后减小,土壤贮水消耗量和降水量占田间耗水量的比例降低。相同补灌水平,由拔节期推迟至拔节后10d补灌则麦田日耗水量减小,挑旗期日耗水量增大,拔节至开花阶段80～120cm土层土壤贮水消耗量增加,生育期总灌水量和田间耗水量亦增加,降水量、灌水量和土壤贮水消耗量占田间耗水量的比例不变;灌浆初期单位土地面积上旗叶叶面积和蒸腾速率降低,株间蒸发量增加;公顷穗数降低,穗粒数、千粒重、籽粒产量、水分利用效率和灌水生产效率增加。本试验条件下,在拔节后10d补灌至0～140cm土层平均土壤相对含水量为75%,开花期补灌至70%(2007—2008年度)是兼顾节水、高产的最优处理。

Water-saving irrigation is a hotspot in cultivation research of winter wheat （Triticum aestivum L.）. Many investigations have been carried out to reduce the irrigation frequency and water amount. However, the conclusions are quite different due to the great discrepancies on precipitation and experimental condition. In this study, a strategy of water-controlled irrigation based on measuing soil water content was adopted, and several delayed irrigation treatments were tested for their effects on water con- sumption, water use efficiency （WUE）, and wheat yield in two sites of Shandong province, China in 2007-2008 and 2008-2009 growing seasons. The expected water content of 0-140 cm soil layer was designed for 65-80% in different treatments, and two irrigations were given at jointing or 10 d after jointing and flowering stages. In the treatments irrigated at the same time, the daily water consumption from jointing to flowering stage and the water consumption amount in the whole growth duration increased with promoting the level of supplemental irrigation, but the soil water consumption amount in 0-120 cm soil layer decreased. The consumption amount of soil water showed an increase-decrease trend, and its percentage to the total water consumption amount decreased. Simultaneously, the comsumption percentage of precipitation to the total water consumption amount was also reduced. Under the same irrigation level, compared with normal irrigation at jointing, the delayed irrigation （at 10 d after jointing） reduced the daily water consumption from jointing to 10 d after jointing stage, but promoted the daily water consumption at flagging stage. From jointing to flowering stage, the comsumption amont of soil water in 80-120 cm soil layer, the total water comsumption amount increased with the more irrigation water supplied. However, the comsumption percentages of precipitation, supplemental irrigation, and soil water were in minor changes. At early filling stage, the flag leaf area and the transpiration per unit area of soil decreased and the evaporation increased in the delayed irrigation treatment. Although reduced spike number per hectare, the grain number, thousand-grain weight, grain yield, WUE, and irrigation production efficiency were higher in the delayed irrigation treatment than in the treatment of irrigation at jointing stage. Under the experimental condition （2007-2008 growing season）, the first supplemental irrigation at 10 d after joining with a relative water content of 75% in 0-140 cm soil layer and the second irrigation at flowering with a relative water content of 70% were considered to be an optimal water-saving management for wheat high-yielding production.