丘陵旱地冬小麦大田和原状土柱模拟耗水量研究

在丘陵旱地对冬小麦进行了大田和原状土柱模拟耗水量研究.结果表明:在大田情况下,小麦4500～6000 kg/hm2产量水平,耗水量216.3～345.2 mm,播种-返青、返青-抽穗、抽穗-成熟不同生育阶段耗水分别占总耗水量的25.9%～36.9%,22.0%～31.1%,31.9%～52.2%,但年际间变幅较大;小麦拔节以后耗水量和耗水强度明显增加,拔节期、灌浆期是小麦两个重要的水分需求期.原状土模拟情况下,冬小麦总耗水量中,丰水年型自然降水占77.2%,平水年型自然降水占67.1%,缺水年型自然降水占64.0%.从作物阶段耗水测定结果看,丰水年型情况下,冬小麦存在奢侈耗水现象;平水年型自然降水能基本满足冬小麦水分需求,突出问题是阶段性、间隙性水分缺乏;缺水年型情况下,自然降水不能满足冬小麦的水分需求,突出问题主要表现为一是水分状况制约着冬小麦正常播种和出苗,二是水分供应状况影响作物的生长发育进程.

Study on Water Consumption of Winter Wheat Field and Millet Using Undisturbed Soil Columns on Dry-land in Hilly Areas

A field experiment was carried out to study the water consumption of wheat in dry-land in hilly region in Henan Province. When wheat yield was 4500-6000 kg/hm2, water consumption was 216.3-345.2 mm. The water consumption percentage in different growth periods was 25.9%-36.9% between seeding and reviving stages, 22.0%- 31.1% between reviving and heading stages, and 31.9%-52.2%. The water consumption density increased drama- tically after jointing stage. The jointing and seed filling stages were two important periods for wheat water consump- tion. The simulating results showed that precipitation of winter wheat in rainy years accounted for 77.2% of the total water consumption, 67.1% in normal years, and 64.0% in dry years. From the results of water consumption stage of crops,luxury water consumption was observed in summer crop season in rainy years,and precipitation could basically meet the demand of autumn crop growth in normal years. Natural precipitation in dry years could not supply enough water for summer and autumn crops, resulting in delaying sowing time, germinating and growth process.