基于大型蒸渗仪的1年2作滴灌小麦-玉米耗水特征

Water Consumption Characteristics of Wheat-maize Double Cropping under Drip Irrigation Based on Large-scale Lysimeter

利用大型称质量式蒸渗仪,分析了滴灌条件下小麦-复玉米蒸散耗水过程。结果表明,中等灌水条件下,滴灌小麦-玉米蒸散耗水总量为777.93mm,其中小麦耗水占45.8%,玉米耗水占54.2%,小麦拔节期和抽穗期耗水量为188.03mm,占1年2作耗水总量的24.2%,玉米拔节期和抽雄期耗水量为235.42mm,占1年2作耗水总量的30.26%;1年2作滴灌小麦-玉米全生育期平均耗水强度为4.25mm/d,其中小麦、复播玉米平均耗水强度分别为3.93、4.57mm/d。不同天气状况下玉米蒸散耗水强度的差异大于小麦,玉米蒸散日变化具有明显"午休"现象。滴灌小麦-玉米受各气象因子的影响不同,春小麦和夏玉米蒸散强度与各气象因子的相关性分别表现为净辐射>相对湿度>30cm土壤水分>总辐射>光合辐射>日平均气温>风速和相对湿度>光合辐射>净辐射>30cm土壤水分>总辐射>风速>日平均气温。

Water consumption processes in wheat-maize double cropping under drip irrigation were studied using large-scale weighing lysimeter. The results showed that under moderate irrigation, the total water consumption of wheat-maize double cropping was 777.93 mm, of which 45.8% was consumed by wheat and 54.2% was consumed by maize. In the elongation and heading stages of wheat, water consumption was 188.03 mm, which was 24.2% of the total consumption of the double cropping system. In the elonga- tion and tasseling stages of maize, water consumption was 235.42 mm, which was 30.26% of the total consumption of the system. The average water consumption intensity in the whole growth period of the wheat-maize double cropping system under drip irrigation was 4.25 mm/d. The average water consumption intensity of wheat was 3.93 ram/d, which was 14% lower than that of maize （4.57 ram/d）. The difference of maize water consumption intensity was bigger than that of wheat under different weather conditions, and the daily evapotranspiration changes of maize had obvious ＂noon break＂ phenomenon. Meteorological factors had different effects on wheat-maize with drip irrigation, and the relative coefficients were that net radiation〉relative humidity〉soil moisture in the 0〉30 cm layer〉total radiation〉photosynthetic radia- tion〉average daily air temperature〉wind speed and relative humidity〉photosynthetic radiation〉net ra- diation〉soil moisture in the 0〉 30 cm layer〉total radiation〉 wind speed〉average daily air temperature for wheat and maize, respectively.