三江平原大豆田蒸散特征及能量平衡研究

试验研究三江平原大豆田蒸散规律、水分利用效率及辐射收支和能量平衡研究结果表明 ,三江平原 5～ 9月份农田蒸散力基本与降雨量持平 ,正常年份作物生育期内降雨量能满足农田蒸散量的需求 ,大豆田蒸散量变化与大豆叶面积指数的变化呈相关性。大豆生育期内净辐射通量占总辐射的比例有所变化 ,播种～苗后期其比值约为 50 %左右 ,开花～结荚期约为 60 % ,灌浆～收获期约为 55%。大豆田能量平衡具有明显日变化与季节变化特征 ,净辐射收入的 90 %以上用于潜热消耗 ,而用于感热通量与土壤热通量的消耗则极少 ,整个生长季分别低于1.5%和 10 %。

Characteristics of evapotranspiration and energy budget of soybean field in the Sanjiang Plain

The evapotranspiration, water use efficiency, radiatio n budget and energy balance of soybean field in the Sanjiang Plain are analyzed in this paper. The results show that the evapotranspiration capabilities of farmla nd are equal to precipitation during the crop growth season, the change of soybe an field evapotranspiration is similar to the change of leaf area index. The ratio s of net radiations to total radiation are different in different soybean growth stages and the value is 50% in the sowing and seedling stage, increases to 60% in the florescence and bear pods, finally decreases to 55%in the milking and har v esting time. The energy balance of soybean field has daily change and seasonal v ariation, the latent heat consumes 90% of net radiation, the sensible heat and t he soil heat flux are very small during the soybean growth season, and the value s respectively are below 1.5% and 10%.