垄植沟灌夏玉米棵间蒸发试验研究

Experiment on soil evaporation of summer maize in furrow irrigation

为了探明沟灌夏玉米农田棵间蒸发规律,采用自制不同直径的棵间蒸发皿在夏玉米全生育期内分别于每天早上8点加以观测,对不同水分下限条件下沟灌夏玉米大田总蒸发量及垄面、沟面蒸发量进行了试验研究.结果表明沟灌夏玉米棵间蒸发量随着土壤水分下限降低呈减少的趋势,在全生育期内棵间蒸发在拔节前占很大比例,苗期和拔节期农田棵间蒸发量各占蒸腾量的90%和40%左右;拟合不同水分处理沟面和垄面蒸发的线性方程,相关系数在0.8以上;最后对比苗期和抽雄后期垄沟蒸发过程,两者都随着时间推移呈减小的趋势.垄面蒸发和沟面蒸发的比例约为20∶13,这为以后沟灌夏玉米农田土壤水分循环模拟提供了数据参考,在沟灌夏玉米农田蒸发中,应在拔节期前控制棵间蒸发量达到节水的目的.

In order to explore the law of the soil evaporation in summer maize farmland under furrow ir- rigaton, the experiment on the evaporation capacity of summer maize farmland soil and that of ridge and ditch under different furrow irrigation controlling lower limits was conducted . The results show that the evaporation capacity of summer maize farmland soil reduce with the decreasing of soil moisture. Soil evaporation took up a great proportion before the jointing stage in the whole growth period. Soil evaporation capacity at the seedling stage and the jointing stage accounted for 90% and 40% in the transpiration capacity respectively. The linear regression equation for the evaporation of ridge and ditch under different water treatments was fitted, the correlation coefficients were over 0. 8, and finally soil e-vaporation after an irrigation after the heading stage and at the seedling stage of summer maize was compared,both of soil evaporation had a decreasing tendency with the lapse of time. The evaporation ratio of ridge to ditch was maintained at about 20：13 ,which will provide a reference for soil water cycle simulation of summer maize farmland under furrow irrigation. In farmland evaporation of summer maize under furrow irrigation, soil evaporation capacity should be controlled before the jointing stage in order to save water.