深圳市3种灌木单株蒸散量及作物系数的研究

Study of Evapotranspiration and Crop Coefficients of Three Shrub in Shenzhen

[目的]测定深圳市3种常见灌木在不同灌水梯度下的蒸散量,并确定其作物系数,为深圳市园林灌木的合理灌溉提供理论依据。[方法]盆栽试验,4种灌水梯度分别为田间持水量的45%-30%、60%-45%、75%-60%和90%-75%。利用称重法测定4种灌水梯度下3种灌木的实际蒸散量,同时利用Makkink方法计算参考作物蒸散量,确定3种灌木的作物系数。[结果]3种灌木的蒸散量均随灌水梯度的增加而增加,灌水量多,蒸散量就多。金叶假连翘和龙船花的蒸散量曲线呈现单峰型,变叶木的蒸散量曲线呈现双峰型。3种灌木的蒸散量排列顺序为：金叶假连翘〉变叶木〉龙船花。变叶木、金叶假连翘、龙船花作物系数的变化范围分别为0.97-1.82、0.95-2.17、0.90-1.58。[结论]确定3种灌木在不同月份和不同灌水梯度下的蒸散量和作物系数。

[Objective]Evapotranspiration and crop coefficients of three shrub under different water gradients in Shenzhen were measured to provide theoretical foundation for rational irrigation of shrub in Shenzhen.[Method]The test was pot experiment.Four water gradients were 45%-30%,60%-45%,75%-60% and 90%-75% of field capacity.The actual evapotranspiration and reference crop evapotranspiration was measured with weight method and Makkink method,respectively.[Result]The evapotranspiration of three shrub increased with increasing of water gradient.The evapotranspiration curve of Duranta repens cv.Dwarf Yellow and Ixora chinensis was single peak curve.And evapotranspiration curve of Codiaeum variegatum was double peak curve.The evapotranspiration order of three shrub was summerized as follows：Duranta repens cv.Dwarf Yellow Codiaeum variegatum Ixora chinensis.The range of crop coefficients of Codiaeum variegatum,Duranta repens cv.Dwarf Yellow and Ixora chinensis were 0.97-1.82,0.95-2.17 and 0.90-1.58,respectively.[Conclusion]The evapotranspiration and crop coefficients of three shrub under different water gradient and in different months were determined.