不同灌水条件对侧柏蒸散量和生长的影响

Influence of Different Irrigation Conditions on Evapotranspiration and Growth of Oriental Arborvitae

为了定量研究侧柏[Ptadtyctadus orientates(L.)Franco]蒸散耗水量与生长的关系,通过控制土壤含水率上下限,进行了盆栽试验研究。试验共设置9种水分处理,结果表明:侧柏的灌水量越多,日蒸散量与累积蒸散量越大。75%～100%FC(田间持水量)时的累计蒸散量最大,达1 075mm。生育期内,株高、冠幅日平均生长量随时间均呈逐渐降低趋势。株高受蒸散量的影响较冠幅显著。鲜(干)叶重、鲜(干)枝重、地上鲜(干)物重、枝含水率、叶含水率均随蒸散量的增加呈现开口向下的二次抛物线规律变化。在最大灌溉量75%～100%FC条件下,鲜(干)叶重均未达到最大生物积累量,而鲜枝重、干枝重、枝含水率在65%～100%FC时达最大值。蒸散量较低时,以株高、冠幅、生物量表示的水分利用效率均较高。对比9种水分处理的生物量,考虑株高与冠幅生长量及其水分利用效率,认为侧柏最佳灌溉量控制区间为45%～100%FC。

In order to quantitatively study the relationship between the evapotranspiration water consumption of oriental arborvitae and its growth, the pot experiment, in which nine kinds of water treatment are set, is conducted through controlliug the lower and upper limit of soil moisture content. The results show that the more irrigation of oriental arborvitae, the greater evapotranspiration and cumulative evapotrans- piration. The largest cumulative evapotranspiration amounts to 1 075 mm（ 75%FC-100%FC ）. During the growth period, the average change of height and crown show gradually decreasing tendency over time The effect of evapotranspiration on plant height is more significant than on crown. The changes of fresh （dry） leaf weight, the fresh （dry） branches weight, dry branches weight and the branches moisture show second-degree parabola shape rules with the increase of evapotranspiration. Under the condition of maximum irrigation amounting 75% -100%FC, the fresh （dry） leaf weight does not reach the maximum accumulation of organic matter. While under the condition of irrigation amounting 65 % -100 %FC, the fresh branches weight, dry branches weight and the branches moisture reach the maximum value The water use efficiency, which is represented by plant height, crown and hiomass, is higher under the lower evapotranspiration. Contrasting the bio- mass change of nine kinds of water treatment and comprehensively considering the change of height and crown diameter and WUE, it is con- sidered that the optimal irrigation range for oriental arborvitae is at 45%-100%FC.