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根据连续8a毛白杨幼林灌溉的技术资料,系统地分析了灌溉效应及其特点。结果表明:灌溉可使毛白杨叶片叶绿素和营养元素含量及其光合作用潜能提高,并可维持较高的生长活力、激发休眠芽萌发、促进叶片生长、加快树体增粗和枝条延长;灌溉对林木生长的促进作用有多面性、相异性、可变性和后效性;灌溉效应可分为生理效应、生长效应、再生长效应和后期效应,光合叶面积的复式增长为其作用核心;灌溉期间随土壤水分阈值提高灌溉效应增加,而停止灌溉后以阈值中等水平的处理后期效应最好。在干旱的4～6月灌溉可使光合叶面积增加3～4倍以上,可使胸径和树高净生长量分别提高30%和40%以上;停止灌溉后的4a内,阈值为50%试验处理的材积生长量平均较对照增加了3967%。
Based on the technical data of continuous cultivation of young Populus tomentosa young plants, the irrigation effect and its characteristics were systematically analyzed. The results showed that irrigation could increase the content of chlorophyll and nutrient elements and the photosynthetic potential of Populus tomentosa and maintain the high growth vigor, stimulate germination of dormant bud, promote the growth of leaves, The promotion effect of tree growth is multifaceted, dissimilarity, variability and aftereffect. Irrigation effect can be divided into physiological effect, growth effect, regrowth effect and later effect. The compound growth of photosynthetic leaf area is the core of its effect. During irrigation The irrigation effect increased with the increase of soil moisture threshold, but the middle-threshold treatment effect after stopping irrigation was the best. During the drought from April to June, the photosynthetic leaf area increased by 3 ~ 4 times, which could increase the DBH and tree height net growth by 30% and 40% respectively. The threshold value was 50% after 4 days of irrigation stopped The average volumetric growth of treatments increased by 3967% compared with the control.