干旱区不同供水量下杨树水分效应和生态用水量研究

Study on Moisture Effects and Ecological Water Consumption of Poplar Stands under Different Water Supply in Arid Area

水分是干旱区林木生长的主要限制因子,科学地确定林木的合理供水量是林木获得速生丰产的关键。以乌兰布和沙区的小美旱杨为研究对象,探讨了不同供水量与土壤环境及小美旱杨生长指征的相互关系,结果表明:不同供水量下土壤的增湿效应存在显著差异,1 500m3/(hm2.a)和3 000m3/(hm2.a)的供水量下的水分补给层主要在50cm以上土层,而4 500,6 000,7 500m3/(hm2.a)供水量下的水分补给层则为70cm以上土层;不同处理间各月土壤含水量差异均随供水量的增加而递减,在供水量不变的条件下,随着林龄的增加,耗水量逐年递增;土壤贮水量、土壤有效含水量、田间持水量、生态用水量、叶片鲜重、蒸腾速率、最佳含水量均随供水量增加而增加,土壤温度随供水量增加而递减,其降温幅度在0.31～1.24℃之间。

Water is the main limiting factor for forest growth in arid region.Scientific determination of reasonable water supply is the key to achieve the fast-growth and high-yield of forest trees.Populus popular′s of Ulan Buh sandy area was selected as the study object to explore the relationship between the different water supplies and soil environment,growth indications of Populus popular′s.The result showed as follows： there were significantly differences of humidification effect of soil between different water supply amounts.Water supply layer mainly occurred in soil layer of 0-50 cm with water addition of 1 500 m3/（hm2·a） and 3 000 m3/（hm2·a）,whereas it occurred in soil layer of 0-70 cm with the water supply rates of 4 500,6 000 and 7 500 m3/（hm2·a）.Soil moisture differences of each month between the different treatments were decreasing with the increase of water supply.Water consumption has been increasing year by year with increase of the stand age under the same water supply rate.Soil water storage,soil available water,field capacity,ecological water consumption,leaf fresh weight,transpiration rate and the optimum moisture content index increased with the increase of the water supply quantity.Soil temperature decreased with the increases of water supply quantity,and drop range of temperature was between 0.31 and 1.24℃.