乌兰布和沙区不同供水量下杨树林地土壤水分和温度效应研究

The Effects of Soil Moisture and Temperature for Poplar Forest Land Under Different Water Supply in the Ulanbuh Sandy Area

为了提高干旱区水资源利用率,确定沙区杨树人工速生林的合理供水量,实现杨树人工林的科学化管控目标,通过4年定位观测试验,研究了乌兰布和沙区‘小美旱杨’林地不同年供水量（1500、3000、4500、6000、7500m3/hm2）下的土壤水分和温度效应。结果表明,不同供水量对土壤的增湿效应存在差异。各土层、各月土壤含水量均随供水量的增加而增加;最大年供水量的土壤含水量峰值出现在7月,而其他的出现在6月;‘小美旱杨’速生丰产的年供水量阈值为7500m3/hm2,它能使剖面土壤水分补给层达70cm以上,且补给层以及6—9月高温时期的土壤含水量均保持在20%以上;供水量越大,土壤含水量随树龄增加而降幅越大。年供水量每增加1500m3/hm2可提高土壤贮水量4.69%~7.43%,增加土壤有效含水量1.42%~15.5%;供水量对田间持水量影响不明显;随供水量的增加,土壤水分亏缺明显趋于平缓,土壤温度递减,在同一土层内下降1.66~3.26℃,沿剖面向下降低8.64~9.66℃。最小和最大供水量应分别在4月低温期和7月高温期进行,以满足林木生长的水分和温度之需。

In order to improve the efficiency of water resources in arid areas, make sure the area of poplar artificial mill reasonable water supply, and realize the goal of poplar plantation scientific control, based on 4-year term located experiment of supplying different annual water supply capacity （1500 m3/hm2, 3000 m3/hm2, 4500 m3/hm2, 6000 m3/hm2 and 7500 m3/hm2）, it was investigated on effects of soil moisture and temperature for forest land of Populus popular’s in the Ulanbuh sandy area. The results showed that： soil humidifying effects of poplar forest land differed significantly among 5 treatments of different annual water supplied. Soil water content of every soil layer and every month increased with the increase of annual water supply. The peak value of soil water content for the maximum annual water supply happened in July and the others happened in June. Fast-growing poplar’s annual water supply threshold was the 7500 m3/hm2, this annual water supply could make recharge layer of soil water maintain above 70 cm depth, and could make soil water content of recharge layer and high temperature period （6-9 months） remained above 20% . Increasing water supply, the decreasing amplitude of soil water content would be enlarged along with the increase of stand age. Each additional water volume of 1500 m3/hm2 could raise 4.69%-7.43% of water storage content and 1.42%-15.5% of effective soil water content. The effect of water supply on field water capacity was unremarkable. With the increase of water supply, the value of soil water deficit mitigated significantly, and soil temperature reduced 1.66-3.26℃ within the same soil layer and reduced 8.64-9.66℃ down along soil profile. Water supply of minimum and maximum should be carried out in April （low-temperature period） and in July （high-temperature period） to meet the needs of water and temperature for stands growth.