浑善达克沙地杨树水分利用特征

为探究浑善达克沙地杨树的水分利用特征。本文利用氢和氧同位素示踪技术,测定了降雨、土壤水与地下水的δ18O值,利用多元线性混合模型定量计算了杨树对不同土层土壤水分的利用比例。结果表明:①浑善达克沙地大气降雨方程线为:δDLWML=7.84δ^18OLWML+9.12,斜率比全国降雨方程偏小,体现了研究区降雨少,蒸发大的气候特征;②土壤含水量与地下水位埋深、降雨量、植物生长期的变化有着显著的相关关系。降雨量较大与地下水位埋深较浅的时期,土壤含水量明显增大,在植物生长前期和中期,土壤含水量明显较低;③杨树在雨季,利用了大量的浅层土壤水(0~40 cm),在较为干旱的旱季,利用了大量的深层土壤(160~200 cm)水与少量的地下水。

Analysis of water use characteristics of poplar trees in Otindag Sandy Land

To explore the water use characteristics of poplar trees in Hunshandake Sandland,the δ18O values of rainfall,soil water,and groundwater were determined using hydrogen and oxygen isotope tracing techniques.A multilinear mixed model was used to quantitatively calculate the utilization ratio of poplar to soil water in different soil layers.The results show the following: (1) The atmospheric rainfall equation line of Otindag Sandy Land is δDLWML= 7.84δ^18OLWML+ 9.12,the slope of which is smaller than the national rainfall equation line,indicating that the rainfall in the study area is low,whereas the evaporation is high.(2) There is a significant correlation between soil water content and groundwater depth,rainfall,and plant growth.When rainfall is relatively high and the groundwater level is shallow,the soil water content is markedly increased.In the early and middle stages of plant growth,the soil water content is significantly lower.(3) Poplars use a large amount of shallow soil water (0-40 cm) during the rainy season,whereas they use a large amount of deep soil water (160-200 cm) and a small amount of groundwater during the dry season.