塔里木河下游地下水及土壤对胡杨林长势的影响

Effects of Groundwater and Soil on the Growth of Populus euphratica Forest in Lower Reaches of Tarim River

胡杨(Populus euphratica)是塔里木河重要的物种之一,也是抑制荒漠化进程的“绿色守卫者”。采用样方调查结合取样测试的方法,获取了塔里木河下游恰拉水库至英苏段16个样方的林分因子及水土理化参数。利用单因素方差分析、聚类分级、相关分析的方法研究了地下水及土壤因子对胡杨长势的影响。结果表明:塔里木河下游不同长势胡杨的林分因子差异显著,长势良好的胡杨平均胸径22.51 cm、树高7.26 m、冠幅3.44 m,均明显高于长势极差、较差的样方。受塔里木河影响,林分因子随河道距离增加呈波浪递减的趋势。古河道附近的胡杨通常拥有较大的树高及冠幅,但长势较差,若不加以治理将很快枯萎。地下水理化性质对胡杨长势的影响均显著高于土壤化学性质,其中地下水埋深、距河道的距离对胡杨长势的影响最为显著,相关系数分别为0.922、0.898,80 cm<h≤120 cm土层土壤全盐量对胡杨长势的影响次之,相关系数为0.871。

Populus euphratica is one of the important species in the Tarim River and also a“green guardian”to suppress the process of desertification.Using the method of sample investigation combined with sampling testing,the forest stand factors and soil and water physicochemical parameters of 16 sample plots from the Qiala Reservoir to Yingsu section in the lower reaches of the Tarim River were obtained.The effects of groundwater and soil factors on the growth of P.euphratica were studied using one-way ANOVA,cluster classification,and correlation analysis methods.The results showed that there were significant differences in stand factors of P.euphratica with different growth conditions in the lower reaches of the Tarim River.The average diameter at breast height,tree height,and crown width of P.euphratica with good growth conditions were 22.51 cm,7.26 m and 3.44 m,respectively,which were significantly higher than those of the samples with extremely poor or poor growth conditions.Affected by the Tarim River,the forest factor shows a wave decreasing trend with the increase of river distance.P.euphratica near the ancient river channel usually has a large tree height and crown width,but its growth is poor,and if left untreated,it will quickly wither.The physical and chemical properties of groundwater have a significant impact on the growth of P.euphratica compared to soil chemical properties.Among them,the depth of groundwater burial and the distance from the river channel have the most significant impact on the growth of P.euphratica,with correlation coefficients of 0.922 and 0.898,respectively.The total salt content of soil in the 80 cm<h≤120 cm soil layer has a second effect on the growth of P.euphratica,with a correlation coefficient of 0.871.