新疆干旱区4种柽柳灌丛碳贮量特征

Carbon storage characteristics of four different Tamarix L. shrubs in the arid land of Xinjiang Province

灌丛有机碳贮量对研究干旱区土壤特性及碳循环具有重要意义。以分布于新疆南北疆荒漠区的4种柽柳灌丛(多花柽柳Tamarix hohenackeri、多枝柽柳Tamarix ramosissima、刚毛柽柳Tamarix hispida、沙生柽柳Tamarix taklamakanensis)为研究对象,对其生物量碳和土壤有机碳的分布特征进行了研究。结果表明:1)生物量碳密度从大到小顺序为刚毛>多花>沙生>多枝,生物量碳密度在0.59—2.35 Mg C/hm^2之间,其中,地上生物量碳密度在0.31—0.94 Mg C/hm^2之间,0—100 cm地下植物碳密度在0.28—1.49 Mg C/hm^2之间,根冠比在0.92—1.71之间。2)土壤有机碳密度从大到小的顺序是多花>刚毛>沙生>多枝,多花和沙生柽柳灌丛土壤有机碳密度的最大值出现在表层0—10 cm,多枝和刚毛柽柳灌丛土壤有机碳密度的最高值出现在土层深度为10—20 cm处。4种柽柳灌丛0—10 cm土层土壤有机碳含量在13%—43.7%之间,地下1 m内,0—50 cm土壤有机碳密度所占比例为82.3%—96.4%之间。3)根据分布面积计算,新疆荒漠区4种柽柳灌丛碳贮量在(0.28±0.03)—(56.96±5.36)Tg(1Tg=10^(12)g)之间,总有机碳贮量为(75.00±6.76)Tg。其中,有机碳贮量最多的是刚毛柽柳灌丛,多花柽柳最低。4)4种柽柳灌丛土壤有机碳和生物量碳均表现出了与土壤含水量和土壤有机质的显著相关性,土壤有机碳(C_s)与土壤含水量(X_1)、有机质(X_2)、全N含量(X_3)和电导率(X_4)呈极显著正相关(P<0.01),多元线性回归方程为C_s=3.433-10.943X_1+0.378X_2-2.935X_3+0.017X_4;生物量碳(C_p)与土壤含水量、有机质呈显著正相关(P<0.05),多元线性回归方程为C_p=2.042-11.930X_1+0.011X_2。说明不同类型的柽柳对水分和有机质的要求不同,碳汇能力和对荒漠生态系统的作用也不同。因此,从物种利用角度来看,选择也应有所侧重。

Organic carbon storage of shrubs is significant in research concerning soil properties and carbon cycle in arid land. However, few studies have investigated both biological biomass carbon （BBC） and soil organic carbon （SOC） of shrubs. In the present study, four different Tamarix L. shrubs （Tamarix hohenackeri, Tamarix ramosissima, Tamarix hispida, and Tamarix taklamakanensis） distributed in the arid land of Xinjiang were chosen as research samples. The aim of the present study is to compare the distribution characteristics of biological biomass carbon, soil organic carbon, and carbon storage of four kinds of shrubs. We investigated 23 sample plots （100 m×100 m） of four different Tamarix L. shrubs in Southern and Northern Xinjiang. We randomly chose three quadrats （10 m×10 m） to obtain the aboveground biomass in each sample plot and dug three sample pits （1 m×1 m） divided into 0-10, 10-20, 20-30, 30-40, 40-50, and 50-100 cm five soil layers. We calculated the biological biomass carbon density （BBCD） and soil organic carbon density （SOCD） to obtain the underground biomass, soil physical and chemical properties, and carbon storage according to the distribution area from the ＂vegetation map of Xinjiang＂. The results showed that： 1） T. hispida had the highest density of plant biomass carbon, followed by T. hohenackeri, T. taklamakanensis, and T. ramosissima. The value of plant biomass carbon density was between 0.59 and 2.35 Mg C/hm^2. The aboveground biomass carbon density was between 0.31 and 0.94 Mg C/hm^2, and the underground biomass carbon density was between 0.28 and 1.49 Mg C/hm^2 of 0-100 cm depth. The root shoot ratio was between 0.92 and 1.71. 2） The SOC value from big to small included T. hohenackeri, T. hispida, T. taklamakanensis, and T. ramosissima. The maximum SOCD value of T. hohenackeri and T. taklamakanensis was 0-10 cm soil layer, and the maximum SOCD value of T. hispida and T. ramosissima was 10-20 cm soil layer. The SOC value of 0-10 cm soil layer was 13%-43.7%, and the SOC value of 0-50 cm soil layer was 82.3%-96.4% from the surface of soil to 100 cm depth. 3） According to the distribution area of four Tamarix L. shrubs in the arid land of Xinjiang, the carbon storage value was between 0.28±0.03 Tg and 56.96±5.36 Tg, and the whole carbon storage value was between 75.00±6.76 Tg. The maximum carbon storage was T. hispida, and the lowest was T. hohenackeri. 4） A significant correlation was presented between BBC, SOC, soil water content, and soil organic matter （SOM）. SOC （Cs） had a distinct positive correlation with soil water content （X1）, SOM （X2）, total nitrogen （TN, X3）, and conductivity （X4） （P〈0.01）; the multiple linear regression equation was calculated as Cs=3.433-10.943X1＋0.378X2-2.935X3＋0.017X4. BBC （Cp） had a positive correlation with soil water content and SOM （P〈0.05）;the multiple linear regression equation was calculated as Cp=2.042-11.930X1＋0.011X2. The results show that different types of Tamarix L. have different requirements of water and organic matter, and their carbon sequestration capacity and effect on the desert ecosystem were different. Therefore, in terms of utilization, the selection needs to be focused on different characteristics of plants.