天山雪岭云杉林土壤CNP化学计量特征随水热梯度的变化

生态化学计量学是研究有机体所需碳(C)、氮(N)、磷(P)等营养元素之间多重平衡关系的科学。本研究以天山雪岭云杉林为研究对象,分析土壤C、N、P化学计量的特征及其与温度和降水的关系,并利用冗余分析(Redundancy analysis,RDA)技术分析了土壤C、N、P化学计量特征与理化因子的关系。结果表明,0—10 cm层C、N、P含量的变化范围分别是44.6—143.4、0.190—0.940、0.086—0.286 g/kg,10—30 m层C、N、P含量分别介于23.0—131.0、0.122—0.589、0.032—0.178 g/kg之间,30—80cm层三者的变化范围分别为14.5—67.0、0.149—0.397、0.062—0.169 g/kg。0—10 cm层C、N、P含量与年均温度存在显著的相关关系,0—10 cm和10—30 cm层P含量与年降水量之间的相关性显著; 0—10 cm层C∶P比与年均温度之间存在显著线性关系,0—10 cm与10—30 cm层N∶P比均随年均温度和年降水量的增大而增大。冗余分析结果表明,在0—30 cm层中,土壤含水量和容重是土壤C、N、P化学计量特征的主要驱动因子,土壤含水量与C∶P和N∶P值成正相关关系,容重与N∶P值成负相关关系;在30—80 cm层中,土壤含水量和土壤粘粒含量是土壤C、N、P化学计量特征的主要驱动因子,土壤含水量与N和P值成正比,容重与C、C∶N、C∶P和N∶P成正比,与N和P成反比;电导率和pH对土壤C、N、P化学计量特征的影响并未达到显著程度,可能是研究区土壤的电导率和pH的差异较小。

Stoichiometric characteristics of Picea schrenkiana forests with a hydrothermal gradient and their correlation with soil physicochemical factors on Tianshan Mountain

Ecological stoichiometry focuses on the equilibrium relationships among carbon (C), nitrogen (N), phosphorus (P), and other nutrients that required by organisms. The present study firstly investigated the soil C, N and P concentrations and their stoichiometric characteristics in Picea schrenkiana (Schrenk''s spruce) forests. Then we evaluated the relationships between these concentrations and stoichiometric characteristics with mean annual temperature (MAT) and mean annual precipitation (MAP). Finally, redundancy analysis (RDA) was used to study relationships between soil stoichiometry and soil C, N and P stoichiometry. The results showed that the C, N, and P concentrations in the 0-10 cm soil layer were 44.6-143.4, 0.190-0.940, and 0.086-0.286 g/kg, respectively; the concentrations were lower with 23.0-131.0 g/kg for C, 0.122-0.589 g/kg for N, and 0.032-0.178 g/kg for P in 10-30 cm depth, compare with 0-10 cm depth. In 30-80 cm depth, C, N, and P concentrations were 14.5-67.0, 0.149-0.397, and 0.062-0.169 g/kg, respectively. C, N, and P concentrations in 0-10 cm soils were significantly correlated with MAT, P concentrations in 0-10 and 10-30 cm soils have significant relationships with MAP. C:P ratios of 0-10 cm soils was linearly correlated MAT. N:P ratios in 0-10 and 10-30 cm soils increased with MAT and MAP. The RDA showed that in the 0-30 cm soils, C, N, and P stoichiometry were mainly affected by soil moisture content and bulk density, soil moisture content was positively correlated with C:P and N:P ratios, soil bulk density was negatively correlated with the N:P ratio. In 30-80 cm soils, C, N, and P stoichiometry were primarily driven by soil moisture content clay content. Specifically, soil moisture content was positively correlated to N and P concentrations, bulk density was positively correlated to C, C:N, C:P, and N:P ratio and negatively to N and P concentrations. Additionally, we did not found significant relationships between electrical conductivity and pH with C, N, and P stoichiometry, which could be due to the non-significant difference in soil EC and pH in our study area.