植被盖度对土壤碳、氮、磷生态化学计量比的影响——以敦煌阳关湿地为例

The effect of vegetation cover on ecological stoichiometric ratios of soil carbon,nitrogen and phosphorus: A case study of the Dunhuang Yangguan wetland

土壤碳、氮、磷生态化学计量比可以广泛地指示群落的生态学动态过程,其研究可以为湿地生态系统的恢复与保护提供依据。以敦煌阳关湿地为研究对象,选取53个样地,分层(0—20、20—40 cm和40—60 cm)采集土壤样品,对3种植被盖度类型(高盖度、中盖度和低盖度)的土壤碳、氮、磷生态化学计量比特征及其影响因素进行了研究。结果表明:(1) 0—20、20—40 cm和40—60 cm土层C/N变化趋势均为:高盖度<中盖度<低盖度,C/P、N/P变化趋势均为:低盖度<中盖度<高盖度。(2)高盖度土壤C/N、C/P和N/P均随土层深度的增加而增大;中盖度土壤C/N随土层深度的增加而增大,C/P、N/P随土层深度的增加先减小后增大;低盖度C/N、C/P和N/P均随土层深度的增加先减小后增大。(3) 0—60 cm土层土壤水分与C/N显著负相关(P<0.01),而与C/P、N/P显著正相关(P<0.01),土壤盐分与C/P、N/P均显著负相关(P<0.01),pH与C/P、N/P均显著正相关(P<0.05),TP与C/N呈显著负相关(P <0.05),TN与C/P、OC与N/P均呈极显著正相关(P<0.01)。由多元线性回归分析可知,土壤水分是土壤C/N、C/P和N/P的关键影响因子。

This study provided a basis for the restoration and protection of wetland ecosystems, and the ecological stoichiometric ratios of soil carbon,nitrogen,and phosphorus widely indicated the ecological dynamic processes of the community. The ecological stoichiometric ratios of soil carbon,nitrogen,and phosphorus,and their influencing factors were studied in three cover types using stratified sampling in the Dunhuang Yangguan wetland. The results showed that:(1) The trends of C/N were high < medium < low cover,whereas the trends of C/P and N/P were low < medium < high cover at0- 20,20- 40,and 40- 60 cm soil layers.(2) The soil C/N,C/P,and N/P of high cover increased with increasing soil depth,similarly to the C/N of medium cover,and the C/P,N/P decreased initially and then increased with soil depth,as did the C/N,C/P and N/P of low cover.(3) At 0- 60 cm soil depths,soil moisture was negatively correlated with C/N(P<0.01),but was positively correlated with C/P and N/P(P<0.01). Soil salinity was negatively correlated with C/P and N/P(P < 0.01) at 0- 60 cm soil depths. Soil pH was positively correlated with C/P and N/P(P < 0.05) at 0- 60 cm soil depths. Soil total phosphorus was negatively correlated with C/N(P < 0.05),soil total nitrogen was positively correlatedwith C/P(P < 0. 01),and soil organic carbon was positively correlated with N/P(P < 0. 01) at 0- 60 cm soil depths.Multiple linear regressions showed that soil moisture was the key factor affecting ecological stoichiometric ratios of soil carbon,nitrogen,and phosphorus.