不同沼泽湿地土壤碳氮磷生态化学计量学特征及其影响因素

Characteristics and determining factors for ecological stoichiometry of soil carbon,nitrogen,and phosphorus in different marsh wetlands

干旱区湿地在改善地区生态环境,维护地区生态稳定等方面发挥着重要作用,研究干旱区湿地土壤碳(C)、氮(N)、磷(P)等元素的生态化学计量学特征,有助于深入了解干旱区湿地土壤养分的供给能力及循环与平衡机制。本文以河西走廊西段,疏勒河中下游的草本沼泽(T1)和季节性咸水沼泽(T2)土壤为研究对象,分析了这两种沼泽湿地土壤C、N、P生态化学计量学特征及其影响因素。结果表明:①0~100 cm土壤C/N、N/P、C/P均为T2(15.07,5.94,98.01)>T1(12.49,2.50,30.22);随土层深度的增加,土壤C/N、N/P、C/P均在T1有两个峰值(0~10 cm和中间层),T2有一个峰值(中间层)。②0~100 cm土壤C/N、N/P、C/P空间变异性大,且均为T2>T1。③T1和T2土壤的N/P与土壤水分呈极显著正相关(P<0.01),C/P与土壤水分、全N呈极显著正相关(P<0.01),与碱解N呈显著正相关(P<0.05);T2土壤C/N、N/P、C/P与土壤容重呈极显著正相关(P<0.01),C/N与土壤水分呈极显著的正相关(P<0.01),N/P与土壤有机C呈显著正相关(P<0.05);T1土壤N/P与土壤有机C呈极显著正相关(P<0.01)。④土壤水分是影响两种沼泽湿地土壤C、N、P计量比的关键因子。因此,保护干旱区湿地土壤关键在于采取合理的节水用水措施,该结果可为干旱区湿地土壤保护、管理以及生态恢复提供科学依据。

Wetlands play an important role in improving the regional ecological environment and maintaining regional ecological stability in arid regions.Studying the ecological stoichiometric traits of wetland soils is therefore conducive to understanding soil nutrient supply capacity and the recycling and balance mechanisms of soil carbon(C),nitrogen(N),and phosphorus(P)in arid wetlands.This study collected soil samples from herbaceous marsh(T1)and seasonal saline marsh(T2)located in the west section of Gansu Corridor,from the middle and lower reaches of the Shule River,and analyzed their traits in order to determine the key factors affecting the ecological stoichiometry of soil C,N,and P.The results showed that:(1)At 0-100 cm soil depths,the C/N,N/P,C/P ratios of T2 soils(15.07,5.94,98.01)were greater than those of T1 soils(12.49,2.50,30.22).With increasing soil depth,C/N,N/P,C/P exhibited two peaks in T1(0-10 cm and interlayers)and one peak in T2(interlayer)soils.(2)At 0-100 cm soil depths,C/N,N/P,C/P showed large spatial variability with the coefficient of variance(CV)being greater in T2 than in T1.(3)At both T1 and T2,soil N/P was significantly positively correlated with soil moisture(P<0.01),C/P was significantly positively correlated with both soil moisture and soil total nitrogen(P<0.01),and also with alkali-hydrolyzable nitrogen(P<0.05).At T2,soil C/N,N/P,C/P were significantly positively correlated with soil bulk density(P<0.01),C/N was significantly positively correlated with soil moisture(P<0.01),and N/P was significantly positively correlated with soil organic carbon(P<0.05).At T1,soil N/P was also significantly positively correlated with soil organic carbon(P<0.01).(4)Soil moisture was found to be the key factor affecting the ecological stoichiometric ratios of soil C,N,and P in both marsh wetlands.As a result,the key to wetland protection in arid areas is to adopt reasonable measures for saving water.These results provide a scientific basis for soil protection,management,and the ecological restoration of wetlands in arid regions.