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筑坝扩容导致湿地面积增加。基于筑坝前后变化,沿淹水梯度采集土壤,了解高原湿地拉市海有机质和全氮分布的现状,比较筑坝蓄水前后有机质和全氮的差异性。结果表明:筑坝蓄水后淹水区土壤有机质和全氮均比未淹水土壤有所增加,同时随着淹水强度的加强,有机质和全氮含量都表现为先增加后减少的趋势;就同一淹水梯度而言,受人为干扰较严重的土壤(弃耕地土壤)有机质和全氮含量显著低于干扰较小的土壤(草甸土壤)。方差分析表明,有机质和全氮含量在干湿交替的季节性淹水区差异不显著(P>0.05),在常年淹水区则差异显著(P<0.05)。相关性分析表明,研究区域内淹水强度与土壤有机质和全氮呈显著正相关,有机质与全氮呈显著正相关,全氮、有机质与碳氮比也呈显著正相关(P<0.01)。研究结果为科学评估筑坝蓄水对湿地生态系统的影响,为高原湿地生态系统的保护管理提供了科学依据。
Dams dam expansion led to an increase in wetland area. Based on the changes before and after dam construction, the soil was collected along the flooding gradient to understand the distribution of organic matter and total nitrogen in the Lashihai Sea, and to compare the differences of organic matter and total nitrogen before and after dam construction. The results showed that soil organic matter and total nitrogen in the flooded area after dam construction were all higher than those in the undrained soil. At the same time, the contents of organic matter and total nitrogen increased at first and then decreased with the intensification of flooding intensity. For the same submergence gradient, the soil organic matter and total nitrogen content in the more disturbed man-made soil (abandoned soil) were significantly lower than those in the less disturbed soil (meadow soil). Analysis of variance showed that the organic matter and total nitrogen content had no significant difference (P> 0.05) in seasonal flooding area alternating wet and dry (P <0.05). Correlation analysis showed that there was a significant positive correlation between flooding intensity and soil organic matter and total nitrogen in the study area. There was a significant positive correlation between organic matter and total nitrogen, total nitrogen, organic matter and carbon / nitrogen ratio (P <0.01). The results provide a scientific basis for the scientific assessment of dam impoundment on wetland ecosystems and for the protection and management of plateau wetland ecosystems.