Seasonal dynamics of carbon, nitrogen and phosphorous in soil profiles from an inland salt marsh

Abstract

本文以向海湿地为例探讨了内陆盐沼湿地土壤剖面中碳氮磷等生源要素的季节动态变化特征及其影响因素。结果表明, 内陆盐沼湿地土壤中有机碳、全氮和全磷含量与土壤深度之间存在显著负相关, 在剖面中均表现为由表层向下层其含量不断减少的趋势, 且具有明显的季节波动特征, 除表层土壤碳氮含量随季节变化呈持续增加外, 生源要素剖面分布的季节变化基本表现为先减少后增加的趋势。有机碳、全氮和全磷含量之间关系密切, 且三者受土壤粒度的影响都非常显著。土壤pH值仅与土壤有机碳之间存在显著的相关关系, 而对全氮和全磷含量的影响则不显著。;Wetlands are widely distributed in the northeast of China, serving as source, sink or transfer of most chemical matter. Owing to worse natural environment such as drought, water shortage and intense human activities, inland salt marshes were extensively developed in the west Songhuajiang-Nenjiang plain with high ecological frangi-bility, in which Xianghai wetland is one typical inland salt marsh located downstream of Huolin river basin, Jilin Province of China. Soil samples were collected in Xianghai wetland during four months ( May, July, September and October) in 2001. The contents of soil organic carbon (SOC), total nitrogen (TN) , total phosphorous (TP), soil pH and soil particle sizes were measured in wetland soils in order to study influencing factors and seasonal dynamics of the life elements in soil profiles from inland salt marsh. Correlation analysis was carried out to show the relationships between SOC, TN, TP, soil pH, clay, silt and sand. Results showed that SOC, TN and TP contents were significantly negatively correlated with depth, and decreased from surface soils down to bottom soil layers in four months; the obvious seasonal dynamics of SOC, TN and TP contents in soil profiles were also observed and the seasonal dynamics of life elements in soil profiles generally showed the consistent changing trends of “ increasing after decreasing” with the exception of continuous increase of SOC and TN contents in surface soils, There were significantly negative correlations between SOC, TN and TP, which were greatly influenced by soil clay, silt and sand contents; soil pH was significantly negatively correlated with SOC content, but weakly influenced TN and TP contents. Since soil nutrient contents are important determining factors of soil fertility, changes of which greatly influence productivity of wetland ecosystem, which can provide scientific basis for further studies of evolvement of soil quality, ecological restoration and sustainable management of wetlands in this region.