白洋淀水生植物腐解释放特征分析

Analysis of the characteristics of decomposition release of aquatic plants in Baiyangdian Lake

为研究白洋淀水生植物衰败期腐解释放特征,采用遥感解译和现场调查相结合的方法,对白洋淀水生植物进行了多维度调查,估算了典型优势水生植物菹草、篦齿眼子菜和莲的全氮、全磷、有机质腐解释放量,提出了白洋淀水生植物管理对策.结果表明:菹草、篦齿眼子菜和莲的腐解释放对白洋淀水质影响较大;易腐解组分在总生物量中的质量分数菹草为72%,篦齿眼子菜为40%,莲为12.14%;难腐解组分在总生物量中的质量分数菹草为28%,篦齿眼子菜为60%,莲为87.86%.优势水生植物全氮、全磷、有机质的释放效率不同,但所有植物腐解前期磷释放速率最快,菹草有机质的释放量最大.水生植物腐解释放具有明显的时间特征,与水生植物生长周期密切相关,集中在优势种的腐解时期.为控制白洋淀水生植物腐解释放污染,应根据水生植物的生长周期及腐解释放规律,在5月中旬对菹草进行收割,9月中下旬对莲和篦齿眼子菜进行收割,并拓展水生植物的资源化利用途径.

To study the decomposition release characteristics of Baiyangdian Lake aquatic plants during decay,a multidimensional survey of Baiyangdian Lake aquatic plants was conducted using a combination of remote sensing interpretation and field surveys to estimate the decomposition release of total nitrogen,total phosphorus and organic matter from typical dominant aquatic plant Potamogeton crispus,P.pectinatus and Nelumbo nucifera,countermeasures for the management of Baiyangdian Lake aquatic plants were proposed.The results showed that the decomposing release of P.crispus,P.pectinatus and N.nucifera had a greater impact on Baiyangdian Lake water quality.The mass fraction of easily decomposed fractions in the total biomass was 72%for P.crispus,40%for P.pectinatus cress and 12.14%for N.nucifera;the mass fraction of difficult to decompose fractions in the total biomass was 28%for P.crispus,60%for P.pectinatus and 87.86%for N.nucifera.The release efficiency of total nitrogen,total phosphorus,and organic matter from dominant aquatic plants varied,but the release rate of phosphorus was fastest in all plants during the pre-decay period,and the release of organic matter was greatest in P.crispus.The decay release of aquatic plants has obvious temporal characteristics,closely related to the growth cycle of aquatic plants,concentrated in the decay period of the dominant species.In order to control the decay and release of aquatic plants in Baiyangdian Lake,we should harvest P.crispus in mid-May and P.pectinatus and N.nucifera in mid-late September according to the growth cycle and decay and release rules of aquatic plants,and expand the resource utilization pathway of aquatic plants.