海涂人工湿地不同利用方式能值特征与生态效应

Study of energy characters and ecological effects on different kinds of utilization mode in costal artificial wetland

在海涂人工湿地进行单一养殖、种养复合 (田菁水植养鱼 )、种养结合 (鱼养在四周沟塘 ,田菁旱植在中央的滩面上 )试验 ,3年 (1999至 2 0 0 1)的试验结果表明 :根据评判人工湿地生态系统可持续发展的 3个指标[1] 进行能值特征分析 ,发现合理的种养复合模式能值产出率 (Yr)、净经济效益 (Np)与系统贮存能值增加分别是单一养殖的 1 36 ,1 35和 1 71倍。在经济反馈投入基本一致的情况下 ,种养复合的经济收入、总能值产出均比单一养殖高 ,从而反映出人工湿地种养复合模式的高效性与可持续性。对 3种利用模式的生态效应进行了研究 ,结果发现 :种养复合模式田菁长势与产量均优于种养结合 ,其田菁根瘤鲜重与田菁籽产量分别为种养结合田菁的 2 0倍和 1 3倍 ;种养复合水体的全磷、全氮、水体高锰酸盐指数 (CODMn)、叶绿素a、水体透明度均比单一养殖高 ,表明种养复合下的水体环境更适应于某些鱼类生长 ;种养复合下滨海盐土脱盐率、全氮与有机碳在 0～ 2 0cm土层的增幅分别为单一养殖的 1 2 5 ,1 6 2和 2 5 7倍 ,表明种养复合模式更有利于滨海盐土肥力的提高。

Different modes were tested on constructing and utilizing artificial wetland ecosystems in the coast of Jiangsu Province,China for three years(19992001).The three modes were as follows:single culture of fish,mixed culture of fish with Sesbania cannabia,and combined culture of fish and Sesbania.Results showed that the energy yield ratio,the net economic profits and the base energy increment of mixed culture were 1.36,1.35 and 1.71 times as much as those of single culture respectively,according to the principle and method of energy evaluation.The fresh weights of root nodules and seed yields of Sesbania grown in the mixed culture were 20 and 1.3 times as much as those in combined culture respectively.In mixed culture,planting Sesbania decreased the contents of total phosphorus(TP),total nitrogen(TN),COD Mn and chlorophyll-a and made the water more transparent,which would be beneficial for some fish of high quality.The rate of salt leaching,the TN and the organic-C of saline soil(020 cm)in mixed culture were 1.25,1.62and 2.57 times those of single culture,respectively.As a result,mixed culture was the most effective and sustainable mode of utilizing the coast soil.