南方涝渍地区退田还渔的一个实例分析

以江汉平原四湖涝渍地区的一个经围湖造田形成的典型农业微域为研究对象,在对其土壤和作物生长状况进行调查的基础上,探讨了退田还渔的必要性与具体方案。结果表明,对小型湖泊通过围湖造田所形成的农业微域,在人工排水和土地平整不充分的情况下,其地貌和土壤还残留有原有湖泊的影响,处于原湖泊低处的土壤表现出明显的沼泽化和严重潜育化的特征。在该地区种植水稻产量比正常地区减产达16%～26.8%。利用数量化理论Ⅰ确定了该地区适宜退田还渔的具体位置和面积。按照这一方案实施的结果,该地区从1997～2001年的5年中精养鱼塘面积增加9倍,养鱼的效益比种植水稻高5～10倍,还减轻了该地区夏季和冬季的排水压力。

A case study on wetland restoration from paddy fields to fishing pools in the waterlogged area of South ern China

Taking a typical farming micro-zone from the reclamation of a small lake in the waterlogged area in Jianghan Plain as an example,we discussed the necessity and the working plan for the wetland restoration from paddy fields to fishing pools.An investigation to the soil and the rice growth showed that the soil and the landforms retained some properties of the influences from the lake when the land reclamation was inadequately done in drainage and land leveling.The soil at the lower part of the original lake was featured by severe gleying.The yield of rice growing there decreased by16%～26.8%in contrast to the nearby regions with normal soil.Apart from the lower yield,the rice was often subjected to flooding.By using the model of Quantification TheoryⅠ,a plan to identify the specific sites and area of the land converting from paddy fields to fishing pools was fulfilled.The implementation of the plan showed that the total fishing area restored from the paddy fields increased9times in comparison to that of the year in1996when the project started5years ago.The benefits of fishing was5～10times more than that of rice growing.The drainage pressure in the farming microzone was mitigated by fishing in the summer and winter at the same time.