小型水库不同蚌、鱼混养模式排放水的水质分析

The discharge water quality in small reservoirs under different polyculture models of fish-freshwater mussel

于2008年5月—11月,以不同蚌、鱼混养模式的6座小型水库为研究对象,比较分析了各水库排放水的水质指标。结果表明：各水库中的pH差异不显著,变动范围为8.0~8.7;红旗水库中NO2-N含量显著低于横塘水库和七里垅水库（P〈0.05）;后垄水库中NO3-N含量显著高于红旗水库和七里垅水库（P〈0.05）;横塘水库中总氨氮（TAN）、无机氮（DIN）、总氮（TN）除与七里垅水库差异不显著外,均显著高于其它水库（P〈0.05）;横塘水库中PO4-P含量除与后垄、七里垅水库差异不显著外,显著高于其它水库（P〈0.05）;横塘水库中总磷（TP）和CODMn含量除与后垄水库差异不显著外,均显著高于其它水库（P〈0.05）。除此之外,其它水库间这些水质指标的差异均不显著（P〉0.05）。其中人工投饵型蚌、鱼养殖水库排放水中CODMn、TAN、TN和TP含量较施有机肥型蚌、鱼养殖水库分别下降40.9%、73.6%、42.0%和97.1%;水库排放水DIN中主要以TAN形态存在,而TN中主要以DIN形态存在;各水库排放水同一水质指标的季节变化规律基本一致。

The discharge water quality was determined in 6 small reservoirs under different polyculture models of fish-freshwater mussel（Hyriopsis cumingii） from May to November in 2008 to evaluate the improvement effect and general applicability of water quality by a fish-freshwater mussel polyculture.The results showed that the mean pH values were ranged from 8.0 to 8.7 in the discharge water from the reservoirs with different fish-freshwater mussel polyculture models,without significant difference among the reservoirs.There were significantly 40.9% lower chemical oxygen demand（CODMn）,73.6% lower nitrite（NO2-N）,and nitrate（NO3-N）,42.0% lower ammonia（TAN）,and 97.1% lower reactive phosphate（PO4-P） and total phosphorus（TP） in the discharge water of the reservoir with feeding fish-freshwater mussel polyculture than those in the fertilizing organic fertilizer fish-freshwater mussel polyculture.No significant differences were found in seasonal dynamics of CODMn,NO2-N,NO3-N,TAN,TN,PO4-P and TP among the reservoirs,indicating that the eutrification of feeding fish-freshwater mussel polyculture on the water quality in discharge water of small reservoirs was lower than fertilizing organic fertilizer.Application of feeding fish-freshwater mussel polyculture is promising for improvement of the water quality in small reservoirs.