Comparison Of Water Quality And Farming Performance Of Ponds With Different Output

The ponds of Nan Chang County,An Yi County,Jin Xian County,green hill Lake district were monitored as the experimental object for eliminating the diversity of the region and representing the local cultivation level.Based on the year output reports,the questionnaire survey and on-the-spot investigation,three gradients of output were established,as output＜500kg/667m~2,500 kg/667m~2＜output＜750kg/667m~2,output＞750kg/667m~2.Twelve ponds were chose.The basic information of whole year rearing in experimental ponds with using the local cultivation pattern were taken,including time of cultivation,main pattern of cultivation,feeding quantity,complexion of using of medicine and fertilizer for cultivation,survival rate,harvest situation,sales income,net profit and so on.In main growing season of fish(from June to October),the water quality in ponds were monitored monthly,including:water temperature,dissolved oxygen,pH,chemistry oxygen demand(COD),ammonia-N,total phosphorus,sulfide,copper,zinc,lead, cadmium,total mercury,total chromium and so on;plankton were analyzed quantitatively and qualitatively;benefit analysis was also carried out to obtain the test's results,in order to make valuation to the cultivation technology and the cultivation pattern in the area.In 2007,the water bodies conformed to the basic water quality requirement, moreover,pond culture itself had not caused the pollution of the water bodies,and there had no significant difference(p＞0.05) among the ponds.There have no significant difference between grads according to quantitative and qualitative analysis of plankton in the trial ponds,the phytoplankton had 36 kinds,the main species were green alga, blue-green alga,euglenophyta and diatom,The zooplankton altogether had 51 kinds,the community composes by the protozoon and the rotifer primarily.Looking from the rearing income,the profit of the ponds of high output margin was highest,were 771.8 kg/667m~2,6230.8 Yuan,2556.5 Yuan respectively.The results of the experiment showed that:the pattern of output＞750kg/667m~2 was successful,its water quality accorded with the national standards.In order to the sustainable development of the aquaculture industry,we should make further study and summary,to form the key technology and the technical specification.