Research Of Water Quality In Shrimp Pond By Different Kind Of Weather And Technique Ecological Plant Rehabilitation

In recent years, shrimp farming industry developed rapidly in China, whichassociated with a high increasing range of annual output. At present shrimp farming stilladopts traditional high–density outdoor breeding method, the water quality factors ofwhich can be fluctuated by the change of weather, and this will bring manydisadvantageous and potential damage to shrimp farming. Create a good waterenvironment to reduce the stimulus of water quality factors to shrimp ponds underdifferent phenology, by which the disease of shrimp was under control to some extent.First of all, physical and chemical factors of outdoor shrimp pond water weremonitored by a breeding cycle in Shanghai, the main Water quality index underdifferent weather was analyzed and the results indicated that, the water temperatureshowed extremely significant positive correlation with the air temperature and so watertemperature can stand for the weather to some extent. Also, water temperature had asignificant correlation with TAN, NO₃^--N and NO₂^--N in breeding stage. In the middleand late breeding period, pH, chlorophyll-a, activated phosphate and transparency weresignificant correlated with water temperature, the chemical oxygen demand wasincreased with the breeding time. There was a close relationship between the climateand water quality factors and the phytoplankton played an important role. The Climatecharacteristics and water quality factors had a close relationship, which thephytoplankton play a important role. The outbreaks of Shrimp disease has a highrelationship with the fluctuate of water quality factors, if nitrogen, phosphorus, organicsuspended solids, the harmful microbes and so on, which ubiquitous in the aquaculturewater, maintain a stable low level, it would prevent the shrimp disease outbreak to a certain degree effectively. According to the climate and the water quality characteristicsof shrimp farming pond, and the principle of priority selecte suitable for the localclimate, stain resistane, the root system developed, the source wide, easy to harvest,local varieties, through critical review of literatures and on-the-spot check, we tookwater fennel, water spinach and lettuce as the economy plants for water treatment inshrimp pond water on the basis of high humidity, reproduction of biomass and rootdistribution, etc.In order to study the purification effect of three vegetables and cultivation onshrimp aquaculture water and identify a suitable vegetable and cultivation, theexperiment was conducted to compare vegetables growth, absorptivity of nitrogen andphosphorus, water chemistry conditions with three vegetables （water fennel, waterspinach, lettuce） with three cultivations planted in the shrimp aquaculture water. Theresults showed: the daily increase biomass per unit and the absorptivity nitrogen andphosphorus by water spinach was significant higher than water fennel and lettuce, andthe survival rate of water spinach was highest too. All of the three plants had a purifyingeffect of the shrimp pond water, especially the water spinach. The contents of TAN、NO₃^--N、 TN、 TP and COD_Mn of the water in spinach ponds decreased by55.0%,78.6%,52.6%,44.2%and41.3%, secondly the water fennel. There was nosignificant influence on biomass increases and concentration of nitrogen andphosphorus for water fennel and water spinach under three floating cultivations.However, the growth condition of lettuce with floating board was the best in the lettucegroup. The study showed environment adaptability of the water spinach to shrimpaquaculture water was widest in the three vegetables, so it was the best suitable forplanting in shrimp ponds and the knot planting pattern was the best way to plant waterspinach. In accordance with status of shrimp culture in Shanghai, it was suggested thathalf of the without being utilized nitrogen in the culture period would be absorbed withplanting the water spinach at0.05kg/m²in an early shrimp culture stage.At last we used the knot type to plant water spinach in outdoor breeding shrimp pond to carry out experiment in Shanghai. This experiment researched effect of waterpurification and the influence of the production of shrimp after planted water spinachduring shrimp farming period. The results showed water transparency, TN, TP, COD_Mnand chlorophyll-a stability of planted water spinach ponds were superior to those in thecontrol pond.The outbreak of harmful bacteria have been inhibitited apparently. Thefresh weight of harvested vegetable was （200.8±3.25）kg every667m²; and thepercentage removal of TN and TP was3.16%and1.79%，respectively．At the end ofexperiment，the shrimp production in planted ponds was significantly higher than incontrol ponds. Percentage removal of total nitrogen （TN） and total phosphorus （TP） byharvested shrimp in the control ponds was33.80%and22.17%respectively．Percentageremoval of TN and TP by harvested fish in the planted ponds was38.65%and25.42%，respectively．The results suggested that the water quality could be improved effectivelyand would not cause the second pollution and gain economic value after harvest in theaquaponic. This system could play an active role on maintain a stable waterenvironment under the changes of the weather.This paper discussed the relativity of phenology and water quality index of shrimppond，explored further study in each factor of ecological system shrimp pond, andaccording the results the research by using aquatic plant to purify and repair the waterenvironment were done. Based on manifold tests, obtained related data and practiceexperience, this paper finally studied the purification and stabilization of water spinachwhich obtain good breeding effect in Shrimp pond water by using outdoor productiveexperiment.