Studies On The Energy Budgets And Organic Carbon Budgets Of Polyculture System Of Portunus Trituberculatus Ponds

The researchers are trying to find a way in the process of conducting outdoorecological ponds research which can make aquaculture resourses highly utilized andthe environment less polluted. The polyculture of the creatures which have beneficialeffects to each other supported them a very effective solution to this problem.According to the study of energy budget and organic carbon budget as well as theenergy and organic carbon conversion coefficiency, it gives researchers the theoreticalbasis of which proportion of the polyculture allocation can make the best breedingefficiency. The swimming crab（Portunus Trituberculatus）is a widely raised breedingspecies in our country’s coastal area. The polyculture of crab and the whiteshrimp（Litopenaeus Vannamei） or crab，shrimp and short-necked clam（RuditapesPhilippinarum） have been conducted by many farmers. But in which proportion ofthese creatures to nurture can get the best results still exist in question, and there is nosystematic research has ever been done before. This partical investigated the suitablepolyculture proportion of crab and shrimp or crab, shrimp and clam, according to thestudy of energy budget, organic carbon budget, energy and organic carbon conversionefficiency in different treatments. Hoping that the results of the research would makesome contributions in pursue of making productive and environmental friendly pondssystem. The exact results are displayed as follow.1Studies on the energy budgets of different poly-culture systems of swimming craband white shrimpThis article studied the energy budget and conversion efficiency in land-basedenclosures where swimming crab and white shrimp were cultured with different densities. Six groups were designed. They were crab （C）, shrimp （S）, four groupsstocked crab and shrimp with different densities （C1S4, C2S3, C3S2, C4S1）. The resultsindicated that the primary productivity were the main part of importing energy. Thenet output energy of farming creatures of C3S2was higher than other groups. Thesolar radiation energy was2241MJ/m2during the experiment, the solar energyutilization rates of phytoplankton ranged from0.47⁰.71%, inside all the groups themono-culture of shrimp ranked the highest place, the group of C2S3was the lowest,there wasn’t significant difference between each group （p>0.05）. The highestphotosynthetic energy efficiency was C3S2, and mono-culture of shrimp ranked thelast one, the group of C3S2was significantly higher than the other groups except theone of C2S3（p<0.05）. The group with highest feeding energy conversion efficiencywas the mono-culture of shrimp, the lowest one was the mono-culture of crab. Thegroup with highest total energy conversion efficiency was C3S2, the lowest one wasthe mono-culture of crab, the group of C3S2was significantly higher than the groupsof mono-culture of shrimp and mono-culture of crab （p<0.05）. The lowest feedingenergy consumption per unit of net yield was the treatment of C3S2, and the treatmentof mono-culture of crab ranks the highest one, the group of C3S2was significantlylower than the group of mono-culture of crab （p<0.05）. The lowest gross energyconsumption per unit of net yield was also group of C3S2, and the group ofmono-culture of crab ranks the highest one, the group of C3S2was significantly lowerthan the group of mono-culture of crab （p<0.05）. The sediment energy, which rangedfrom1.65⁶.98MJ/m2, the groups of C2S3and the mono-culture of shrimp stand thehighest and the lowest one respectively. the sediment energy of each group accountfor its total energy input were between9.87³2.47%, the group of S is significantlylower than the groups of C2S3、C3S2and C （p<0.05）. This study demonstrated that thepoly-culture of C3S2owns higher energy conversion efficiency, higher yields than theother groups. So the best poly-culture group we got in this experiment is the onewhose crab density at6ind/m2、shrimp density at45ind/m2.2Studies on the energy budgets of different poly-culture systems of swimming crab,white shrimp and short-necked clam This article studied the energy budget and conversion efficiency in land-basedenclosures where swimming crab, white shrimp and short-necked clam were culturedwith different densities. Seven groups were designed, they are crab （C）, crab and clam（CB2）, crab and shrimp （CS） and four groups stocked crab, shrimp and clam with fourdifferent densities（CSB1, CSB2, CSB3, CSB4）. The results indicated that the primaryproductivity and the feeds input constitute the main parts of the importing energy. Thenet output energy of farming creatures of CSB3and CSB4were higher than the othergroups （which was significant （P<0.05））. The energy sedimented on the bottom of theenclosures, ranged from1.68⁵.43MJ/m2, the group of CSB3was the highest one andshowed significant difference with other groups（P<0.05）, the sediment energy ofeach group account for its total energy input was between25.57³3.47%, there is nosignificant difference between each group（p>0.05）. the solar radiation energy was1550MJ/m2during the experiment, the solar energy utilization rates of phytoplanktonranged from0.16⁰.38%, the mono-culture of crab was the highest and thepoly-culture of CB was the lowest, there was significant difference between eachgroup （p<0.05）. The highest photosynthetic energy efficiency was CSB3, then CSB4,the SB2was the lowest one, there was significant difference between each treatment（p<0.05）. The treatments with highest total energy conversion efficiency were CSB3and CSB4, which were significantly higher than the groups of CSB1, CS, CB and themono-culture of crab （p<0.05）. The feeding energy consumption per unit of netyield in mono-culture of crab was the lowest, so as the parameters of the gross energyconsumption per unit of net yield and the feeding energy consumption per unit of netyield, but it had no significant difference with CSB4（P>0.05）. The present studydemonstrated that the poly-culture of CSB3, CSB4had higher energy conversionefficiency, higher yields and a more reasonable ecological effect than the other groups.So the best poly-culture group we got in this experiment is that the crab density at6ind/m2, shrimp density at45ind/m2and clam density at30⁶0ind/m2.3Total organic carbon budgets of polyculture system of swimming crab and whiteshrimpThe budget of total organic carbon （TOC）, utilization ratio and the culture effect were studied in land-based enclosures with different polyculture systems ofswimming crab and white shrimp. The experiment set up six different groups whichare shrimp monoculture group （S）, crab monoculture group （C）, crab and shrimppolyculture groups （C1S4, C2S3, C3S2, C4S1）. The results showed that the appropriatepolyculture system of crab and shrimp can effectively improve the utilization rate oforganic carbon and aquaculture production of the farming system. Primary productionof phytoplankton was the main TOC（accounting for30.04⁵8.70%）inputs in theenclosures while the feed provided23.95～52.67%of TOC inputs. Among the outputitems, the major output of TOC was the respiration of plankton in the water, whichaccounted for24.96⁴8.44%of TOC outputs. The sediment accumulation accountsfor7.85³3.42%of TOC outputs. Comepared with other systems, the highestutilization efficiency of TOC of polyculture systems was C3S2system, whichimproved0.68⁴.98%than the other systems. The results showed that the treatmentgiving the best culturing benefit was crab at6ind/m2, shrimp at45ind/m2under theconditions of this study.4Storage of the organic carbon of polyculture system of swimming crab and whiteshrimpThe storage of organic carbon was studied with land-based enclosures withdifferent polyculture systems of swimming crab and white shrimp. The resultsindicated that the storage of particulate organic carbon（POC） ranged from（1.43±0.20）^6.55±1.21mgC/L and the dissolved organic carbon（DOC） ranged from（6.30±0.32）^8±0.80mgC/L, The ratios of DOC to POC was2.46. Organic carbon storage ofphytoplankton and zooplankton ranged from0.38±0.073to4.20±0.59mgC/L,（1.33mgC/L） and0.025±0.0047to0.27±0.0096mgC/L,（0.12mgC/L） respectively.The ratios of DOC and POC to total organic carbon（TOC） were50.94⁸6.14%and14.20⁴9.14%, respectively. The ratios of detritus and bacterial organic carbon（BDC）,phytoplankton organic carbon（PBC） and zooplankton organic carbon（ZBC） to totalorganic carbon（TOC） were7.14³3.36%,4.23²7.86%and0.19².59%,respectively.