Water Environment Monitoring And Application Of Internet Of Things Technology In The Production And Marketing Of River Crabs

River crab,scientific name of Chinese mitten crab,commonly known as crab,hairy crab and clear water crab,is a rare aquatic product in China.Because of its rich nutrition and delicious meat quality,it is sought after by consumers.River crabs are mainly distributed in Jiangsu,Anhui,Jiangxi and other coastal areas of our country.The mature period of river crabs is concentrated from September to November every year.The centralized listing of river crabs leads to difficult sales and low prices.In order to ease the sales pressure and sell a good price at the same time,farmers choose to "temporarily raise river crabs indoors" and sell them when the price is higher around the Spring Festival to obtain greater benefits.The main problem in the process of holding crabs is that the crab mortality rate is too high or the weight loss is serious.The water area is the main place for the growth of crabs and is the key factor affecting the mortality of river crabs.The main indicators of water quality include:water temperature,dissolved oxygen concentration,pH value,nitrite concentration,ammonia nitrogen concentration and permanganate index.In the traditional temporary cultivation of river crabs,there are mainly the following problems:lack of water quality detection instruments,water exchange depends entirely on cultivation experience,disordered water exchange cycle,and untimely water exchange easily leads to a large number of river crab deaths.The water exchange and oxygenation depends entirely on manpower,without water environment control system and with low intelligence.At the same time,the crab breeding department and the marketing department cannot realize effective information sharing due to their far separation,which leads to low production and marketing efficiency and mutual shirking of responsibilities after problems occur.In order to solve the problem that the water environment regulation and the information of production and marketing departments cannot be shared during the temporary cultivation of river crabs,we have carried out periodic water enviromnent testing tests.The results show that among the six major factors affecting water quality,ammonia nitrogen concentration is the first to exceed the standard,and the water change period is 4.5 days.Based on this result,two new water exchange methods of"chemical reagent detection auxiliary water exchange" and "controller detection intelligent water exchange" are proposed,and a set of water environment control system integrating intelligent detection and monitoring is designed based on the principle of "ammonia nitrogen balance water exchange calculation method".The water environment control system includes a water quality sensor,a controller,an early warning device,and a water exchange aeration device.The controller adopts modular programming mode,developed and compiled with KEIL uVision4,communication adopts MG323 processing,built-in early warning system,dissolved oxygen sensor adopts Danish Oxy Guard,ammonia nitrogen sensor model is ANB-300,can monitor water quality information in real time,and can detect results according to test The water exchange required at this concentration is accurately settled,and the water is automatically turned on and off by the relay to complete the water change.At the same time,the "Remote information transmission system based on GPRS"and "wireless video surveillance system" was built,which can realize the aquaculture data transmission and video surveillance between the breeding department and the sales department,and increase the connection,coordination and cooperation between the two departments of production and sales.Through this system,the sales department can observe the specific situation of river crab farming in real time,and the production department can understand the sales information,timely stocking,and improve the efficiency of production and sales.After the system was completed,the impact test of three different water exchange methods on the holding of river crabs was carried out.From December 17,2018 to January 30,2019,a total of three trials were conducted,each for 15 days.The results showed that the average mortality rate of crabs in the three batches of traditional water-changing methods was 12.2%(12.8%,11.9%,12.0%),and the average mortality rate of river crabs was 9.5%(9.9%,9.4%).9.3%),the controller detected the intelligent water change method,the average mortality rate of crabs was 8.2%(8.6%,7.8%,8.1%).The chemical reagent detection auxiliary water exchange method is 2.7 percentage points lower than the traditional water exchange method.The controller detects that the average death rate of river crabs in the intelligent water exchange mode is 4.0 percentage points lower than that in the traditional water exchange mode and 1.3 percentage points lower than that in the chemical reagent detection auxiliary water exchange mode.