Research On Water And Fertilizer Coupling Irrigation Control System Based On Labview

With the improvement of people's living standard, Facility agriculture has become an important part of modern agriculture. Affected by lacking of water resources and low utilization of fertilizer, Research of water and fertilizer coupling has very important meaning. In china irrigation automation is still at the starting stage, which automatic degree is relatively low. because of the simple equipment and outmoded production, which affected the yield and quality of greenhouse crops. With the development of computer technology, Virtual instrument has already become a major tool in the development of controlling field. Virtual instrument possesses features of good capability,high extensibility,low exploiture period and seamless integration. Virtual instrument for irrigation water and fertilizer coupling will be a development trend of modern greenhouse controlling field.According to the development of domestic high-efficiency agriculture, a system for real-time controlling the irrigation and fertilization of greenhouse was designed. The main works were as follows:(1) Analysis of soil moisture and fertilizer containing rate effect on greenhouse crops such as cucumbers,green peppers, Then the soil moisture and fertilizer containing rate were collected and transferred with the AQUA-TEL-TDR soil moisture/temperature sensor,the HI4321 Conductivity Instrument, the PCI6024E data acquisition card and RS232 transmission line.(2) Water and fertilizer coupling irrigation control system was designed. In which the software-developing platform was based on Labview of NI Company and the hardware was mainly based on a laptop computer,sensor,data acquisition card,transmission line together with Pump,valves and combination of various instruments.(3) The datas, such as soil moisture,EC value, which were collected by the water and fertilizer coupling irrigation control system, Then these datas were transferred to the laptop computer by data acquisition card and communication input device, and saved in the laptop compute as data log file. While the datas were analyzed,the data signal were displayed real-time in the laptop computer. The signal was transferred by the control line to control the switches of water pump and solenoid valve, achieved to control irrigation, regulate the growth of crops environment.(4) Water and fertilizer coupling irrigation control system was designed based on modular ideology, which had a has good scalability. Affected by the nonlinear,time-varying,time-delaying of the greenhouse environment system, it was difficult to build the precision mathematical model. The fuzzy control method was used to regulate the irrigation system of the greenhouse.(5) Experiments on the relation of electric conductivity and fertilizer concentration, the Relation Curve of concentration and EC value was obtained, which equation as follows, The resulting irrigation water and fertilizer coupling mode. By the operation of the system tests, proved that the system was running well.