Design Of Intelligent Irrigation System For Slide Cover Greenhouse

China is not only a big agricultural country,but also a big irrigation country.Agricultural irrigation water accounts for about 70%of the global fresh water consumption,and waste up to 30%~40%.At present,greenhouse is an important part of facility agriculture,but there are some problems such as low utilization rate of water resources,large labor force and poor ability of environmental regulation and control.Therefore,on the premise of meeting the requirements of crop water demand,a set of intelligent irrigation control system is designed to improve the utilization rate of water resources.Under the guidance of the research group of the national"13th five-year plan"key research and development project fund(2016YFD0201004),MeiSheng tomato was selected as the research object.according to the situation of sliding greenhouse in the research base of Shenyang agricultural university and the relevant knowledge of water demand characteristics of tomato,the crop transpiration model was applied to system irrigation,and the relevant environmental parameters of greenhouse were collected through the data collector,and the crop was controlled irrigation through the opening and closing of the control solenoid valve of the electrical cabinet in the greenhouse.The specific research contents of the system are as follows:Firstly,according to the actual demand,make the overall scheme of the system,respectively for the hardware design and software design.STM32F103ZET6 is selected as the core of the hardware design of the main controller,the host computer sends irrigation instructions through RS-485 bus to the data collector,data collected by the data collector to the host computer and save,through the control relay to control the opening and closing of the solenoid valve,in order to real automatic irrigation.The software program is programmed by C language developed by Keil software.The lower computer software mainly includes system initialization module,alarm module,display module,clock module and wireless communication module.Wherein that wireless communication module realize a greenhouse irrigation mode which is remotely controlled by a us.The communication between the upper computer and the lower computer of the system chooses serial communication mode to realize the requirements of real-time data acquisition and on-demand irrigation.Secondly,in order to realize the real-time detection of on-demand irrigation,the evapotranspiration penman-Monteith equation is selected as the irrigation model according to the water demand characteristics and influencing factors(humidity,temperature,net solar radiation)of tomato in each growth period,and the evapotranspiration of crops is calculated,and the automatic irrigation or timing irrigation control mode is selected,so as to effectively adjust the water demand of crops.Finally,the experiment was carried out on 12 days in seedling stage,flowering stage and fruit stage of tomato.The results showed that penman-Monteith equation could stably measure the evapotranspiration of tomato,and the correlation coefficient reached R~2=0.9549.The water loss of transpiration was from more to less in the fruit stage,flowering stage and seedling stage.This shows that the irrigation control system can realize on-demand irrigation and meet the design requirements.