Design And Study Of Water Requirement Information System For Crop Growth

Developing efficient water-saving irrigation agriculture is the first and foremost condition for the sustainable development of national griculture.The main problems that face the development of China irrigated agriculture are low utilization ratio of agricultural water resources and coexistence of shortage and waste at present. Because of the crop itself whether need to be irrigated is the best indicator. Increasingly importance has been attached to guide the irrigation based on water-needed of crop growth.Monitoring the moisture content real-time and accuratly is the foundation for irrigation system which bases on the crop itself,so stduy on imformation collecting system of crop growth water-demand is tremendously significant.On the basis of sufficient research on national and foreign status of water-saving irrigation, the article advances the principles of the collection system based on area of plant leaf and non-destructive testing of the the moisture content, and puts the emphasis on the design of capacitive sensor to measure the crop growth-water and the system's hardware and software design.In the respect of hardware design, according to the precision, time and the cost of the detector, we select the appropriate main chips which is SPCE061A micro-controller and divide the whole hardware system into several modules to design respectively following the theory of module design. When each module is adjusted successfully, we combine them into a complete entity to ensure the high quality of hardware and makes it easy to test and maintain. In the respect of software, according to the predicted function of this detector and the design of the hardware circuit, the software is specified as follows: initialization for MCU and system chips, sampling analog signals, signal process, real time display and serial port communication on MCU, and program interface design, serial port communication, etc.Informations collected by the system are divided into two parts, the crop growth-water and image of plant leaf. Collecting crop water status of crops by using stem capacitive moisture sensor,The moisture sensor will collect client acquisition value of the water by the conditioning circuit to sub-MCU, then,the signal will be sent to the A / D conversion circuit, by the sub-station PTR8000 to the main station, which decoded into the PC, stored in the database.Using CCD image sensor and video blaster to collect leaf's image of crops. The PC system can process the images and calculate the proportion of leaf surface pixel value which reflect the changes in leaf area, According to crop water status and leaf area, the system can diag water requirement of crops.Computer terminal of the system is achieved by using the graphical language LabVIEW. Using LabVIEW to process the data from front-ends which accessed by the MCU SPCE061A . Data switching between them is done through serial port.So the data collecting system is low-budget and simple-interface.