Research On Water & Fertilizer Coupling Irrigation Control System

The development of automatic control technology accelerates greatly the development of modern agriculture. The automatic irrigation control technology in not only facilities agriculture technology but also field crop technology is one of the hotspots of the development of modern agriculture. It is water-fertilizer coupling irrigation which has many advantages such as: water-saving, fertilizer-saving, energy-saving, labor resources-saving, improving quality and yield, alleviating contamination bought out by fertilizer. In contrast to other advanced countries like the USA, Israel, Canada et al. The degree of automation is low and automatic water-fertilizer coupling control technology is still in study period, thus it is meaningful to conduct the project so as to satisfy the urgent requirements in our country.Based on consulting plenty of the related information domestic and overseas, this research designed an automatic water-fertilizer coupling irrigation system, which can control automatically concentration of original irrigation solution and apply for all of the crop and their concrete growing stage by MCU technology with communication technology.This system is consisted of slave-computer and super-computer and adopts AT89C51 and PC as key parts. On the slave-computer system, data sampling, data processing, display, output controlling, sending information to the super-computer. Meanwhile, the procedures programmed with MCS51 assemble language. The super-computer system could detect data information and deliver the data in serial communication between a PC and a MCU through the MAX232 chip realizes to finish voltage conversion and RS232. VB high-level language is used to build up the friendly main-machine interface on PC. The user can select conveniently the needing crop and related growing stage, also would set the related alarm parameters for its security, which could display in the system information monitoring main window.This system could provide the water-fertilizer mixture solution with certain concentration to the corps according to actual requirements. Therefore, how to control the mixed solution is the most important part of the system. Thus this system adopted fuzzy logic control technology of two-input one-output to realize the system control function. Meanwhile, this system adopted Fuzzy Logic toolbox in MATLAB to model and analyze relation for arguing input & output. Furthermore, this paper analyze the water & fertilizer coupling relationship and reach priority adjustment factor by experiment, and arrive at the corresponding valve theoretical opening time according to Fluid Mechanics and hydromechanics theories by coupling experiment, provide theory foundation to this design of controlled system.This system has many characteristics such as: low cost, good flexibility, easily operation, extensible and so on. It will have a vaster development vista.