Study On Intellectualized Irrigation Decision System Of The Urban Green Land

Water is one of the basic elements which maintain the human's existence and thedevelopment of society. In our country, the problem of water shortage is particularlyserious. With the rapid urbanization in our country, urban green area raises rapidly andmajor environmental issues such as water pollution cause great threats, so that problemsabout urban water supply become more serious. Therefore, improving the utilization ofwater resource and implementing water conservation are the fundamental ways to solvethe problems of water supply in the urban area. Then precise and intelligentwater-saving irrigation would replace the current extensive irrigation.Firstly, PSO-BP neural network is created to forecast the reference cropevapotranspiration ET0. Then the fuzzy reasoning system of the irrigation coefficientsand the fuzzy decision system of the irrigation are established. Ultimately, the greenland can achieve a timely irrigation with a balanced amount.In this paper,9groups of meteorological factors are used as the inputs to build theBP neural network, and the network structure is determined through the theoreticalanalysis and a lot of repeat experiments. Then the PSO algorithm is adopted to optimizeweights and thresholds of the BP neural network, and the PSO-BP neural network isestablished. The trained PSO-BP model is applied to forecast the reference cropevapotranspiration. The forecast results of the various inputs are compared with PM ET0,the results show that only4impact factors (the average temperature?the averagerelative humidity?the wind speed and the sunlight hours) are chosen as inputs, theaccurate value of reference crop evapotranspiration can be obtained. The paper provides a feasible method for the accurate prediction of the reference crop evapotranspiration incase of the absence of some meteorological data.In this paper, the green crop coefficients which are fuzzy-processed are used toestimate the actual crop evapotranspiration. The actual crop evapotranspiration and theeffective soil moisture are used as inputs, irrigation coefficients as outputs to build thefuzzy reasoning system of the irrigation coefficients. Then the irrigation quota formulasand water balance equations are combined to establish fuzzy decision system of theirrigation and decide irrigation amount and time. The related data of2005are applied totest the fuzzy decision system of the irrigation, the results show that making theirrigation decision with this system can make the effective soil moisture kept in anappropriate range of the crop' growth. Under the precondition of the crop' healthygrowth, the water source is saved to the greatest degree, and the paper provides someguidance about the wide implementation of the water-saving irrigation.