| Geting the soil moisture information and improving the efficiency of agricultural irrigation water as the goal,combining with field experiment,theoretical research,numerical analysis,system design and integration,this paper makes a deep study on the soil moisture monitoring technology,the location of the moisture sensor probe,the model of soil moisture monitoring and irrigation automatic control and system design,and so on.And the main research results can be summarized as follows.(1)Taking drying method as standard,the change trend of soil moisture content was consistent with TDR method and FDR method,but the TDR method was more accurate.Compared with the TDR method,the mean absolute error of the FDR method was increased by 1.45%,the average relative error was increased by 10%,and the correlation coefficients of the TDR method and the FDR method and the drying method were up to 0.98;Using KMO statistic and spherical hypothesis test Bartlett 's determines the certain correlation among soil water content of different soil layers,And through the principal component analysis and factor analysis to determine the 10 cm,30cm,60 cm,90cm four deep are appropriate to bury soil moisture sensor probe;Through the study of 0~100cm soil water dynamics,the soil moisture fluctuation of winter wheat and summer maize in the 0~40cm soil layer was the largest,and the amplitude decreased with the increase of soil depth.(2)It was clear that using Penman-Monteith and Zhengzhou area average crop coefficient method to calculate crop water requirement had high precision.On the basis of effective rainfall and crop water requirement,and so on,soil moisture monitoring model was established based on the water balance principle,and the irrigation prediction model was established based on soil moisture monitoring,which included forecasting irrigation water and irrigation time.(3)Based on related research in soil moisture monitoring technology,moisture detector layout and dynamic changes of soil moisture and crop water requirement and so on,this paper designed the database of the system,hardware and software,and it was relized that the collection of soil moisture information,soil moisture information processing,soil moisture prediction,irrigation decision-making in soil moisture monitoring and irrigation automatic control system based on PLC.This system was applied to Yangqiao irrigation area,and the results showed that the operation of the whole system was stable. |
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