Fitting Of Soil Temperature-Moisture Content And Numerical Simulation Of Soil Temperature In Solar Greenhouse

In the solar greenhouse where crops are cultivated in the cold and arid regions of the North,the soil has a direct effect on the growth of the plant roots and the germination of the seeds.Among them,changes in soil temperature and moisture content have a greater impact on the growth of greenhouse crops.This thesis takes the typical"San-li-yi-Po"（Three standing walls and one slope）solar greenhouse in Hohhot as the research object,in this paper,the temperature and moisture content of soil in greenhouse were measured by ms-10 soil moisture sensor for two consecutive years,and the effective actual data were obtained.Using Origin、Excel software to analyze data,to study the relationship between the moisture content and the temperature of the greenhouse soil,and a soil temperature numerical model was established using Gambit,and the model was numerically simulated using Fluent.The results showed that:（1）The linear fitting model was used to analyze the measured data to obtain the change equation of soil temperature on the surface layer of soil with respect to water content,and the relationship between soil temperature and water content was converted into an equation with independent variables as soil temperature.The fitting equation of the modified soil moisture content with the change of soil temperature is as follows:at-0.05 m soil layer,Y_WN1=(X_TN1+157.1768)/4.561 5+0.15 Z+0.05 Z、Y_WM1=(X_TM1+216.723)/5.900 6+0.15 Z-0.05 Z、Y_WS1=(X_TS1+177.557)/5.331 4+0.15 Z+0.05 Z;at-0.15 m soil layer,Y_WN2=(X_TN2+42.4386)/1.4578+0.05 Z、Y_WM2=(X_TM2+106.9583)/3.1419+0.05 Z、Y_WS2=(X_TS2+37.9246)/1.4159+0.05 Z.We then verified the accuracy of these equations by matching the other test data of different weathers,and found that the moisture of topsoil can be obtained as long as the temperature of topsoil is determined.（2）Based on CFD method（Computational Fluid Dynamics）,a numerical simulation of greenhouse soil temperature was conducted,and the soil temperature prediction model with relative error less than 5%was obtained,which could predict soil temperature.The variation equations between the moisture and temperature of topsoil and soil temperature prediction model can effectively reduce the number of test points,and provide theoretical guidance for the study of soil moisture content and temperature change and greenhouse crop production in north China.