Study On Simple Calculation Method Of Water Consumption Of Orchard Based On Real-time Meteorological Data

In this study,an automatic timing weighing evaporating dish device and an automatic weighing pot test device were used to monitor the real-time water surface evaporation and plant transpiration,combined with local meteorological factors,through correlation analysis,partial correlation analysis,BP neural network,multiple Non-linear regression fitting and other methods were used to determine the main meteorological factors and plant physiological and ecological indicators that affect evapotranspiration,and establish“temperature and humidity”based on the main meteorological factors and the hourly evaporation?Epanhour?and daily evaporation?Epanday?,“RH-ET₀"model;and use this simple model to predict the actual evapotranspiration of apple trees in Yan'an Orchard.The following conclusions are obtained,?1?The main meteorological factors that affect the evaporation of the evaporation surface of the evaporating dish are temperature?T_a?,average relative humidity?RH?and solar net radiation?R_n?.On the daily scale,the correlation between evaporation and meteorological factors is:Ta?r=0.809?>Rn?r=0.526?>RH?r=-0.44?;on the hour scale,the correlationbetweenthetwoisinorderItis:Ta?r=0.843?>Rn?r=0.808?>RH?r=-0.780?>U?r=0.538?>P?r=-0.113?,temperature,humidity and net solar radiation will evaporate The influence of the quantity is significant and stable,and the partial correlation analysis proves that the effect of solar net radiation on ET₀ can be reflected to a large extent by the comprehensive effect of temperature and humidity.In addition to meteorological factors,the main plant factors affecting plant transpiration are:leaf area index?r=0.666?,total leaf area?r=0.592?and crown width?r=0.539?,among which the leaf area index has the most significant influence.?2?When the temperature increases by 1°C,the evaporation of the water surface of the evaporating dish increases by 0.07mm/day on average,an increase of 4.32%.In summer?June-August?,when the temperature increases by 1°C,the evaporation increases by an average of 0.078mm/day,an increase of 3.17%,in winter?November-February?,when the temperature increases by 1°C,the evaporation of water on the evaporating plate average An increase of 0.043mm/day,an increase of 5.19%,the lower the temperature,the more severe the effect of increasing temperature on the evaporation of the water surface of the evaporating dish.?3?Temperature and humidity can better reflect the evaporation of water surface.The“temperature and humidity-evaporation”model is established by nonlinear multiple regression.The effective coefficient of hourly evaporation model is NSE=0.889 and the effective coefficient of daily evaporation prediction model is NSE=0.923.After multiplying the temperature-humidity-evaporation model by the evaporating dish coefficient Kp=0.668,the model can better simulate the change of ET₀.In 2018 and 2019,the Yanan Orchard ET0 fitting model NSE=0.674,0.611,the overall trend is higher.The prediction results of this model are compared with those of Priestley-Taylor?P-T?,Hargreaves?H-G?,Blaney-Criddle?B-C?,and BP neural network algorithms,which have obvious advantages.?4?By determining the crop coefficient K_c of apple trees at different growth stages,it is calculated that the water consumption of apple tree transpiration in Yan'an Orchard is concentrated between June and October,and the maximum average daily transpiration amount is 4.25mm/day in July.In addition,the peak surface water content of the orchard soil all occurred in September.In the horizontal direction,the difference in the surface water content of the soil at 20,40,and 60 cm from the main trunk of the fruit tree was small.In the vertical direction,affected by the process of alternating rainfall and evaporation the water is distributed in an"S"shape at different depths,resulting in a water turning point at the 20-30cm soil layer.