Estimation Of Farmland Evapotranspiration Of Corn And Wolfberry In Ningxia Based On Different Models

Dispersion is the process of water circulation in the soil-plant-atmosphere system.Accurate calculation of farmland water consumption has important reference value for farmland irrigation and real-time management.The penman model recommended by FAO is widely used as a reference model for the calculation of evapotranspiration of farmland plants.The Shuttle-wallace model,as a sparse crop integration model,has received extensive attention in recent years.In this paper,the main crops of Lycium barbarum and corn in the Weining Irrigated Area under the Yellow River Diversion Irrigation Area of Ningxia are studied.Field experimental observations and manual observations are carried out in the Jiusheng Agricultural Park of the Weining Irrigated Area of the Yellow River Irrigation Area of Ningxia,including the crop canopy temperature of corn and wolfberry.Environmental temperature,solar radiation,photosynthetically active radiation,soil temperature,soil moisture,soil moisture and crop growth indicators,etc.,analyze the spatial change characteristics of crop canopy temperature;soil moisture change characteristics;use continuous simultaneous observation of crop canopy temperature and field weather According to the data,the penman model recommended by FAO,which is now the benchmark for plant evapotranspiration,and the SW model used to calculate sparse crop evapotranspiration are used to calculate the daily evapotranspiration during the growth period of planted corn and wolfberry.Calibrate and verify the applicability of the SI model in the Zhongwei irrigation area in the Yellow River irrigation area in Ningxia;calibrate the underlying surface parameters of the SI model to study the evapotranspiration law of medlar and corn farmland in Zhongwei City,Ningxia,and to achieve accurate real-time water irrigation and irrigation in the irrigation area.Management provides scientific basis and technical support.After analyzing the full text,the main conclusions are as follows(1)During the main growth period of corn and wolfberry,the difference in canopy temperature during the horizontal growth period of corn and wolfberry fields is very small,and the variation index is within 3%.There is a significant difference in field temperature between corn and wolfberry in the vertical direction.Shows a gradient trend.The performance is canopy temperature>air temperature>20cm soil temperature.(2)The SW model and PM model are used to estimate the daily evapotranspiration of corn and wolfberry fields in Ningxia.Both the Penman model and the SW model meet the accuracy requirements.During the corn growth period,the PM model calculates the daily evapotranspiration greater than the simulation result of the SW model.During the growth period of corn.During the emergence and jointing stage,soil evaporation accounts for about 96%of daily evapotranspiration,and canopy evapotranspiration accounts for about 3%of daily evapotranspiration.In mid-June,in corn farmland evaporation in Zhongwei City,Ningxia Hui Autonomous Region,the ratio of canopy evapotranspiration to total evapotranspiration was the same as that of soil evaporation.During the filling-harvesting period,the canopy evapotranspiration of the com field accounted for about 80%of the total evapotranspiration,and remained unchanged,and the soil evaporation accounted for about 20%of the total evapotranspiration.The SW model calculates the canopy transpiration and soil evaporation of the wolfberry field.The ratio of soil evaporation to evapotranspiration is about 40%.The ratio of canopy evapotranspiration to evapotranspiration is about 60%.(3)In 2019,the change range of corn growth period(Etd-Rnd)and canopy temperature difference(TC-TA)between 10:00-16:00(R2)is 0.61-0.75.It shows that the difference between daily evapotranspiration and net daily radiation(Etd-Rnd)and canopy air temperature difference(TC-TA)have a good linear relationship in the corn plot.The Etd and measured Etd models are calculated by the model model at each time of the maize growth period in 2018 from 10:00 to 16:00.The regression coefficients in the regression equations of the model calculated ETd and the measured ETd range from 0.92-0.96,and the regression coefficients vary.(0.93-0.95)are(0.92-0.96)respectively,which are very close to 1.The SI model can estimate the daily evapotranspiration of corn very accurately.In 2019,during the growth period of Lycium barbarum(Etd-Rnd)and the canopy temperature difference(TC-TA),the variation range between 11:00-16:00(R2)is 0.29-0.42.It shows that the linear relationship between the difference between daily evapotranspiration and net daily radiation(Etd-Rnd)and canopy air temperature difference(TC-TA)in wolfberry fields is slightly worse than that of corn.The variation range of the regression coefficient in the regression equation of the model calculated ETd and the measured ETd is 0.65-0.75.The S-I model can estimate the daily evapotranspiration during the growth period of wolfberry,and further research is needed.