Based On AquaCrop Model Research On Sunflower Irrigation Schedule In Hetao Irrigation Area

According to sunflower irrigation water at present is unreasonal in Hetao irrigation area,using AquaCrop model recommended by FAO to simulate water use of Hetao irrigation district,canopy cover,yield and biomass on sunflower in Hetao irrigation area,in order to study the local irrigation schedule on sunflower to relieve the pressure of local and downstream water.AquaCrop model is used in abroad and domestic arid and semi-arid lands,but the precision of model size is uniform,and the model is seldom used on sunflower in Hetao irrigation area.The model was calibration by the data collected in 2015,and the model data were validated in 2016 years in order to obtain the applicability of the model in the region.The main research results are as follows:(1)Based on the field data of 2015 and 2016,it was found that the soil water content in the sunflower growth period decreased gradually,and the decline was the most obvious at the budding to flowering stage.The leaf area index and the plant height trend were consistent.Sowing to the growth and development of the fastest buds,in 2015 due to the impact of autumn irrigation and washing brine before sowing,the treatment yield difference is not significant,2016 to reduce the amount of washing brine and irrigation water productivity differences in the sowing to the present Buds drought,budding to flowering irrigation,yield and irrigation water use efficiency is higher,compared with the traditional irrigation yield increased 4.85%.(2)Through the two years of experimental data on AquaCrop model calibration and validation found that canopy coverage,soil water content simulation values and observations are more consistent;The canopy coverage and soil water content coefficient of determination R2 were above 0.86,0.63,root mean square error RMSE between 4.02?18.19%,1.37?2.67(m3·m-3),the model efficiency coefficient is above 0.67,0.56;the relative error of yield and biomass is respectively 0.11-13.39%,0.41-21.05%.(3)Considering the situation where the groundwater level is shallow in the test area,the parametric AquaCrop model is used to simulate the groundwater level greater than 2.5m and less than 2.5m.In two cases,the appropriate drought treatment of crops before budding is beneficial to crop growth;groundwater level is less than 2.5 production is relatively higher;simulation of the current status of irrigation are not high utilization rate.In the buds to flowering or flowering to grouting during the irrigation,farmers gain highest income,more conducive to water conservation.(4)Based on the field experiment data and the AquaCrop model,it is considered that under the current situation,the key irrigation period of the sunflower in the Hetao irrigation area is the budding period to the flowering stage.Irrigation twice can save water and increase yield in full growth period,that is,Buds to flowering irrigation 50mm,irrigation quota of 110mm;using the recommended irrigation schedule,compared with 2016 the status of the irrigation system to reduce the irrigation water nearly 180mm,yield increased by 7%.