The Response Of Different Irrigation And Soil Texturein Ulan Buh And Region And Optimizing Of Irrigation Schedule Based On AquaCrop

In view of the current situation of low water use efficiency and low yield caused by poor soil,serious percolation in Ulan Buh sand area of Inner Mongolia,this paper takes corn as the test object and sets different irrigation methods(drip irrigation,border irrigation)and different soil texture(sand,sandy loam)tests in water saving test station of Mulitan,Ulan Buh sand area from 2016 to 2018,including sandy drip irrigation(T1),sandy border irrigation(T2),sandy loam drip irrigation(T3)and sandy loam border irrigation(T4).The effects of different irrigation methods and soil texture combinations on corn growth,water consumption and water use efficiency were studied.Based on AquaCrop,the water consumption mechanism and irrigation system were analyzed and optimized.The monitoring and evaluation of the growth of crops,find out the law of water consumption in the sand area,and put forward the water management mode suitable for different irrigation and soil quality in the drought sand area.The research is of great significance for grain production and water efficient utilization in the sand area.The main results are as follows:(1)The application of AquaCrop model in the condition of different treetments in Ulan Buh sand area was calibirited and validated.The RMSE of soil water content,canopy cover and biomass were 1.37cm 3/cm3,8.38%and 2.17kg/hm2,and the R2 were 0.88,0.91 and 0.95,and the d were 0.97,0.98 and 0.95,respectively.The total accuracy was high.(2)Based on the method of DualCrop Coefficient,the ETc estimation model of corn in farmland with different treetments in Ulan Buh and sand area was constructed.Compared with water balance,the maximum and minimum relative error was 16.78%and 3.83%,respectively.In general,the order of water consumption of different treatments was T3? T1? T4? T2.Under the same soil texture,the water demand intensity and modulus of drip irrigation field at jointing stage are 16%and 21%higher than those of border irrigation,and 5%and 9%higher at tassel stage,respectively.Under the same irrigation mode,the water demand intensity of sand loam field is 7.38%higher than sand,among which the water demand intensity and modulus of drip irrigation field at jointing stage are 17%and 4%higher than that of sand,and 10%and 2%higher at tassel stage,respectively.(3)Under the same soil texture,the ET of drip irrigation is 10.77%higher than that of border irrigation,the percolation at 40cm and 100cm is 74.96%and 64.34%lower,the yield is 19.33%higher,the field water use coefficient is 26.15%higher and WUEGrain is 2.11%higher.Under the same irrigation method(drip irrigation),the water consumption of sandy loam field is 6.62%higher than that of sand,but the deep percolation is 24.56%lower,and the yield is increased 10.02%higher,0.31%higher in field water use coefficient and 2.31%higher in WUEGrain.Among them,the T3 is the highest,with an average of 11.88t/hm2,which is 12.80%,19.22%and 29.88%higher than T1,T4 and T2 respectively;the WUE is the highest,with an average of 3.10kg/m3,which is 1.14%,2.31%and 5.45%higher than T4,T1 and T2 respectively.(4)According to the field monitoring of regional scale sand area,drip irrigation accounts for 65.8%,border irrigation 34.2%,sand 63.2%and sandy loam 36.8%.The regional soil texture and water distribution are not uniform.The average yield of corn in drip irrigation sandy soil(T1),drip irrigation sandy loam(T3),border irrigation sandy soil(T2)and border irrigation sandy loam(T4)were 10.84 t/hm2,12.17 t/hm2,7.21 t/hm2 and 8.06 t/hm2,respectively.The corn yield of drip irrigation area is 50.63%higher than that of border irrigation area,but under the same irrigation mode,the corn yield of sandy loam farmland is 12.11%higher than that of sandy soil,the difference is not significant.(5)The SWDtof different treatments was estimated by AquaCrop model.The average SWDt of T1,T2,T3 and T4 were 0.38,0.16,0.36 and 0.34,respectively.Under border irrigation condition,the water deficit(SWDt?0)was 6 days longer than drip irrigation,while sandy soil was 4 days longer than sandy loam,of which the longest was border irrigation,which was 12 days longer than drip irrigation.Through different scenario simulation and quadratic function optimization,we get the better irrigation schedule under different irrigation methods in Ulan Buh sand area.When the drip irrigation quota is 371.93mm and that of border irrigation is 412.09mm,the water consumption is 407.42mm and 367.27mm,respectively.The optimal WUE is 3.23kg/m3 and 3.03kg/m3,and the yield is 13178.40kg/hm2 and 11138.62kg/hm2,respectively.