Yield Advantage And Nitrogen Economy In The Intercropping System Of Peanut With Rice Cultivated In Aerobic Soil

Object:Sediment siltation in Yellow River irrigation problem is caused by normal operation of Yellow River irrigation area and one of the main reasons for restricting the development of agricultural irrigation area,irrigation channel deposition seriously in recent years,water conveyance ability decline year by year,the lower is difficult to get water,at the same time,along with the modern irrigated areas,the pipeline is gradually popularized in irrigation area,in the face of high sand content in water,solve the problem of pipeline sedimentation is also a key factor in the development of irrigation area,so the tube drainage combined with efficient water technology is particularly important,explore the irrigation channel sediment migration characteristics and the variation of the sediment gradation along the regularity,find out the method to minimize the channel sedimentation.At the same time,on the basis of reasonable water conveyance,the technical parameters of efficient water conveyance are tested,the siltation mechanism of pipelines is studied,and the method of efficient water conveyance is put forward to ensure the normal operation and development of irrigation areas.Methods:For high honour village typical main canal irrigation district of sands contained stream flow to the real time monitoring sampling of 10 typical changes in cross section,analysis of suspended load sediment characteristics along the sediment concentration change and grading,and according to the measured data adopts four typical the sediment-carrying capacity formula of screen is suitable for the sediment-carrying capacity formula of the village of irrigation area,irrigation channels for further improvement and village the sediment-carrying capacity formula,flows through a transformation period of the measured data,calculate balance by scouring and silting in main canal slope calculation formula.And the village level 2 station before laying pool test pipes,300 m to set high and low gradient under the condition of different water flow rate control monitoring sediment transport rule,under different working conditions,monitoring pipe laying length of sediment deposition,and adopt the method of CFD numerical simulation simulation,explore the causes and reduce aggradations of the pipeline sedimentation method.Results:1.The sediment content of the incoming water in the channel is significantly reduced compared with that in the 1990s.The head sedimentation tank can effectively reduce the sand content in the diversion water.The sediment deposition problem still exists in the dredging and repairing section of a main channel,It is calculated that when the design flow of a main channel transformation section is 46 m~3/s,J=0.0004,and the remaining unreconstructed part of a main channel is suggested to increase the specific gradient if conditions permit.2.channels in different particle size of sediment transport characteristics of the different,suspended load of the main canal sediment concentration increases with the increase of sediment concentration and sediment,the channel siltation mainly related to the amount of silt and sand,the sand act is most sensitive to the change of sediment concentration and sediment,and the clay was taken away by the water,more channels by non-equilibrium sediment erosion and deposition by scouring and silting reach equilibrium sediment process slowly.3.Pipeline suspended load sediment particles,silt content,clay,sand content is the lowest,most of the coarse sediment deposition in the first,a few large sediment to the downstream pipe by water,low flow in the pipeline sedimentation particle size under the conditions of silt and clay are especially sensitive,deposition of sediment are main from silt and clay.With the increase of sediment content,the critical non-silting velocity of the pipeline increases gradually.Meanwhile,with the increase of the diameter of the water conveyance pipeline,the critical non-silting velocity also increases gradually.4.The settlement of coarse particles has an extruding effect on fine particles.The collision probability of coarse particles and the growth rate of pipeline strength of sediment fluid with two particle sizes are much higher than those with a single particle size.Under the same solid-phase concentration,the collision probability of particles in the multi-particle size fluid is greater at a low flow rate.With the increase of the flow rate,the particle size has a greater impact on the wall shear force.Conclusion:When the sediment content of the channel is within 2 kg/m~3,the inflow water of the first-stage station is about 8 m3/s,and the channel basically realizes the balance of erosion and silting.When the fluid in the pipeline is at a low velocity,the fine particles in the sediment fluid with two particle sizes form a layer of lubrication on the near wall surface,which makes the flow state of the coarse particles change from saltation to sliding bed and reduces the energy consumption of pipeline transportation.When combined with the balance of erosion and silting of the channel water,the sediment content of the inflow from the channel is 2 kg/m~3,the median particle size is 0.04 mm,and the critical non-silting velocity of the pipeline water is 0.8 m/s.