Experimental Study On Root Region Soil Water And Salt Transport And Growth In Southern Xinjiang Jujube Under Indirectly Subsurface Drip Irrigation

Indirect subsurface drip irrigation is a new and efficient water-saving irrigationtechniques, by the ordinary surface drip irrigation systems and soil hydraulic conductivitybeneath the emitter device is configured, the device includes an upper portion of the guidewater impermeable boundary (PVC pipe), the lower part of permeable boundaries and bottompermeable (cylindrical grit body) consists of three parts; when irrigation water through dripemitters into surface water guide device (PVC pipe) in coarse sand quickly reach the bottomof the water guiding device, through the lower part of the permeable boundaries and bottompermeable to the surrounding soil infiltration, reaching underground drip irrigation effect.Compared with ordinary surface drip irrigation to reduce surface evaporation; compared withsubsurface drip irrigation, but also avoid the problem of clogged emitters easily. This papertests and test research field indoor indirect subsurface drip salt and water movementcharacteristics, and jujube in this growth and development of irrigation mode.â‘ Laboratory tests with dripper flow aqueduct diameter, permeable layer thickness, theinitial salt content of factors that impact studies on various factors under different levels ofsalt and water movement; field trials with irrigation amount, dripper flow aqueduct diameter,orthogonal design permeable layer thickness for four factors and three levels, the study ofwater and salt distribution and jujube jujube tree root zone growth and development, thefollowing conclusions:horizontally and vertically up and down, the smaller the wetting front flow more slowly,the larger the wetting front flow faster, when the same amount of flow irrigation wetting frontalong the horizontal transport distance greater, the flow of small vertical migration distance islarge. Wetting front distance versus time quadratic function.Aqueduct same diameter, per unit area and the total cumulative infiltration infiltrationtime were flooded with water guide device increases the height decreases. When permeablelayer thickness constant, cumulative infiltration per unit area with water guide devicediameter increases. Aqueduct and a combination of different diameter permeable layer, thetotal permeable area, the smaller the suction surface of the surrounding soil, the slower therate of lateral migration of moisture. The total permeable area, the greater the volume of moistbody, the relationship between soil filtrate conductivity and soil moisture logarithmicfunction.The higher the initial soil salinity, water leaching efficiency is higher, the more saltaccumulation at the wetting front.â‘¡In indirect subsurface drip emitter flow, the smaller the diameter of the aqueduct, thehigher the moisture content of the soil surface; greater the amount of irrigation, dripper flowis smaller, the larger the diameter of the downward migration of the aqueduct water depthmore large; greater the amount of irrigation, soil from the jujube tree trunk near the watercontaining the greater rate; dripper flow, permeable layer thickness and size of the PVC pipediameter lateral migration of moisture effects on the size of the impact is greater than theamount of irrigation.â‘¢Compared with surface drip irrigation, higher indirect subsurface drip irrigation wateruse efficiency; considering the distribution of water and salt and jujube jujube tree roots growing areas, yield, fruit quality and water use efficiency, plant irrigation amount19L,aqueduct diameter of75mm, permeable layer thickness of40mm, dripper flow3L/h indirectsubsurface drip irrigation is the best combination of factors.