| Subsurface drip irrigation,as a high-efficiency water-saving technology,is widely used in the field crop planting.However,problems such as insufficient upward movement of water and prone to deep leakage occur in the practical application,in view of this phenomenon,this paper proposes a membrane controlled irrigation technology.To explore the technical characteristics of moisture migration and the impact of winter wheat growth,this study has carried out the indoor experiment and field experiment,indoor test,the underground drip irrigation,for comparison,set up three kinds of flow rate(1.0,1.3,1.6 L/h)and three kinds of specifications(40×30 cm,40×25 cm,40×20 cm),a total of 12 kinds of processing,to explore the characteristics of water transport under the condition of membrane controlled irrigation,and the influence rules of flow rate and membrane specification on the shape and size of wetting body,vertical and transverse distribution of water quantity;In the field experiment,subsurface drip irrigation was used as the control,different membrane specifications(40×30 cm,40×20 cm),irrigation amount(1350 m3·hm-2,1800 m3·hm-2)and emitter spacing(80 cm,100 cm)were set in 12 treatments,To explore the the effects of membrane controlled irrigation on field water transport,winter wheat growth indexes,yield and water use efficiency.The main results are as follows:(1)For the membrane-controlled irrigation,the shape of the wetted body on the membrane was approximately semi-ellipsoid with the horizontal width and vertical height of the wetted body as the long and short radii,and the approximate cross-section shape under the membrane was semicircular annular wetted body;Compared with subsurface drip irrigation,the vertical height and horizontal width of wetted body film increased by 30.7%and 45.6%,respectively,while the vertical depth under the film decreased by 69.4%.The horizontal width and vertical depth of the wetting body decrease with the decrease of the size and flow of the upper film,while the vertical height increases;(2)Compared with subsurface drip irrigation,the total amount of water in the moistened body under membrane control increased by 91.9%,and the total amount of water in the moistened body under membrane decreased by 72.4%;The amount of water in different depths of the wetted body increases with the decrease of the size and flow of the upper film,while the amount of water in each layer of the wetted body below the film decreases;Compared with subsurface drip irrigation,the amount of water in the wetted body in the range of 0-10 cm from the emitter level under membrane control irrigation decreased,and the amount of water in the range of 10～25 cm level increased;The variation range of water in each horizontal position in the wetted body decreased compared with subsurface drip irrigation,and the variation range tended to decrease with the increase of the size and flow of the upper membrane.(3)Compared with subsurface drip irrigation,the water content in the 10～40 cm soil layer of winter wheat field under membrane control irrigation increased,while the water content in the 40～70 cm soil layer decreased.Reducing the distance between the emitters,the size of the upper film or the amount of irrigation can promote the water migration to the soil layer above the film and reduce the water seepage under the film;Compared with subsurface drip irrigation,the amount of water in the 0～20 cm range of winter wheat field spacing emitters under membrane control irrigation decreased,the amount of water in the 20 cm range to the center of adjacent emitters increased,and the difference of water distribution between different horizontal locations decreased,up to 53.61%;The difference of water distribution between different horizontal positions can be reduced by decreasing the distance between emitters,increasing the size of the upper film or the irrigation amount;(4)Plant height,leaf area index(LAI),dry matter accumulation and other growth indexes of winter wheat under mulching irrigation were higher than those under subsurface drip irrigation,and the differences were gradually significant after the starting stage;Increasing irrigation amount,decreasing emitter spacing or upper film size could increase the above growth indexes,and the effects were significant after anthesis;(5)Compared with subsurface drip irrigation,the yield and water use efficiency under membrane control irrigation increased by 1.36%to 12.60%and 5.09%to 17.39%,respectively,reaching the maximum of 8 839.9 kg·hm-2 and 2.87 kg·m-3,respectively.Reducing the emitter spacing and the size of the upper film can increase the yield and WUE,and increasing the irrigation amount can increase the yield,but the WUE decreases to a certain extent.In conclusion,compared with subsurface drip irrigation,membrane controlled watering irrigation can increase the upward and horizontal wetting range of wetted body,increase the upward movement of water and the water distribution outside the wetted body,and reduce the infiltration range and the water distribution outside the wetted body,which is more conducive to the concentrated distribution of water in the upper soil and improve the horizontal distribution uniformity of water.The growth index,yield and water use efficiency of winter wheat were improved in different degrees. |
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