Effects Of Subsurface Irrigation With Porous Ceramic Emitters On Crop Growth And Yield

Subsurface irrigation with porous ceramic emitters is a new type of irrigation method,which has the advantages of energy saving,environmental protection and adaptive irrigation,and can provide relatively stable soil moisture environment for crop growth,which is different from the soil moisture environment of dry-wet alternate in traditional irrigation.In order to clarify the effects of this different soil moisture environment on crop growth and yield,vegetable(Spinach)and economic fruit(Lycium barbarum)were selected as the research objects.Through indoor pot experiments,the effects of subsurface irrigation with porous ceramic emitters and subsurface drip irrigation on spinach growth and yield in different seasons were compared and analyzed,and the water-saving and yield-increasing effects of subsurface irrigation with porous ceramic emitters were clarified;the effects of different design flow rates of porous ceramic emitters and capillary arrangement on the growth,physiology,yield and water use efficiency of Lycium barbarum were further studied,and the appropriate technical parameters of subsurface irrigation with porous ceramic emitters for Lycium barbarum were proposed,so as to provide certain theoretical support for the popularization and application of subsurface irrigation with porous ceramic emitters.The main conclusions are as follows:(1)The effects of different design flow rates of porous ceramic emitters and capillary arrangement of subsurface irrigation with porous ceramic emitters on the growth and yield of Lycium barbarum were analyzed.In winter and summer,the average soil moisture content of subsurface irrigation with porous ceramic emitters of spinach was maintained at 74%-77%and 57%-66%of field water capacity,respectively,while the average soil moisture content of subsurface drip irrigation was 60%-90%and 40%-90%of field water capacity.Subsurface irrigation with porous ceramic emitters could promote the growth of spinach,and its plant height and leaf number per plant increased by 13.8%and 5.4%respectively compared with subsurface drip irrigation.The diurnal variation trend of net photosynthetic rate of subsurface irrigation with porous ceramic emitters was more stable than subsurface drip irrigation.Subsurface irrigation with porous ceramic emitters can significantly improve the yield and water use efficiency of spinach.The yield of spinach in winter and summer is 258.14 kg/mu and 1922.87 kg/mu,respectively,which is 37.8%and 19.0%higher than subsurface drip irrigation,respectively.And its water use efficiency was 5.78 kg/m~3 and 30.03 kg/m~3,respectively,which is 2.5%and 0.4%higher than subsurface drip irrigation,respectively.(2)The effects of different emitters’design flow rate and capillary arrangement on the growth and yield of Lycium barbarum were analyzed.Under the same capillary arrangement,with the increase of emitters’design flow rate,the growth index,net photosynthetic rate,yield and water use efficiency of Lycium barbarum increased first and then decreased.The indexes of Lycium barbarum were the highest when the emitters’design flow rate was 0.3 L/h,and the plant height,crown width,ground diameter growth and net photosynthetic rate reached 34 cm,27.33 cm,6.02 mm and 18.6μmol/(m~2·s),respectively.Its yield and water use efficiency reached 228.71 kg/mu and 1.10 kg/m~3,respectively,which increased by 49.8%and 44.3%compared with the treatment of 0.1 L/h.Under the same design flow rate of the emitters,the growth and physiological indexes of two-tube and one-row treatment were significantly increased compared with one-tube and one-row treatment,and the plant height,crown width,ground diameter and net photosynthetic rate increased by 3.6%,4.3%,2.8%and 1.9%,respectively.While yield and water use efficiency of Lycium barbarum were decreased by15.0%and 12.0%,respectively.(3)The technical parameters of subsurface irrigation with porous ceramic emitters suitable for spinach and Lycium barbarum were proposed.Considering the requirements of growth,agricultural water saving and crop high yield of spinach and Lycium barbarum,the application technical parameters of subsurface irrigation with porous ceramic emitters suitable for them were proposed.For spinach,it is suggested to adopt the technology of subsurface irrigation with porous ceramic emitters,select the porous ceramic emitters with the design flow rate of 0.05 L/h and the buried depth of 15 cm for irrigation.For Lycium barbarum in Ningxia:It is suggested that when using the technology of subsurface irrigation with porous ceramic emitters in Lycium barbarum in Ningxia semi-arid area,the emitters’flow rate should be 0.3 L/h,and the capillary tubes should be arranged one-tube and one-row.