| In this paper,we combine agricultural drainage filtration with saline land management to form a dark pipe drainage type non-full-flow filtration device in response to the problems of low yield and difficult filtration of water with high sand content in saline land.According to the technical specification of dark pipe drainage and previous experience of non-full-flow filtration,three kinds of dark pipe drainage type non-full-flow filtration devices with different sand filter media,such as fine sand grain(F1),1:2 mixture of fine sand grain and fine gravel(F2),and fine gravel(F3),are designed,and rice is used as the test crop and flood irrigation is adopted to systematically study the effects of different treatment devices on farmland drainage filtration,saline land management,and the effects on rice The effects of different treatment devices on the drainage and filtration effects,saline land management effects and the effects on rice growth,photosynthesis,yield and quality were systematically investigated.The research results can provide theoretical basis and technical support for saline land management,irrigation and drainage synergistic water conservation and salt control,and high-sand water reuse in Ningxia Yellow Irrigation Area.The main research results are as follows.(1)Revealed the effects of different treatment dark pipe drainage type non-full-flow filtration devices on the filtration effect of farmland drainage.The test showed that:the average filtered water flow rate of F2 treatment device in the test period was 0.38 m3/h,which was 2.24 times and 2.0 times of the filtered water flow rate of F1 and F3 treatment,respectively;at the end of the test compared with the beginning,the conductivity in the farm drainage water of F1,F2 and F3 treatment decreased by 59.75%,80.17%and 57.83%,respectively;the turbidity in the steady flow period of F1,F2 and F3 treatment drainage water decreased by 95.48%,96.62%and 89.47%,respectively,compared with the irrigation water The turbidity of F1,F2 and F3 treatment drains decreased by 95.48%,96.62%and 89.47%,respectively,compared with irrigation water.It shows that the salt and sand filtration capacity of F2 treatment is higher than other treatments.(2)Revealed the effect pattern of different treatments of dark pipe drainage type non-full flow filtration device on soil water salinity,particle size and nutrient transport.The experiment showed that during the rice irrigation,the soil volumetric water content of F1 treatment in 0-60 cm was in a relatively stable state,the soil volumetric water content of F2 treatment in 0-60 cm showed a decreasing trend with time,and the soil volumetric water content of F3 treatment in 0-60 cm showed an increasing trend with time;during the irrigation,the soil desalination rates of F2 treatment in 0-20,20-40,40-60 cm The desalination effect of F2 treatment was better than F1 and F3 treatments with 71.28%,60.10%and 47.71%respectively;the soil particle size D50 of F2 treatment increased significantly before and after rice planting compared with F1 and F3 treatments,and its soil particle D50 increased by 47.05%、92.53%and 23.44%at 0～20cm,20～40 and 40～60cm respectively;F2 treatment of soil nutrient loss at 0～20cm,20～40cm,and 40～60cm soil layers decreased by 6,37and92 mg/kg before and after crop planting,respectively.(3)The effects of different treatments of dark pipe drainage type non-full flow filtration device on rice growth,photosynthesis,yield and quality were revealed.The experiment showed that the plant height of F2 increased by 10.8%and 8.19%compared with F1 and F3 treatments at the rice maturity stage;the leaf SPAD values of F2 increased by 10.23%and 8.67%compared with F1 and F3 treatments at the rice nodulation stage;the rice yields of F1,F2 and F3 treatments were 8011,9758 and 8464 kg/hm2,respectively.Although the protein content of F2 treatment decreased by 4.41%and 5.80%compared with F1 and F3 treatment,the protein content of F2 treatment still increased by 18.18%compared with CK group. |
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