| Yinbei Irrigation Area of Ningxia is located in the lower reaches of Ningxia Yellow River Diversion Irrigation Area.Because of the gentle terrain and poor drainage conditions,the groundwater level has been high for a long time and a large area of saline-alkali wasteland has been formed.Soil salinization has a serious impact on local crop yields,and also restricts the economic development of Yinchuan Plain.Through comparative experiments,the effects of solar energy drainage on the soil environment,such as groundwater depth,groundwater salinity,soil total salinity and soil particle size distribution in fields of oil sunflower and maize,and on the yield and growth index of oil sunflower and maize were studied.The AquaCrop model was used to optimize the irrigation system of oil sunflower under the condition of solar energy drainage in Huinong,which was solar energy.The application of underground drainage technology in local areas and the cultivation of oil sunflower provide basis and guidance.The main results are as follows:1.Contrastive experiments were conducted to study the effects of solar energy drainage on the improvement of saline-alkali soil environment and the yield of oil sunflower and maize.(1)the solar shadow pipe drainage can effectively control the groundwater depth and reduce the groundwater salinity.In 2017,the solar shadow pipe drainage reduced the average field groundwater level and the groundwater salinity of okra in the whole growth period by 4.5%and 7.9%,decreased the average field groundwater level and the groundwater salinity of maize in the whole growth period by 5.3%and 3.3%respectively.In 2018,the solar shadow pipe drainage will reduce the average field groundwater level and groundwater salinity of oil sunflower in the whole growth period by 6.4%and 9.0%,and reduce the average field groundwater level and groundwater salinity of corn in the whole growth period by 8.3%and 6.6%,respectively.(2)solar dark pipe drainage has a good desalination effect on field soil of oil sunflower and corn,and the best desalination effect on soil layer 0-20cm.In 2017,the average desalination rate of field soil of okra was 3.8%by solar shadow drainage and 4.0%by corn.In 2018,the overall desalination rate of field soil of ovalva oil was 8.8%with solar shadow pipe drainage,and that of corn was 6.1%.(3)under the action of solar shadow pipe drainage,fine particles in the upper soil will move down with the drainage,thus improving the aeration of the upper soil.(4)solar shadow pipe drainage has a certain lifting effect on plant height and stem diameter of oil sunflower and corn.In 2017 and 2018,the final plant height of oil sunflower in the treatment area was 1.9%higher than that in the control area and 3.0%higher than that in the control area.In 2017 and 2018,the final plant height of corn in the treatment area was 1.2%higher than that in the control area and 4.9%higher than that in the control area.In 2017 and 2018,there was no significant difference in stem diameter between the treatment area and the control area.In 2017 and 2018,the final stem diameter of corn in the treatment area was 2.5%and 4.7%higher than that in the control area,respectively.(5)solar shadow drainage promoted the yield of oil sunflower and corn.In 2017,oil sunflower treatment area increased yield by 13.8%and corn treatment area increased yield by 10.4%.In 2018,the oil palm processing area increased production by 21.6%,and the corn processing area increased production by 13.7%.Solar shadow drainage promoted the water production efficiency of oil sunflower and corn.In 2017,the irrigation water production efficiency of the oil-sunflower treatment area increased by 13.3%,the crop water production efficiency increased by 16.4%,the irrigation water production efficiency of the maize treatment area increased by 10.4%,and the crop water production efficiency increased by 12.6%.In 2018,the irrigation water production efficiency of the oil-sunflower treatment area increased by 21.8%,the crop water production efficiency increased by 22.9%,the irrigation water production efficiency increased by 13.7%and the crop water production efficiency increased by 15.0%.2.Using AquaCrop model to optimize the irrigation schedule of oil sunflower.AquaCrop model simulation results show that the average groundwater level in 120 cm growth period is an important demarcation point for sunflower production.Overall,treatment T14,i.e.irrigation of 1500 m3/hm2 at emergence-budding and budding-flowering stages,is the optimal irrigation system for sunflower drainage by solar energy in Huinong.Maize treatment T15,i.e.irrigation 2400 m3/hm2 during emergence-jointing and jointing-tasseling stages,is the optimal irrigation system for solar energy drainage Maize in Huinong.Irrigation increased by 150 m3/hm2,yield increased by 125 kg/hm2,and increased by 1.2%.In conclusion,the existing irrigation system for maize is more economical and more suitable for current planting conditions. |
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