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Soil Water Distribution And Water Use Of Winter Wheat-summer Corn In Subsurface Membrane Regulated Moist Irrigation

Posted on:2024-01-02Degree:MasterType:Thesis
Country:ChinaCandidate:Y B ZhangFull Text:PDF
GTID:2543306935487254Subject:Agricultural Soil and Water Engineering
Abstract/Summary:PDF Full Text Request
Underground membrane regulated moist irrigation is an efficient water-saving irrigation technology that combines drip irrigation and film mulching technology by burying the drip irrigation pipe underground.The upper and lower layers of the control film are square impermeable polyethylene film,25cm multiplied by 40cm,with a permeable substrate layer of filter cotton in the middle and the same size as the upper film.The drip head is designed for a flow rate of 2.0 L/h and a spacing of 80 cm.After the drip irrigation pipe is placed in the ground at 35 cm,the upper and lower films are placed at the top and bottom of the drip head respectively,and the symmetrical centres of the upper and lower films coincide with the drip head.The principle of underground film regulated wet irrigation is to use the water absorption force of soil water to make water and fertilizer stay and evenly distribute in the main root layer of the crop,which will help the root system to fully absorb and use water resources,thus reducing the loss of ineffective water and fertilizer,and play an important role in promoting the solution of the problem of water scarcity in agriculture in the North China Plain.In this study,pit and field trials were conducted at the Baoding Irrigation Experiment Station with winter wheat and summer corn as the test crops and surface pipe irrigation as the control.The pit test was conducted in a pit with an automated retractable rain shelter,which isolated the water exchange between the soil inside the pit and the soil outside and eliminated the effect of groundwater and rainfall.The pit test analyzes the proportional changes of soil water storage in each soil layer to the total irrigation volume after irrigation,and reveals the influence of the regulated membrane on soil water transport and distribution;analyzes the proportional changes of soil water storage in each soil layer to the total irrigation volume after irrigation for the same irrigation treatment with different initial soil water content,and also analyzes the changes of soil water content in each soil layer before and after irrigation in each fertility period in combination with field tests to find out We also investigated the effect of irrigation limit and irrigation volume on the growth,yield and water use of winter wheat and summer maize through field experiments,and explored the water consumption pattern of winter wheat and summer maize at different growth stages under the elimination of the influence of groundwater and rainfall.We also investigated the water consumption patterns of winter wheat-summer maize in different growing periods under the elimination of groundwater and rainfall,and provided a theoretical basis for formulating suitable irrigation systems.The main results of the study are as follows:(1)The pit test revealed that the soil water distribution before and after two irrigations was analyzed at the pulling stage,and it was found that irrigation at a lower initial water content could increase soil water content more quickly.In the field test,it was found that the proportion of water stored in the main root layer of the crop to the total irrigation volume was higher in the S treatment with a lower irrigation limit of 55%field water holding rate than in the N treatment with a lower irrigation limit of 65%field water holding rate under the same irrigation volume,and the fluctuation of soil water content was more frequent than in the N treatment.This is consistent with the results of the pit test.(2)It was found through the winter wheat field experiment that increasing irrigation water has a certain effect on the increase of spike length,spike grain number and thousand grain weight of winter wheat within a certain range of total irrigation water,except for NL and SL treatments with less irrigation water,the yield of NH,NM,SH and SM treatments under subsurface film regulated wet irrigation were higher than the control CK treatment,and the yield increase was 0.62%-2.32%compared with the CK treatment,and the yield of winter wheat The minimum WUE of CK treatment was 1.69 kg/m3,and the increase in WUE of underground film-controlled irrigation treatment was 27.57%~40.77%compared with CK treatment.(3)It was found that the water consumption and yield of summer corn increased with the increase of irrigation water within a certain range of total irrigation water,and the WUE increased and then decreased with the increase of irrigation water.By comparing the actual yield increase,there was a significant difference between the yield of T1,T2 and T3 treatments(P<0.05).Under the same total irrigation amount,T1 treatment increased yield by 6.75%compared with CK treatment,and T2 treatment,which was smaller than CK treatment,also increased yield by 2.52%compared with CK treatment,while WUE of CK treatment was the smallest at 2.11 kg/m3 and decreased by 6.61%-14.42%compared with T1,T2 and T3 treatments,while WUE of T2 treatment was the largest at 2.46 kg/m3 and T3 was the second largest.It can be seen that compared with surface pipe irrigation,the yield and water use efficiency of summer maize with subsurface film-controlled wet irrigation were improved to different degrees,and the irrigation method of subsurface film-controlled wet irrigation was more conducive to achieving the effect of water saving and high yield.(4)Through the winter wheat field trial,it was determined that the better irrigation treatment for winter wheat under underground film-controlled wet irrigation was the SM treatment,the irrigation rate was 450m3/hm2,under the SM treatment,the yield of winter wheat could reach 9520.03kg/hm2 and the water use efficiency could reach 2.85kg/m3;Taking into account the yield and water use efficiency,the better irrigation treatment for summer maize under subsurface film-controlled wet irrigation was T2 treatment with the irrigation quota of 450 m3/hm2,and the yield of summer maize could reach 10254.50 kg/hm2 and the water use efficiency could reach 2.46 kg/m3.The results of this experiment can provide a reasonable reference basis for exploring efficient and feasible irrigation methods for winter wheat-summer maize cultivation in water-scarce areas.
Keywords/Search Tags:membrane regulated moist irrigation, soil water distribution, crop yield, water use efficiency, irrigation quota
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