| In view of the current situation that subsurface drip irrigation technology is not widely used in Xinjiang and even in China,and there are few studies related to subsurface drip irrigation maize deep sowing technology and farmland supporting management.In this paper,four factors were selected for the study of subsurface drip irrigation and deep sowing of maize,including sowing depth(10 cm,15 cm,20 cm)and burial depth of subsurface drip irrigation capillary(20 cm,25 cm,30 cm);irrigation regime elements:irrigation quota(45 mm,60 mm,75 mm)and number of irrigation(6 times,7 times,8 times).Three levels of each factor were selected,and an orthogonal test design was used to conduct a multi-factor combination of subsurface drip irrigation trials on maize at the Xinjiang Irrigation Center Experiment Station in Changji;Drip irrigation under film for maize was used as a control experiment at a sowing depth of 5 cm,with an irrigation quota of 45 mm and 10 times of irrigation.The growth,water consumption pattern,and yield of deep-sown maize were studied to investigate the farm technology and irrigation regime of subsurface drip irrigated maize under the conditions of deep-sown multi-factor combination,and to provide a reference basis for future research and application of subsurface drip irrigation.The main research and analysis results of this paper are as follows:(1)The seedling emergence rate of all treatments with subsurface drip irrigation was lower,ranging from 90.5%to 96.5%;the seedling emergence rate of CK with drip irrigation under film was 97%.The seeding depth affected the seeding emergence rate of maize to a greater extent,and the seeding emergence rate decreased to a certain extent with the increase of seeding depth.The seeding emergence rate of maize was reduced when the distance between the buried capillary and the sowing depth was large,and the effect of the distance between the capillary and the seed on the seeding emergence rate could be mitigated by an appropriate irrigation quota.(2)The trend of plant height change in each treatment of subsurface drip irrigation was the same as that of CK drip irrigation under film.Plant height was higher in CK with submersed drip irrigation than in the subsurface drip irrigation treatments in the early stages of growth,and vice versa in the later stages.The leaf area index of drip irrigation under film CK was higher than that of the subsurface drip irrigation treatments during the whole reproductive period.The SPAD values of maize leaves were higher in the early stage of growth and similar in the late stage of growth.Among the four selected factors,sowing depth had a greater effect on maize plant height than other factors;burial depth of capillary had a greater effect on leaf area index than other factors;and leaf SPAD values were more affected by the number of irrigations.(3)The soil moisture distribution of subsurface drip irrigation was lower in the tillage layer and increased gradually in the middle layer,while the soil moisture distribution in the tillage layer and middle layer of drip irrigation under film CK was the opposite,and the soil moisture distribution in the deep layer was similar in both cases,and subsurface drip irrigation had good moisture storage and soil moisture retention performance.The water consumption and water consumption modulus of maize stage in all treatments showed a bimodal trend change during the whole reproductive period.The total water consumption of all treatments of subsurface drip irrigation ranged from 351.02 to 412.96 mm,showing a linear increasing trend with irrigation quota.Subsurface drip irrigation had different degrees of deep seepage for larger irrigation quotas.The water use efficiency of subsurface drip irrigation treatments ranged from 21.58 to 28.77kg/(hm~2·mm),all of which were higher than that of CK.The irrigation water use efficiency of subsurface drip irrigation treatments ranged from 16.63 to 33.11 kg/(hm~2·mm),and the subsurface drip irrigation treatments had better irrigation water use efficiency.(4)The number of grains per ear was higher in the subsurface drip irrigation treatments than in the drip irrigation under film CK,the effective number of ears was higher in the CK than in the subsurface drip irrigation treatments,and the difference in thousand grain weight between the treatments was small.Maize yield was 8416.78 kg/hm~2 for CK with drip irrigation under film and 8843.03 to 9976.03 kg/hm~2 for subsurface drip irrigation.maize yield showed a decreasing trend with increasing sowing depth and a parabolic trend with increasing irrigation frequency.maize yield also increased gradually with increasing irrigation quota.Subsurface drip irrigation had slightly lower emergence than CK,but better yield than CK.The most significant effect on maize yield with subsurface drip irrigation was seeding depth,followed by the number of irrigations,then the burial depth of the capillary tube,and the least effect was the irrigation quota.(5)The T7 treatment(sowing depth of 20 cm,burial depth of 20 cm,irrigation quota of 45 mm,and7 times of irrigation)was obtained as the optimal test solution by using the Entropy weight-TOPSIS comprehensive evaluation method and Entropy weight-Fuzzy comprehensive evaluation method.In the actual farm application,the burial depth of capillary can be selected as 20 cm,the irrigation quota can be selected as 30 m~3/Acre,and the number of irrigation can be selected as 7 times.In the selection of sowing depth,the sowing depth can be adjusted appropriately according to the seed variety and nature. |
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