| In saline-alkali soil,the irrigation of field crops by means of membrane hole furrow irrigation not only has the advantages of mulching film to preserve soil moisture,increasing temperature and preventing weeds from growing,but also has the advantages of using water more highly efficient,reducing the evaporation of farmland soil moisture.In this paper,the characteristics of water infiltration in saline-alkali soil by membrane hole irrigation under three different infiltration modes were studied at laboratory test,and the effects of different soil factors and main technical factors on soil water and salt migration in saline and alkali soil film hole furrow irrigation and the response mechanism of field maize under different technical factors of film hole furrow irrigation were studied.The results are as follows:(1)In this paper,we studied the infiltration characteristics of different infiltration ways,including free infiltration,unidirectional intersection infiltration and multi-direction intersection infiltration.The following conclusions were drawn.In the same infiltration time,the cumulative infiltration amount of the intersecting infiltration of the membrane hole and furrow irrigation was smaller than that of the free infiltration cumulative infiltration,that is to say the cumulative infiltration amount of multi-direction intersection infiltration was less than unidirectional intersection infiltration,and the cumulative infiltration amount of unidirectional intersection infiltration was less than free infiltration.In the process of free infiltration,the cumulative infiltration amount,the distance of wetting front migration and the time were all well related to the power function.One-way intersection infiltration and multi-direction intersection infiltration are more complex,so the relationship between cumulative infiltration amount and time under these two intersecting infiltration modes is analyzed by various models,which is convenient to select models according to different known data.In the process of unidirectional and multi-direction intersecting infiltration,the relationship between the distance of wetting front migration and time in different infiltration stages is power function.(2)The effects of different soil factors on salt migration in saline soil were studied.The soil factors included soil bulk density and initial soil water content.The following conclusions were obtained: the soil bulk density is high,the cumulative infiltration of film hole furrow irrigation was small and the wetting front distance was smaller,the cumulative infiltration with the infiltration time,and wetting front transport distance with the infiltration time were all showed power function relation;the soil water content decreased with the increase of soil bulk density,while the soil salt content increased with the increase of soil bulk density;the amount of irrigation was the same,the distance of wetting front migration of furrow irrigation was smaller than that of film hole irrigation,the range of wetting was small,the area of desalting area was small,and the desalting effect was poor;the higher the initial water content of soil,the smaller the cumulative infiltration amount,the smaller the infiltration rate of soil;the wetting front migration distance was smaller;the smaller the initial soil moisture content was,the greater the soil moisture content was from the same position of the membrane hole in the moist body,the larger the range of the desalination area of the membrane hole furrow irrigation was,and the smaller the salt content in the desalination area was,the deeper the salt accumulation area was and the larger the range was,so the more salt was washed out.(3)This paper studies the effect of main technical factors on salt migration in saline soil.The main technical factors include irrigation amount,membrane pore diameter,and the following conclusions are drawn: the longer the irrigation duration,the larger the cumulative infiltration amount of membrane hole irrigation,the larger the migration distance of the wetting front of membrane hole irrigation,and both of them were power function relation with time,the higher the soil moisture content was at the same position in the wetting zone,and the larger the range of desalting area,the more salt leaching,the better the leaching effect of salt in saline-alkali soil;the larger the membrane pore diameter,the larger the cumulative infiltration amount,the smaller the infiltration amount per unit membrane pore area,the larger the migration distance of wet front,the greater the soil moisture content in the same position,the smaller the soil salt content,the larger the desalination area,and the higher the salt content in the desalting area,the deeper the salt accumulation area was and the larger the range was,the more salt was washed out.(4)The effects of main technical factors on soil water and salt transport and maize yield in outdoor field of saline and alkali soil were studied.The main technical factors included irrigation amount,membrane hole diameter and plant spacing.The following conclusions were drawn: the larger the irrigation amount,the greater the water content of saline-alkali soil at the same depth;with the increase of plant spacing,the water content of surface soil increases,and the salt content of soil decreases;the water content of surface soil decreases gradually with the increase of membrane pore diameter,but the salt content in the surface soil increased gradually;the water content in the surface layer of furrow irrigation was smaller than that in film hole irrigation under the same irrigation amount,and the salt content in the surface layer was higher than that in the film hole irrigation;the irrigation amount and the diameter of the film hole irrigation had significant effects on the ear length,grain weight per ear and weight per ear.There was no significant effect on ear diameter,length of bald tip,number of rows per ear,weight of 100 grains;plant spacing had a certain effect on yield indexes of maize. |
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