Effect Of Cracks On Soil Moisture Distribution And Plant Growth In Open Pit Coal Mine Dump Under Micro Sprinkler Irrigation

How to alleviate the water demand of soil and soil vegetation in open-pit dump is an important problem for ecological environment restoration of mine wasteland.In order to reveal the effect of soil cracks on water distribution and plant growth under the action of micro sprinkler irrigation,field sampling and indoor simulated micro sprinkler irrigation test were used,In the whole growth cycle of Astragalus adsurgens,Micro Sprinkling Irrigation with different intensities was carried out to explore the spatiotemporal dynamic changes of water and plant growth characteristics under the influence of cracks.The results are as follows:(1)The variation range of soil crack width is 8.0-14.2cm,10.0-16.7cm and 12.0-20.4cm.The coefficient of variation is between 0.08 and 0.16,and the change of crack width is different under different micro sprinkler irrigation intensity.The larger the micro sprinkler irrigation intensity is,the more obvious the change of crack width is.The total depth of soil cracks is between 11.4-35.0 cm,and the coefficient of variation is 0.13-0.43.On the whole,there is a negative correlation between the micro spray strength and the change of crack depth.(2)The change of the depth and width of soil cracks is more obvious in the germination stage of Astragalus adsurgens.When Astragalus adsurgens seedling stage,with the increase of micro irrigation times,the influence on the width and depth of soil cracks is small.The results showed that the growth of Astragalus adsurgens under 12L/h micro sprinkler irrigation was better than that under 6L/h and 24L/h micro sprinkler irrigation.(3)The results showed that the soil water content of 0-10cm,10-20cm and 20-30cm soil layers was 11.6-12.9%,8.9-12.8%and 9.5-13.9%respectively after 1 hour of micro sprinkler irrigation with the intensity of 6L/h;The Micro Sprinkling Irrigation intensity is 12L/h 19.7-21.7%,20-1-21.9%,20.2-22.2%.The strength of 24L/h was 24.1-25.0%,24.2-24.9%and 24.2-25.0%respectively.In the soil trough with cracks,the maximum water content mostly appears in 20-30cm soil layer.After 6 hours of Micro Sprinkling Irrigation,the upper soil water infiltrated into the deep layer,and the overall soil water content decreased.(4)After 7 days of Micro Sprinkling Irrigation with 6L/h,the soil water content varied from 8.2-9.6%,8.3-9.8%and 8.5-9.9%in 0-10 cm,10-20 cm and 20-30 cm soil layers,respectively;The water content of 12L/h and 24L/h strength is 16.8-18.3%,17.5-18.9%,16.9-19.0%and 20.2-23.5%,20.4-23.1%,20.8-23.2%respectively.With the increase of soil depth,the water content tends to increase.(5)In the same soil layer,when the distance from the monitoring point is different,the maximum water content will appear in a short time in the soil layer of 20-30 cm after micro sprinkler irrigation for 1 hour.Over time,the location of the maximum value changes.After 6 hours of Micro Sprinkling Irrigation,the soil moisture increased with the distance from the crack,but it was not significant.After 7 days of micro sprinkler irrigation,the farther the monitoring points are from the cracks in the same soil layer,the larger the water content is.