Effects Of Irrigation And Grass Mulching On Soil Water And Salt Migration And Caragana Korshinskii Growth In Coal Gangue Pile In Arid Area

In order to reveal the effects of irrigation and grass mulching on soil water and salt migration and growth of Caragana korshinskii in coal gangue hills in arid area,so as to maintain soil moisture,inhibit salt surface accumulation and promote growth of Caragana korshinskii,P1:40d/time,P2:20d/time and P3:Three irrigation frequencies of 10d/time,three irrigation amounts of W1:90mm,W2:135mm and W3:180mm,G1:0cm and G2:Three mulch thicknesses of 0.5cm and G3:1.0cm were used to study the effects of irrigation frequency and mulch thickness on water evaporation by indoor simulated evaporation experiments with coal gangue pile soil in arid area as the research object,and irrigation frequency and mulch thickness as independent variables were used to conduct indoor simulated evaporation experiments.In the arid region of Lingwu coal gangue pile,Ningxia,a field experiment was carried out using the complete design method to analyze the effects of irrigation amount and the thickness of grass mulching on the soil water and salt migration and the growth of Caragana korshinskii in arid area of Lingwu coal gangue pile,and the following conclusions were drawn:（1）Increasing irrigation frequency could significantly（P<0.05）reduce the cumulative soil evaporation.There was a significant correlation between mulch thickness,irrigation frequency and cumulative evaporation（P<0.01）.Cumulative evaporation was influenced by the interaction of mulch thickness and irrigation frequency（P<0.01）.（2）Irrigation amount affected the location and size of the high value of soil moisture content.The increase of irrigation amount could promote water migration to deeper soil layers,and W1 treatment significantly（P<0.05）increased soil moisture content in 0-20cm soil layer.W2 treatment significantly（P<0.05）increased the moisture content of 0-30cm soil layer,W3 treatment significantly（P<0.05）increased the moisture content of 0-10cm soil layer and extremely significantly（P<0.01）increased the moisture content of 10-30cm soil layer;Increasing the thickness of mulch can increase the moisture content of 0-50cm soil layer.（3）Increasing irrigation amount can restrain the surface accumulation of salt in soil.Grass mulching could significantly（P<0.05）change the total salt content in 0-10cm soil layer,and make the distribution of total salt in 0-50cm soil layer more uniform..（4）The vertical distribution of Na⁺in soil was different with different irrigation amount.Grass mulching can reduce the Na⁺content of deep soil.With the increase of irrigation amount,the overall content of Ca²⁺in the soil decreased and the distribution became more uniform.Cl^-showed a trend of decreasing first and then increasing and then decreasing with the increase of depth in all treatments.Under W1 and W2 treatments,the maximum content of HCO₃^-+CO₃^2-in soil firstly increased and then decreased with the increase of depth.In W3 treatment,HCO₃^-+CO₃^2-tended to accumulate in the 10-20cm soil layer.The vertical distribution and migration of HCO₃^-+CO₃^2-in 0-50cm soil layer were not significantly affected by different mulch thickness（P>0.05）.（5）W2 could promote the increase of crown width,and the increase of crown width increased with the increase of the thickness of mulch.W1 could regulate the growth of plant height of Caragana korshinskii,and there was no significant difference in the effect of different thickness of mulch on the growth of plant height（P>0.05）.（6）Principal component analysis was used to calculate the scores of each treatment,and the highest score of W2G2 treatment was 0.881.Therefore,on the premise of saving water and cost,it is suggested to adopt W2G2 treatment in coal gangue hills in arid area to better regulate soil water and salt migration,increase soil water content,inhibit salt surface accumulation and promote the growth of Caragana korshinskii.