废弃煤矿复垦区根际效应对土壤养分和酶活性的影响OA

[Objective]This study aimed to investigate the influence of rhizosphere effects on soil nutrient and enzyme activity in reclaimed areas of an abandoned coal mine,providing theoretical and data support for soil reclamation in mi-ning areas.[Method]The research objects were gangue soil in a non-reclaimed area of abandoned coal mine(BS),rhizo-sphere soil(RS)and non-rhizosphere soil(NRS)of Sambucus chinensis Lindl.in vegetated areas(including reclaimed and native vegetated areas).The basic physicochemical properties,nutrient contents,and enzyme activities of soil were determined,and correlation analysis and path analysis were performed.[Result]The soil water content in reclaimed area was significantly higher than that in non-reclaimed area(P<0.05,the same below),while the salinity in reclaimed area was significantly lower than that in non-reclaimed area,with no significant difference in soil water content between the re-claimed and native vegetated areas(P>0.05).The soil pH in the non-reclaimed area was weakly alkaline,the rhizosphere soil pH in reclaimed and native vegetated areas was neutral,and the non-rhizosphere soil pH was weakly acidic.The ac-tivities of catalase,sucrase,urease,and phosphatase in reclaimed area were significantly higher than those in non-reclaimed area;the activities of sucrase and urease in rhizosphere soil in reclaimed and native vegetated areas were signifi-cantly higher than those in non-rhizosphere soil.Basic soil physicochemical properties,nutrient content indicators,and activities of catalase,sucrase,and urease in vegetated area exhibited positive rhizosphere effects,whereas phosphatase activity in vegetated area showed negative rhizosphere effects;the positive effects on pH and total phosphorus content in reclaimed area were significantly greater than those in native vegetated area,the positive effects on alkali-hydrolyzable ni-trogen content in reclaimed area were extremely significantly lower than those in native vegetated area(P<0.01,the same below),and the negative effects on phosphatase activity in reclaimed area were higher than those in native vegetated area.Catalase and sucrase activities showed the strongest correlation with alkali-hydrolyzable nitrogen content;urease activity exhibited the strongest correlation with available phosphorus content;phosphatase activity had the strongest correlation with total phosphorus content;available phosphorus content exerted the greatest direct effects on activities of catalase,urease,and phosphatase,while alkali-hydrolyzable nitrogen content had the greatest direct effects on sucrase activity.Contents of alkali-hydrolyzable nitrogen and available phosphorus exhibited the highest coefficients of determination for activities of catalase,sucrase,and urease;their explanatory contributions to activities of catalase and sucrase were inhibi-tory effects,whereas their explanatory contribution to urease activity showed synergistic effects but with functional redun-dancy.Contents of total phosphorus and available phosphorus exhibited the largest coefficients of determination for phos-phatase activity,and their explanatory contribution to phosphatase activity displayed synergistic effects.[Conclusion]The rhizosphere effects of Sambucus chinensis Lindl.in the reclaimed area can increase soil nutrients and enhance soil enzyme activities in the abandoned coal mining area,thereby contributing to the improvement of soil health.To restore the soil quality of abandoned mining area to the original or even higher levels,continuous reclamation and appropriate combined application of nitrogen and phosphorus fertilizers are still required.