复垦模式对矿区土壤团聚体组成及其有机碳、氮分布的影响

Effects of Reclamation Mode on Soil Aggregate Composition and Organic Carbon and Nitrogen Distribution in Mining Area

为研究不同复垦模式对矿区土壤团聚体组成及其有机碳、氮分布的影响,以平朔矿区安太堡露天煤矿3 a荞麦复垦、3 a苜蓿复垦为研究对象,以3 a自然恢复地为对照,分别采集3种模式下表层0~20 cm土样,测定机械稳定性团聚体、水稳性团聚体含量及其有机碳、氮含量,并进行相关指标分析。结果表明,随着团聚体粒径的减小,荞麦复垦与自然恢复地下的土壤机械稳定性团聚体含量均呈现出先增加后减少的趋势,且主要集中在>1~2、>0.25~1.00、≤0.25 mm粒径内,其中,>2 mm粒径中机械稳定性团聚体含量表现为苜蓿复垦显著高于荞麦复垦和自然恢复地,>0.25~1.00 mm粒径中苜蓿复垦显著低于荞麦复垦和自然恢复地,≤0.25 mm粒径中各复垦模式间无显著性差异;土壤水稳性团聚体主要集中于≤0.25 mm微团聚体内,而苜蓿复垦显著提高了>0.25 mm粒径的水稳性团聚体含量,其中,苜蓿复垦下>2 mm粒径的水稳性团聚体含量达23.77%,比荞麦复垦与自然恢复地分别高出13.37%和14.12%;土壤团聚体稳定性从大到小表现为苜蓿复垦>荞麦复垦>自然恢复地。团聚体有机碳、氮含量主要集中于>0.25 mm粒径内,其中,苜蓿复垦下>0.25~1.00 mm粒径的团聚体有机碳、氮含量分别达到最大值7.66、1.35 g/kg,各处理团聚体碳氮储量均以>0.25 mm大团聚体为主;植物复垦提高了>0.25 mm土壤团聚体C/N值,降低了≤0.25 mm粒径团聚体C/N值。植物复垦能够提高>0.25 mm粒径机械稳定性团聚体和水稳性团聚体含量,增强团聚体的稳定性,并且可提高土壤团聚体有机碳、氮含量;苜蓿效果优于荞麦,其可作为矿区复垦优选植被。

To study the effect of different reclamation modes on soil aggregate composition and distribution of organic carbon and nitrogen in the mining area,3 years alfalfa reclamation and 3 year buckwheat reclamation soils in Antaibao opencut coal mine of Pingshuo mining area were taken as the research objects,and the 3 year natural recovered land was taken as the control.The content of mechanical stability aggregate,water stability aggregate,organic carbon and nitrogen in 0-20 cm soil were measured,and the relevant indexes were analyzed.The results showed that with the decrease of the aggregate particle size,the content of soil mechanical stability aggregate in buckwheat reclamation and natural restoration increased first and then decreased,and was mainly concentrated in particle size of>1-2,>0.25-1.00,≤0.25 mm,among which the content of mechanical stability aggregates in>2 mm particle size of alfalfa reclamation was significantly higher than that of buckwheat reclamation and natural recovered land,>0.25-1.00 mm particle size of alfalfa reclamation was significantly lower than buckwheat reclamation and natural recovered land,and there was no significant difference among the reclamation models in≤0.25 mm particle size.Soil water stable aggregates was mainly concentrated in the micro-aggregates(≤0.25 mm),while alfalfa reclamation significantly increased the content of water stable aggregates in>0.25 mm particle size,the content of water stable aggregates in>2 mm particle size of alfalfa reclamation was 23.77%,which was 13.37%and 14.12%higher than that of buckwheat reclamation and natural recovered land,respectively.The stability rate of soil aggregates varied from large to small was the alfalfa reclamation>buckwheat reclamation>natural recovered land.The contents of organic carbon and nitrogen in the aggregates was mainly concentrated in>0.25 mm particle size,and the contents of organic carbon and nitrogen in the aggregates with>0.25-1.00 mm particle size under alfalfa reclamation reached the maximum values of 7.66,1.35 g/kg,respectively.The carbon and nitrogen reserves of the treated aggregates were mainly>0.25 mm large aggregates.Plant reclamation increased the soil aggregate C/N value of>0.25 mm and decreased the aggregate C/N value of≤0.25 mm.The results showed that plant reclamation could improve the content of>0.25 mm particle size mechanical stability aggregate and water stability aggregates,enhance the stability of aggregates and improve the content of organic carbon and nitrogen in soil aggregates.Alfalfa was better than buckwheat,and could be used as the optimal vegetation for mining area reclamation.