采煤塌陷对毛乌素沙地油蒿(Artemisia ordosica)根际环境影响

以毛乌素沙地油蒿根际土壤为研究对象,研究了1~3a内塌陷对油蒿根际土壤主要肥力指标(理化性质、根际微生物数量及酶活性)的影响.结果表明:与未开采区相比,采煤塌陷区土壤容重、田间持水量下降,根际土壤速效磷、速效钾、碱解氮含量显著降低(P<0.05),土壤pH值、电导率显著增大.塌陷区表层0~20cm细菌、放线菌数量下降,真菌数量增加;20~40cm、40~60cm层土壤细菌、真菌、放线菌数量较未开采区有所增加.塌陷1~3a区域根际土壤酸性磷酸酶显著高于未开采区(P<0.05);塌陷2a、3a表层土壤蔗糖酶活性显著高于未开采区,深层土壤蔗糖酶活性高于未开采区但未达到显著差异(P>0.05).塌陷3a时土壤速效磷、碱解氮、表层细菌数量、脲酶、蔗糖酶等指标与未开采区无显著差异,而其他指标仍未恢复到未开采前状态.植物根际具有一定的自修复能力,但是恢复到未开采状态下仍需要较长时间.

Effects of coal mining subsidence on the rhizosphere environment of Artemisia ordosica in Mu Us sandland,northwest China

Taking the rhizosphere soil of Artemisia ordosica in Mu Us sandland as an example, the effects of soil physi chemical properties, soil microorganism and enzyme activities after 1-3 years subsidence were analyzed. The results showed that soil bulk density and field capacity decreased, and rhizosphere soil available phosphorus, potassium and nitrogen content decreased significantly (P<0.05) after subsidence, but soil pH and conductivity increased significantly compared with the un disturbance area. The quantities of bacteria and actinomycetes decreased in the depth of 0-20 cm, while the quantities of fungi increased. As compared to the un disturbance area, soil microbial quantity increased in the 20-40 cm and 40-60 cm layers. Soil acid phosphatase activity increased significantly after subsidence (P<0.05). Soil invertase activity in the surface increased significantly after 2-3 years subsidence, while there was no significant difference in the deep soil (P> 0.05).There was no significant difference on soil available phosphorus and nitrogen, the quantities of bacteria in surface soil, soil urease and invertase activity between subsidence area and the un disturbance area after 3 years. The rhizosphere environment of plants has a certain self repair capacity, but it will take a long time to reach the level of nature eco environment after mining subsidence.