Dong Shaogang, Liu Baiwei, Ma Mingyan, Xia Manhong, Wang Chao
School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, Inner Mongolia, China.
Key Laboratory of River and Lake Ecology of Inner Mongolia Autonomous Region, Hohhot, 010021, Inner Mongolia, China.
Environ Geochem Health. 2023 May;45(5):1793-1806. doi: 10.1007/s10653-022-01292-y. Epub 2022 Jun 1.
Coal mine in arid and semi-arid area is one of the most severely degraded ecosystems on the earth. The continuous decrease in groundwater level caused by coal mining will inevitably affect biogeochemical environment of the vadose zone, and then lead to the replacement of surface vegetation. Yimin open-pit coal mine was taken as an example to reveal the relationship between the groundwater depth and soil water content (SWC), soil salt content, soil electrical conductivity (SEC), soil organic matter (SOM), soil available potassium (SAK), soil available nitrogen (SAN), vegetation coverage, aboveground biomass and species richness. The results show that, the change of groundwater depth can affect soil properties and then change the characteristics of surface vegetation, and the change of surface vegetation can also react on soil properties. Vegetation coverage and aboveground biomass are negatively correlated with groundwater depth, and positively correlated with SWC, SEC, SOM and SAK. The shallow groundwater table is conducive to the accumulation of SOM, so that the surface biomass and vegetation coverage are high. The higher the surface biomass, the more the SAN is absorbed. Under natural conditions, the relative strength of biological nitrogen fixation and plant absorption determine the content of SAN. In the research area, when the depth of groundwater is less than 0.4 m will cause soil salinization, then lead to low species richness; Species richness is exponentially correlated with groundwater depth and decreases with the increase in groundwater depth.
干旱和半干旱地区的煤矿是地球上退化最严重的生态系统之一。煤炭开采导致地下水位持续下降，不可避免地影响包气带的生物地球化学环境，进而导致地表植被更替。以伊敏露天煤矿为例，揭示地下水位与土壤含水量、土壤盐分含量、土壤电导率、土壤有机质、土壤速效钾、土壤速效氮、植被覆盖度、地上生物量和物种丰富度之间的关系。结果表明，地下水位的变化会影响土壤性质，进而改变地表植被特征，而地表植被的变化也会反作用于土壤性质。植被覆盖度和地上生物量与地下水位呈负相关，与土壤含水量、土壤电导率、土壤有机质和土壤速效钾呈正相关。浅地下水位有利于土壤有机质的积累，使地表生物量和植被覆盖度较高。地表生物量越高，吸收的土壤速效氮越多。在自然条件下，生物固氮和植物吸收的相对强度决定了土壤速效氮的含量。在研究区，当地下水位深度小于0.4米时会导致土壤盐碱化，进而导致物种丰富度较低；物种丰富度与地下水位呈指数相关，并随地下水位的升高而降低。
