煤炭开采沉陷区土壤有机碳空间变化

为研究矿区土壤碳动态,以焦作矿区为例,分析了沉陷坡与裂缝区两种破坏地表的土壤有机碳空间变化。结果表明:与未沉陷的矿区土壤相比较,沉陷坡与裂缝区表土(0~10 cm)有机碳含量降低且空间变异性增大,土壤剖面各层次有机碳含量均出现降低,特别是10~30 cm的土壤剖面层有机碳含量降低最明显,降幅为29%~38%;两种破坏地表土壤剖面有机碳库损失高达20.8~47.3 t/hm2。沉陷坡上,表土有机碳含量从上坡到中坡明显的降低,从中坡到坡底逐渐增加;中坡、下坡与坡底有机碳含量沿土壤剖面层次向下表现出一致的线性下降趋势,但上坡在土壤剖面内的波动较大;各坡位土壤剖面有机碳储量均出现损失,尤其是坡底以上的坡位有机碳储量损失最大。矿区土壤有机碳的空间变化与土壤侵蚀、土地利用、裂隙渗漏及低生物量输入有关。

Spatial variation of soil organic carbon in coal mining subsidence areas

In order to understand carbon dynamics in mine soil，the spatial variation of soil organic carbon (SOC) contents was investigated in two types of landscapes destroyed by coal mining，i.e.，subsidence slope and ground fissure site from Jiaozuo mine area，China.It is found that the SOC contents in topsoil (0-10 cm) decreases and their spatial variability increases in both subsidence slope and ground fissure site in comparison with those in non subsidence site.The SOC contents at all the layers of depth profile decrease，especially at the layers of 10-30 cm depth，where a decrease of 29%-38% in the SOC contents is observed.The depletion of SOC pool in the study area was estimated up to 20.8-47.3 t/hm2.For the subsidence slope，the SOC contents in topsoil obviously decrease from upper slope to middle slope positions，and then gradually increased from middle slope to toe slope positions.At the middle，lower and toe slope positions of soil profiles，the SOC contents decrease linearly along with depth，but vary irregularly in those of the upper slope positions.The loss of SOC storages occurs on the whole subsidence slope，especially at the upper，middle and lower slope positions.The spatial variation patterns of SOC in the study area could be attributed to soil erosion，land use，and fissure induced leakage as well as the low input of crop biomass to mine soils.