The impact of closed depressions on soil organic carbon storage in
eroded loess landscapes of E Poland
Abstract
Soil erosion is an important problem in the loess landscapes of Europe,
resulting in a lowering of soil quality and landscape changes. As a
result of soil erosion, SOC is redistributed and stored in SOC pools
within the landscape. Understanding the SOC dynamics is important
because changes in the SOC stocks may have large impacts on global
climate change. Closed depressions (CDs) in loess landscapes collect
colluvial sediments resulting from soil erosion and constitute sediment
stores enabling the calculation of soil erosion phases and rates. CDs
are also SOC pools enabling assessing of SOC erosion and storage in
loess landscapes over long periods. Colluvial sediments and fossil
soils, infilling five representative CDs in the Polish loess areas used
for agriculture during several millennia, were documented. The mean SOC
content in CDs were calculated, the area of CDs at the regional scale
were mapped. Between 11.66 and 31.78 Mg of SOC are stored in each CD.
The SOC within CDs represents a significant SOC storage in the landscape
of the studied region and can reach values between 178.96 and 206.73
Mg·ha-1(mean 192.85 Mg·ha-1), the SOC content in the soil cover of the
surrounding eroded slopes and plateaus is 102.38 Mg·ha-1. This study
indicates that CDs are a key morphological features for a better
understanding of the spatial distribution of SOC in agricultural used
loess landscapes of eastern Poland. SOC storage in CDs needs to be taken
into account when calculating total soil carbon storage at the regional
scale.