Changes in soil organic carbon stocks and chemical properties in
organogenic soils under long-term agricultural use in Central Europe,
Poland
Abstract
Organic soils, particularly peatlands, are important carbon sinks. In
Europe, almost half of its area has been drained and is primarily used
for agriculture as grasslands. In Poland, 86% of the drained peatland
area causes problems with high carbon dioxide emissions due to organic
matter oxidation. The aim of the study was to analyze changes in organic
soils between 1975 and 2017 using data from 476 reference soil profiles.
The results showed a significant decrease in organic soils (≥12% SOC)
from 62% to 35%, and an increase in organo-mineral (6.0-12.0% SOC)
and non-humose mineral soils (≤1.75% SOC) by a similar percentage. The
depth of SOC rich layers also decreased significantly, with deep soils
(>100 cm) dropping from 20% to 5% and shallow soils (21-50
cm) increasing from 24% to 58%. The average SOC stock loss was almost
273 Mg C·ha -1 (from 500.42 Mg C·ha
-1 to 228.04 Mg C·ha -1), with the
median being four times lower. A decrease in SOC stock was observed in
64% of sites, while an increase was seen in 36%. The most significant
decrease in SOC stock, by 64.67% compared to 1975, occurred in organic
soils (from 762.19 Mg C·ha -1 to 269.26 Mg C·ha
-1). There was an increase in SOC stock in
organo-mineral, humose, and non-humose mineral soils, although it was
not statistically significant. Moreover, the results indicated that
continuous grassland use on organic soils does not offset carbon losses
from organic matter oxidation due to drainage.