Assessing the effect of land cover on organic carbon concentrations in
European soils under various pedoclimatic conditions, using the LUCAS database
DINGKUHN, Elsa;
LATHEROW, Tamisan; LAUBRIET, Valentin; LOMBARD, Lucie
Abstract
The
soil represents a large carbon sink that plays a major role in the carbon cycle
and ultimately on the climate. There is a growing interest to understand the
mechanisms that affect SOC at a large scale in order to adapt environmental
policies. The Joint Research Center alongside with EUROSTAT has created data
(LUCAS) points which enable researchers and the general public to monitor Soil
Organic Carbon (SOC) concentrations in soils across Europe.
Based
on an extensive literature review, we confirmed the assumptions that climate,
soil texture and land cover are key determinants of SOC concentrations through
use of the LUCAS data points. We focused on the impact of land cover on SOC
concentration at a European scale which was accomplished by creating pedoclimatic
zones based on biogeographic regions and soil texture classes, in which we analyzed
patterns between land cover and SOC. We demonstrate that different land covers
under similar pedoclimatic conditions and soil textures have different SOC
concentrations and that at European scale, grasslands and vineyards have
significantly higher and lower SOC respectively, when compared to other crops.
Cereals, maize, leguminous plants, vegetables, orchards, root crops, fiber and
oil and ‘others’ did not show significant difference in SOC at a European
scale.
However,
these factors aren’t sufficient to explain all the variances observed, thus
other potential influences need to be taken into account such as farm practices
or other soil properties like aggregate size. Furthermore, substantial
variability in SOC levels still occur among samples with the same land cover
under the same pedoclimatic conditions, implying that this approach, although
relevant, should be based on less extensive pedoclimatic zones to gain greater
accuracy. In addition, the method developed in this study couldn’t be applied
to the targeted scope and scale (EU23) due to limited sample sizes in some land
cover and pedoclimatic cases.
Moreover,
the relative influence of factors such as rainfall or temperature may vary
across scales and from one biogeographic region to another, and thus may need
to be attributed different relative weights. The feasibility of applying such
nuances pinpoints the limits of such large scale studies. Nonetheless, this doesn’t
question the meaningful benefit of LUCAS database, as it can be extensively
used in research and extension to inform and guide agri-environmental policy
design and land use planning.
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