Assessing the effect of land cover on organic carbon concentrations in European soils under various pedoclimatic conditions, using the LUCAS database

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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