Carbon stock changes and carbon sequestration potential of Flemish cropland soils

Abstract

Evaluations of soil organic carbon (SOC) stocks are often based on assigning a carbon density to each one of a number of ecosystems or soil classes considered, using data from soil profiles within these categories. A better approach, in which the use of classification methods by which extrapolation of SOC data to larger areas is avoided, can only be used if enough data are available at a sufficiently small scale. Over 190 000 SOC measurements (0–24 cm) have been made in the Flemish cropland (the Northern part of Belgium) in the 1989–2000 period. These SOC data were grouped into 3‐year periods and as means plus standard deviation per (part of) community (polygons). This large dataset was used to calculate SOC stocks and their evolution with time, without data extrapolation. Using a detailed soil map, larger spatial groups of polygons were created based on soil texture and spatial location. Linear regression analysis showed that in the entire study area, SOC stocks had decreased or at best had remained stable. In total, a yearly decrease of 354 kton OC yr−1 was calculated, which corresponds with a net CO2 emission of 1238 kton CO2 yr−1. Specific regions with a high carbon sequestration potential were identified, based on SOC losses during the 1989–2000 period and the mean 1999 SOC content, compared to the average SOC content of soils in Flanders with a similar soil texture. When restoring the SOC stocks to their 1990 level, we estimated the carbon sequestration potential of the Flemish cropland soils to be some 300 kton CO2 yr−1 at best, which corresponds to a 40‐year restoration period. In conclusion, we can say that in regions where agricultural production is very intense, carbon sequestration in the cropland may make only a very modest contribution to a country's effort to reduce greenhouse gas emissions.

Winter cover crops as green manure in a temperate region: the effect on nitrogen budget and yield of silage maize

“…Some recent studies suggest that SOC in European agricultural land is decreasing (Vleeshouwers and Verhagen, 2002;Sleutel et al, 2003). Bellamy et al (2005) used data from the National Soil Inventory of England andWales obtained between 1978 and to show that an average of 0.6% of the organic carbon content was lost per year from soils across England and Wales over that period, with some soils loosing up to 2 g kg -1 yr -1 (Fig.…”

The fate of buried organic carbon in colluvial soils: a long-term perspective

“…the oldest and youngest possible ages to illustrate this. The SOC content of eroding soils (and hence also that of the deposited sediment) is expected to vary temporally: for example, previous studies have found that the C storage in the cropland of Flanders or Belgium has experienced a decrease of 5-18 % in the past decades (Lettens et al, 2005;Sleutel et al, 2003;Goidts and van Wesemael, 2007). Although it is not possible to reconstruct temporal changes in SOC content of surface soils for the last millennia, we assumed that a variation of 25 % with respect to the current values is a realistic range.…”

Recent Changes in Soil Total Phosphorus in the Everglades: Water Conservation Area 3

“…Such "change maps" express the data not in terms of simple concentrations but in terms of change in concentrations from 1992 to 2003. While GIS-based change maps have been produced for soil properties such as total carbon (Van Meirvenne, Pannier, Hofman, & Louwagie, 1996;Sleutel et al, 2003;Zhang & McGrath, 2004), to our knowledge, this is the first time change maps have been produced for TP in a wetland ecosystem. Mapping space-time trajectories of soil properties has applicability not only for Everglades wetlands, but also for various other types of ecosystems.…”