Publication Type:
Journal Article
Source:
Biotechnol. Agron. Soc. Environ., Volume 8, Issue 2, p.133-139 (2004)
Abstract:
Inventories of soil organic carbon (SOC) stocks for 1960, 1990 and 2000 have
recently become available for Belgium. From these inventories we selected three
agricultural regions (Polders, Loam belt and Condroz) with 60 to 80 % of the
agricultural area under cropland in order to analyse the driving forces of the
changes in SOC stocks over time. The observed values of SOC stocks of typical
soil associations for each agricultural region are compared to simulations with
the RothC soil carbon model. After estimating the local parameters by fitting
the model to SOC values from a long term experiment in central Belgium, the
model was run from 1960 to 2000 for typical soil profiles of soil associations
in the three agricultural regions. The main factors inducing changes in SOC
stocks are the increase in plough depth as a result of continued mechanisation
in the 1960’s and the sustained input of organic amendments in the form of farm
yard manure and slurry. In contrast to earlier publications on CO2 emissions
from agricultural soils, the model did not predict a decrease in SOC stocks for
the period 1990–2000. The decrease in animal manure production observed during
the 1990’s for those regions with a concentration of intensive livestock
breeding in Flanders suggests that SOC stocks in croplands will continue to
decrease. This will lead to an emission of 0.41 Mt CO2 per year for the three
main cropland areas of Belgium in the near future and hence partly offset the
carbon sequestration potential of improved cropland management (0.95 Mt CO2 per
year).
