Assessment on the rates and potentials of soil organic carbon sequestration in agricultural lands in Japan using a process-based model and spatially explicit land-use change inventories – Part 1: Historical trend and validation based on nation-wide soil monitoring
In order to estimate a country-scale soil organic carbon (SOC) stock change in agricultural lands in Japan, while taking into account the effect of land-use changes, climate, different agricultural activities and the nature of soils, a spatially explicit model simulation system was developed using R...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-08-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/4429/2014/bg-11-4429-2014.pdf |
| Summary: | In order to estimate a country-scale soil organic carbon (SOC) stock change
in agricultural lands in Japan, while taking into account the effect of land-use
changes, climate, different agricultural activities and the nature of soils, a
spatially explicit model simulation system was developed using Rothamsted
Carbon Model (RothC) with an integration of spatial and temporal
inventories. Simulation was run from 1970 to 2008 with historical
inventories. Simulated SOC stock was compared with observations in a
nation-wide stationary monitoring program conducted during 1979–1998.
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Historical land-use change, characterized by a large decline in the area
of paddy fields as well as a small but continuous decline in the area of
orchards, occurred along with a relatively large increase in upland crop
fields, unmanaged grasslands, and settlements (i.e. conversion of
agricultural fields due to urbanization or abandoning). Results of the
simulation on SOC stock change under varying land-use change indicated that
land-use conversion from agricultural fields to settlements or other lands,
as well as that from paddy fields to croplands have likely been an increasing
source of CO<sub>2</sub> emission, due to the reduction of organic carbon input to
soils and the enhancement of SOC decomposition through transition of soil environment
from anaerobic to aerobic conditions.
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The area-weighted mean concentrations of the simulated SOC stocks calculated
for major soil groups under paddy fields and upland crop fields were
comparable to those observed in the monitoring. Whereas in orchards, the
simulated SOC stocks were underestimated. As the results of simulation
indicated that SOC stock change under managed grasslands and settlements has
been likely a major sink and source of CO<sub>2</sub> emission at country-scale,
respectively, validation of SOC stock change under these land-use types,
which could not have been accomplished due to limited availability or a lack
of measurement, remains a forthcoming challenge. |
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| ISSN: | 1726-4170 1726-4189 |