|
|
Historical and simulated ecosystem carbon dynamics in Ghana: land use, management, and climate
Z. Tan1, L. L. Tieszen2, E. Tachie-Obeng3, S. Liu1,4, and A. M. Dieye4
1Science Applications International Corp (SAIC), contractor to USGS Earth Resources Observation and Science Center, Sioux Falls, SD 57198, USA
2USGS Earth Resources Observation and Science Center, Sioux Falls, SD 57198, USA
3Ghana Environmental Protection Agency, Accra, Ghana
4Geographic Information Science Center of Excellence, South Dakota State University, Brookings, SD 57007, USA
|  |
Abstract. We used the General Ensemble biogeochemical Modeling
System (GEMS) to simulate responses of natural and managed ecosystems to
changes in land use, management, and climate for a forest/savanna
transitional zone in central Ghana. Model results show that deforestation
for crop production during the last century resulted in a substantial
reduction in ecosystem carbon (C) stock from 135.4 Mg C ha−1 in 1900 to
77.0 Mg C ha−1 in 2000, and in soil organic C stock within the top
20 cm of soil from 26.6 Mg C ha−1 to 21.2 Mg C ha−1. If no land use
change takes place from 2000 through 2100, low and high climate change
scenarios (increase in temperature and decrease in precipitation over time)
will result in losses of soil organic C stock by 19% and 25%,
respectively. A low nitrogen (N) fertilization rate is the principal
constraint on current crop production. An increase in N fertilization under
the low climate change scenario would increase crop yield by 14% with 30 kg N ha−1 and by 38% with 60 kg N ha−1,
leading to an increase in the average soil C stock by 12% and 29%, respectively, in all
cropland by 2100. The results suggest that the climate changes in the future
from current climate conditions will not necessarily become a determinant
control on ecosystem C fluxes and crop production, while a reasonable N
fertilization rate is critical to achieve food security and agricultural
sustainability in the study area through the 21st century, and current
cropping systems could be optimized to make full use of the rainfall
resource.
Discussion Paper (PDF, 1555 KB) Interactive Discussion (Final Response, 3 Comments)
Citation: Tan, Z., Tieszen, L. L., Tachie-Obeng, E., Liu, S., and Dieye, A. M.: Historical and simulated ecosystem carbon dynamics in Ghana: land use, management, and climate, Biogeosciences Discuss., 5, 2343-2368, 2008. Bibtex EndNote Reference Manager
|
|
