Mapanda, F., Mupini, J., Wuta, M., Nyamangara, J., Rees, R.M., 2010. A cross-ecosystem assessment of the effects of land cover and land use on soil emission of selected greenhouse gases and related soil properties in Zimbabwe. Eur. J. Soil Sci. 61, 721-733.
Land used for agricultural production can contribute significantly to
greenhouse gas (GHG) emissions; however, there is very little
information on the role of management and land use change in influencing
these emissions in Africa. Thus, exploring GHG emissions that occur at
the soil-atmosphere interface is an essential part of the effort to
integrate land management strategies with climate change mitigation and
adaptation in southern Africa. We measured soil emissions of carbon
dioxide (CO2), methane (CH4) and nitrous oxide (N2O)
from rain-fed perennial tropical grassland, wastewater-irrigated
perennial tropical pastureland, recently cleared woodland, miombo
woodland, a Eucalyptus plantation, regular cropland and
recently cleared-and-cropped land, on two contrasting soils at five
sites in one cropping season in Zimbabwe. Gas samples were collected
using static chambers and analysed by gas chromatography. Considerably
high GHG emissions were found on sewage effluent-irrigated pastureland
(means, 190 mg CO2-C m−2 hour−1, 102 µg CH4-C m−2 hour−1 and 6 µg N2O-N m−2 hour−1 from sandy soil) and altered woodlands (mean ranges, 38–70 CO2-C m−2 hour−1, 12–43 µg CH4-C m−2 hour−1 and 20–31 µg N2O-N m−2 hour−1
from deforested and cultivated woodland on clay and sandy soils).
Relatively low and less variable emissions were found among the rain-fed
perennial tropical grasslands, regular croplands and Eucalyptus plantations (mean ranges, 19–39 mg CO2-C m−2 hour−1, −9.4–2.6 µg CH4-C m−2 hour−1 and 1.0–4.7 µg N2O-N m−2 hour−1). Variability in CO2, CH4 and N2O
emissions from soils was to the greatest extent influenced by soil
temperature, but soil moisture, mineral-N and pH were also important.
The increased N2O emissions from cleared woodland on clay
soil were attributed to increased mineralization and N availability when
no tree could take up that N, while the N mineralized on the sandy soil
could have been largely leached due to the soil's poor nutrient holding
capacity, resulting in a relatively lower N2O emission
response to clearing. We concluded that the alteration of woodlands by
deforestation and cultivation increased soil temperature, resulting in
increased soil respiration, while the establishment of Eucalyptus plantations may provide an option for reduction in soil emissions of CO2 and N2O and a sink for CH4.