| 1. |
- Nsabimana, Donat, 1968, et al.
(författare)
-
Soil carbon and nutrient accumulation under forest plantations in southern Rwanda
- 2008
-
Ingår i: African Journal of Environmental Science and Technology. - 1996-0786. ; 2:6, s. 142-149
-
Tidskriftsartikel (refereegranskat)abstract
- Tree and soil interactions may result in changes in soil carbon and nutrient contents. Forest plantations made up of monodominant stands of 17 different species, some native and some exotic to Rwanda, as well as a stand with mixed native tree species were investigated. Biosequential sampling was used followed by basic soil chemical analyses. Results revealed that the plantation species composition influenced the soil chemical properties. Total soil C and N, C: N ratio, available P, pH, and cation exchange capacity (CEC) differed significantly between plantation stands of different species (P < 0.001, N = 54). Increases in the levels of soil C, total N, CEC and base saturation (BS) were observed mainly in mixed native species (MNS), Polyscia fulva, Casuarina equisetifolia and Eucalyptus saligna. The pH declined slightly in soil beneath some Eucalyptus species treatments and increased in others. The high nutrient uptake by fast-growing trees and the acidic parent material were involved in the acidification process. The findings suggest that the species used in afforestation maintain soil fertility and protect the environment. It is recommended that afforestation of abandoned and less productive lands in Rwanda should utilize fast growing Eucalyptus species in combination with agroforestry and native species in order to maintain or improve soil chemical properties.
|
|
| 2. |
- Nsabimana, Donat, 1968, et al.
(författare)
-
Soil CO2 flux in six monospecific forest plantations in Southern Rwanda
- 2009
-
Ingår i: Soil Biology & Biochemistry. - : Elsevier BV. - 0038-0717. ; 41:2, s. 396-402
-
Tidskriftsartikel (refereegranskat)abstract
- Forest soils contain the largest carbon stock of all terrestrial biomes and are probably the most important source of carbon dioxide (CO2) to atmosphere. Soil CO2 fluxes from 54 to 72-year-old monospecific stands in Rwanda were quantified from March 2006 to December 2007. The influences of soil temperature, soil water content, soil carbon (C) and nitrogen (N) stocks, soil pH, and stand characteristics on soil CO2 flux were investigated. The mean annual soil CO2 flux was highest under Eucalyptus saligna (3.92 mu mol m(-2) s(-1)) and lowest under Entandrophragma excelsum (3.13 mu mol m(-2) s(-1)). The seasonal variation in soil CO2 flux from all stands followed the same trend and was highest in rainy seasons and lowest in dry seasons. Soil CO2 flux was mainly correlated to soil water content (R-2 = 0.36-0.77), stand age (R-2 = 0.45), soil C stock (R-2 = 0.33), basal area (R-2 = 0.21), and soil temperature (R-2 = 0.06-0.17). The results contribute to the understanding of factors that influence soil CO2 flux in monocultural plantations grown under the same microclimatic and soil conditions. The results can be used to construct models that predict soil CO2 emissions in the tropics. (c) 2008 Elsevier Ltd. All rights reserved.
|
|
