Effects of exotic tree plantations of teak (Tectona grandis) and gmelina (Gmelina arborea) on a forest soil in south‐western Nigeria
ABSTRACT The properties of soil under 15-year-old plantations of gmelina (Gmelina arborea) and teak (Tectona grandis) were compared with logged forest soil in south-western Nigeria. The soil was significantly denser in the 0–10 cm layer of plantation soil and total porosity less than that of forest soil. Organic carbon was significantly greater in the 0–10 cm layer of forest soil. Similarly, the concentrations of total N, exchangeable Ca, Mg and K were greater under forest soil, but the concentrations of available P were similar under all three ecosystems. The smaller organic carbon and nutrient content of plantation soil is mainly due to its more open organic matter and nutrient cycles and nutrient immobilization in the fast-growing exotics.
- SourceAvailable from: Charles Igwe[Show abstract] [Hide abstract]
ABSTRACT: Four land use practices were investigated for their differences in soil structural properties. The land use types are native forest, grassland, oil palm/cocoyam and arable land. Structural parameters as bulk density, total porosity, water stable aggregates (WSA)> 0.25 mm, volumetric moisture content at field capacity (FC) and organic matter content. Structural properties which are affected by land use are total porosity, bulk density, and organic matter.International Agrophysics 01/2001; · 1.03 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Aim The effects of planted forests on soils are of great concern in the context of the increasing demands for timber production and atmospheric CO2 sequestration. However, the effects of plantations on soil properties have not well been quantified. We determined the effects of plantation practice on soil properties based on a comparison between natural forests and plantations.Locations All the continents except for Antarctica.Methods The meta-analysis approach was used to examine the differences in 14 soil variables in the mineral layer, including pH, bulk density, C, N, P, K, Ca, Mg, Na and Al concentrations, C/N ratio, cation exchangeable capacity, base saturation, and moisture between plantations and their adjacent natural forests from 73 published studies.Results Plantations did not differ from natural forests in soil pH or soil Na and Al concentrations. Soil bulk density below plantations increased by 12.5%, and soil C and N concentrations decreased by 36.0% and 26.5%, respectively, relative to natural forests. The other eight variables were 8.4–30.6% lower in plantations than in natural forests. The general patterns also held true for planted trees from the genus Pinus and for study regions in China. The patterns for soil bulk density and C and N concentrations were not different between the two groups in relation to various factors: stand age (< 25 years versus ≥ 25 years), leaf form (broadleaved versus coniferous) and leaf seasonality (deciduous versus evergreen), tree species origin (native versus exotic), land-use history (afforestation versus reforestation) and site preparation for plantations (burnt versus un-burnt treatment), and biogeographic zone (tropical versus temperate).Main conclusions Our results suggest that the level of soil fertility in plantations is unlikely to restore to the level in natural forests, implying that the replacement of natural forests by plantations may be a practice best avoided to maintain the ecosystem sustainability.Global Ecology and Biogeography. 06/2011; 21(3):318 - 327.
- [Show abstract] [Hide abstract]
ABSTRACT: The effects of land use change on soil carbon stocks are of concern in the context of international policy agendas on greenhouse gas emissions mitigation. This paper reviews the literature for the influence of land use changes on soil C stocks and reports the results of a meta analysis of these data from 74 publications. The meta analysis indicates that soil C stocks decline after land use changes from pasture to plantation (−10%), native forest to plantation (−13%), native forest to crop (−42%), and pasture to crop (−59%). Soil C stocks increase after land use changes from native forest to pasture (+ 8%), crop to pasture (+ 19%), crop to plantation (+ 18%), and crop to secondary forest (+ 53%). Wherever one of the land use changes decreased soil C, the reverse process usually increased soil carbon and vice versa. As the quantity of available data is not large and the methodologies used are diverse, the conclusions drawn must be regarded as working hypotheses from which to design future targeted investigations that broaden the database. Within some land use changes there were, however, sufficient examples to explore the role of other factors contributing to the above conclusions. One outcome of the meta analysis, especially worthy of further investigation in the context of carbon sink strategies for greenhouse gas mitigation, is that broadleaf tree plantations placed onto prior native forest or pastures did not affect soil C stocks whereas pine plantations reduced soil C stocks by 12–15%.Global Change Biology 11/2002; 8(4):345 - 360. · 8.22 Impact Factor