water-extractable C and N; Ruhande Arboretum; exotic tree species; organic matter; soil quality; Eucalyptus
Abstract :
[en] Abstract
Effects of forest restoration tree species on soil properties in Southern Rwanda
1,2 Peter Rwibasira*, 2Francois Xavier Naramabuye, 2Donat Nsabimana, and 1Monique Carnol
1University of Liège, Belgium – Plant and Microbial Ecology; 2University of Rwanda, Rwanda.
*Corresponding Author: prwibasira@ur.ac.rw
Understanding the effects of tree species on soil properties is primordial for the development of forest restoration policies regarding the choice of species that will meet both environmental and local livelihood needs. We investigated the effects of exotic and native tree species, planted in 27 plots (31-82 years old), on selected soil properties (pH, SOM, water-extractable C and N) and soil exchangeable base cations (EBC) at two soil layers (0-5 cm and 5-10 cm) in the arboretum of Ruhande, Southern Rwanda. Given that trees were planted on one site with similar land-use history, climatic conditions, parent material, and soil type, we expect current differences in soil characteristics to reflect the influence of the tree species.
The effects of tree species were most apparent in the upper thin layer (0-5 cm) and the values of parameters were higher in this layer compared to the lower soil layer. The influence of tree species at 5-10 cm depth, was less marked and the values were lower for all measured parameters except for Al3+ and Fe2+ concentration. Eucalyptus species stands had the lowest soil pH (3.7) and mixed native species had the highest soil pH (5.8) as well as the highest exchangeable base cations (EBC) at both 0-5 cm depth (63±1.4 cmol (+)/kg) and 5-10 cm depth (9.3±0.2 cmol (+)/kg). Water extractable C and N fractions were higher at the upper soil layer compared to the lower layer. At 0-5cm, hot and cold water-extractable C and N fractions were positively correlated to soil organic matter (SOM) and negatively correlated to pH, but no significant correlation was observed at 5-10 cm. Our results showed that: (i) the two soil layers (0-5 cm and 5-10 cm depths) which were visibly undistinguishable under most of the species significantly differed in soil properties. This highlights the importance of the upper thin layer (0-5 cm depth) in tropical soils, which are generally poor and rely heavily on internal nutrient cycling through rapid decomposition of above-and belowground litter from vegetation (ii) Eucalyptus had negative consequences on soil pH and EBC, whereas soil under mixed natives had higher pH and EBC (iii) The sensitivity of water-extractable C and N fractions to detect tree species effects and their correlation with SOM indicates that these fractions could be used as substitutes to SOM analysis.
Keywords: Eucalyptus; organic matter; water-extractable C and N; exotic tree species; soil nutrients; soil quality; Ruhande Arboretum
Research Center/Unit :
InBioS-Plant and Microbial Ecology
Disciplines :
Environmental sciences & ecology
Author, co-author :
Rwibasira, Peter ; Université de Liège - ULiège > Form. doct. sc. (biol. orga. & écol. - paysage)
Naramabuye, Francois Xavier; University of Rwanda > Soil Science > CAVM
Nsabimana, Donat; University of Rwanda > Forestry > CAVM
Carnol, Monique ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Ecologie végétale et microbienne
Language :
English
Title :
Effects of forest restoration tree species on soil properties in Southern Rwanda
Publication date :
27 September 2019
Number of pages :
6
Event name :
Joint Minimally Invasive Surgery (MIS) and the 3rd Rwanda Biotechnology Conference
Event organizer :
ARES, University of Rwanda, Rwanda ministry of Health
Event place :
Kigali, Rwanda
Event date :
From 26-09-2019 to 27-09-2019
Audience :
International
References of the abstract :
https://www.rwandamisurgery.org/img/abstracts.pdf
Name of the research project :
ARES - Rwanda (Result1)
Funders :
ARES CCD - Académie de Recherche et d'Enseignement Supérieur. Coopération au Développement [BE]