Biodiversity,carbon stocks and sequestration potential in aboveground biomass in smallholder farming systems of western Kenya |
| |
| Authors: | M Henry P Tittonell RJ Manlay M Bernoux A Albrecht B Vanlauwe |
| |
| Institution: | 1. Institut de Recherche pour le Développement, IRD, UR SeqBio, SupAgro, Bat. 12, 2 place Viala, 34060 Montpellier Cedex 1, France;2. Institut des Régions Chaudes, IRC-Montpellier Supagro - 1101, avenue Agropolis, BP 5098, 34033 Montpellier Cedex 1, France;3. Tropical Soil Biology and Fertility Institute of the International Centre for Tropical Agriculture (TSBF-CIAT), United Nations Avenue, P.O. Box 30677, Nairobi, Kenya;4. Paris Institute of Technology for Life, Food and Environmental Sciences, AgroParisTech-ENGREF, GEEFT, 648 rue Jean-François Breton, BP 7355, 34086 Montpellier Cedex 4, France;5. Plant Production Systems, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands;6. Institut de Recherche pour le Développement, IRD-Madagascar, BP 434, 101 Antananarivo, Madagascar;1. International Maize and Wheat Improvement Center (CIMMYT), P.O. Box MP 163, Mount Pleasant, Harare, Zimbabwe;2. Department of Biosystems Engineering and Soil Science, University of Tennessee Institute of Agriculture, 2506 E. J. Chapman Drive, Knoxville, TN 37996-4518, USA;3. International Center for Agricultural Research in the Dry Areas (ICARDA), ICARDA c/o ILRI, P.O. Box 5689, Addis Ababa, Ethiopia;4. Institute for Agricultural Sciences, Plant Nutrition, ETH Zurich, Eschikon 33, 8315 Lindau, Switzerland;1. World Agroforestry Centre (ICRAF), United Nations Avenue, Gigiri, P.O. Box 30677-00100, Nairobi, Kenya;2. Swedish University of Agricultural Sciences (SLU), P.O. Box 7043, SE-750 07 Uppsala, Sweden;3. Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00100, Nairobi, Kenya;1. CATIE, DID, 7170, Cartago, Turrialba 30501, Costa Rica;2. CIRAD, UMR System, F-34070 Montpellier, France;3. CATIE, PAAS, CR-7170 Turrialba, Costa Rica;1. Forest & Nature Lab, Ghent University, Geraardsbergsesteenweg 267, 9090 Gontrode, Belgium;2. Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Burgemeester Van Gansberghelaan 109, 9820 Merelbeke, Belgium;3. VITO, Boeretang 200, 2400 Mol, Belgium;4. Department of Plant Production, Ghent University, Proefhoevestraat 22, 9090 Melle, Belgium |
| |
| Abstract: | While Carbon (C) sequestration on farmlands may contribute to mitigate CO2 concentrations in the atmosphere, greater agro-biodiversity may ensure longer term stability of C storage in fluctuating environments. This study was conducted in the highlands of western Kenya, a region with high potential for agroforestry, with the objectives of assessing current biodiversity and aboveground C stocks in perennial vegetation growing on farmland, and estimating C sequestration potential in aboveground C pools. Allometric models were developed to estimate aboveground biomass of trees and hedgerows, and an inventory of perennial vegetation was conducted in 35 farms in Vihiga and Siaya districts. Values of the Shannon index (H), used to evaluate biodiversity, ranged from 0.01 in woodlots through 0.4–0.6 in food crop plots, to 1.3–1.6 in homegardens. Eucalyptus saligna was the most frequent tree species found as individual trees (20%), in windrows (47%), and in woodlots (99%) in Vihiga and the most frequent in woodlots (96%) in Siaya. Trees represented the most important C pool in aboveground biomass of perennial plants growing on-farm, contributing to 81 and 55% of total aboveground farm C in Vihiga and Siaya, respectively, followed by hedgerows (13 and 39%, respectively) and permanent crop stands (5 and 6%, respectively). Most of the tree C was located in woodlots in Vihiga (61%) and in individual trees growing in or around food crop plots in Siaya (57%). The homegardens represented the second C pool in importance, with 25 and 33% of C stocks in Vihiga and Siaya, respectively. Considering the mean total aboveground C stocks observed, and taking the average farm sizes of Vihiga (0.6 ha) and Siaya (1.4 ha), an average farm would store 6.5 ± 0.1 Mg C farm?1 in Vihiga and 12.4 ± 0.1 Mg C farm?1 in Siaya. At both sites, the C sequestration potential in perennial aboveground biomass was estimated at ca. 16 Mg C ha?1. With the current market price for carbon, the implementation of Clean Development Mechanism Afforestation/Reforestation (CDM A/R) projects seems unfeasible, due to the large number of small farms (between 140 and 300) necessary to achieve a critical land area able to compensate the concomitant minimum transaction costs. Higher financial compensation for C sequestration projects that encourage biodiversity would allow clearer win–win scenarios for smallholder farmers. Thus, a better valuation of ecosystem services should encourage C sequestration together with on-farm biodiversity when promoting CDM A/R projects. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
