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Estimating spatially distributed SOC sequestration potentials of sustainable land management practices in Ethiopia

Abera, Wuletawu and Tamene, Lulseged and Abegaz, Assefa and Hailu, Habtamu and Piikki, Kristin and Söderström, Mats and Girvetz, Evan and Sommer, Rolf (2021). Estimating spatially distributed SOC sequestration potentials of sustainable land management practices in Ethiopia. Journal of Environmental Management. 286 , 112191
[Research article]

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Abstract

The sustainable land management program (SLMP) of Ethiopia aims to improve livelihoods and create resilient communities and landscape to climate change. Soil organic carbon (SOC) sequestration is one of the key cobenefits of the SLMP. The objective of this study was to estimate the spatial dynamics of SOC in 2010 and 2018 (before and after SLMP) and identify the SOC sequestration hotspots at landscape scale in four selected SLMP watersheds in the Ethiopian highlands. The specific objectives were to: 1) comparatively evaluate SOC sequestration estimation model building strategies using either a single watershed, a combined dataset from all watersheds, and leave-one-watershed-out using Random Forest (RF) model; 2) map SOC stock of 2010 and 2018 to estimate amount of SOC sequestration and potential; 3) evaluate the impacts of SLM practices on SOC in four SLMP watersheds. A total of 397 auger composite samples from the topsoil (0?20 cm depth) were collected in 2010, and the same number of samples were collected from the same locations in 2018. We used simple statistics to assess the SOC change between the two periods, and machine learning models to predict SOC stock spatially. The study showed that statistically significant variation (P < 0.05) of SOC was observed between the two years in two watersheds (Gafera and Adi Tsegora) whereas the differences were not significant in the other two watersheds (Yesir and Azugashuba). Comparative analysis of model-setups shows that a combined dataset from all the four watersheds to train and test RF outperform the other two strategies (a single watershed alone and a leaveone-watershed-out to train and test RF) during the testing dataset. Thus, this approach was used to predict SOC stock before (2010) and after (2018) land management interventions and to derive the SOC sequestration maps. We estimated the sequestrated, achievable and target level of SOC stock spatially in the four watersheds. We assessed the impact of SLM practices, specifically bunds, terraces, biological and various forms of tillage practices on SOC using partial dependency algorithms of prediction models. No tillage (NT) increased SOC in all watersheds. The combination of physical and biological interventions (?bunds + vegetations? or ?terraces + vegetations?) resulted in the highest SOC stock, followed by the biological intervention. The achievable SOC stock analysis showed that further SOC stock sequestration of up to 13.7 Mg C ha?1 may be possible in the Adi Tsegora, 15.8 Mg C ha-1 in Gafera, 33.2 Mg C ha-1 in Azuga suba and 34.7 Mg C ha-1 in Yesir watersheds.

Authors/Creators:Abera, Wuletawu and Tamene, Lulseged and Abegaz, Assefa and Hailu, Habtamu and Piikki, Kristin and Söderström, Mats and Girvetz, Evan and Sommer, Rolf
Title:Estimating spatially distributed SOC sequestration potentials of sustainable land management practices in Ethiopia
Series Name/Journal:Journal of Environmental Management
Year of publishing :2021
Volume:286
Article number:112191
Number of Pages:12
Publisher:ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
ISSN:0301-4797
Language:English
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Environmental Sciences related to Agriculture and Land-use
Keywords:Climate change, Ethiopia, Random forest, Resilience, Sustainable land management, SOC sequestration
URN:NBN:urn:nbn:se:slu:epsilon-p-111561
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-111561
Additional ID:
Type of IDID
DOI10.1016/j.jenvman.2021.112191
Web of Science (WoS)000634991000005
ID Code:23323
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: SLUpub Connector
Deposited On:22 Apr 2021 11:03
Metadata Last Modified:22 Apr 2021 11:11

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