Understanding the impact of irrigated agricultural systems on soil organic carbon storage
department or school: Science, Irving K. Barber Faculty of (Okanagan)
department or school: Biology, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Emde, David
issued: 2022-01-17T21:24:23Z
issued: 2021
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Over the last 200 years, conversion of noncultivated land for agriculture has substantially reduced global soil organic carbon (SOC) stocks in upper soil layers. While many agricultural management practices have been well-studied, the specific effects on SOC of cropping systems that incorporate irrigation are poorly understood. Given the large, and expanding, agricultural landbase under irrigation across the globe, this is a critical knowledge gap for climate change mitigation. I undertook a systematic literature review and subsequent meta-analysis of data from studies that examined changes in SOC through time on irrigated agricultural sites across the globe. I followed this work with a regional assessment of mineral-associated organic carbon (MAOC) deficits in irrigated perennial cropping systems of the Okanagan Valley, British Columbia. In the meta-analysis study, I investigated changes in SOC with the following objectives: i) to examine the impact of irrigated agriculture on SOC storage, ii) and to identify the conditions under which irrigated agriculture is most likely to enhance SOC. In the regional assessment of MAOC deficits, I compared specific surface area (SSA) and fine fraction soil texture in combination with random forest and stepwise multiple regression with Akaike Information Criterion modelling in order to iii) determine the best model approach for estimation of MAOC, iv) determine if there is a MAOC deficit present in Okanagan soils, and v) identify the Okanagan soil types with the greatest potential to store additional MAOC. Overall, the meta-analysis indicated that irrigated agriculture has increased SOC stocks by 5.9% globally; however, changes in SOC varied by climate and soil depth. Models using random forest with either SSA or fine fraction soil texture produced the most accurate estimates of current MAOC concentration. By employing a 90th quantile method, we further determined that woody cropping systems across the Okanagan Valley have the po…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/80664
note: UNDERSTANDING THE IMPACT OF IRRIGATED AGRICULTURAL SYSTEMS ON SOIL ORGANIC CARBON STORAGE by David Emde B.Sc., The University of British Columbia, 2019 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Biology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) December 2021 © David Emde, 2021ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis entitled: Understanding the impact of irrigated agricultural systems on soil organic carbon storage Submitted by David Emde in partial fulfilment of the requirements of the degree of Master of Science in Biology. Dr. Melanie Jones, Faculty of Science, UBC Okanagan Co-Supervisor Dr. Kirsten Hannam, Faculty of Science, UBC Okanagan Co-Supervisor Dr. Lael Parrott, Faculty of Science, UBC Okanagan Supervisory Committee Member Dr. Denise Neilsen, Faculty of Science, UBC Okanagan Supervisory Committee Member iii Abstract Over the last 200 years, conversion of noncultivated land for agriculture has substantially reduced global soil organic carbon (SOC) stocks in upper soil layers. While many agricultural management practices have been well-studied, the specific effects on SOC of cropping systems that incorporate irrigation are poorly understood. Given the large, and expanding, agricultural landbase under irrigation across the globe, this is a critical knowledge gap for climate change mitigation. I undertook a systematic literature review and subsequent meta-analysis of data from studies that examined changes in SOC through time on irrigated agricultural sites across the globe. I followed this work with a regional assessment of mineral-associated organic carbon (MAOC) deficits in irrigated perennial cropping systems of the Okanagan Valley, British Columbia. In the meta-analysis study, I investigated changes in SOC with the following objectives: i) to examine the impact of irriga…
has type: Thesis/Dissertation
date issued: 2022-02
is shown at: 10.14288/1.0406288
language: eng
degree discipline: Biology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Jones, Melanie D.
contributor: Hannam, Kirsten
type: Text
identifier URI: http://hdl.handle.net/2429/80664