Assessing the Social, Economic, and Environmental Impacts of a Multifunctional Crop: The Case of Moringa Oleifera

Graduation Year

2024

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

James Mihelcic, Ph.D.

Co-Major Professor

Kebreab Ghebremichael, Ph.D.

Committee Member

Qiong Zhang, Ph.D.

Committee Member

Nancy Diaz-Elsayed, Ph.D.

Committee Member

Tara Deubel, Ph.D.

Keywords

Agriculture, Food Security, Life Cycle Assessment, Sustainable Development Goals, Systems Thinking

Abstract

Multifunctional crops have the potential to support societal goals toward more sustainable production of food, feed, and fuel. The production and processing of multifunctional crops, with their numerous uses and coproducts, is accompanied by social, economic, and environmental impacts that need to be systematically evaluated to avoid unintended consequences from widespread adoption. Complexity emerges in the presence of multifunctionality, and counterintuitive system responses can occur. As a result, this dissertation has sought to enhance and apply frameworks to assess multifunctional crop sustainability holistically. Systems thinking and life cycle approaches are applied to a multifunctional crop case study, Moringa oleifera (MO). MO is a multifunctional crop with numerous food, energy, and water uses. Its leaves can be used as foods, medicines, or biostimulants to enhance crop growth. MO's seeds have applications in cosmetics, cooking, and potentially as a biofuel. The seedcake, a byproduct of the seed oil extraction process, can be used in animal feeds, fertilizer, or as a water purifier.

Considering these numerous uses, MO has drawn the attention of multiple NGOs and international agencies as a means to support rural livelihood improvement. Therefore, it is pertinent that multifunctional crop sustainability is evaluated, and the results from holistic assessments support decision-making. The primary research-assessed questions in this dissertation are: (1) how are MO's food, energy, and water uses interrelated? (2) How do MO leaves and seeds' social, economic, and environmental impacts compare? Finally (3), does MO cultivation lead to improved welfare for farmers? Chapter 2 addressed research question (1) using causal loop diagrams and the "Success to the Successful" systems archetype. After completing a comprehensive, critical review of MO's multifunctionality, the dynamic hypothesis was established. One conclusion was that tradeoffs are present due to reduced seed yields if leaves are regularly harvested. This, in turn, was shown to lead to tradeoffs among their uses, while the loops associated with MO seed production offer opportunities to leverage seed oil and seedcake coproduction and positively impact livelihoods via their corresponding causal links. The causal loop diagram was also an effective tool in summarizing literature.

To answer research question (2), a life cycle sustainability assessment (LCSA) was completed to compare MO leaf-only, leaf-and-seed, and seed-only cultivation and processing. The LCSA framework was implemented using a cradle-to-gate environmental life cycle assessment (E-LCA), life cycle costing assessment (LCCA), and social life cycle assessment (S-LCA), focusing on smallholder farmers in Ghana who were interviewed as stakeholders. E-LCA results showed leaf-only cultivation as the most environmentally sustainable option, while seed-only cultivation had the most significant environmental impact. Electricity consumption during the processing of leaves and transportation during the collection of the seeds emerged as having a more significant environmental impact.

The LCCA results showed leaf production to be the most economical for farmers due to its frequent harvests, allowing for a higher 10-year NPV and faster payback period. Seed processors had the highest 10-year NPV, while leaf processors had a shorter payback period. The S-LCA impact categories assessed included farmer age, membership in an MO organization, access to inputs/training, household food consumption scores, fraction of food expenditure, total household expenditure per capita, and alternative sources of income. Leaf-only producers outperformed the two other harvesting alternatives socially since they had most social indicators exceeding the reference point values (six out of seven assessed total). These three assessments were then compared and integrated into a composite sustainability score using the Characterization Objects Method (COMET). COMET is a Multicriteria Decision Analysis method that is rank-reversal free. Applying COMET allowed for comparison and ranking of the results for each supply chain considered. The results showed that the leaf-only supply chain had the highest score of the three alternatives. The critical distinction between leaf-only producers and the other two alternatives was its rapid payback period and the exceedance of the reference point for membership in an MO organization. Therefore, more coordination among the seed farmers could lead to better market access and a lower transportation environmental footprint so that suppliers can collect seeds from a central location.

Finally, an S-LCA using an impact pathway approach was conducted to investigate the impact of MO production on farmer welfare. The indicators used in this study were monthly household expenditure per capita and household food consumption score. For the first time, endogenous switching regression was used in this study's S-LCA framework. Results suggest that MO production does impact monthly household expenditure per capita with a statistically significant Average Treatment Effect of the Treated (ATT) value. However, non-MO farmers' monthly household expenditure was not predicted to be affected if they were to grow MO. Additionally, impacts on household food consumption scores did not result in a statistically significant ATT. Nevertheless, adopting techniques for estimating the causal effects of interventions is a promising incorporation into S-LCA that can help address issues such as relation to a functional unit, quantifying social impacts, and assessing uncertainty in S-LCA results.

The frameworks and methodologies used in this dissertation, such as systems thinking, E-LCA, LCCA, S-LCA, MCDA, and causal inference, contribute to the scientific advancement of sustainability assessments. This research has found that MO cultivation has some positive impacts on farmers in Ghana, but those impacts may differ across MO farmers or demographics. The approaches adopted in this study can improve the representativeness of LCSA results while better characterizing the three dimensions of sustainability. This study also presented the first E-LCA of MO conducted from a socioeconomic perspective. Considering different economic perspectives in the LCCA was another significant contribution, as the results included indicators from the perspectives of both farmers and processors. Additionally, the inclusion of welfare indicators in the S-LCA was particularly relevant and contributed to the study's significance. Integrating the LCSA results using COMET for the first time offers sustainability assessment researchers a demonstration of another MCDA tool. Finally, the incorporation of causal effect calculations using endogenous switching regression as an S-LCA impact assessment method offers a promising approach that could further refine the S-LCA methodology. Each of these analyses can readily be adapted to other multifunctional crop systems in Ghana or elsewhere in Sub-Saharan Africa and the world.

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