Browsing by Author "Metcalfe, Helen"

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    An agent-based model of farmer decision making: application to shared water resources in Arid and semi-arid regions
    (Elsevier, 2025-04-01) El Fartassi, Imane; Milne, Alice E.; Metcalfe, Helen; El Alami, Rafiq; Diarra, Alhousseine; Alonso-Chavez, Vasthi; Zawadzka, Joanna Ewa; Waine, Toby W.; Corstanje, Ron
    The study presents an agent-based modelling framework that integrates behavioural and biophysical models to investigate shared irrigation water management in an arid region. The behavioural model simulates farmers' decisions about their water irrigation sources (dam or groundwater) and whether to continue cultivating in the face of drought. This model was parameterised using survey data. The biophysical model component quantifies the impact of water availability and irrigation sources on soil salinity accumulation and its effects on crop productivity. Applied to the Al Haouz Basin, in Morocco, the integrated model reveals several key findings: (1) Increased groundwater access through water abstraction authorization can initially boost productivity but leads to widespread salinisation and farm abandonment, particularly under climate change scenarios. (2) Scenarios with reduced dam water availability demonstrate that mixed irrigation strategies mitigate short-term productivity losses but fail to prevent long-term soil salinity issues. (3) Land abandonment is significantly influenced by the level of water abstraction authorizations, with higher abstraction leading to more severe environmental degradation and social impacts. (4) Policy scenarios reveal that there is a theoretical optimal level of groundwater abstraction that maximises productivity while minimising land abandonment and salinity build-up. These results highlight the complex trade-offs between short-term gains and long-term sustainability, emphasising the need for holistic water governance policies that balance individual and collective interests.
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    Agent-based modelling of crop management
    (Cranfield University, 2024-07) El-Fartassi, Imane; Waine, Toby W.; Milne, Alice E.; El-Alami, Rafiq; Corstanje, Ronald; Metcalfe, Helen; Alonso-Chavez, Vasthi
    This study aims to explore the benefits of integrating Agent-Based Models (ABMs) of farmer behaviour with biophysical models to describe and understand the complex agroecological systems that influence decision-making in arid and semi-arid regions. Through a mixed-methods approach combining surveys, interviews, and ABM, the research provides insights into the complex dynamics shaping farmer behaviour and evaluates the potential impacts of various management strategies on agricultural sustainability. Initial online surveys across diverse agro-climatic zones in Morocco revealed that farmer decisions are influenced by environmental pressures, crop characteristics, and water availability. Follow-up in-depth interviews in the Al Haouz Basin highlighted institutional barriers like land tenure insecurity and bureaucratic processes as key constraints to adopting sustainable practices. The study integrates empirical data with Structural Equation Modelling and the Theory of Planned Behaviour to parameterize an ABM. This coupled behavioural-biophysical simulation captures feedback loops between environmental conditions and human decisions. Model simulations revealed potential unintended consequences of policies aimed at increasing productivity, such as increased soil salinization and land abandonment resulting from expanded groundwater access. Key contributions include advancing the understanding of temporal adaptation dynamics in agricultural systems under climate change and developing a novel methodological framework integrating qualitative and quantitative approaches for studying complex socio- ecological systems. By bridging social and natural sciences, this research establishes a comprehensive framework for addressing agricultural sustainability challenges in water-scarce regions.
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    Trade-offs associated with changing cropping patterns in semi-arid areas of Morocco
    (Elsevier, 2025-06-01) El Fartassi, Imane; Milne, Alice E.; Oulaid, Bader; Bezrhoud, Youssef; Metcalfe, Helen; Alonso Chavez, Vasthi; Coleman, Kevin; Diarra, Alhousseine; El Alami, Rafiq; Prout, Jonah; Waine, Toby W.; Zawadzka, Joanna Ewa; Corstanje, Ronald
    We developed a model-based framework to support land-use and management decision-making. This framework integrates data and models to support an assessment of scenarios related to crop choices and irrigation management. The framework includes the IPCC models to describe nutrient losses, the Rothamsted carbon model to predict soil organic carbon and Cornel's Environmental Impact Quotient model to predict impacts from pesticides (fungicides, herbicides and insecticides). We used Monte Carlo simulations to quantify model uncertainties. Shaded arrays were used to communicate the uncertainties to end users of the framework. We parameterised our framework to explore outcomes for an irrigated agricultural area in a semi-arid region of Morocco. We used the framework to explore scenarios that were codesigned with farming stakeholders. The scenarios related to crop diversification, and to recent policies on the expansion of olive cultivation and the adoption of efficient irrigation technologies. For the outcomes considered (production, profitability, soil carbon, nutrient losses, pesticide impacts), there were clear trade-offs associated with the cropping system choice. Compared to the baseline scenario of rotated crops, olive production led to greater carbon sequestration (average 4 % increase by doubling olive production), reduced water use (average 3 % reduction by doubling olive production), and reduced emissions (average 42 % reduction by doubling olive production) but was less profitable and provided fewer edible calories. Additionally, olive cultivation was associated with higher environmental impacts from pesticides. Diversified systems, while less profitable, were associated with less harmful pesticide use. Drip irrigation was associated with positive outcomes for profit (average 23 % increase), water use (average 13 % reduction in water use), and reduced nitrogen leaching (average 40 % reduction) with negligible changes in other metrics. However, we did not account for factors associated with increased groundwater depletion. We conclude that such frameworks are a useful means for policy-stakeholders to explore the outcomes of their decisions, thereby, helping to minimise unintended consequences.