agriLOVE: agriculture, land-use and technical change in an evolutionary, agent-based model with M. Coronese, F. Lamperti and A. Roventini
This paper presents a novel agent-based model of land use and technological change in the agricultural sector under environmental boundaries, finite available resources and changing land productivity. In particular, we model a spatially explicit economy populated by boundedly-rational farmers competing and innovating to fulfill an exogenous demand for food, while coping with a changing environment shaped by their production choices. Given the strong technological and environmental uncertainty, farmers learn and adaptively employ heuristics which guide their decisions on engaging in innovation and imitation activities, hiring workers, acquiring new farms, deforesting virgin areas and abandoning unproductive lands. Such activities in turn impact on land productivity, food production, food prices and land use. We firstly show that the model can replicate key stylized facts of the agricultural sector. We then extensively explore its properties across several scenarios featuring different institutional and behavioral settings. Finally, we showcase the properties of model in different applications considering deforestation and land abandonment; soil degradation; and climate impacts.
Rain does not fall on one roof alone: the share of local knowledge in idir mediates farmers' rainfall risk perception in rainfed marginal agroecosystems with A. Mantino, G. Ragaglini, C. Fadda, M.E. Pè and A. Nuvolari
Available upon request
The awareness of precipitation variability is key to food security of smallholder farmers. In rainfed agricultural areas, households able to interpret correctly short-term precipitation deviations and extremes do retain a significant advantage in terms of resilience. Despite the communitarian nature of these rural societies, we know little about how the share of local knowledge influences rainfall risk perceptions. In our study, we combine data from agronomic and socioeconomic surveys together with daily rainfall estimates to explore links between the households’ rainfall risk perceptions and the social dimension of communities’ local knowledge. We build a panel dataset, interviewing 280 smallholder households in the Ethiopian highlands in the spring of 2013 and 2019, while computing the mean, the standard deviation, and the maximum value of three rainfall parameters during the crop growing seasons of the same period. By analyzing varietal and soil management choices, we identify a novel indirect measure of farmer’s risk perception on rainfall abundance and scarcity. This measure shows high heterogeneity among neighboring households. Regressing the perception indices on rainfall parameters, we find that changes in parameters volatility and maximum are rarely perceived by farmers. We further interact changes in the rainfall parameters with idir membership, to see whether the share of local knowledge mediates rainfall risk perceptions. Findings reveal that idir membership mediates the risk perception on rainfall parameters and that the share of local knowledge makes changes at the variance and maximum of the rainfall distribution more intelligible. Our findings suggest that the share of local knowledge in informal institutions like idir should be considered in programs of rainfall change mitigation and risk reduction.
The effect of centralized and crowdsourced participatory variety testing approaches on bean varietal diversification and household food security in the Trifinio area with K. de Sousa, M. Dell'Acqua, J. Sellare, K. Paredes, J. Robalino and J. van Etten
Participatory approaches for crop variety testing have been shown to improve on-farm agrobiodiversity and foster innovation. However, conventional approaches fail to incorporate traditional knowledge and to consider site-specific sociocultural complexities, while participatory approaches used over the last decades have a number of drawbacks and are seldomly scaled. In this study, we analyze the effects a new crowdsourced citizen science approach for on-farm variety testing in the Trifinio area in Central America. We compare a state-of-the-art group-based participatory variety testing approach (or GB-PVS) with a crowdsourced citizen science approach, called triadic comparisons of technologies (or tricot -CCS) to evaluate their impact on i) farmer on-farm diversification and ii) food security. A total of 1978 smallholder farmers growing common bean (Phaseolus vulgaris L.) and belonging to 140 communities were randomly assigned to either GB-PVS, tricot-CCS or control (no participatory approach) to perform varietal testing and selection. A survey was then used to quantify the effects on farmers’ engagement, adoption, diversification, and food security. Regressions revealed that farmers involved in GB-PVS and tricot-CCS had comparable level of variety adoption and a higher degree of on-farm count varietal diversification with respect to control farmers. We found that tricot-CCS ensured a lower attrition rate, thus enhancing the effectiveness of this feedback approach. Moreover, data show that GB-PVS approaches decreased households’ food insecurity with respect to controls. Our results support the use of crowdsourced citizen science approaches to enhance the effectiveness of breeding programs.
Is green the new black? An ABM approach on transition toward sustainable agriculture with M. Coronese, F. Lamperti and A. Roventini
Since the last decades economic and population growth increasingly pressured the Earth system. Land management is essential to ensure sustainability of future food security, but it needs to cope with rising global environmental risks and constraints. In this work we extend the agriLOVE agent-based model of an agricultural sector to investigate interactions between different agricultural regimes in an economy exposed to explicit environmental boundaries. In particular, we study the ability of the system to favor a transition to a sustainable regime when prolonged cultivation with conventional techniques yields a slowdown in productivity dynamics, due to soil degradation. We investigate transition dynamics under several behavioral, environmental and policy scenarios. Our results point to strong path-dependece and show how the agricultural sector has a very limited capacity to ease transition towards a sustainable regime if not supported by appropriate policies. Intuitively, the transition is negatively affected by the velocity and timing of the phenomenon of soil-erosion. The presence of incomplete information has an ambiguous role: being endowed with more information paradoxically lower transition likelihood, although it speeds up the velocity of the transition itself. We further show the existence of trade-offs between distinct spatial configuration, particularly between different degrees of sustainable farms clusterization. Finally, we demonstrate how subsidies to sustainable farming are relevant to avoid lock-ins of conventional farming, but they are only marginally effective in fostering transition. Taxes on conventional farming can help the diffusion of sustainable practices, but conditional on being severe and targeted at R&D activities.