The benefits and limits of agricultural diversity

Diminishing the environmental and social impact of global food production while maintaining agricultural productivity and reducing the level of food insecurity and malnutrition is among the major global challenges of our century. Adopting and maintaining agricultural diversification strategies can provide multiple benefits to improve the sustainability of farming systems, either at the environmental, social and economic level. The objective of this PhD project was to study the benefits and limits of agricultural diversity, with a major focus on the factors that influence farmer decisions in the adoption or dis-adoption of practices that enhance agricultural diversity in different agroecological and socio-economic contexts. Based on these premises, I employed both qualitative and quantitative methods and study farm-scale diversification strategies in different regions in terms of geographical and socio-economic characteristics.
In the first chapter, I introduced the background and the objectives of this doctoral thesis. I also provided context and definitions adopted, and presented the structure of this research.
Chapter 2 consists of a systematic review of the recent literature analysing the driver and constraints of on-farm diversity at the farm scale, defined as the variety of crop and livestock species grown. The main objectives were to identify drivers and constraints of on-farm diversity emerging from studies focusing on diverse locations around the world and identify agroecological or socio-economic patterns associated with these drivers and constraints. From 2,312 studies, we selected a total of 97 from 42 different countries. We identified a total of 239 drivers and constraints, which we categorised using the Sustainable Rural Livelihood Framework. Then, we reported the number of times they were assessed as having a positive (driver), negative (constraint) or neutral relationship with on-farm diversity. Our review presented some heterogeneous results, with a few variables acting as drivers or constraints of on-farm diversification depending on the context or the characteristics of the farm. These findings showed that the adoption of diversification strategies is influenced by both production and demand dynamics, and that to understand, promote and enhance on-farm diversity, where it is a useful strategy, it is crucial to consider farmer objectives and the opportunity-cost of alternative management or livelihood strategy.
Chapter 3 focuses on small farming systems in South and Southeast Asia. These regions are still characterised by high levels of undernourishment, especially in rural areas. Hence, the purpose of this study was to test the role of agricultural diversity on rural household dietary diversity. We examined a secondary dataset of 4,772 rural households located in Cambodia, India, Lao PDR and Vietnam. We used generalized linear regression models to test a set of factors derived from the literature as potential drivers or constraints of on-farm diversity. Then, we analysed the impact of on-farm diversity on dietary diversity in comparison with other livelihood strategies. To explore potential differences between farm characteristics, we also analysed different farm groups based on the size of land cultivated. The results of this study showed that environmental and climate variables have a significant impact on the decision to diversify within our sample, but that it is also influenced by household characteristics. The diversification of farm production, but also the level of market orientation of the household and the engagement in off-farm activities were all strategies with a positive correlation with household and individual dietary diversity. However, the magnitude and significance of their effect differed between the farm size groups. The positive effect of farm diversity on dietary diversity was larger for smaller farms, while it decreased for farms of larger size that may improve their diet more by increasing their engagement in off-farm activities and markets. These findings confirm that considering the differences between farms and the situational context of analysis is necessary when targeting intervention for improving smallholder farm livelihoods.
In Chapter 4, we examined the role of agricultural diversity in Tasmania. Tasmania has a thriving agricultural sector, a diverse climate and geography, that make it one of the most “agro-diverse” regions in Australia. Conducting a mixed-method survey, we interviewed 95 farmers with different characteristics, productions and from different areas of Tasmania. In this study, we use qualitative analysis with the objective to identify the different farmer perceptions about agricultural diversity, the role of diversity and how it is used by Tasmanian farmers, and finally, the potential incentives and barries for increasing the adoption of diversification practices. The farmers in our sample offered different perceptions of agricultural diversity that spans from the diversification of crops and livestock species to more complex definition that include risk management or farm’s overall sustainability. We could identify a net distinction between farmers using diversification strategies: (1) as integral components of their farming activities to respond to different needs and purposes, (2) purely as additional business opportunities or (3) for motivations that go beyond the financial value and involve the objective to improve the sustainability of their farms. This study shows that understanding farmers perspectives is another key element to take into account when looking for strategies that reduce the trade-offs between farm economic and environmental sustainability.
Chapter 5 presents the synthesis of the findings from the three studies of this thesis by summarising and comparing the final results. I also provide final reflections and suggestions for future research and policies around agricultural diversity. In conclusion, the evidence from thesis shows that agricultural diversity is a strategy that can benefit farmers in different ways, however, it should not be considered a panacea, but needs to be calibrated to the contextual contingencies, farmers’ objectives and characteristics of the farming systems considered.