Julián Chará

The environmental costs and benefits of high-yield farming

How we manage farming and food systems to meet rising demand is pivotal to the future of biodiversity. Extensive field data suggest that impacts on wild populations would be greatly reduced through boosting yields on existing farmland so as to spare remaining natural habitats. High-yield farming raises other concerns because expressed per unit area it can generate high levels of externalities such as greenhouse gas emissions and nutrient losses. However, such metrics underestimate the overall impacts of lower-yield systems. Here we develop a framework that instead compares externality and land costs per unit production. We apply this framework to diverse data sets that describe the externalities of four major farm sectors and reveal that, rather than involving trade-offs, the externality and land costs of alternative production systems can covary positively: per unit production, land-efficient systems often produce lower externalities. For greenhouse gas emissions, these associations become more strongly positive once forgone sequestration is included. Our conclusions are limited: remarkably few studies report externalities alongside yields; many important externalities and farming systems are inadequately measured; and realizing the environmental benefits of high-yield systems typically requires additional measures to limit farmland expansion. Nevertheless, our results suggest that trade-offs among key cost metrics are not as ubiquitous as sometimes perceived.High-yield farming systems have the potential to spare non-farmed land for other uses (such as nature conservation), but raise concerns about their other environmental impacts (such as greenhouse gas emissions and soil erosion). This study argues such impacts should be measured per unit of production and shows that viewed this way, some land-efficient systems have less impact than lower-yielding alternatives.

Intensive Silvopastoral Systems: Economics and Contribution to Climate Change Mitigation and Public Policies

Intensive Silvopastoral Systems (ISPS) are agroforestry arrangements that combine high-density cultivation of fodder shrubs (4000–40,000 plants ha−1) with improved tropical grasses, and trees or palms at densities of 100–600 individuals ha−1. The ISPS were initially developed in Colombia and have expanded to Mexico and Brazil, among other countries. The main fodder shrubs currently used are Leucaena leucocephala and Tithonia diversifolia due to their fast growth, tolerance to heavy grazing by cattle, and reduction in the emissions of greenhouse gases. Among their advantages, ISPS produce more edible dry matter and nutrients per hectare; increase milk or meat production while reducing the need of chemical fertilizers and concentrate feeds, thus improving farm profitability; increase carbon sequestration and reduce methane emissions from enteric fermentation; and improve animal welfare and biodiversity. The present chapter is a review of recent experiences and research findings in ISPS in Latin America and their effect on production efficiency, greenhouse gas emissions, and economic performance. It also reviews the need of public policy and research to improve access to capital, incentives, and extension services in cattle ranching areas to promote ISPS. ISPS are an important tool in supplying beef and dairy products for local and global markets, while also providing environmental services and increasing resilience to climate change.