Embedding circularity into the transition towards sustainable agroforestry systems in Peru.

Peru is promoting the adoption of agroforestry systems with the aim to halt the deforestation of tropical forests caused by smallholder farmers. However, deficient soil conservation practices and nutrient management are common among the targeted smallholders, hampering the success of this strategy. In this study, we explore the potential of valorizing municipal biowaste as compost to be used as soil amendment in coffee agroforestry systems and in silvopastoral systems. The analysis was concentrated in four Peruvian regions and the most populous city in each of them. For lands with coffee production, it was assumed that 90 kg N ha-1 (i.e., 50% of the N requirements) should come from compost, while for pastures, the requirement was 40 kg P ha-1. We found that composting could lead to large greenhouse gas (GHG) reductions compared with the current waste disposal methods (i.e., deep dumping and landfilling), as it only emits 5-10% of the GHG emissions produced with the other methods. Nonetheless, the area of agroforestry and silvopastoral systems that could be fertilized with compost obtained from the main city of each region is limited and insufficient. If all compost were to be used for the coffee agroforestry system, less than 3% of the coffee agroforestry area could be fertilized, while in the case of pastures, only 4% would be attained. Large amounts of compost could be obtained from Lima, the most populated city; however, its transportation to the agroforestry areas would increase compost GHG emissions by 15-60%. Although composting municipal food waste and loss may bring GHG benefits and should be promoted, its use as a fertilizer requires mixing with N-rich sources to improve its nutrient quality.

Articulating the effect of food systems innovation on the Sustainable Development Goals.

Food system innovations will be instrumental to achieving multiple Sustainable Development Goals (SDGs). However, major innovation breakthroughs can trigger profound and disruptive changes, leading to simultaneous and interlinked reconfigurations of multiple parts of the global food system. The emergence of new technologies or social solutions, therefore, have very different impact profiles, with favourable consequences for some SDGs and unintended adverse side-effects for others. Stand-alone innovations seldom achieve positive outcomes over multiple sustainability dimensions. Instead, they should be embedded as part of systemic changes that facilitate the implementation of the SDGs. Emerging trade-offs need to be intentionally addressed to achieve true sustainability, particularly those involving social aspects like inequality in its many forms, social justice, and strong institutions, which remain challenging. Trade-offs with undesirable consequences are manageable through the development of well planned transition pathways, careful monitoring of key indicators, and through the implementation of transparent science targets at the local level.

Perspective article: Actions to reconfigure food systems.

There is broad agreement that current food systems are not on a sustainable trajectory that will enable us to reach the Sustainable Development Goals by 2030, particularly in the face of anthropogenic climate change. Guided by a consideration of some food system reconfigurations in the past, we outline an agenda of work around four action areas: rerouting old systems into new trajectories; reducing risks; minimising the environmental footprint of food systems; and realigning the enablers of change needed to make new food systems function. Here we highlight food systems levers that, along with activities within these four action areas, may shift food systems towards more sustainable, inclusive, healthy and climate-resilient futures. These actions, summarised here, are presented in extended form in a report of an international initiative involving hundreds of stakeholders for reconfiguring food systems.