Lessons from the Short-Lived 2021 Fertilizer Import Ban in Sri Lanka Based on Analysis of Nutrient Flows

The Sri Lankan government’s 2021 policy to ban mineral fertilizer imports and shift to green agriculture provides an opportunity to examine the potential for nutrient recycling in a more circular economy. Here, we examined national-level nutrient flows in Sri Lanka to determine the capacity to offset mineral fertilizer with alternative nutrient sources, considering nitrogen (N) and phosphorus (P). Beyond animal manure already applied to croplands, other nutrient sources, including municipal solid waste (MSW) compost and human excreta, have limited potential to offset mineral fertilizer imports. For example, MSW compost and early adoption of nutrient recovery from human excreta could provide N and P equal to only ≤10% of mineral fertilizer use. Furthermore, we used a grid-based resource recovery and distribution model to identify priority areas for the nutrient management transition in Sri Lanka. Reuse of recovered nutrients from MSW compost and human excreta in model scenarios was in urban and peri-urban areas, including home gardens, distant from much of the nation’s agriculture. Our findings reinforce calls for long-term strategic planning for transitions in nutrient management. Future policies should consider fundamental constraints on alternative nutrient sources and emphasize increasing capacity for both effective nutrient recycling and efficient mineral fertilizer use.