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.