In partnership with Tidal Vision, this project looks at the challenges of creating sustainable and effective fertilizers that can boost agricultural productivity while minimizing environmental harm. Current synthetic fertilizers, especially nitrogen-based ones, cause major environmental issues like greenhouse gas emissions, water pollution, and soil damage. Controlled-release fertilizers (CRFs) could help by releasing nutrients gradually, reducing excess nitrogen, and preventing environmental problems, but current CRFs don’t work well enough—they release nutrients too quickly and can form harmful aggregates.
The ideal CRF should release nutrients steadily over time and break down into substances that don't harm the environment or soil quality. The team explored three main CRF strategies, each designed for different soil types:
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Egg-inspired CRF: This uses a fertilizer core surrounded by a chitosan hydrogel and a brittle shell. The release of nutrients can be controlled by adjusting the hydrogel’s properties, such as its polymer length and crosslinking density, allowing for a release period of 60-110 days.
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Clay-based CRF: This mimics natural nitrogen sources like manure. It involves fertilizer pellets and biopolymers in a clay matrix that releases nutrients as the biopolymers break down.
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Glass fertilizer: This uses a silica glass matrix filled with plant nutrients. Nutrients are released through ion exchange and work well for sandy, porous soils.
The team evaluated each strategy based on performance, health risks, and environmental impact, using reliable data sources. The egg-inspired CRF is the most versatile, suitable for various soil types. The clay-based CRF works best for clay soils, while the glass fertilizer is ideal for sandy soils and has low environmental risks.
The report recommends using bio-based polymers and greener additives to reduce hazards from synthetic coatings, excess fertilizer, water pollution, and health issues from microplastics. It also suggests guidelines for workplace safety to avoid occupational hazards. However, further research is needed to confirm the effectiveness, scalability, and long-term environmental impact of these strategies.