Sustainable Alternatives to Petroleum-derived Substances for Preventing Fertiliser Caking

This study addresses the environmental concerns associated with the conventional anti-caking products by developing plant-based alternatives to petroleum-derived materials. Conventional anti-caking products often leave long-lasting residues in soil, which can transform into harmful, mutagenic forms, posing environmental risks. To mitigate these issues, eco-friendly compositions were developed and applied as coating to two different types of compound fertilisers, namely, 20.20.0 (7/13) and 15.15.15 (15/0), which are known for their high caking tendency. The coated fertilisers were subjected to several tests to evaluate their caking tendency, moisture absorption, dust formation, and crushing strength. The uncoated fertilisers exhibited a significant caking tendency, ranging from 30.89 %wt to 38.14 %wt, with dust formation between 1.91 %wt and 2.84 %wt, and crushing strength measuring between 473.8 and 593.0 g per granule. In contrast, the application of plant-based coatings improved product performance by significantly reducing the caking tendency to a range of 0–16.33 %wt, yielding results comparable to petroleum-derived coatings, which showed a tendency of 0–17.45 %wt. Notably, the most substantial improvement was observed when a coating containing stearylamine, plant-oils and waxes was applied, resulting in granules with a crushing strength of 4274.2–5318.0 g per granule and a reduction in dust formation. Additionally, the plant-based coatings exhibited low moisture absorption, remaining below 20 mg cm–2 indicating the presence of a moisture-repellent film.