Mechanosynthesis of urea–hydroxybenzoic acid cocrystals as sustained-release nitrogen fertilizer

Abstract

Nitrogen is a key nutrient source in agriculture, which has a crucial impact on crop productivity. Out of available nitrogen fertilizers, urea is identified as the major nitrogen source, accounting for ∼60% of global use. However, due to the low nutrient usage efficiency of urea, it has become unsustainable, as 50–70% nitrogen applied is lost due to leaching, volatilization and nitrification, causing a series of environmental hazards and economic losses. Moreover, the recent global pandemic as well as war disrupt the food supply chain and fertilizer market. Here we used mechanochemistry to prepare a series of novel urea cocrystals that showed sustained-release behavior with significant improvement (∼4 times), lower volatilization, and improved hydration stability compared to commercial urea. Therefore, the proposed urea cocrystal based fertilizer system demonstrates a potential sustained-release nitrogen source in agriculture where excessive use of fertilizer and nutrient loss can be minimised.