Sulfur coated urea (SCU) is a fertilizer product that utilizes a sulfur coating to gradually release nitrogen to plants and soil over an extended period. The sulfur coating acts as a diffusion barrier, controlling the rate at which urea dissolves and the nitrogen becomes plant-available. https://articlescad.com/sulfur-coated-urea-an-environmentally-friendly-slow-release-fertilizer-41757.html