Efficient use of fertilizers, especially nitrogen, is essential and strategic to agricultural production. Among the technologies that can contribute to efficient use of fertilizers are slow- or controlled-release products. This study describes the impact on structure, urea release rate, and function in the field of urea nanocomposites associated with an exfoliated clay mineral prepared using various concentrations of hydrophilic or hydrophobic polymers. The nanocomposites have a high nutrient load (75% by weight), which itself acts as a structural matrix. Our manufacturing process-the extrusion of a plastic mixture-is simple and can be scaled up, allowing granule production without high costs. Nanocomposites were prepared by adding varying amounts (less than 4% by weight) of polyacrylamide hydrogel or polycaprolactone, which influenced mechanical properties and urea release profiles. Nitrous oxide (N2O) emissions in the field were reduced substantially for nanocomposites, whether composed of polyacrylamide hydrogel or polycaprolactone.