Urea Coated with Iron and Zinc Oxide Nanoparticles Reduces Nitrogen Leaching in Sandy Soil and Improves the Performance of Young Corn Plants

Abstract

Nitrogen (N) is the most widely used nutrient in agriculture in the form of urea, yet it is one of the least efficient in terms of application due to losses through volatilization and leaching. The combination of urea with micronutrient sources, especially in the form of nanoparticles, is a promising technology for reducing these losses. Two greenhouse experiments were conducted with the objective of evaluating the influence of coating urea with zinc oxide nanoparticles (NPZnO) and iron oxide nanoparticles (NPFe2O3), associated with elemental sulfur (S°), on the leaching of mineral nitrogen and the production of dry mass and accumulation of N in young corn plants. The coating (0.26% w/w) of urea with elemental sulfur (S°) and NPZnO and NPFe2O3 reduced N losses through leaching (−21.3%) and delayed the nitrification process of N in the soil (−71.8%). This coating increased the efficiency of nitrogen fertilization in young corn plants, boosting the production of dry mass in leaves (+39.4%), stems (+68.8%), and roots (+61.6%), as well as the absorption of N in the above-ground biomass (+64.1%), compared to conventional urea. The use of urea coated with NPZnO and NPFe2O3 associated with S° is an environmentally sound solution for supplying N and micronutrients such as Fe and Zn in a more efficient and sustainable manner, especially in sandy soils with low organic matter content, which are common in the semi-arid region of Brazil.