Development and characterization of enhanced urea through micronutrients and established technology addition

Abstract

It is necessary to increase the agronomic use efficiency of urea to reduce ammonia volatilization and increase crop yield. However, relying solely on urea for the enhanced efficiency technologies development could harm fertilizer integrity, resulting in reduced application quality and fertilizer storage time. The authors aimed at developing and characterizing the physical, chemical, and physicochemical quality of a novel enhanced efficiency fertilizers, synthesized from urea plus boron (B), zinc (Zn), nickel (Ni), or molybdenum (Mo) addition, with or without N-(n-butyl) thiophosphoric triamide (NBPT) associated. Hygroscopicity, hardness, salt index (SI), pH, and thermogravimetric decomposition were the parameters evaluated. Fertilizer quality was assessed through microscopic X-ray fluorescence, microtomography, and scanning electron microscopy. Micronutrients were added by coating or granulation; they were homogeneously distributed over the fertilizer's granules. The fertilizers’ hardness increased up to 86% with Zn coated compared with uncoated. Granulated urea with B, Zn, Ni, or Mo had greater internal porosity, which resulted in lower hardness. Boron and Zn addition to the fertilizers increased the hygroscopicity in average 388% and 473%, respectively, compared with hygroscopicity observed for urea. Moreover, hygroscopicity was increased by an average of 56% with NBPT addition. Micronutrients addition to the urea granules increased the SI, while thermal decomposition stages of urea were unaffected by micronutrients addition. Enhanced efficiency fertilizers require characterization before agronomic efficiency tests due to changes in their physical, chemical, and physicochemical properties. Unfavorable changes could harm granules integrity and application efficiency in the field, resulting in economic losses to the industry and farmers.