Nanometric phosphates dispersed in urea on the agronomic efficiency of phosphorus in oxidic soil

Abstract

Phosphorus (P) is an important macronutrient responsible for the growth and yield of agricultural crops. Developing efficient fertilization practices has become increasingly important because of the growing global demand for food. About 80-90% of P applied as fertilizer is lost to the environment or chemically bound in soil, therefore not available to plants. Nanoparticle fertilizers have a potential for improvement in P efficiency, based on the hypothesis that nanometric particles present greater mobility and availability in the soil. However, one challenge to be overcome is to develop strategies to maintain phosphate particles on a nanoscale scale and prevent their clustering. Recent studies have demonstrated that urea fertilizer presents potential as a matrix for the dispersion of mineral phosphates, avoiding the agglomeration of the particles, increasing the solubility and changing the soil P dynamics. Therefore, the central proposal of this work will be to process and characterize nanocomposites based on the dispersion of hydroxyapatite (Hap) (used as a model source of mineral phosphates) or Triple Superphosphate (TSP) in urea matrix and to evaluate the agronomic aspects related to the dynamics of P and N in soil and supply of these nutrients to plants. The preparation of the new fertilizer will be based on the extrusion process, from Hap or ST fractions ground to nanometric bands and dispersed in the urea matrix by this method. Next, the characterization of the nanocomposites will be carried out, followed by evaluations of the availability and dynamics of P and N in the soil, besides the availability of these nutrients to the plants. Understanding the synergism and interaction of urea with phosphate particles may provide support for the development of more efficient and sustainable fertilizers with direct implications for plant mineral nutrition and ultimately for food production. (AU)