Different Zn loading in Urea–Formaldehyde influences the N controlled release by structure modification

Abstract

Nitrogen fertilization has been a critical factor for high crop productivity, where urea is currently the most used N source due to its high concentration and affordability. Nevertheless, urea fast solubilization leads to frequent losses and lower agronomic efficiency. The modification of urea structure by condensation with formaldehyde has been proposed to improve nutrient uptake by plants and to reduce environmental losses. Herein we show that the co-formulation with Zn strongly modifies the N release (in lab conditions) and, more important, the Zn source—ZnSO4 or ZnO—has a critical role. Urea–formaldehyde (UF) served as a matrix for the zinc sources, and chemical characterizations revealed that Zn particles influenced the length of the polymeric chain formation. Release tests in an aqueous medium showed that the UF matrix favors ZnO release and, on the other hand, delays ZnSO4 delivery. Soil incubation with the fertilizer composites proved the slow-release of N from UF, is ideal for optimizing nutritional efficiency. Our results indicated that the ZnO-UF system has beneficial effects for both nutrients, i.e., reduces N volatilization and increases Zn release.

Improving crop productivity and nitrogen use efficiency using sulfur and zinc-coated urea: A review

“…The release pattern of coated urea is directly proportional to the microbial activity in soil (Gil-Ortiz et al, 2020). Soil microbes cause complete urea breakdown, allowing plants to absorb nitrogen, reducing nitrogen volatilization, and increasing zinc release from zinc-coated urea (Giroto et al, 2021). Bacteria convert nitrogen in the compound to nitrate, lowering soil pH and diminishing soil microbial diversity, which has a detrimental influence on the coated urea release pattern with zinc nanoparticles (Sadiq et al, 2021).…”

“…For instance, Muster et al (2011) reported that Zn uptake is greatly affected by high temperatures in humid environments. High humidity contributes to accelerating the release of nitrogen from Zn-coated urea by increasing the amount of water retained at the soil surface (Giroto et al, 2021). Humidity affects soil temperature and water potential, reducing the efficiency of Zn-coated urea in soil and making it easier to solubilize the urea granules by adding water through coatings (Sadiq et al, 2021).…”

Zinc loading in urea-formaldehyde nanocomposites increases nitrogen and zinc micronutrient fertilization efficiencies in poor sand substrate

“…The use of urea:urea-formaldehyde polymers (UF polymers) as N fertilizers has been proven an excellent option to overcome urea losses, as this material can deliver nutrients at a controlled rate, avoiding fast hydrolysis in soil (Giroto et al, 2021;Giroto and Ribeiro, 2018;Guo et al, 2018;Xiang et al, 2018;Zhang et al, 2020). Although most studies addressed macronutrient management, there are strong indications that micronutrient deficiencies significantly limit crop productivity (Kihara et al, 2017;Vanlauwe et al, 2015).…”

Effect of Wood-Derived Porous Carbon Framework on Zinc Adsorption–Desorption Kinetics for Nutrient Flow

“…5 Zn loading can also help in controlling the release of Nfertilizers via structural modifications. 6 Zn adsorption− desorption with favorable desorption kinetics can be achieved by using Zn-based engineered materials for controlled Zn release into soil by suppressing the Zn leaching loss after fertilizer application. In such a strategy, biopolymers such as cellulose, chitosan, and alginate were utilized to deliver ZnO nanoparticles.…”

“…In the past, zeolite and bentonite were known as nutrient adsorbents with controlled release of plant nutrients by the understanding of the sorption in zeolite and bentonite by following the Langmuir and Freundlich isotherm in which case a higher adsorption of Zn caused a lower percentage of desorption as can be found in slow-release fertilizers for Zn . Zn loading can also help in controlling the release of N-fertilizers via structural modifications . Zn adsorption–desorption with favorable desorption kinetics can be achieved by using Zn-based engineered materials for controlled Zn release into soil by suppressing the Zn leaching loss after fertilizer application.…”