Zinc Plus Biopolymer Coating Slows Nitrogen Release, Decreases Ammonia Volatilization from Urea and Improves Sunflower Productivity

Abstract

Currently, the global agriculture productivity is heavily relied on the use of chemical fertilizers. However, the low nutrient utilization efficiency (NUE) is the main obstacle for attaining higher crop productivity and reducing nutrients losses from these fertilizers to the environment. Coating fertilizer with micronutrients and biopolymer can offer an opportunity to overcome these fertilizers associated problems. Here, we coated urea with zinc sulphate (ZnS) and ZnS plus molasses (ZnSM) to control its N release, decrease the ammonia (NH3) volatilization and improve N utilization efficiency by sunflower. Morphological analysis confirmed a uniform coating layer formation of both formulations on urea granules. A slow release of N from ZnS and ZnSM was observed in water. After soil application, ZnSM decreased the NH3 emission by 38% compared to uncoated urea. Most of the soil parameters did not differ between ZnS and uncoated urea treatment. Microbial biomass N and Zn in ZnSM were 125 and 107% higher than uncoated urea, respectively. Soil mineral N in ZnSM was 21% higher than uncoated urea. Such controlled nutrient availability in the soil resulted in higher sunflower grain yield (53%), N (80%) and Zn (126%) uptakes from ZnSM than uncoated fertilizer. Hence, coating biopolymer with Zn on urea did not only increase the sunflower yield and N utilization efficiency but also meet the micronutrient Zn demand of sunflower. Therefore, coating urea with Zn plus biopolymer is recommended to fertilizer production companies for improving NUE, crop yield and reducing urea N losses to the environment in addition to fulfil crop micronutrient demand.

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

“…With the application of zinc-coated urea, NO 3 -N leaching decreased to 35.1% (Jadon et al, 2018). Nitrogen use efficiency improved by up to 55% using Zn-coated urea, and ammonia volatilization losses were greatly reduced (Sadiq et al, 2021). Zn-coated urea enhanced NUE by up to 80%, increased rice yield by 50%, and grain Zn content by 126%.…”

“…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). Soil bacteria infiltrate the coating through fractures in the material and break down the urea granules; the microbial population alters the nutrient release and duration of zinc-coated urea fertilizer (Santos et al, 2018).…”

“…Zinc-coated urea enhances pecan (a fruit having a single stone) growth and development by increasing photosynthesis and catching greater light intensity. Although low light intensity does not influence the release mechanism of Zn-coated urea, Zn absorption in plants is limited, which has a detrimental impact on plant development and production (Sadiq et al, 2021).…”

“…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).…”

“…Using Zn-coated urea to slow down the hydrolysis and nitrification process resulted in enhanced N absorption and, as a result, a higher yield (Affendi et al, 2018). Zinc-coated urea also increased the yield by improving NUE while completing the Zn need of the sunflower crop (Sadiq et al, 2021). The application of zinc-coated urea to rice resulted in an increased transpiration rate and a higher percentage of normal kernels while lowering the percentage of opaque, abortive, and chalky kernels (Irshad et al, 2021).…”