Zinc oxide nanoparticles coated urea enhances nitrogen efficiency and zinc bioavailability in wheat in alkaline calcareous soils.

Nitrogenous fertilizers have low efficiency in alkaline calcareous soils due to volatilization and denitrification. These losses cause economic environmental constraints. Coating of urea with nanoparticles (NPs) is an innovative strategy to improve crop yields by sustaining N availability. In the current study, zinc oxide nanoparticles (ZnO NPs) were synthesized by precipitation method and characterized for morphology and configuration, bond formation, and crystal assemblage using the X-ray diffraction and scanning electron microscope (SEM). The SEM results confirmed the size of ZnO NPs in the size range of 25 nm with cuboid shape. Urea fertilizer, coated with ZnO NPs, was applied to wheat crop in a pot trial. Two rates of ZnO NPs at 2.8 and 5.7 mg kg-1 were selected to coat the commercial urea. A batch experiment was conducted to ensure the ammonium (NH4+) and nitrate (NO3-) ions release by amending the soil with ZnO NPs coated urea and comparing with non-amended soil. The gradual release of NH4+ was observed for 21 days from the ZnO NP-coated urea. In the second part of trial, seven different treatments of coated and uncoated urea were tested on wheat crop. Urea coated with ZnO nanoparticles at 5.7 mg kg-1 improved all growth attributes and yields. The ZnO NP coated urea increased the N content shoot (1.90 g 100g-1 DW) and potentially biofortified Zn content (47.86 mg kg-1) in wheat grain. The results are indicative of viability of a novel coating for commercial urea that will not only reduce N losses but also supplement Zn without additional cost of labor.

Zinc portioning and allocation patterns among various tissues confers variations in Zn use efficiency and bioavailability in lentil genotypes.

Zinc (Zn) is essential for plants and animals as it plays significant roles in several physiological and biological processes. Its deficiency in soil results in low Zn content food and is one of the major reasons for Zn malnutrition in humans. Biofortification of crops with zinc (Zn) is a viable approach to combat malnutrition, especially in developing countries. A hydroponic study was executed to study response and Zn partitioning in various lentil genotypes. Eight preselected lentil genotypes (Line-11504, Mansehra-89, Masoor-2006, Masoor-85, Line-10502, Markaz-09, Masoor-2004, and Shiraz-96) were grown in solution culture with two Zn levels (control and adequate Zn). Plants were sown in polythene lined iron trays with a two inch layer of prewashed riverbed sand. After 10 days of germination, seedlings were transplanted to a 25L capacity container with nutrient solution for 15 days, and afterward, these plants were divided into two groups, receiving either 2.0 mM Zn or no Zn levels. Three plants of each genotype were harvested at the vegetative growth stage (60 DAT) and the remaining three at physiological maturity (117 DAT). Plants were partitioned into roots, shoots, and grains at harvest. Significant variations in root and shoot dry matter production, grain output, partitioning of Zn in plant parts (root, shoot, and grain), grain phytate reduction, and Zn bioavailability were observed among genotypes. Lentil root accumulated more Zn (54 mg kg-1) with respect to shoot Zn (51 mg kg-1) under Zn supply. The Zn efficient genotypes (Line-11504 and Mansehra-89) produced more root and shoot dry weights at both harvests. There was a positive correlation between the relative growth rate of root and grain phytate concentration (r = 0.55) and [phytate]:[Zn] ratio (r = 0.67). Zn-efficient genotype Mansehra-89 had a maximum root shoot ratio (0.57) and higher grain Zn (60 mg kg-1) with a respectively reduced grain phytate (17 µg g-1) and thus, had more Zn bioavailability (3.01 mg d-1). The genotypic ability for Zn uptake and accumulation within different plant tissues may be incorporated into future crop breeding to improve the nutrition of undernourished consumers.

Potassium ferrite nanoparticles on DAP to formulate slow release fertilizer with auxiliary nutrients.

Low use efficiency of nitrogen (N) and phosphorus (P) is major challenge of modern agriculture. Coating of conventional fertilizers with nanomaterials is a promising technique for improved nutrient use efficiency. In current study, nanoparticles (NPs) of potassium ferrite (KFeO2 NPs) were coated on di-ammonium phosphate (DAP) fertilizer with three rates (2, 5, 10%) of KFeO2 NPs and were evaluated for release of N, P, K and Fe supplementation in clay loam and loam soil up to 60 days. The NPs were characterized for crystal assemblage, bond formation, morphology and configuration using the x-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform-infra red spectroscopy (FT-IR). The results showed that size of NPs ranged between 7 and 18 nm. The controlled release of P in 10% KFeO2 nano-coated DAP was observed throughout the incubation period. The P release kept on increasing from day-1 (14.5 µg g-1) to day-60 (178.6 µg g-1) in coated DAP (10%) in loam soil. The maximum release of 50.4 µg g-1 NH4+1-N in coated DAP (10%) was observed after 30 days of incubation. The release of NO3-1-N was consistent up to 45 and 60 days in clay loam and loam soil, respectively. The average release of potassium and iron in 60 days was 19.7 µg g-1 and 7.3 µg g-1 higher in 10% coated DAP than traditional DAP in clay loam soil. It was concluded that KFeO2 nano-coated DAP supplied P and mineral N for longer period of time in both soils, and some higher coating levels should be tested in future.