Search

To evaluate the potential of cooked field peas to be used in Zn biofortification programs, all combinations of soil Zn application of 0, 4 and 8mgZnSO4·7H2Okg(-1) and foliar Zn application of 0 and two sprays of 0.25% or 0.5% (w/v) ZnSO4·7H2O before flowering and at early grain-filling stage were tested. Soil Zn application increased Zn-DTPA concentration 3.7- to 5.6-times depending on the Zn soil treatments. Grain Zn concentrations higher than 60mgZnkg(-1) were obtained with all foliar Zn applications, alone or in combination with soil Zn applications, and grain Zn bioavailability was adequate (phytate:Zn ratios lower than 15). Processing (freezing and cooking) caused a decrease of about 30% in grain Zn concentration and a 17%-increase in phytate:Zn ratios (to ⩽9.5). The combined application of 8mgZnSO4·7H2Okg(-1) soil+0.25% (w/v) ZnSO4·7H2O foliarly could be a good option for biofortifying field peas., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

[Objective] Incorporating contemporary research issues into educational curricula is essential in bridging the gap between theoretical knowledge and practical application. This study is designed to integrate the emerging topic of "novel fertilizers" with the fundamental theories of soil science and fertilizer resource development. In particular, this study explores the efficacy of biochar-based zinc fertilizers in increasing the zinc content in rice grains, an essential micronutrient that is often deficient in common diets. Biochar, as a carbon-rich product derived from the pyrolysis of organic materials, is used in this experiment as a carrier for zinc to enhance the soil microenvironment around rice roots, facilitating the uptake of zinc into the rice plants. [Methods] This experiment involved the preparation of biochar-enriched zinc fertilizers and their application to rice paddy fields. The biochar was derived from wheat straw pyrolyzed at 600°C, and zinc oxide nanoparticles (nZnO) were loaded onto the biochar using zinc acetate as a precursor. XRD and SEM analyses confirmed the successful loading of nZnO onto the biochar surface. The pot experiment included eight treatments: (1) no biochar and nZnO (T1), (2) 20 t/ha biochar (T2), (3) 100 kg/ha nZnO (0.5%nZnO, T3), (4) 20 t/ha biochar + 100 kg/ha nZnO (BC+0.5%nZnO, T4), (5) 200 kg/ha nZnO (1.0%nZnO, T5), (6) 20 t/ha biochar + 200 kg/ha nZnO (BC+1.0%nZnO, T6), (7) 200 kg/ha nZnO (2.0%nZnO, T7), and (8) 20 t/ha biochar + 200 kg/ha nZnO (BC+2.0%nZnO, T8). Students measured rice growth, yield, and nutrient content in the plants and grains, analyzing zinc fertilizer utilization and the impact of biochar-based nano-zinc on soil nutrients. The subsequent analyses focused on the bioavailability of zinc in the rhizosphere, i.e., the root zone of the plants. [Results] The results from this study indicate that the application of biochar-based zinc significantly improved the nutrient availability within the rhizosphere. The study observed that the concentration of available zinc in the root soils markedly increased, which, in turn, promoted the accumulation of zinc in both the rice plants and the harvested grains. This increment in zinc content is crucial, considering the role of zinc in enhancing immune function and overall human health. Further analysis confirmed that biochar-based nano-zinc exerted a considerable impact on the microenvironment of the root zone, modifying physical and chemical soil properties in a manner conducive to nutrient uptake. Statistical analysis employing advanced software tools supported these findings, demonstrating a clear trend of enhanced zinc accumulation due to the novel fertilizer application. [Conclusions] This study not only confirms the potential of biochar as an effective carrier for micronutrients like zinc but also illustrates the transformative impact of integrating innovative agricultural inputs with traditional farming practices. Through this study, students engaged in soil science, plant nutrition, agricultural chemical analysis, and related disciplines can enhance their ability to apply theoretical knowledge in analyzing and solving real-world agricultural challenges. In conclusion, the study highlights the significant potential for novel zinc-enriched biochar fertilizers to improve crop micronutrient density. This approach not only addresses the global challenge of micronutrient deficiencies in diets but also offers a sustainable and efficient strategy for resource utilization in agriculture. The experiment thus serves as a valuable model for educational practices, fostering a deeper understanding and practical skills among students in the field of agricultural science. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Zinc deficiency is a significant global health concern, affecting around two billion people due to insufficient dietary intake. The extensive utilization of cereal-based meals with inadequate zinc content and limited bioavailability stands as the primary cause for this issue. Children who possess low levels of zinc experience stunted growth and developmental delays. They also have higher rates of morbidity from pneumonia, diarrhoea, and malaria. Inadequate zinc intake has been correlated with a heightened risk of mortality in children due to specific diseases. It is crucial to secure a satisfactory level of zinc in rice grains because of its indispensable function in various biochemical processes that are fundamental for the growth and advancement of plants. A deficiency in zinc can lead to reduced grain yield and nutritional value in rice. Recently, the utilization of registered biofertilizers and microbial technology is widely recognized in contemporary intensive farming practices. Some indigenous zinc-solubilizing bacterial strains discovered can increase rice yield and zinc content in grains. The objective of this study was to impact of a biofertilizer formula consisting of native zinc solubilizer strains on the growth, productivity, and zinc concentration in the grains of three rice varieties, namely Inpari IR Nutrizinc, Inpari 48, and Inpago 13 Fortiz. The study was conducted in a paddy field located in the Inceptisol of Subang Regency, West Java, during the year 2023. METHODS: The field trial was conducted to study the impact of a biofertilizer comprising a group of non-pathogenic zinc-solubilizing bacteria, including Enterobacter cloacae, Klebsiella pneumoniae, Serratia marcescens, Bacillus thuringiensis, and Enterobacter bugandensis on rice growth, yield, zinc levels, and uptake in grains. The rhizosphere soils were the origin of these bacteria, which were obtained using agar media containing zinc oxide as insoluble zinc compounds. Prior to this, the bacterial strains were evaluated for their capacity to dissolve zinc and generate the plant hormone indole-3-acetic acid. To gauge their zinc-solubilizing prowess, Pikovskaya agar media, supplemented with insoluble zinc oxide and calcium phosphate, respectively, were utilized. The presence of distinct clear areas surrounding the colonies demonstrated the effectiveness of the microbes in converting insoluble zinc and phosphorus into soluble forms. The concentration of the plant hormone indole-3-acetic acid was measured using the Salkowski reagent. The field trial was organized using a split-plot design with three replications. The application of the biofertilizer mixture as a seed treatment was carried out before the transplantation of the rice nursery. The seedlings were prepared individually for each rice variety, with a comparison made between those treated with the biofertilizer and those that were not. FINDINGS: The study found that the consortium of indigenous non-pathogenic zinc-solubilizing bacteria significantly increased the yield of rice varieties by about 5.6 percent and zinc content in grains by 16.3 percent. However, the application of zinc containing fertilizer treatments did not enhance the rice yield and zinc content in grains in this Inceptisol paddy soil. In terms of zinc content in grains, the rice variety Inpago 13 Fortiz exhibited a notable increase compared to the Inpari IR Nutrizinc variety, with levels of 40.3 milligrams per kilogram as opposed to 34.1 milligrams per kilogram. CONCLUSION: the utilization of a native combination of carefully chosen zinc-solubilizing bacterial strains could augment the productivity, zinc concentration, and absorption in rice grains of various varieties in a paddy field with Inceptisols soil type, characterized by a moderate to high overall zinc content and limited zinc accessibility. The addition of zinc containing fertilizer treatments did not enhance rice yield compared to the addition of other tratments or control. This is probably because of the medium-high level of the total zinc content of the soil, suggesting that the addition of Biofertizinc will reduce or delete the crop requirement for zinc fertilizer in Inceptisol paddy fields. This implies that the biofertilizer is ecologically sustainable as it eliminates the use of harmful chemicals, reduces the reliance on synthetic fertilizers, and lowers costs. [ABSTRACT FROM AUTHOR]

Zinc (Zn) is an essential micronutrient that participates in several plant metabolisms. Soil application of Zn is an effective strategy to increase the productivity and Zn concentration in maize grains, but the effect of Zn fertilizers on the nutrients uptake and biofortification still needs more studies. In this study, a greenhouse plot experiment was conducted to evaluate the effect of the optimum Zn fertilizer doses (0, 5.7, and 11.4 kg ha−1) on the nutrients uptake and Zn biofortification of maize crops. Zn applications were found to increase significantly the transpiration rate; photosynthesis rate, Zn, and P concentration in the maize shoot at the VT (Tasseling) stage as well as the grain Zn and maize grain yield. P, Mg, and phytic acid (PA) concentration in grains was also increased with a Zn application of 11.4 kg ha−1. The PA/Zn molar ratio in grains decreased due to the Zn application doses as compared with the control treatment, but there was no significant difference between Zn 5.7 and 11.4 kg ha−1 doses, while Zn 5.7 kg ha−1 achieved a higher PA/Fe molar ratio in maize grains compared to other treatments. [ABSTRACT FROM AUTHOR]

Zinc (Zn) deficiency is a major public health issue worldwide. The biofortification of Zn in popular vegetables could be a promising way to address this burning issue. To enrich tomatoes with bioavailable Zinc through agronomic biofortification. Seven tomato varieties were examined to identify the best one for Zn biofortification based on fruit Zn concentrations. Then six levels of Zn viz., 0, 2, 3, 4, 5, and 6 kg ha−1 were applied to screen out the best Zn dose for maximum biofortification. Finally, the identified Zn dose was applied using six strategies viz., 100% seedling priming, 50% soil + 50% foliar spray at seedling stage, 50% seedling priming + 50% foliar spray, 100% foliar spray at seedling stage, 100% foliar spray at flowering stage and 100% foliar spray at the fruiting stage to recognize the best application strategy. These three experiments were executed following a completely randomized design with three replications. In screening, BARI Tomato-14 showed the lowest Zn concentration compared to all other varieties. The application of 5 kg Zn ha−1 showed the highest Zn concentration in tomato with better yield and quality. Finally, 5 kg Zn ha−1 as 50% soil application + 50% foliar spray showed the maximum biofortification of Zn in BARI Tomato-14 with the highest growth, yield and quality. Therefore, application of 5 kg Zn ha−1 as 50% soil and 50% foliar spray on BARI tomato-14 could be a potential option to mitigate Zn deficiency. [ABSTRACT FROM AUTHOR]

During the summer and rainy seasons (April-October) of 2020 and 2021, two consecutive field experiments were conducted at the research farm of the ICARIndian Agricultural Research Institute, New Delhi, India. In this study, we examined the effects of summer green manuring crops (GM) and a variety of zinc fertilizers (ZnF) on Basmati rice (Oryza sativa L.) growth, physiological development, yield response, zinc nutrition and economic returns. A combination of GM residues and nano zinc fertilization helped significantly enhancing Basmati rice’s growth and its physiological development. Following the incorporation of Sesbania aculeata (Sesbania), successive Basmati rice physiological parameters were significantly improved, as well as grain, straw, biological yields, harvest index and economic returns. The highest Zn content of 15.1 mg kg-1 and the lowest of 11.8 mg kg -1 in milled rice grain were recorded in Sesbania green manuring (G2) and control i.e., in the fallow (G1), respectively. Coating onto urea with 0.2% nano zinc oxide (NZnCU) was observed to be more effective than other zinc sources in terms of growth parameters, yield attributes, zinc nutrition, grain and straw yields for succeeding Basmati rice crop; however, the effects were comparable to those of bulk zinc oxide-coated urea (BZnCU) of 1%. The highest Zn content of 15.1 mg kg -1 was recorded with the application of 1% BZnCU and the lowest of 11.96 mg kg -1 with the soil application of 5 kg Zn ha -1 through bulk ZnO in the milled rice grain. Application of 1% BZnCU led to a 26.25% increase in Zn content of milled rice grain compared to soil application of 5 kg Zn ha -1 through bulk ZnO. As a result, the combination of inclusion of Sesbania aculeata (Sesbania) residue and 0.2% NZnCU was identified as the most effective treatment, for Basmati rice growth and physiological development. A combination of nano Zn fertilization in conjunction with the incorporation of green manure can be advocated for better growth, physiological performance, zinc dense grains, and higher profitability of Basmati rice for farmers and consumers. [ABSTRACT FROM AUTHOR]

The application of zinc fertilizers in the soil has been an agronomic practice to correct Zn deficiency in plants, aiming to increase productivity and/or nutritional quality. This study evaluated how zinc sulfate fertilization affects plant growth, yield performance and nutrient accumulation in the cassava 'IAC 576-70'. The experimental design was in randomized blocks with eight replications. The treatments consisted of 0, 1.5, 3.0, 4.5 and 6.0 g p1-1 ZnSO4. Results showed improvement in yield with soil fertilization with ZnSO4, with the optimal dose of 2.5 g pl-1. The uptake of nutrients in plant parts is favored with lower doses of zinc fertilizer, with maximum points ranging from 0.8 to 3.2 g pl-1 for macronutrients and 1.6 to 3.6 g pl-1 for micronutrients. The Zn content in tuberous roots increases by more than 40% with fertilization up to 2.8 g pl-1 of fertilizer, which contributes to the nutritional value of roots. [ABSTRACT FROM AUTHOR]

The search for an effective zinc fertilizer and its application method to effectively increase zinc content and enhance aroma in rice grains is a crucial objective. In this study, a 2-year field plot experiment was conducted to investigate the influence of ZnO NPs foliar spraying on rice quality, grain zinc and aroma content, along with exploring the physiological mechanisms underlying these effects. Our results demonstrated that the rice breakdown value and taste value of foliar spraying zinc oxide nanoparticles were improved by 31.0–41.7% and 8.2–13.0% compared with CK (control treatment involved spraying water), improving the tasting and steaming quality of rice. While Fe and Cu content in grains decreased for the application of zinc oxide nanoparticles, zinc oxide nanoparticles foliar spraying significantly increased the zinc content and accumulation of grains by 33.6–65.1% and 37.8–74.7%, respectively. Further analysis showed that the sprayed zinc oxide nanoparticles achieved effective enrichment of zinc in edible parts and increased the final bioavailability of Zn. In addition, foliar spraying of zinc oxide nanoparticles significantly increased activities of nitrate reductase and glutamine synthetase in leaves, which elevated nitrogen content in leaves and grains, and ultimately enhanced 2-acetyl-1-pyrroline (2-AP) content in grains at maturity by 6.1–21.4% compared to CK. Our findings indicated that zinc oxide nanoparticles can be practically applied as a foliar fertilizer at the gestation for quality improvement, zinc enrichment and aroma enhancement of rice grains. [ABSTRACT FROM AUTHOR]

Micronutrient deficiency is a serious health issue in resource-poor human populations worldwide, which is responsible for the death of millions of women and underage children in most developing countries. Zinc (Zn) malnutrition in middle- and lower-class families is rampant when daily calorie intake of staple cereals contains extremely low concentrations of micronutrients, especially Zn and Fe. Looking at the importance of the problem, the present investigation aimed to enhance the growth, yield, nutrient status, and biofortification of wheat crop by inoculation of native zinc-solubilizing Bacillus spp. in conjunction with soil-applied fertilizers (NPK) and zinc phosphate in saline soil. In this study, 175 bacterial isolates were recovered from the rhizosphere of wheat grown in the eastern parts of the Indo-Gangetic Plain of India. These isolates were further screened for Zn solubilization potential using sparingly insoluble zinc carbonate (ZnCO3), zinc oxide (ZnO), and zinc phosphate {Zn3(PO4)2} as a source of Zn under in vitro conditions. Of 175 bacterial isolates, 42 were found to solubilize either one or two or all the three insoluble Zn compounds, and subsequently, these isolates were identified based on 16S rRNA gene sequences. Based on zone halo diameter, solubilization efficiency, and amount of solubilized zinc, six potential bacterial strains, i.e., Bacillus altitudinis AJW-3, B. subtilis ABW-30, B. megaterium CHW-22, B. licheniformis MJW-38, Brevibacillus borstelensis CHW-2, and B. xiamenensis BLW-7, were further shortlisted for pot- and field-level evaluation in wheat crop. The results of the present investigation clearly indicated that these inoculants not only increase plant growth but also enhance the yield and yield attributes. Furthermore, bacterial inoculation also enhanced available nutrients andmicrobial activity in the wheat rhizosphere under pot experiments. It was observed that the application of B. megaterium CHW-22 significantly increased the Zn content in wheat strawand grains along with other nutrients (N, P, K, Fe, Cu, andMn) followed by B. licheniformis MJW-38 as compared to other inoculants. By and large, similar observations were recorded under field conditions. Interestingly, when comparing the nutrient use efficiency (NUE) of wheat, bacterial inoculants showed their potential in enhancing the NUE in a greater way, which was further confirmedby correlation and principal component analyses. This study apparently provides evidence of Zn biofortification in wheat upon bacterial inoculation in conjunction with chemical fertilizers and zinc phosphate in degraded soil under both nethouse and field conditions. [ABSTRACT FROM AUTHOR]

Due to climate changes, we encounter irregular and low rainfall. It is important to effectively use groundwater and to select crops that can be grown with deficit irrigation in the summer period. Restricted irrigation reduces water consumption but it may cause losses in terms of yield and quality. Different agronomic practices can be used to minimize these losses. One of these practices is the application of foliar zinc fertilizer. In previous studies, zinc application was found to increase the bioavailability of cowpea grain. In this study, the effects of the application of zinc fertilizer on yield, some yield components, physiological traits, and grain quality characteristics of three different cowpea genotypes (Akkız, Karagöz, and a Local variety) were investigated under full (100%) and deficit (50%) irrigation. The field experiment was conducted using a randomized complete block split–split plot design with irrigation rates (100% and 50%) and foliar zinc application (0 and 60 kg ha−1) with three replicates used each season (2020 and 2021 growing seasons of cowpea) in the field crops trial fields of the Aydin Adnan Menderes University, at the Faculty of Agriculture, located in the western region of Turkey. Yield and quality characteristics such as grain yield, some yield components, grain protein content, grain mineral matter content, and grain amino acid content were measured. According to the data obtained, a 40% yield reduction was observed under restricted irrigation in the first year of the study. It was determined that zinc application under restricted irrigation increased the yield by approximately 10%. The second-year results found that the amount of essential amino acids such as histidine, phenylalanine, valine, and lysine increased with the zinc application. This study highlights that deficit irrigation conditions caused stress in the plant and caused losses in the yield and quality. Still, the severity of this stress was reduced by foliar zinc application, and it was determined that it positively affected grain yield and bioavailability in cowpea. [ABSTRACT FROM AUTHOR]

The present study is carried out to establish the biofortification of zinc in potato (Solanum tuberosum L.) and tomato (Solanum lycopersicum L.) plants through the application of zinc oxide nanoparticles (ZnONPs). The mycogenic ZnONPs are synthesized by using Aspergillus flavus biomass and characterized to ascertain the size, shape, and concentration of synthesized nanoparticles. The ZnONPs are applied by foliar spray to the field‐grown potato and tomato crops and the biofortification level is recorded by Atomic Absorption Spectroscopy (AAS). A nanotoxicity assessment is done by comparing the amount of cell death and accumulation of reactive oxygen species (ROS) in control and ZnONPs treated plants. The AAS analysis reveals significant accumulation of the zinc in leaves of potato plants but insignificant accumulation is observed in the tubers. However, a significant accumulation of zinc is observed in the leaves and fruits of the tomato plants (p ≤ 0.05). The nanotoxicity evaluation studies show comparable and statistically insignificant toxicity in control plants as compared to plants treated with ZnONPs. The study concludes that biofortification through the means of ZnONPs is a cost‐effective and eco‐friendly approach that can be used as an alternative to the hazardous chemical zinc fertilizers. [ABSTRACT FROM AUTHOR]

Zinc (Zn) is an essential element involved in human metabolism, which can be supplied by an appropriate diet. Enhancing Zn enrichment in rice grains through agronomic biofortification is advocated as an immediate and effective approach to combat micronutrient malnutrition in hu-man. It has been well-documented that high grain Zn accumulation in rice can be achieved by Zn fertilizers management. This study evaluated the effects of foliar nitrogen (N) and Zn applied at the flowering and milky stages of brown rice plants with and without soil Zn application. A glasshouse pot experiment was conducted using a completely randomized design with four replicates. Soil Zn in the form of ZnSO4 was applied at 0 and 50 kg ha−1. Foliar fertilizer of 1% urea along with 0.5% ZnSO4 was applied and assigned as (1) nil foliar N and Zn (N0Zn0), (2) foliar N with nil Zn (N+Zn0), (3) nil foliar N with foliar Zn (N0Zn+), and (4) foliar N and Zn (N+Zn+) at flowering and milky stages. Foliar application of N and Zn increased grain yield and yield components in both soil Zn conditions. Grain Zn concentration in brown rice was the highest when foliar N and Zn were applied under nil soil Zn conditions; however, grain N concentration decreased by 13.1–28.5% with foliar application at flowering and 18.8–28.5% with application at the milky stage. The grain Zn content was increased by foliar application of N0Zn+ and N+Zn+ at flowering and milky stages. Applying foliar N and Zn at flowering or milky stages tended to increase the grain N content when Zn was applied to the soil, while nil soil Zn decreased the N content by 26.8% at flowering and milky stages under N0Zn+. The results suggest that the milky stage is the most suitable for foliar application of Zn for increasing (i) grain yield and (ii) N and Zn concentrations in brown rice without having a dilution effect. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Zinc is an important micronutrient needed for the optimum growth and development of plants. Contrary to chemical zinc fertilizers, the use of zinc-solubilizing bacteria is an environmentally friendly option for zinc enrichment in edible parts of crops. This study was conducted with the objective of selecting potential zinc-solubilizing rhizobacteria from the rhizosphere of chickpea grown in soils of eastern Uttar Pradesh and further assessing their impact on the magnitude of zinc assimilation in wheat crops. Among 15 isolates, CRS-9, CRS-17, CRS-30, and CRS-38 produced net soluble zinc in broth to the tune of 6.1, 5.9, 5.63, and 5.6 μg ml–1, respectively, in zinc phosphate with the corresponding pH of 4.48, 5.31, 5.2, and 4.76. However, the bacterial strains CRS-17, CRS-30, CRS-38, and CRS-9 showed maximum zinc phosphate solubilization efficiency of 427.79, 317.39, 253.57, and 237.04%, respectively. The four bacterial isolates were identified as Bacillus glycinifermentans CRS-9, Microbacterium oxydans CRS-17, Paenarthrobacter nicotinovorans CRS-30, and Bacillus tequilensis CRS-38 on the basis of morphological and biochemical studies and 16S rRNA gene sequencing. Bacterial inoculants significantly colonized the roots of wheat plants and formed a biofilm in the root matrix. These strains significantly increased seed germination (%) and vigor indices in wheat grown under glasshouse conditions. After 30 days of sowing of wheat under microcosm conditions, eight zinc transporter (TaZIP) genes were expressed maximally in roots, with concomitant accumulation of higher zinc content in the bacterially treated plant compared to the absolute control. Out of the four strains tested, two bacteria, B. tequilensis CRS-38 and P. nicotinovorans CRS-30, improved seed germination (%), vigor indices (2–2.5 folds), plant biomass, grain yield (2.39 g plant–1), and biofortificated grains (54.25 μg g–1Zn) of wheat. To the best of our knowledge, this may be the first report on the presence of zinc solubilization trait in B. glycinifermentans CRS-9, M. oxydans CRS-17, and P. nicotinovorans CRS-30. [ABSTRACT FROM AUTHOR]

Current study explored the possibility of increasing zinc (Zn) content in potato tubers by foliar, seed tuber soaking, and soil application of Zn fertilizers. During first year, a single application of 5 kg Zn ha-1 through zinc sulphate (ZnSO4) increased the Zn concentration by ~30 % followed by split application of ZnSO4 (19.6%), and a single application of 1 kg Zn as Zn-EDTA (17.6%) in whole tubers. Single and split soil application of either zinc sulphate (5 kg ha-1) or zinc-EDTA (1.0 kg Zn ha-1), foliar application (ZnSO4) and soaking of seed tubers in zinc sulphate solution before planting also increased its concentration significantly in tuber peels. During 2nd year of experimentation, a single soil application of zinc sulphate (5 to 10 kg Zn ha-1), Zn-EDTA (1 to 2 kg Zn ha-1) increased the Zn concentration in peeled (tuber flesh) as well as unpeeled whole tuber significantly. Application of 2 kg zinc as Zn-EDTA resulted in highest increase of 4.4 mg kg-1 Zn (25.7%) in tuber flesh which was comparable with 10 kg Zn as ZnSO4 (24.9%). On application rate basis, compared to ZnSO4, the 5-times lesser quantity of chelated Zn resulted in equivalent increase in tuber Zn concentration. Since, the bioavailability of Zn from potatoes is high, the soil application of Zn fertilizers during the initial crop growth stage, as revealed by this study, can be adopted as a simple strategy to increase its content in tubers for addressing Zn - related malnutrition issues. [ABSTRACT FROM AUTHOR]

Zinc is an essential micronutrient necessary for the optimal development and yield of Okra (Abelmoschus esculentus L.). Plants absorb zinc in soluble form as Zn2+; a large amount of zinc in the soil are in insoluble forms. Zinc solubilizing microbes could be substitutes for zinc fertilizers and transform inorganic zinc into plant accessible forms. The study was aimed to isolate and screen a range of Zinc solubilizing bacteria (ZSB) from vermicompost for their plant growth-promoting properties with okra. Thirty bacterial isolates from vermicompost were examined for zinc solubilization with ZnO and ZnCO3 using dilution plate method on Kings B medium. Two strains, i.e., VBZ4 and VBZ17, were found most prevalent Zn solubilizing isolates with 32 mm and 43 mm solubilization zone for ZnO supplemented media. Atomic absorption spectroscopy (AAS) was used for quantitative assessment of Zn solubilization, where VBZ4 displayed significantly higher solubility of ZnO (26.8 ppm) compared with VBZ17 (22.2 ppm). The quantitative results of plant growth promotion characters showed that VBZ4 and VBZ17 isolates to solubilize the maximum amount of phosphate with 316.72 μg/ml and 214.0 μg/ml, and indole acetic acid production, 10.2 μg/ml and 17.1 μg/ml respectively. Further, ZSB isolates were introduced with Okra seeds under pot experiment, where treatment P4 (seeds + VBZ4 + VBZ17) found significantly effective on plant growth and maximum zinc content in Okra fruit (2.85 mg/100g) compared to control. Application of these bacteria may help to provide sufficient amounts of Zn bioavailability, including improved plant growth in a sustainable manner. [ABSTRACT FROM AUTHOR]

Improving the development of inferior grains is important for increasing maize yield under high-density conditions. However, the effect of micronutrients, especially zinc (Zn), on the development of inferior grains and maize yield under field conditions has not been evaluated to date. A field experiment with six Zn application rates (0, 2.3, 5.7, 11.4, 22.7, and 34.1 kg/ha) was conducted to investigate the effects of soil application of Zn fertilizer on the development of inferior grains. Pollen viability was measured at the tasseling stage. The maize spike was divided into apical (inferior grain), middle, and basal sections for further measurement at harvest. Results showed that soil application of Zn fertilizer increased maize yield by 4.2–16.7% due to increased kernel number and weight in the apical, but not in the middle and basal sections. Zn application also significantly increased pollen viability at the tasseling stage. The critical Zn concentrations in shoots at the tasseling stage for obtaining high pollen viability and high kernel numbers of inferior grains were 31.2 and 35.6 mg/kg, respectively. Zn application also increased the 1,000-kernel weight of inferior grain due to high biomass accumulation. Furthermore, the grain Zn concentration of inferior grain with Zn application increased by 24.3–74.9% compared with no Zn application. Thus, soil application of Zn fertilizer successfully increased grain yield of maize by improving pollen viability, kernel number, and kernel weight of inferior grains (apical section), also contributing to grain Zn biofortification. [ABSTRACT FROM AUTHOR]

Zinc (Zn) deficiency is a concern for nearly half of the world population. Biofortification through foliar Zn application is an approach to reduce human Zn deficiency. Knowledge available on effect of foliar applied zinc towards biofortification efficiency and bioavailability of rice grain is limited. Pot experiment with rice was conducted to study the effect of foliar applied zinc along with soil application of recommended dose of N : P : K : Zn for rice. Two contrasting groups of four cultivars each with respect to seed zinc based on previous screening were selected (high seed zinc types and low seed zinc types). Zinc was applied in the form of ZnSO4.7H2O foliar application at vegetative stage and at reproductive stage in three different doses (recommended dose, 10% lower than recommended dosage and 10% higher than recommended dosage). Results suggest that foliar zinc application is effective in enhancing grain zinc when applied with recommended dose of soil zinc fertilizer irrespective of inherent zinc acquisition capacity by roots. Stem had higher Zn accumulation at 65 DAS indicating translocation of foliar applied zinc. At 50% panicle initiation stage, there was higher zinc in leaf compared to stem and developing grain implying Zn movement from stem to seed. Zn analyzed at different stages of grain filling till harvest showed an increase in Zn content both in high and low zinc types. Higher seed Zn was observed in long duration varieties. Using long duration varieties for foliar biofortification could be an effective strategy to overcome Zn deficiency. [ABSTRACT FROM AUTHOR]

Poor zinc (Zn) nutrition of wheat is one of the main causes of poor human health in developing countries. A field experiment with no zinc and foliar zinc application (0.5% ZnSO4.7H2O) on bread wheat (8), durum wheat (3), and triticale (4) cultivars was conducted in a randomized block design with three replications in 2 years. The experimental soil texture was loamy sand with slightly alkalinity. The grain yields of bread wheat, triticale, and durum wheat cultivars increased from 43.6 to 56.4, 46.5 to 51.6, and 49.4 to 53.5 t ha−1, respectively, with foliar application of 0.5% ZnSO4.7H2O. The highest grain yield was recorded by PBW 550 (wheat), TL 2942 (triticale), and PDW 291 (durum), which was 5.22, 4.24, and 4.56% and significantly higher over no zinc. Foliar zinc application increased zinc in bread wheat, triticale, and durum wheat cultivars grains varying from 31.0 to 63.0, 29.3 to 61.8, and 30.2 to 62.4 mg kg−1, respectively. So, agronomic biofortification is the best way which enriching the wheat grains with zinc for human consumption. [ABSTRACT FROM AUTHOR]

Humans around the world suffer from micronutrient deficiency due to an inadequate intake of essential micronutrients in the daily diet. Agronomic biofortification offers the easiest and the quickest way for biofortification of cereal grains with zinc, iron or other micro mineral nutrients in developing countries especially Asia and Africa, where cereals form the staples. It is the only approach to reach the poorest of the poor rural masses, who can't afford to buy mineral supplements nor can afford animal by-products. From the agronomic biofortification viewpoint, foliar application is better and requires lesser amount of zinc and iron fertilizers than their soil application. Even when cultivars or GM crops with higher zinc and iron content in grains are developed, adequate zinc and iron fertilization will be necessary. Thus, for the long term, agronomic biofortification is a complimentary approach to plant breeding as well as modern biotechnology for increased micronutrients in the food basket. [ABSTRACT FROM AUTHOR]

Zinc is essential micronutrients for plants. This element improves plant growth and yield and plays a role in the metabolism of carbohydrates. Zinc deficiency in soils and Iranian crops is possible due to numerous reasons such as calcareous soils, excessive use of phosphorus fertilizers and unbalanced fertilizer use. The effect of zinc solubilizing bacteria on some wheat properties was considered as a factorial experiment in greenhouse conditions based on a completely randomized design. Treatments consisted of four levels of bacteria comprising B1 (control), B2 (Bacillus megaterium), B3 (Enterobacter cloacae) and B4 (consortium of both bacterium), and ZnSO4 fertilizer at three levels including Zn0 (control), Zn20 (20 Kg/ha) and Zn40 (40 kg/ha). During the experiment, some parameters such as plant height and chlorophyll index were measured. At the end of the cultivation period, soil available zinc, dry weight of root and aerial part, and the zinc concentration of the root, shoot and grain were determined. Grain yield and zinc uptake in the grain were also calculated. The results indicated soil exchangeable zinc content was increased significantly (P<0.05) in all bacterial treatments, as compared to the control treatment. The maximum amount of soil exchangeable zinc, grain yield, zinc concentration and uptake in grain were observed in the treatment containing bacteria consortium with the application of 40 kg/ha of zinc sulfate fertilizer, which was followed by the treatment containing Enterobacter cloacae with the application of 40 kg/ha of the zinc sulfate fertilizer. The maximum amount of all measured properties in the treatment containing Enterobacter cloacae and Bacillus megaterium indicated the possibility of applying those bacteria for zinc enrichment in wheat, crop optimal production, and the sustainable agriculture. [ABSTRACT FROM AUTHOR]

Agronomic biofortification is one of the main strategies for alleviation of micronutrient deficiencies in food and feed. The objective of this study was to investigate the effect of N supply on total concentration of Zn and Fe and their chemical species in the soluble extracts of maize silage grown under field conditions. Total concentrations of Zn, Fe, Cu, Mn, S and P were measured by flow-injection inductive coupled plasma (ICP) – mass spectrometer (MS). Soluble Fe and Zn were extracted and analyzed by size exclusion−inductively coupled plasma mass spectrometry. Using the same set-up for total elemental and speciation analysis enabled direct quantitative comparison of the detected speciated molecules with the total element sample content. N or Zn treatment, except in control plots, did not significantly affect concentrations of Zn and Fe in the maize silage and grain samples. Significant positive correlation was observed between Zn and Fe maize silage (r = 0.64, p < 0.01) and maize grain (r = 0.85, p < 0.01) concentrations. N and Zn treatment did not affect solubility of Zn and Fe, while available Zn and Fe were affected by increase in Zn soil treatment. Soluble Zn was speciated in LMW complexes, while soluble Fe was speciated in MMW and LMW complexes. [ABSTRACT FROM AUTHOR]

The combined application of nitrogen (N) and zinc (Zn) fertilizers is a promising agronomic strategy for the biofortification of wheat grain with Zn for human nutrition. A glasshouse experiment was carried out to assess the effects of supplying N on the uptake, translocation and accumulation of Zn in tissues of two wheat genotypes (Quartzo and BRS Parrudo) with contrasting potential for grain Zn biofortification. Winter wheat genotypes were grown to maturity in 5 cm diameter, 100 cm length tubes filled with a mixture of sand, grit and gravel (40:40:20 v/v/v) over a layer of 0.1 m3 of gravel, and supplied a full nutrient solution with low Zn (0.15 μM) or high Zn (2.25 μM) and low N (0.4 mM) or high N (4.0 mM) concentrations. High N supply increased biomass production, Zn concentration and Zn content of straw and grain in both Quartzo and BRS Parrudo. Grain Zn content more than doubled when the supplies of Zn and N were both increased from low to high in both genotypes. Quartzo had a greater grain yield than BRS Parrudo. BRS Parrudo had greater grain Zn concentration and Zn content than Quartzo. A greater N supply promoted better uptake, translocation to the shoot and accumulation of Zn within the grain. Quartzo and BRS Parrudo differed in their partitioning of biomass and Zn between tissues. It might be possible to combine the greater grain yield of Quartzo with the greater grain Zn accumulation of BRS Parrudo to deliver a greatly improved genotype for human food security. [ABSTRACT FROM AUTHOR]

Due to potential international marketing concerns, North Dakota durum wheat (Triticum turgidum L. Desf.) producers require strategies that limit cadmium (Cd) in harvested grain. These trials were conducted in order to determine the impact of type and placement of zinc (Zn) fertilizer on harvested grain seed Cd levels and to determine the best timing of foliar Znethylenediaminetetraacetic acid (EDTA). Foliar Zn-EDTA applied at Feekes 10 growth stage had the lowest grain Cd of 0.97 mg kg-1 when evaluating different fertilizer sources and application timings. Application of 22.4 kg ha-1 potassium chloride with the seed at planting resulted in the highest grain Cd of 0.151 mg kg-1 and might be a concern when environmental conditions are conducive for Cd uptake from soil. Stepwise linear regression determined that soil pH and chloride explained 96% of the variability of grain Cd. Applying 1.1 kg Zn ha-1 as foliar Zn-EDTA in combination with 33 kg nitrogen ha-1 at Feekes 10.54 growth stage resulted in significantly lower grain Cd, and significantly higher grain Zn, iron, and protein content. Treatments that significantly lowered grain Cd did not decrease grain yield, test weight, or protein content. The treatments that most reduced grain Cd resulted in the most benefits from a production, marketing, and nutritional standpoint and represents an agronomic approach to biofortification of durum wheat. [ABSTRACT FROM AUTHOR]

Given that plant uptake and transport systems for metals have some similarities, zinc (Zn)-biofortified cultivars may concurrently accumulate non-essential toxic heavy metals in grains. However, Zn-biofortified cultivars have never been tested for heavy metal accumulation in grains. In a pot experiment, we compared Zn-biofortified wheat (Zincol-2016) with a standard wheat (Faisalabad-2008) cultivar on heavy-metal-contaminated soils for yield response and grain accumulation of Zn, lead (Pb) and cadmium (Cd), without or with Zn fertilisation (8 mg Zn kg − 1 ). The soils, collected from agricultural fields in (i) industrial zone and (ii) peri-urban area, had been receiving industrial and city effluents for > 20 years. In the two soils, Zn fertilisation significantly ( P ≤ 0.05) increased grain yield of both cultivars. Zinc fertilisation increased grain Zn concentration of Zincol-2016 and Faisalabad-2008 by respectively 32 and 18% in industrial-zone soil, and by 15 and 2% in peri-urban soil. Averaged across Zn rates, Zincol-2016 accumulated in grains more than double the Zn amount than Faisalabad-2008 in industrial-zone soil. At 0 mg Zn kg − 1 , grain Pb and Cd concentrations were respectively 26 and 33% greater in Zincol-2016 than Faisalabad-2008 in industrial-zone soil, and 86 and 50% greater in Zincol-2016 than Faisalabad-2008 in peri-urban soil. Zinc fertilisation significantly ( P ≤ 0.05) decreased concentration of Pb and Cd in grains of both cultivars. In industrial-zone soil, a toxic level of Pb in grains (0.24 mg kg − 1 ) was attained at control rate of Zn by Zincol-2016, and was decreased to a safe level (0.07 mg kg − 1 ) by application of 8 mg Zn kg − 1 . Therefore, biofortified cultivars should not be grown in contaminated soils, and/or sufficient Zn must be applied, to decrease accumulation of non-essential toxic heavy metals in grains. Moreover, future breeding efforts should be directed toward selection of biofortified cultivars that would selectively accumulate Zn in grains, but not the contaminants. [ABSTRACT FROM AUTHOR]

Micronutrient deficiencies or 'hidden hunger' particular for zinc (Zn) deficiency affect more than 270 million people worldwide and about one-third population of the world is residing in the developing countries. Globally, rice is a staple food of the population and grown approximately 90% in south, south-east and east-Asia, which is inadequate soil Zn level and ultimately causes dysfunctional food system and unbalanced diets. Therefore, the present field experiment was undertaken to study the effect of agronomic Zn fertilization on grain yield, grain Zn and efficiencies of five rice varieties viz., Pusa Basmati 1121, Pusa Basmati 1509, Sugandh 5, CSR 43 and CSR 30. A field study resulted that Pusa Basmati 1121 and Pusa Basmati 1509 were found better for improvement of grain Zn, while Pusa Basmati 1509 and Sugandh 5 for yield in response to Zn fertilization. The effect of 50 kg/ha soil Zn application on grain yield of Pusa Sugandh 5 was recorded highest during both the years of study during 2015 and 2016 and was significantly superior to other four varieties. For the human and animal nutrition points of view, zinc fertilization in rice cultivars is an important cost-effective approach, reduces Zn malnutrition and it can save the life of millions of people in Asian countries. [ABSTRACT FROM AUTHOR]

Thirty field experiments were conducted during rabi seasons of 2014-15 and 2015- 16 across farmers' fields of four villages of district Faridabad, Haryana, India using wheat as test crop to evaluate the effects of soil and foliar mode of application of zinc fertilizer on grain yield and Zn concentration. The application of Zn fertilizer in soil increased grain yield of wheat significantly over control at few locations during both the years where low Zn soils existed i. e. from 3.9 to 12.6% and 3.3 to 10.5% during 2014-15 and 2015-16, respectively, over no soil Zn addition. However, foliar treatment of Zn fertilizer on grain yield was quiet less effective. The foliar Zn application resulted in significant increases in grain Zn content over control at all locations. Maximum increase in grain Zn concentration with foliar spray of Zn was 125.73 and 122.82% higher during 2014-15 and 2015-16, respectively, over control. It was found that foliar application of Zn is an important agronomic practice for the farmers to enrich wheat grains with zinc. Increasing grain yield by soil application and grain Zn concentration by foliar application of zinc fertilizer also provides additional positive impacts in terms of economic benefits and to secure nutritional quality and mitigate hidden hunger. [ABSTRACT FROM AUTHOR]

BACKGROUND Excessive rates of nitrogen (N) fertilizers may result in elevated concentrations of nitrate ( NO3−) in plants. Considering that many programs of biofortification with trace elements are being performed, it has become important to study how the application of these elements affects plant physiology and, particularly, N utilization in leaf crops. The main objective of the present study was to determine whether the NO3− accumulation and the nitrogen use efficiency was affected by the application of different doses of Zn in Lactuca sativa plants. RESULTS Zn doses in the range 80-100 µmol L−1 produced an increase in Zn concentration provoking a decrease of NO3− concentration and increase of the nitrate reductase, glutamine synthetase and aspartate aminotransferase activities, as well as the photorespiration processes. As result, we observed an increase in reduced N, total N concentration and N utilization efficiency. Consequently, at a dose of 80 µmol L−1 of Zn, the amino acid concentration increased significantly. CONCLUSION Adequate Zn fertilization is an important critical player in lettuce, especially at a dose of 80 µmol L−1 of Zn, because it could result in an increase in the Zn concentration, a reduction of NO3− levels and an increase the concentration of essential amino acids, with all of them having beneficial properties for the human diet. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The combined application of nitrogen (N) and zinc (Zn) appears to be a promising agronomic strategy for the biofortification with Zn. To evaluate such efficiency, a field experiment was conducted in south-eastern Portugal under Zn-deficient soil. Four advanced breeding lines and two commercial varieties of bread wheat (Triticum aestivum L.) were fertilized with five treatments: i) control, ii) two foliar Zn applications, iii) one foliar Zn+N application, iv) soil and two foliar Zn applications, and v) soil and one foliar Zn+N application. Grain Zn content varied greatly across treatments and INIAV-1 and the commercial varieties were the most interesting cultivars in all the treatments. Grain Zn concentrations higher than the target level of 38 mg Zn kg-1 were obtained only when two foliar Zn applications were applied, alone or in combination with soil Zn applications, and grain Zn bioavailability also was more adequate (phytate:Zn ratios similar to 15). Soil Zn application resulted in grain yield increases between 7-10%, which virtually offset the extra application cost. The combined soil and two foliar treatment could be a good option for biofortifying bread wheat under Zn-deficient soils. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glyzinc exhibited lower phytotoxicity to wheat than ZnSO 4. • Foliar spray of Glyzinc did not affact grain yield while improved grain quality. • Glyzinc was more effective to increase grain Zn content and bioavailability. • Glyzinc inhibited the translocation of Cd from leaves to grain, resulting in low Cd accumulation in grain. Sustainable strategies are essential for zinc (Zn) biofortification and cadmium (Cd) reduction in staple food crops. Herein, we evaluated the phytotoxicity of Glyzinc under foliar and root application (FA&RA) in a lab-scale experiment, and then investigated its Zn efficiency and Cd reduction through foliar application on wheat (Triticum aestivum L.) under field conditions. Compared to RA, FA of Glyzinc exhibited no adverse effect on wheat growth and oxidative stresses at all doses. In field conditions, FA of Glyzinc remarkably increased Zn (28.7 %), S (10.4 %), Cu (17.3 %) and crude protein (9.1 %) content in wheat grain at 100 mg/L without damaging wheat yield. Furthermore, FA of Glyzinc significantly reduced the grain phytic acid (PA) (23.7 %) and Cd level (19.5 %), as well as PA to Zn molar ratio (32.3 %). Overall, our results indicate that Glyzinc has great potential as a high-efficiency foliar fertilizer for Zn biofortification and safe crop production in nano-enabled agriculture. [ABSTRACT FROM AUTHOR]

Maize (Zea maysL.) is generally low in bioavailable zinc (Zn); however, agronomic biofortification can cure human Zn deficiency. In the present experiment, Zn was applied in pots as ZnSO4 · 7H2O to maize cultivar DK-6142 as foliar spray (0.5% w/v Zn sprayed 25 days after sowing and 0.25% w/v at tasseling), surface broadcasting (16 kg Zn ha−1), subsurface banding (16 kg Zn ha−1at the depth of 15 cm), surface broadcasting + foliar and subsurface banding + foliar in comparison to an unfertilized control. As compared to control, all treatments significantly (P ≤ 0.05) increased growth, yield and nutritional attributes in maize. Grain Zn and protein concentrations were correlated and ranged from 22.3 to 41.9 mg kg−1and 9 to 12 %, respectively. Zinc fertilization also significantly reduced grain phytate and increased grain Zn concentration. Zinc fertilization, especially broadcasting and subsurface banding combined with foliar spray decreased grain [phytate]:[Zn] ratio to 28 and 21 and increased Zn bioavailability by trivariate model of Zn absorption to 2.04 to 2.40, respectively. Conclusively, broadcasting and subsurface banding combined with foliar spray is suitable for optimal maize yield and agronomic Zn biofortification of maize grain. This would also be helpful to optimize Zn and protein concentration in maize grain. [ABSTRACT FROM AUTHOR]

Background and aims: The combination of plant breeding and agronomic biofortification is the most reasonable approach to minimize zinc (Zn) deficiency-related problems in humans, but also in crop production. However, its efficiency and suitability under Mediterranean conditions and its effects on the grain yield and quality parameters are not well known. Methods: Field experiments were conducted over two years in south-eastern Portugal, where soils are deficient in Zn. Ten advanced breeding lines and three commercial varieties of bread-making wheat were fertilized with four Zn treatments as following: i) control, ii) soil Zn application, iii) foliar Zn application and iv) both soil and foliar Zn application. Results: Low rainfall produced 46 % more of grain Zn concentration but about 67 % less of grain yield. Grain Zn concentration varied greatly across treatments and cultivars with INIAV-1, INIAV-6, INIAV-9 and the commercial varieties being the most efficient. There were no significant increases in Zn concentrations due to soil Zn application, but gains higher than 20 mg kg were obtained both with foliar and soil+foliar Zn applications. Grain yield was not significantly higher in foliar application, but increased to about 10 % in soil, and about 7 % in soil+foliar applications, respectively. Conclusions: In soils with low Zn availability, the best strategy to improve grain Zn concentrations has been to select the most efficient cultivars for Zn accumulation with the added application of Zn in soil+foliar form. [ABSTRACT FROM AUTHOR]

Because nutrients consumed by human beings are derived from the soil-plant system, biofortification of the edible parts of horticultural crops can be a very useful technique for countering human malnutrition. The objective of this study is to evaluate the transfer of Zn from the soil to the edible parts of carrots, kale and okra in latosol treated with increasing doses of Zn. The experiment was conducted in a randomized block design with a 4 x 3 x 4 factorial scheme, consisting of four Zn doses (0, 50, 150, and 300 mg kg-1 of soil), three plant species (carrot, kale and okra) and four parts of the plants (root, stem, leaf and edible parts), with four repetitions. It was found that with an increase in the content of Zn in the soil, the plant species, in general, presented a higher concentration of this element, showing that fertilization practices can increase the availability of Zn to plants. The kale plants exhibited a potential to concentrate Zn in their edible parts, as opposed tocarrot and okra plants. For this reason, these are suitable for use in Zn biofortification programs Zn. [ABSTRACT FROM AUTHOR]

Background: Increasing zinc (Zn) concentration of rice seed has potential benefits for human nutrition and health. Enhanced levels of Zn in grain also contributes greatly to crop production through better germination and seedling vigor of rice plants grown on soils with limited Zn supply. Aims and methods: This study evaluated the effect of soil and/or foliar Zn fertilizer application on grain yield and grain Zn concentration of rice grown in 17 field trials conducted in 2008 to 2010 in China, India, Lao PDR, Thailand and Turkey on soils ranging in pH from 4.8 to 8.8 and DTPA- extractable Zn from 0.5 to 6.5 mg kg. Results: Zinc fertilization had little effect on rice grain yield with the exception of increases of up to 10 % in some locations in China and India. As an average of all trials, Zn application increased grain yield by about 5 %. Grain Zn concentrations were, however, more effectively increased by Zn fertilization, especially with foliar Zn applications. On average, Zn concentration in brown rice (whole caryopsis with husk removed) was increased by 25 % and 32 % by foliar and foliar + soil Zn applications, respectively, and only 2.4 % by soil Zn application. The Zn concentration of un-husked rice (whole grain with husk), which was increased by 66 % by foliar Zn, showed a close association with the Zn in brown and white rice, indicating a possible penetration of Zn from the husk into the inner layers of the rice endosperm. Increase in grain Zn concentration by foliar Zn spray was significantly affected by the timing of the foliar application. More distinct increases in grain Zn by foliar Zn application were achieved when Zn was applied after flowering time, e.g., at early milk plus dough stages. Conclusions: Foliar Zn spray offers a practical and useful means for an effective biofortification of rice grain with Zn. This practice consistently and significantly contributed to increases in grain Zn of rice irrespective of cultivars, environmental conditions and management practices in 5 different countries. [ABSTRACT FROM AUTHOR]

Aim: Zinc (Zn) fertilization is an effective agronomic tool for Zn biofortification of wheat for overcoming human Zn deficiency. But it still needs to be evaluated across locations with different management practices and wheat cultivars, since grain Zn concentrations may be significantly affected by locations, cultivars and management. Materials: Field experiments were conducted over 3 years with the following four Zn treatments: nil Zn, soil Zn application, foliar Zn application and soil + foliar Zn application to explore the impact of Zn fertilization in Zn biofortification of wheat. The experiments were conducted at a total of 23 experimental site-years in China, India, Kazakhstan, Mexico, Pakistan, Turkey and Zambia. Results: The results showed that foliar Zn application alone or in combination with soil application, significantly increased grain Zn concentrations from 27 mg kg at nil Zn to 48 and 49 mg kg across all of 23 site-years, resulting in increases in grain Zn by 84 % and 90 %, respectively. Overall, soil Zn deficiency was not a growth limiting factor on the experimental sites. A significant grain yield increase in response to soil Zn fertilization was found only in Pakistan. When all locations and cropping years are combined, soil Zn fertilization resulted in about 5 % increase in grain yield. Foliar Zn application did not cause any adverse effect on grain yield, even slightly improved the yield. Across the 23 site-years, soil Zn application had a small effect on Zn concentration of leaves collected before foliar Zn application, and increased grain Zn concentration only by 12 %. The correlation between grain yield and the effectiveness of foliar Zn application on grain Zn was condition dependent, and was positive and significant at certain conditions. Conclusion: Foliar Zn application resulted in successful biofortification of wheat grain with Zn without causing yield loss. This effect of Zn fertilization occurred irrespective of the soil and environmental conditions, management practices applied and cultivars used in 23 site-years. Foliar Zn fertilizer approach can be locally adopted for increasing dietary Zn intake and fighting human Zn deficiency in rural areas. [ABSTRACT FROM AUTHOR]

Background: Zinc (Zn) deficiency is one of the important abiotic factors limiting rice productivity worldwide and also a widespread nutritional disorder affecting human health. Given that rice is a staple for populations in many countries, studies of Zn dynamics and management in rice soils is of great importance. Scope: Changing climate is forcing the growers to switch from conventional rice transplanting in flooded soils to water-saving cultivation, including aerobic rice culture and alternate wetting and drying system. As soil properties are changed with altered soil and water management, which is likely to affect Zn solubility and plant availability and should be considered before Zn management in rice. In this review, we critically appraise the role of Zn in plant biology and its dynamics in soil and rice production systems. Strategies and options to improve Zn uptake and partitioning efficiency in rice by using agronomic, breeding and biotechnological tools are also discussed. Conclusions: Although soil application of inorganic Zn fertilizers is widely used, organic and chelated sources are better from economic and environmental perspectives. Use of other methods of Zn application (such as seed treatment, foliar application etc., in association with mycorrhizal fungi) may improve Zn-use efficiency in rice. Conventional breeding together with modern genomic and biotechnological tools may result in development of Zn-efficient rice genotypes that should be used in conjunction with judicious fertilization to optimize rice yield and grain Zn content. [ABSTRACT FROM AUTHOR]

Increasing iron (Fe) concentration in food crops is an important global challenge due to high incidence of Fe deficiency in human populations. Evidence is available showing that nitrogen (N) fertilization increases Fe concentration in wheat grain. This positive impact of N on grain Fe was, however, not studied under varied soil and foliar applications of Fe. Greenhouse experiments were conducted to investigate a role of soil- and foliar-applied Fe fertilizers in improving shoot and grain Fe concentration in durum wheat ( Triticum durum) grown under increasing N supply as Ca-nitrate. Additionally, an effect of foliar Fe fertilizers on grain Fe was tested with and without urea in the spray solution. Application of various soil or foliar Fe fertilizers had either a little positive effect or remained ineffective on shoot or grain Fe. By contrast, at a given Fe treatment, raising N supply substantially enhanced shoot and grain concentrations of Fe and Zn. Improving N status of plants from low to sufficient resulted in a 3-fold increase in shoot Fe content (e.g., total Fe accumulated), whereas this increase was only 42% for total shoot dry weight. Inclusion of urea in foliar Fe fertilizers had a positive impact on grain Fe concentration. Nitrogen fertilization represents an important agronomic practice in increasing grain Fe. Therefore, the plant N status deserves special attention in biofortification of food crops with Fe. [ABSTRACT FROM AUTHOR]

Zinc deficiency is the most ubiquitous micronutrient deficiency problem in world crops. Zinc is essential for both plants and animals because it is a structural constituent and regulatory co-factor in enzymes and proteins involved in many biochemical pathways. Millions of hectares of cropland are affected by Zn deficiency and approximately one-third of the human population suffers from an inadequate intake of Zn. The main soil factors affecting the availability of Zn to plants are low total Zn contents, high pH, high calcite and organic matter contents and high concentrations of Na, Ca, Mg, bicarbonate and phosphate in the soil solution or in labile forms. Maize is the most susceptible cereal crop, but wheat grown on calcareous soils and lowland rice on flooded soils are also highly prone to Zn deficiency. Zinc fertilizers are used in the prevention of Zn deficiency and in the biofortification of cereal grains. [ABSTRACT FROM AUTHOR]

[Display omitted] • Spraying Zn fertilizers at high concentrations was an overlooked Zn fortification strategy. • Zn form rather than pH or EC was primarily responsible for foliar burn. • Glycine and Zn interacted in both glycine-chelated and glycine-mixed Zn. • Actual grain Zn recovery rate was overestimated using grain 68Zn recovery rate. To determine whether high spraying concentrations of Zn sources increase the Zn concentration in waxy corn (Zea mays L. var. ceratina Kulesh) seeds without compromising agronomic performance, field experiments were conducted between 2018 and 2020. Excess ZnSO 4 application caused foliar burn, barren ear tip, and grain yield loss. ZnEDTA and Glycine-chelated Zn (ZnGly) caused less foliar burn, but Glycine-mixed Zn caused more foliar burn than ZnSO 4. The seed Zn concentration increased with spraying Zn concentration. ZnEDTA (≤0.8%) had a higher threshold concentration than ZnGly (≤0.4%). Nevertheless, Zn biofortification efficacy did not significantly differ between 0.4% ZnGly and 0.8% ZnEDTA, and the grain Zn recovery rate of 0.4% ZnGly was much higher than that of 0.8% ZnEDTA. Additionally, dual-isotope labelling tests confirmed that 15N-glycine and 68Zn in ZnGly interacted. In the future, chelating technology is essential for developing new Zn fertilizers to optimize Zn biofortification efficacy. [ABSTRACT FROM AUTHOR]

The development of rice ( Oryza sativa L.) cultivars with a higher Zn content in their grains has been suggested as a way to alleviate Zn malnutrition in human populations subsisting on rice in their daily diets. This study was conducted to evaluate the effects of native soil Zn status and fertilizer application on Zn concentrations in grains of five rice genotypes that had previously been identified as either high or low in grain Zn. Genotypes were grown in field trials at four sites ranging in native soil-Zn status from severely deficient to high in plant available Zn. At each site a −Zn plot was compared to a +Zn plot fertilized with 15 kg Zn ha−1. Results showed that native soil Zn status was the dominant factor to determine grain Zn concentrations followed by genotype and fertilizer. Depending on soil-Zn status, grain Zn concentrations could range from 8 mg kg−1 to 47 mg kg−1 in a single genotype. This strong location effect will need to be considered in estimating potential benefits of Zn biofortification. Our data furthermore showed that it was not possible to simply compensate for low soil Zn availability by fertilizer applications. In all soils fertilizer Zn was taken up as seen by a 50–200% increase in total plant Zn content. However, in more Zn deficient soils this additional Zn supply improved straw and grain yield and increased straw Zn concentrations by 43–95% but grain Zn concentrations remained largely unchanged with a maximum increase of 6%. Even in soils with high Zn status fertilizer Zn was predominantly stored in vegetative tissue. Genotypic differences in grain Zn concentrations were significant in all but the severely Zn deficient soil, with genotypic means ranging from 11 to 24 mg kg−1 in a Zn deficient soil and from 34 to 46 mg kg−1 in a high Zn upland soil. Rankings of genotypes remained largely unchanged from Zn deficient to high Zn soils, which suggests that developing high Zn cultivars through conventional breeding is feasible for a range of environments. However, it may be a challenge to develop cultivars that respond to Zn fertilizer with higher grain yield and higher grain Zn concentrations when grown in soils with low native Zn status. [ABSTRACT FROM AUTHOR]

Agricultural spraying unmanned aerial vehicles (UAVs) can be used to avoid human exposure to agrochemical mists and to obtain many extra benefits in crop protection, and concentrated Zn fertilizer is needed for low-volume UAV sprays applied for Zn biofortification. Applying the widely used ZnSO 4 fertilizer at high spraying rates improved Zn biofortification, but it also caused leaf burn, yield losses, and fertilizer losses. To determine whether there is an alternative UAV-supported Zn source that further improves Zn concentration in rice seeds without compromising agronomic performance, a 3-year field experiment was conducted. Initial tests at different spraying rates showed that Zn-EDTA, Zn-Gly, and Zn-Glc had approximately two-fold higher safe threshold rates (≤0.8%) than ZnSO 4 and ZnNO 3. Furthermore, Zn biofortification was optimally improved by applying ZnNO 3 at a normal rate, and Zn-Gly was the best at a high spraying rate. The third-year results demonstrated that two sprays of 0.81% Zn-Gly by UAV achieved equivalent Zn biofortification levels as those after three sprays of 0.27% ZnNO 3 by manual spraying. In addition, UAV-based spraying greatly lowered the risk of fertilizer residual in rice paddies because of its low Zn input and its high Zn recovery rate. This safer and cleaner technology will expand the existing fertilizing options to produce highly Zn-biofortified grain with low input costs. [Display omitted] • ZnNO 3 achieved greater Zn-biofortification than ZnSO 4. • Excess spraying Zn rates damaged foliage and decreased yield of rice. • Chelated Zn lowered the foliar phytotoxicity than excess inorganic Zn. • Zn-Gly achieved the highest Zn-biofortification among chelated Zn sources. • UAV-based spraying of Zn-Gly improved Zn recovery rate. [ABSTRACT FROM AUTHOR]

Purple rice is recognized as a staple food for humans and as a source of anthocyanins and micronutrients such as zinc (Zn). This study examined how nitrogen (N) and Zn fertilizers affected grain yield and grain N, Zn, and anthocyanin concentration among purple rice genotypes. Six purple rice genotypes (PIZ, KAK, KS, KH-CMU, KDK, and HN) were grown under two levels of N, the optimum N60 (60 kg/ha) and high N180 (180 kg/ha) rates, along with three Zn application methods (no Zn application (Zn0), soil Zn application (ZnS; 50 kg ZnSO4/ha), and foliar Zn spray (ZnF; 0.5% ZnSO4 at the rate of 900 L/ha three times at heading, flowering, and early milk stages). Grain yield of the five purple rice landraces increased by 21–40% when increasing N from N60 to N180, although no response was found with HN. The higher N rate increased grain N concentration by 10–50% among the genotypes, while anthocyanin concentration increased by 100–110% in KAK and KS, and grain Zn was increased in KS. Applying ZnS increased grain yield by 16–94% but decreased anthocyanin and N concentrations compared to the control Zn0. Applying ZnF effectively increased grain Zn concentration by 40–140% in the genotypes without adversely impacting grain anthocyanin or N concentration. This study demonstrated that the appropriate management of N and Zn fertilizers for specific purple rice genotypes would be one way to increase productivity and grain N, Zn, and anthocyanin concentration. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) is one of the main foods globally. Nutrition problems associated with Zinc and Iron deficiency affect more than two billion individuals. Biofortification is a strategy believed to be sustainable, economical and easily implemented. This study evaluated the effect of combined Zn and Fe applied as foliar fertilizer to winter wheat on grain yield, quality, Zn and Fe concentration in the grains. Results showed that treatments containing high Fe increased the yield. Grain crude fat content remained unaffected. Crude fiber was enhanced up to three-fold by 60% Zn + 40% Fe5.5 (5.5 kg ha−1 of 60% Zn + 40% Fe). Moreover, 80% Zn + 20% Fe5.5 (5.5 kg ha−1 of 80% Zn + 20% Fe) was the best combination for increasing crude protein. Zinc applied alone enhanced Zn concentration in grain. In addition, Fe was slightly improved by an application of Zn and Fe in the first year, but a greater increase was observed in the second year, where 100% Fe13 (13 kg ha−1 of 100% Fe) was the best in improving Fe in grain. Foliar application of Zn and Fe is a practical approach to increase Zn and Fe concentration, and to improve the quality of wheat grains. [ABSTRACT FROM AUTHOR]