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Human zinc (Zn) deficiency is prevalent in areas where cereals dominate in the diet. Soil Zn application may enhance the concentration of Zn in wheat grains and dietary Zn intake by target populations. However, its value has never been practically quantified in Zn nutrition of any population group. We, therefore, studied farming families in rural Punjab (Pakistan). The selected adults (n = 156, grouped based on age and gender) were Zn undernourished (as assessed by estimated Zn bioavailability in their diet) and their plasma Zn levels also indicated Zn deficiency. On average, wheat consumption by the adults contributed about 68% in total Zn and 93% in total phytate intakes. Soil Zn application to wheat fields significantly increased Zn and decreased phytate concentration in chapati (flatbread made of whole-wheat flour). From dietary phytate intakes by the adults, we calculated desired chapati Zn concentration and dietary Zn intake that would meet their daily Zn requirement. The physiological Zn requirements of adult women and men were estimated to be achieved by intake of, respectively, 10.4-15.3 mg Zn d -1 (37-46 mg Zn kg -1 in chapati) and 14.4-23.3 mg Zn d -1 (41-52 mg Zn kg -1 in chapati). It was evident that soil Zn application aiming at optimum grain yield of wheat significantly improved Zn nutrition of the studied adults, but not up to desired levels. High Zn applications (via soil and/or foliage) to wheat and growing cultivars specifically selected for Zn biofortification may be needed to optimise Zn nutrition in rural Pakistan.

Zinc (Zn)-biofortified wheat may contribute to decreasing widespread human Zn deficiency. Such genotypes may also accumulate cadmium (Cd) in grains that would expect to be decreased by Zn application. However, the influence of soil and foliar Zn application on grain Cd accumulation in Zn-biofortified versus standard wheat is unknown. In our experiment, we grew standard (Faisalabad-2008) and Zn-biofortified (Zincol-2016) wheats in pots having uncontaminated (T 0 ) or Cd-spiked (8 mg kg -1 ) soil. Plants in Cd-amended pots were treated with no Zn (T 1 ), 8 mg Zn kg -1 to soil at sowing (T 2 ), 0.5% w/v ZnSO 4 ·7H 2 O to foliage at booting and heading (T 3 ), or soil (as in T 2 ) + foliar (as in T 3 ) Zn application (T 4 ). Only in the uncontaminated control, grain yield of Faisalabad-2008 was greater than Zincol-2016. Any Zn application to Zincol-2016 grown in Cd-spiked pots increased grain yield compared with the uncontaminated control. In both cultivars, grain Zn concentration was influenced more by foliar than soil Zn application. However, Zincol-2016 had 6 to 14 mg more Zn kg -1 in grains than Faisalabad-2008 in the comparable treatments. Cadmium exposure (T 1 vs. T 0 ) decreased grain yield of only Faisalabad-2008, and decreased grain Zn concentration only in Zincol-2016. Without any Zn application, grain Cd concentration in both cultivars exposed to Cd was above the permissible level (0.20 mg kg -1 ). Zinc application decreased grain Cd concentration, although it remained above the permissible level in both cultivars except in Faisalabad-2008 when treated with soil + foliar Zn. Foliar Zn application decreased grain Cd concentration more than soil Zn application, and more in Zincol-2016 than Faisalabad-2008. In the comparable Cd-spiked treatments, Zincol-2016 had 73 to 134% higher grain Cd concentration than Faisalabad-2008. The Zn-biofortified genotypes accumulating toxic metals may pose serious health issues. Therefore, future breeding for biofortification should focus on the selective accumulation of Zn., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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 (8mgZnkg -1 ). The soils, collected from agricultural fields in (i) industrial zone and (ii) peri-urban area, had been receiving industrial and city effluents for >20years. 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 0mgZnkg -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 (0.24mgkg -1 ) was attained at control rate of Zn by Zincol-2016, and was decreased to a safe level (0.07mgkg -1 ) by application of 8mgZnkg -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., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Above‐permissible levels of arsenic (As) in irrigation water lead to toxic levels in wheat grains, increasing health risks for humans. In this study, two zinc (Zn)‐biofortified wheat (Triticum aestivum L.) cultivars (Akbar‐2019 and Zincol‐2016) were grown in pots with two Zn application rates (0 and 8 mg Zn kg−1) and three levels of As in irrigation water (distilled‐water control, 100 and 1000 µg As L−1). Irrigation with As‐contaminated water decreased dry matter yields, concentrations of grain phosphorus (P) and Zn, and estimated daily intake (EDI) of Zn. Conversely, it increased grain As concentration and As EDI. Soil Zn application mitigated the negative effects of As on dry matter yields of both cultivars while simultaneously enhancing grain Zn concentration and Zn EDI. On average, Zn application increased grain Zn concentration by 114% compared to no Zn application. Additionally, Zn application decreased grain As concentration at all As levels. In conclusion, this study suggests that applying Zn to Zn‐biofortified wheat irrigated with As‐contaminated water can mitigate the toxic effects of As on wheat. It increase Zn concentration and decrease As concentration in wheat grains, which is vital for enhancing grain quality for human consumption. [ABSTRACT FROM AUTHOR]

Context: Arsenic (As) is a noxious metalloid for plants, animals and humans. Elevated levels of As in soils may cause it to accumulate to above-permissible levels in wheat grains, posing a threat to human health. Moreover, vulnerable population groups in developing countries have inadequate dietary zinc (Zn) linked to cereal-based diets. Aims: The present study evaluated the effect of soil Zn application on accumulation of As and Zn in grains of two Zn-biofortified wheat (Triticum aestivum L.) cultivars (Akbar-2019 and Zincol-2016). Methods: Wheat plants were grown on an alkaline calcareous soil spiked with three levels of As (0, 5 and 25 mg kg−1). Before sowing, two rates of Zn (0 and 8 mg kg−1) were also applied to the soil. Key results: Arsenic spiking in soil decreased plant dry matter yield, chlorophyll pigments, and phosphorus (P) and Zn accumulation, and increased As accumulation in wheat. By contrast, soil Zn application enhanced crop yield and increased P and Zn accumulation, with a simultaneous decrease in As accumulation in both cultivars. Compared with the Zn control, soil Zn application decreased grain As concentration by 26%, 30% and 32% for plants grown in soil spiked with 0, 5 and 25 mg As kg−1, respectively. Conclusions: Applying Zn to As-spiked soil mitigates the harmful effects of As by increasing Zn and decreasing As concentrations in wheat, resulting in improved grain quality for human consumption. Implications: Zinc application to crop plants should be recommended for addressing the health implications associated with As-contaminated crops and human Zn deficiency. Wheat grown on soils contaminated by arsenic (As) may accumulate toxic levels of As in grains, allowing As to enter the human food chain. The study evaluated the effect of soil zinc (Zn) application on grain As and grain accumulation of Zn in two Zn-biofortified wheat cultivars grown on As-contaminated soil. Soil Zn application decreased grain As accumulation to below the permissible limit of 0.15 mg As kg−1 and simultaneously increased grain Zn accumulation. [ABSTRACT FROM AUTHOR]

Context: Cadmium (Cd) is a toxic metal for both plants and humans. Wheat grown on Cd-contaminated soils may accumulate toxic levels of Cd in grains. Aim: This study aimed to compare soil zinc (Zn) application and seed Zn-priming for decreasing grain Cd concentration in standard and Zn-biofortified wheat cultivars grown on Cd-spiked soil. Methods: Standard (Jauhar-2016) and Zn-biofortified (Zincol-2016) wheat cultivars were grown in pots filled with Cd-spiked soil (8 mg Cd kg−1). The tested Zn treatments were un-primed, hydro-primed, and Zn-primed seeds with and without soil Zn application at 8 mg kg−1. Key results: Zinc treatments significantly mitigated the toxic effects of Cd on the growth and physiological parameters of both cultivars. As compared to control, all Zn treatments significantly increased Zn and decreased Cd concentration in grains of the cultivars. On average, the maximum increase in grain Zn concentration over control was approximately 36% with Zn-priming + soil Zn. The same treatment, as compared to control, decreased grain Cd concentration by 42% in Zincol-2016 and 35% in Jauhar-2016. Grain Cd concentration was within the permissible level (≤0.2 mg kg−1) in Jauhar-2016 at all Zn treatments and in Zincol-2016 at Zn-priming + soil Zn. Conclusion: Soil Zn application, seed Zn-priming, and their combination were effective in decreasing grain Cd accumulation in wheat grown on Cd-contaminated soil. Implication: Zinc treatments, especially the combination of soil Zn application and seed Zn-priming, should be recommended for wheat grown on Cd-contaminated soil. Wheat grown on Cd contaminated soils may accumulate toxic levels of Cd that may enter the human food chain. This study compared Zn treatments for standard and Zn-biofortified wheat cultivars grown on Cd-spiked soil. Seed Zn-priming, soil Zn application and their combination were effective in decreasing grain Cd concentration below the permissible limit of 0.2 mg Cd kg−1. [ABSTRACT FROM AUTHOR]

Zinc (Zn) deficiency is prevalent in human populations in developing countries. The present study compared two wheat (Triticum aestivum L.) cultivars [Jauhar-2016 (standard wheat) and Zincol-2016 (Zn-biofortified wheat)] for Zn biofortification with optimum soil Zn application. For this, Zn (at 0, 3, 6, 12 and 24 mg Zn kg−1) was applied to pots having an alkaline calcareous soil. Grain yield, grain Zn concentration and grain Zn bioavailability in both cultivars were significantly increased by Zn fertilization. However, Zn application decreased iron (Fe) and phytate concentration in grains of both cultivars. As compared to Jauhar-2016, Zincol-2016 had significantly higher grain Zn concentration and grain Zn bioavailability at all the respective soil Zn rates excepting only at control. At 6 mg Zn kg−1, Zincol-2016 attained in grains a desired concentration of Zn (53 mg Zn kg−1) and a desired level of human Zn bioavailability (2.8 mg d−1 for women and was 3.0 mg d−1 for men). Jauhar-2016 also attained such comparative levels but only at a plant toxic rate of Zn (24 mg Zn kg−1). Conclusively, soil Zn application (agronomic biofortification) to Zn-biofortified wheat (Zincol-2016) may be a promising approach to decrease human Zn deficiency in population groups dependent on wheat-based diets. [ABSTRACT FROM AUTHOR]

Soil salinity and sodicity are major limiting factors in crop production globally. Priming with osmolytes has been proposed to mitigate the negative effects of these limiting factors. However, most of the priming studies have been conducted in hydroponics and only limited information is available regarding the impacts of seed priming in natural soil conditions. In the present study, untreated and primed (with distilled water, 4 mM ZnSO4 and 23 mM K2SO4) seeds of maize were grown in pots filled with a saline soil or a saline-sodic one. In the saline and saline-sodic soil, ZnSO4 priming increased the shoot dry biomass of 30-day-old plants by 38 and 69%, and the root dry biomass by 22 and 48%, respectively, when compared to the controls. Water priming (hydro-priming) was also effective in the saline soil, increasing shoot dry biomass by 28% over the control values. In both soils, ZnSO4 priming increased significantly the shoot Ca and Zn concentrations, whereas it decreased shoot Na concentrations. Moreover, ZnSO4 priming increased leaf chlorophyll contents and photosynthesis rates over those in the controls. Priming treatments, especially with water and ZnSO4, also increased significantly the shoot K/Na, Ca/Na, and Mg/Na concentration ratios. In conclusion, priming with ZnSO4 may improve shoot growth in both soils, whereas water priming was suitable for the saline soil. [ABSTRACT FROM AUTHOR]

It is still unclear if different sources of nitrogen (N) can variably influence grain accumulation of zinc (Zn), N, and phytate. We tested foliar treatments of 0 or 0.25% Zn as zinc sulfate in combination with 0 or 1% N as ammonium chloride, ammonium sulfate or urea sprayed on field-grown-wheat (Triticum aestivum L.) foliage at anthesis and 10 days later. Leaf burning caused by ammonium chloride significantly decreased grain yield. Grain N concentration was the highest in the urea +0.25% Zn treatment. Foliar N application influenced grain Zn concentration only if Zn was included in the spray. Grain phytate concentration was significantly decreased by both N and Zn sprays. Estimated Zn bioavailability in grains was the highest at 0.25% Zn and was not influenced by the N sources. Based on grain yield, grain N concentration, and Zn bioavailability in grains, foliar application of Zn + urea is an optimal strategy. [ABSTRACT FROM AUTHOR]

Application of fertilizer at the right time is necessary for profitable yields. Phosphorus (P) and zinc (Zn) are important nutrients often found deficient in calcareous soils. Plant growth promoting rhizobacteria may increase availability of P and Zn from such soils. A pot experiment was conducted to compare the basal and late applications of Zn and P with or without rhizobacteria inoculation for improving fodder yield of maize (Zea maysL.). The application times of Zn (5 mg kg–1) and P (30 mg kg–1) fertilizers to plants with or without rhizobacteria inoculation were (i) basal P + basal Zn, (ii) late P + basal Zn, (iii) basal P + late Zn, and (iv) late P + late Zn. Basal doses were applied at sowing and late applications were applied 30 days after. As compared to basal applications of both P and Zn, optimum fodder yields were achieved with basal P + late Zn without rhizobacteria inoculation, and with late P + basal Zn with rhizobacteria inoculation. Uptake of Zn and P, and root growth were also influenced by rhizobacteria inoculation and time of fertilizer application. This might relate with nutrient–nutrient and nutrient–inoculum interactions for a particular soil–crop combination. Therefore, the nutrients under consideration and rhizobacteria inoculation determines the right time of fertilizer application in maize. [ABSTRACT FROM PUBLISHER]

Higher grain Zn concentration is desirable to combat human Zn deficiency. A total of 58 farmers' fields were surveyed from districts of Multan and Lodhran to represent cotton-wheat rotation zone of Punjab. Soils were sampled separately from the surface (0–15 cm depth) and subsurface (15–30 cm depth) layers. Within 5 m2 of soil sample, about 100 spikes from mature tillers of wheat were also collected. Nearly all subsurface and 76% of the collected surface soil samples were deficient in plant available Zn resulting in grain Zn concentration of 20 µg g–1, on average. The inherent capacity of subsurface soil layer to supply Zn positively correlated with grain Zn concentration (r=0.33, n=58; P=0.01). Organic matter content (r=0.32, n=58; P=0.02) in subsurface layer and soil salinity (ECe) of both layers (r=–0.53, n=58; P<0.01 for ECe of both layers) were the other major soil characteristics that significantly correlated with grain Zn concentration. Zinc bioavailability in wheat grains, estimated by [phytate]:[Zn] ratios and trivariate model of Zn absorption, was low. Present study indicated a need to reduce current grain [phytate]:[Zn] ratio (46, on average) and to increase the current trivariate model based estimated Zn bioavailability (1.5 mg Zn for 300 g flour, on average) by about 2-folds. Conclusively, Zn fertilization strategy for southern Punjab was suggested as a solution to human Zn deficiency and low grain yields. [ABSTRACT FROM AUTHOR]

Zinc biofortification of cereal grains is suggested for controlling widespread human Zn deficiency in developing countries. In present field trail, various Zn treatments [control, priming of seeds in 0.5% (w/v) Zn solution (seed priming), dipping of roots in 0.5% (w/v) Zn solution (root dipping), application of 20 kg Zn ha–1 (soil application), sprays of 0.25% (w/v) Zn each at tillering and heading stages (foliar application) and combination of soil + foliar Zn applications] were applied as ZnSO4·7H2O to rice grown under submerged conditions on a Zn deficient calcareous soil. Treatments significantly (P≤0.05) increased grain and straw yield; however, seed priming and root dipping increased paddy yield only by ≤5%. Increased grain weight also significantly increased grain phytate content. Whole grain Zn concentration increased from 22 (at control) to 29 mg kg–1 (at soil + foliar application).Zinc applications methods, especially soil + foliar application, decreased grain [phytate]:[Zn] ratio and increased estimated human Zn bioavailability in grains based on trivariate model of Zn absorption. Conclusively, soil + foliar Zn application is suitable for optimum paddy yield and agronomic Zn biofortification of rice grains. However, a limited increase in grain Zn concentration (7 mg kg–1) by Zn application suggested exploitation of molecular and genetic approaches in Zn biofortification programs. [ABSTRACT FROM AUTHOR]

In present study, control and Zn-biofortified grains were milled to estimate Zn bioavailability in various grain milling fractions and flours of various extraction rates. In all tissues of wheat grains, soil Zn application increased Zn concentration and bioavailability, while decreased phytate concentration and [phytate]:[Zn] ratio. Compared with control grains, trivariate model of Zn absorption based estimated Zn bioavailability in various flour fractions of biofortified grains was greater by 50% or more. On average, bran had higher concentration of Zn and phytate as compared to whole grain and other milling fractions. Therefore, a large decrease was observed in concentration and estimated bioavailability of Zn from both control and biofortified wheat flour at lower flour extraction rates (80 and 65% extraction) when compared to flour of 100% extraction rate. Compared with four commercial wheat flours of similar flour extraction rate (80%), Zn bioavailability was significantly lower in flour from the control grains, while significantly greater in flour from the biofortified grains. Conclusively, only biofortified whole grain flour can ensure optimum Zn bioavailability (≈3 mg Zn per 300 g flour) for the human population groups reliant on wheat grains. [ABSTRACT FROM AUTHOR]

Zinc application is generally recommended to enrich wheat grains with Zn; however, its influence on Zn bioavailability to humans has not received appreciable attention from scientists. In this pot experiment, seven Zn rates (from 0 to 18 mg kg−1soil) were applied to two wheat cultivars (Shafaq-2006 and Auqab-2000). Application of Zn significantly increased grain yield, grain Zn concentration and estimated Zn bioavailability, and significantly decreased grain phytate concentration and [phytate]:[Zn] ratio in wheat grains. The response of grain yield to Zn application was quadratic, whereas maximum grain yield was estimated to be achieved at 10.8 mg Zn kg−1soil for Shafaq-2006 and 7.4 mg Zn kg−1soil for Auqab-2000. These estimated Zn rates were suitable for increasing grain Zn concentration and Zn bioavailability (>2.9 mg Zn in 300 g grains) to optimum levels required for better human nutrition. Conclusively, Zn fertilization for Zn biofortification may be practiced on the bases of response curve studies aimed at maximizing grain yield and optimum Zn bioavailability. Moreover, additive Zn application progressively reduced the grain Fe concentration and increased the grain [phytate]:[Fe] ratio. However, a medium Zn application rate increased grain Ca concentration and decreased the grain [phytate]:[Ca] ratio. Hence, rate of Zn application for mineral biofortification needs to be carefully selected. [ABSTRACT FROM AUTHOR]

Adsorption and desorption reactions of zinc (Zn) in soils control its availability to plants. In the present investigation, time-dependent Zn release was evaluated using three organic acids [diethylenetriaminepentaacetic acid (DTPA), citric acid, and maleic acid] to depict the Zn fraction controlling Zn release rate from slightly calcareous to calcareous soils. Eight surface and two subsoil samples of selected soil series varied in their physicochemical properties, amount of Zn held in different chemical pools, and Zn-retention capacities (21-61%). Each soil was extracted for a total period of 24 h at 1:10 soil/extractant suspension ratio using 0.005 M DTPA. The time-dependent parabolic diffusion model best described the Zn release in six consecutive extractions. Soils differed in cumulative Zn extracted (1.09-3.81 mg kg-1 soil) and Zn release rate. Under similar conditions, three soils differing in Zn-retention capacities were also extracted with five different concentrations (0.01-0.0001 M) of citric and maleic acids. Although both maleic and citric acids released soil Zn at greater rates and in greater amounts than DTPA, maleic acid was more efficient. Soil Zn bound to amorphous iron (Fe) + manganese (Mn) oxides was the main Zn pool that controlled Zn release characteristics. [ABSTRACT FROM AUTHOR]

The zinc (Zn) requirement of a maize (Zea mays L.) hybrid ('FHY-396') and an indigenous variety ('EV-7004') was measured at low (22.4 ± 5°C) and high (28.8 ± 5°C) root-zone temperatures (RZT). Four Zn rates (0, 3, 9 and 27 mg kg-1 soil) were applied to a calcareous loam soil in pots for the glasshouse study. Shoot and root dry matter yields were significantly more at the higher RZT. Regardless the RZT, maximum relative shoot dry matter yield in hybrid and variety was produced, respectively, at 9 and 3 mg Zn kg-1 soil. Zinc concentration in roots and shoots of both the cultivars increased with Zn rates and it was significantly more at the higher RZT. Cultivars differed in critical Zn concentration (CZnC) required for maximum shoot dry matter yield. The CZnC ranged from 25 to 39 μg Zn g-1 plant tissue for optimum growth of both the cultivars at low and high RZT. [ABSTRACT FROM AUTHOR]

Hunger and zinc (Zn) malnutrition are major health risk factors in the developing countries. Wheat is a major staple food in the world but it is inherently low in grain Zn concentration especially when grown on Zn deficit calcareous soils. Therefore, producing Zn enriched wheat grains at the farmers' fields is the best solution against human Zn deficiency. Biofortification approaches include selection, improvement and management of cultivated wheat genotypes to ensure optimum grain Zn concentration for human consumption. Soil and foliar application of Zn to wheat grown on Zn deficient soils enhances both the grain yield and grain Zn concentration. Genotype screening for higher grain yield and grain Zn concentration is prerequisite to ensure adoptability of poor farmers to newly developed genotypes for Zn biofortification. Conclusively, simultaneous consideration of grain yield and grain Zn concentration of wheat is the sustainable and economical approach to achieve our food targets. [ABSTRACT FROM AUTHOR]

Improving efficiency of applied nutrients is important to produce optimum crop yields with reduced fertilizer inputs. Phosphorous (P) has antagonistic effect on zinc (Zn) uptake by plants and information on the efficiency of these each nutrients in maize cultivars are limited. This study evaluated the response of different levels of Zn (0, 9 mg kg-1 soil) and P (0, 40 mg kg-1 soil) on growth, nutrient uptake and their utilization efficiency in four maize cultivars differing in their growth behavior (DK-6142, P1543, Neelam and Afghoi) when grown under natural greenhouse conditions. Maize cultivars significantly differed for above given traits and among treatments, combined Zn+P application increased dry matter, nutrient uptake and their efficiency as compared with control. Agronomic, physiological and recovery efficiency of P increased in Neelam, Afghoi and DK-6142 cultivars with Zn applied and vice versa. Afghoi and DK-6142 cultivars were more responsive for agronomic, physiological and apparent Zn and P recovery efficiency than other ones. For P1543 cultivar, Zn and P physiological efficiency decreased while recovery efficiency increased, respectively with combined application of both nutrients. However, for each of the nutrients utilization efficiency, none of these were related to open pollinated or hybrid maize cultivars and rather dependent on genetic makeup for internal higher utilization efficiency. Overall, nutrient efficiency of applied Zn or P are interdependent on each other and maize cultivars had a differential response to their applications. [ABSTRACT FROM AUTHOR]

Zinc application is required for optimum crop growth especially in calcareous soils located in semiarid to arid regions. The use of poor quality brackish water in arid zone agriculture further poses threat to soil productivity. Effect of Zn application (0, 3 and 9 mg kg-1) and sodium absorption ratio of irrigation water (SARiw; distilled-water control, 8 and 16 (mmolc L-1)½) on plant growth and mineral concentration (Ca, Na, K and Zn) in shoots of two contrasting maize cultivars (hybrid, FHY-993 and synthetic variety, C-20) were evaluated in a pot study. Plant shoots showed a significant decrease (up to 31%, on average basis) due to increasing levels of SARiw and a significant increase (up to 13%, on average basis) in dry matter with the application of Zn to soil. Both cultivars varied significantly in response to Zn application and SARiw. Maximum increase in growth was observed in FHY-993 with application of Zn; while minimum decrease in plant growth due to increased level of SARiw was observed in C-20. The results indicated mitigation of sodicity effects by Zn application especially for FHY-993 with higher Zn requirement. Zinc application reduced shoot Na concentration while increased shoot Ca and K concentration; therefore, significantly increased Ca:Na and K:Na ratios in plant shoots. Conclusively, Zn application to maize improved growth by balancing K:Na and Ca:Na concentration ratios in shoots of stressed maize. However, the response may vary among cultivars depending upon their Zn requirement and Na susceptibility. © 2014 Friends Science Publishers [ABSTRACT FROM AUTHOR]

Zinc is widespread deficient in calcareous soils and its management is more complex in reduced root-zone conditions of rice grown on saline-sodic soils. Present pot study was conducted in a wire house, Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan during 2010 to compare Zn enriched farm yard manure (FYM) with chelated (Zn-EDTA) and non chelated (zinc sulphate, ZnSO4) Zn sources for optimum grain yield and higher Zn concentration in grains of rice (cv. Shaheen Basmati) grown in a salt-affected soil. Treatments comprised of 1.5, 3 or 6 mg Zn kg-1 soil in the form of both ZnSO4 and Zn-EDTA, and Zn-enriched farm yard manure 5% of soil (w/w). Zn enrichment was done with same three levels of Zn using ZnSO4. Application of Zn increased plant growth, grain yield and Zn concentration in various tissues, irrespective of the Zn source. The increase in plant growth and Zn concentration was higher when plants were grown with Znenriched FYM compared to ZnSO4 or Zn-EDTA application alone. The maximum Zn concentration in rice grains (13.9 mg kg-1) and straw (19.1 mg kg-1) were obtained with the same treatment. It was concluded that application of ZnSO4 enriched FYM proved better over application of alone ZnSO4 or Zn-EDTA indicating the positive role of organic matter in increasing grain yield and grain Zn concentration on soils affected with salts and depleted in organic matter. [ABSTRACT FROM AUTHOR]

Abstract Constructing ZnCo 2 O 4 nanosheet arrays (NSAs)@MnO 2 nanosheets core-shell nanostructures directly on the current collector (Ni foam) was successfully realized via hydrothermal process and heat treatment. The whole surfaces of uniform ZnCo 2 O 4 NSAs were covered with well-ordered MnO 2 nanosheets, which make the whole system have a large specific surface area. At a low current density of 2 mA cm−2, supercapacitor electrode made of ZnCo 2 O 4 @MnO 2 composite gave rise to a superior specific capacity about 929.2 C g−1. Although at an ultrahigh current density of 40 mA cm−2, it still kept a satisfactory specific capacity about 751.1 C g−1, and retained ∼95.75% of the capacity even after 5000 cycles. Because of the synergistic effect between ZnCo 2 O 4 and MnO 2 and the great surface area of the system with the special core-shell structure, ZnCo 2 O 4 @MnO 2 composite has the excellent rate performance, considerable capacity, and quite good cycle performance, which make it a candidate for a new generation of superior-performance electrochemical supercapacitors. Graphical abstract Image 1 Highlights • ZnCo 2 O 4 nanosheet arrays@MnO 2 nanoflakes were constructed on Ni foam. • Ultra-high specific capacity 929.2 C g−1 after being decorated with MnO 2 nanoflakes. • 3D Ni@ZnCo 2 O 4 @MnO 2 electrode presents excellent rate performance. • The electrode keeps 95.75% capacity remains after 5000 cycle. [ABSTRACT FROM AUTHOR]

Electric arc furnace dust (EAFD) has attracted more and more attention as a kind of metallurgical solid waste with huge production. How to reduce its harm to the environment and efficiently recover valuable metals such as zinc, lead and iron from its complex components to realize the comprehensive utilization of EAFD is the aim of various EAFD treatment processes. In this paper, the physical and chemical properties of EAFD are discussed from the micro and macro perspectives, the microstructure, chemical composition and phase composition of EAFD in various countries are summarized in detail. According to the zinc content, EAFD can be divided into three types: high-zinc, medium-zinc and low-zinc. The results show that Fe, Ni, Cr and other elements increase with the decrease of zinc content in EAFD. Not only the zinc oxide but also abundant Fe–Ni–Cr alloy of high value can be recycled from the low-zinc EAFD, which provides guidance for EAFD treatment. At the same time, the general mechanism of direct reduction and smelting reduction pyrometallurgical processes of EAFD is expounded, and the existing pyrometallurgical processes such as rotary kiln process, rotary hearth furnace process, Primus process, ESRF process and Coke-packed bed process are summarized and compared from the aspects of energy consumption, production capacity, process flow to actual application status. In addition, the properties of directly reduced iron and zinc-rich dust obtained by pyrometallurgical processes of EAFD are also discussed. Finally, a new process of treating EAFD by combining direct reduction process and smelting reduction process is proposed to overcome the defects existing in two types of pyrometallurgical processes, and the development of preparing zinc oxide micropowder and high valued Fe–Ni–Cr alloy by pyrometallurgical process of EAFD is prospected. [ABSTRACT FROM AUTHOR]