Soil Zn Application Research Articles

Arsenic and zinc concentrations in wheat grains under soil zinc application and arsenic‐contaminated irrigation

AbstractAbove‐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.

Optimizing Grain Zinc Biofortification in Bread Wheat: Innovative Fertilization Strategies for Field Conditions

Zinc deficiency in humans is of worldwide concern. The aim of this study is to enrich grains with Zn through soil application at different doses and foliar application from various sources. For this purpose, two independent field experiments have been conducted. In Experiment I, Zn (ZnSO4.7H2O) was applied through soil as basal and top dressing. The treatments were Zn0: control, Zn1: 5 kg Zn ha−1 as basal, Zn2: 2.5 kg Zn ha−1 as basal and 2.5 kg Zn ha−1 as top dressing and Zn3: 5 kg Zn ha−1 as top dressing. In Experiment II, Zn was applied as foliar from different sources (ZnSO4.7H2O, Zn-Methionine, Zn-Polyol and Zn-EDTA) at different growth stages with or without urea. In both experiments, Zn concentration in the grain and leaves of wheat and grain yield increased while phytic acid and PA/Zn molar ratio decreased due to soil or foliar Zn application. It was determined that the application of ZnSO4.7H2O in the soil at the top dressing period in Experiment I and the application of ZnSO4.7H2O and Zn-Methionine forms together with urea in Experiment II were effective methods in increasing grain yield and grain Zn concentration. The application of ZnSO4.7H2O from both soil and foliar sources, especially in combination with urea, has proven to be highly effective in the Zn biofortification of wheat grains. It is possible to assert that the use of ZnSO4.7H2O, which is cost-effective compared to other sources, could contribute significantly to enhancing zinc nutrition in humans.

Biofortification of wheat in salt-affected soil through seed priming and soil application of zinc

ContextGiven the global significance of wheat production and consumption, it is imperative to achieve high yields of nutritious wheat grains. However, the inadequate availability of zinc (Zn) in salt-affected soils can aggravate salt stress, decrease wheat grain yield, and grain Zn concentration. This study compared the effectiveness of soil Zn application and seed Zn priming in increasing Zn biofortification and grain yield of Zn-biofortified wheat grown in alkaline-calcareous soil affected by salts. MethodsEighteen pots were filled with alkaline-calcareous soil containing elevated levels of soluble salts and exchangeable sodium (Na). The pots were subjected to soil Zn application (0 or 8 mg kg−1) and seed priming (control/non-, hydro-, or Zn-primed seeds) treatments, applied to a Zn-biofortified wheat (cv. Zincol-2016). Plant samples were collected at the heading and maturity stages to measure parameters related to plant growth and grain quality. FindingsSoil Zn application increased grain and straw yields across seed priming treatments by a maximum of 23 %, and seed Zn priming increased grain and straw yields across soil Zn rates by a maximum of 21 %. This yield response was accompanied by significant increases in grain potassium and Zn concentrations at maturity, as well as non-significant to significant increases in photosynthetic parameters (stomatal conductance, photosynthetic rate and transpiration rate) in flag leaves during heading. Additionally, compared to control, the combined treatment of soil Zn application and seed Zn priming decreased grain Na concentration by 14 %. Compared to control, both soil Zn application and seed Zn priming significantly increased grain Zn concentration. With the combined application treatment, the grain Zn concentration reached 27 mg kg−1, but it remained significantly below the desired level of >37 mg kg−1. Seed Zn priming decreased the phytate-to-Zn molar ratio in grains, while the treatments that received soil Zn application exhibited the lowest values of this ratio, potentially increasing Zn bioavailability to humans. ConclusionsThe findings suggest that soil Zn application is more effective in enhancing grain yield and Zn concentration, while seed Zn priming remains crucial in low-Zn and high-salt soils. Future research should optimize Zn application strategies for Zn-biofortified wheat cultivated in salt-affected fields.

Agronomic Biofortification of Fodder Maize (Zea mays L.) with Zn for Improving Herbage Productivity and Its Quality

Zinc (Zn) deficiency in soils not only reduces the productivity of forage crops, but also results in inadequate dietary zinc intake for livestock. The objective of this study was to evaluate the impact of different rates and methods of applying ZnSO4 to both soil and foliage on the yield and quality of fodder maize grown in a sandy loam soil testing low in DTPA-extractable Zn. A 2-year field experiment was conducted with six treatments including control, foliar application of 0.3% ZnSO4 at 30 days after sowing (DAS) (F1), foliar application of 0.3% ZnSO4 at 30 and 40 DAS (F2), soil application of 16 kg ha−1 ZnSO4 (S16) and a combination of both soil and foliar ZnSO4 application (S16 + F1 and S16 + F2). Increase in green herbage yield by 25%, dry matter yield by 47% and Zn content by 79% was observed under S16 + F2 treatment over the control. Zinc application improved N, K, Cu and crude protein content of herbage significantly over the control. Thus, the study shows that significant improvement in growth parameters, herbage yield and quality of maize can be achieved with soil Zn application + two foliar sprays of ZnSO4 at 30 and 40 DAS, thereby ensuring availability of improved fodder Zn to the livestock.

Soil zinc application decreases arsenic and increases zinc accumulation in grains of zinc-biofortified wheat cultivars

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.

Response of nutrients uptake and bio fortification to the optimum zinc fertilizer doses for maize crop (Zea mays L.)

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.

Improving the Productivity and Nutritional Values of Sweet Potato (Ipomoea batatas L.) with a Combination of Soil and Foliar Zinc

Sweet potato (Ipomoea batatas L.) is an important crop and is a staple food in many countries across the globe; since they are a good source of nutrients including zinc (Zn). Zn is essential for plant growth and development, and a zinc deficiency can significantly impact crop productivity as well as the nutritional quality of the produce. The value of enrichment with Zn in many crops by applying Zn either to foliar or soil through agronomic biofortification has been investigated, but this information is still unavailable for sweet potatoes. Therefore, the current study aimed to evaluate the effect of soil and foliar Zn applications on yield, biochemical traits, and nutrient concentrations of different sweet potato genotypes. The study was conducted using a split-plot design with treatments of two doses (0 and 2.5 kg Zn ha-1) of soil application and four doses (0, 15, 30, and 45 ppm) of foliar application of Zn on five sweet potato genotypes (SP-2, SP-14, SP-15, SP-16, SP-20). It was observed that growth and yield performance as well as nutrient concentrations in the tubers of sweet potatoes were greatly influenced by Zn application method and genotype. An increasing rate of foliar Zn, with or without soil-applied Zn, showed an increasing trend in amino acid, β-carotene, flavonoid, and phenolic content. The foliar Zn application had a more obvious effect on most of the examined traits than the soil Zn application and except for a few characteristics (dry matter and amino acids), most traits responded up to the foliar application of 15 ppm Zn, and thereafter no increase was seen with further increments of foliar Zn application.

Impact of conservation tillage and agronomic biofortification strategies on soil health and grain quality aspects under soybean–wheat cropping system

A field experiment was initiated in 2018 at ICAR-IISR Indore (MP), to study the effect of crop establishment techniques and agronomic biofortification methods on grain yield, crop and soil quality aspects under long-term conservation agriculture (CA) based soybean-wheat cropping system. The experiment was laid out in split plot design with two crop establishment techniques and eight agronomic biofortification methods. The results revealed that significantly higher grain yield, lowest soil pH, highest available nutrients (DTPA-Zn and DTPA-Fe), increased soil enzyme (Dehydrogenase) of soybean and wheat under conservation tillage. Among different agronomic biofortification methods soil application of Zn+Fe (DTPA-Zn and DTPA-Fe) reported significantly higher grain yield, compared to control. However, seed inoculation of microbial strains MDSR 14 + MDSR 34reported significantly lowest soil pH, highest soil enzyme. Soybean and wheat grain phytic acid/Zn (<15) and phytic acid/Fe (<10) molar ratio was found significantly lower under conservation tillage and foliar application of Zn+Fe. Thus, in long term, adaptation of conservation tillage along with soil or foliar application of Zn+Fe and seed inoculation of MDSR 14 + MDSR 34 could be prominent options to improve yield, soil and crop quality parameters under CA based soybean-wheat cropping system.

Combined zinc and urea application enhances productivity and profitability of lentil (Lens culinaris Medik.)

The present study investigated the effect of sole as well as combined foliar application of zinc (Zn) and urea at flowering and pod formation stages and soil application of Zn on symbiotic parameters, growth, yield, and economics of lentil. Field experiments were conducted at two locations (Ludhiana and Faridkot, northern India) during the winter season of 2018–19 and 2019–20 in randomized complete block design. The experiment comprised of 11 treatments [control (no soil/foliar application of ZnSO4 and no urea foliar application), soil Zn (25 kg ZnSO4 ha−1), foliar application of sole Zn (0.5% ZnSO4) or urea (2%) and combined Zn + urea at flowering, pod formation, or flowering + pod formation stages] and three replications. Zn and urea fertilization significantly improved the grain yield and related traits and economics in both the years of study at both the locations. The treatment of combined foliar application of Zn + urea at flowering + pod formation stages recorded the highest symbiotic parameters, chlorophyll content, growth and yield attributes, grain yield (29.5% higher than control), gross returns (29.5% higher), net economic returns (56.2% higher), and benefit cost ratio. The combined foliar application of Zn + urea can be done to improve growth, productivity, and economics of lentil and, therefore, it can help in upliftment of economic status of farmers.

Enhancing wheat production and quality in alkaline soil: a study on the effectiveness of foliar and soil applied zinc

Cultivation of high-yield varieties and unbalanced fertilization have induced micronutrient deficiency in soils worldwide. Zinc (Zn) is an essential nutrient for plant growth and its deficiency is most common in alkaline and calcareous soils. Therefore, this study aimed to evaluate the effect of Zn applied either alone or in combination with foliar application on the quality and production of wheat grown in alkaline soils. Zn was applied in the form of zinc sulfate (ZnSo4) to the soil and as a foliar spray during the sowing and tillering stages, respectively. Results showed that Zn fertilization of wheat, irrespective of modes of application, significantly increased grain and biological yield, grain per spike, and 1,000 grains weight over control; however, its effect was more noticeable when applied as 7.5 kg ha−1of soil Zn combined with foliar Zn at 2.5 kg ha−1. Zn application significantly increased the grain protein content from 9.40% in the control to a maximum of 11.83% at soil Zn of 10 kg ha−1. Similarly, Zn application improved Zn, phosphorus (P), and potassium (K) concentrations in wheat grains. Moreover, correlation analysis showed that the grain Zn concentration was positively correlated with the grain P concentration. The correlation between P concentration in wheat grains and 1,000 grain weight was not significant. A total of 1,000 grains weight was positively correlated with tillers per plant, grain yield, and biological yield. There were positive correlations between protein content, biological yield, grain yield, and tillers per plant. Therefore, soil-applied Zn + foliar application in alkaline soils with limited Zn availability is crucial for improving wheat yield and grain quality.

Validation of Bio-stimulant Seed Treatment, Soil and Foliar Application of Nano DAP, Urea, K, Zn, Cu, B Formulations in a Flood Affected Bt Hybrid Cotton

Bt hybrid cotton faced 30-60% excess rains in 70% years since its release and four times water logging in 2021, in a deep and shallow Vertisols with Calcareous sub-strata forced to confirm all the agronomical advices to it. Water logging reduced the biomass, boll number and cotton lint yields to more than 50 percent except the fibre quality. Prevailing runoff and leaching losses of soil applied fertilizer nutrients were accumulated at downstream, which increased the soil test values. Water logging caused reduction of index leaf N, P, K, Zn and B nutrient status below the threshold levels. Soil application of Zn and B once in three years alone or seed treatment formulation with N, P, K Bio-inoculant consortia along with nano ZnO 0.0004% + CuO 0.0001% as seed treatment at the time of sowing with or without foliar application of NPK WSF 2%, Zn 0.5%, B 0.3% or 0.04% nano formulations of DAP alternated with Urea alongwith ZnO and K with common insecticides and fungicidal sprays significantly improved index leaf nutrient status, biomass, boll number and seed cotton yields in both the soils. Validation of these results in station trials during 2022-24 found the need for atleast two foliar application of nano nutrients each DAP + ZnO + K followed by nano Urea+ ZnO + K 0.004% alternately at the mid and end September and October months. This increased N, P, K, Zn, B content in index leaves and seeds with additional cotton lint yield 209 kg ha-1 worth 174 US $ ha-1 net profit by soil application ZnSO4 20 and Borox 5 kg ha-1 yr -3 in Vertisols and three times foliar application at squaring, flowering and boll formation stage with nano ZnO 0.004%+ B 0.3% or ZnSO4 0.36% +Boron 0.2% in Vertisols with calcareous sub-strata.

Response of Capsicum (Capsicum annuum L.) Hybrids to Micro-nutrients under Protected Conditions

The field experiment was carried out during rabi season of 2021-22 and 2022 at Vegetable Research Farm of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur to find out the response of capsicum hybrids to micronutrients under protected conditions. The experiment was laid out in Split Plot Design (SPD) with 15 treatment combinations and replicated thrice. The experiment comprised three hybrids viz., Indira, Swarna and Bomby and five levels of micronutrients viz., control (no micronutrients application), soil application of Zn, Fe & B, fertigation of EDTA of Zn & Fe and solubor at 15 days interval, foliar application of vegetable special @ 5g/lit at 15 days interval and foliar application of chelated combo micronutrients @ 1g/lit at 15 days interval. Recommended package of practices for the crop were followed except treatments. Results of the experiment revealed that the hybrid Indira recorded significantly highest plant height (91.30 and 94.89 cm), number of branches (11.87 and 12.30), stem girth (4.31 and 4.60 cm), number of leaves (102.94 and 106.43), internode length (13.82 and 14.01 cm), number of flowers per plant (38.22 and 38.36), fruit set (55.10 and 55.44%), no. of fruits per plant (20.99 and 21.22), fruit weight per plant (3.69 and 3.74 kg) and fruit yield per 1000 m2 (70.36 and 71.35 q) while fruit length (11.45 and 11.71 cm), fruit diameter (10.54 and 10.66 cm), weight of placenta (18.51 and 18.71g) and average weight of fruit (193.31 and 195.90g) were significantly highest in Swarna. In case of micronutrients, foliar application of vegetable special @ 5g/at 15 day recorded significantly highest value of plant height (93.72 and 96.77cm), no. of branches (12.66 and 13.39), stem girth (4.75 and 5.12 cm), no. of leaves (105.52 and 108.68), internode length (14.75 and 15.04cm), no. of flowers per plant (41.34 and 41.95), fruit set (56.66 and 57.45%), no. fruits per plant (20.56 and 20.73), fruit length (11.85 and 12.07cm), fruit diameter (10.62 and 10.80cm), weight of placenta (18.31 and 18.46g), average fruit weight (189.03 and 191.33g), fruit weight per plant (4.12 and 4.17 kg) and fruit yield (78.64 & 79.60q/1000 m2). Hence, hybrid Indira and foliar application of vegetable special @ 5g/at 15 days may be recommended for higher productivity from capsicum crops under protected conditions.

Effect of Biofortification with Zinc and Iron on Growth Parameters, Yield Attributes and Yield of Barley (Hordeum vulgare L.)

A field experiment was conducted during Rabi season of 2021-2022 at Students' Instructional Farm (S.I.F.) of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh to evaluate the effect of biofortification with zinc and iron on growth parameters, yield attributes and yield of Barley. The present experiment having 16 treatment combinations replicated thrice in factorial randomized block design. Barley variety Prakhar (K 1055) (K508/NDB1081) was grown with recommended agronomic practices. On the basis of the results emanated from present investigation, it could be concluded that application of 100% RDF + soil application of Zn @ 25 kg ZnSO4 ha-1 + two foliar application of Fe (0.5%) significantly recorded maximum growth parameters such as plant height (102.00 cm) and number of effective tillers (302.00 m-2) and maximum yield attributing characters such as ear length (8.9 cm), number of grains spike-1 (50.75) and test weight (42.497 g). The result showed highest grain yield (59.55 q ha-1), straw yield (69.673 q ha-1), biological yield (129.22 q ha-1) and harvest index (46.08 %) with 100% RDF + soil application of Zn @ 25 kg ZnSO4 ha-1 + two foliar application of Fe (0.5%) in comparison to all the treatments during 2021-2022.

Zinc fertilizer application improves growth, yield and profit of paddy (Oryza sativa L.) in a zinc deficient Inceptisol

A field experiment was conducted at the Central Farm, Regional Research and Technology Transfer Station of Coastal Zone, OUAT Bhubaneswar in kharif 2021 to study the effect of zinc fertilizer application on growth, yield and income of rice in a zinc (Zn) deficient soil. The soil was sandy loam, acidic (pH 5.4), medium in organic carbon (0.61%) and available P (10.3 kg ha-1) while low in available N (155.4 kg ha-1) and K (82.1 kg ha-1). Eight treatment combinations comprising rate, source and method of Zn application were laid out in a randomized block design with 3 replications. The results revealed that soil application of Zn 5 kg ha-1 as basal followed by foliar spray of Zn @ 0.1% produced highest LAI (3.87), dry matter production (25.9 g hill-1), panicles m-2 (315.8), test weight (22.76 g), grain yield (4937 kg ha-1), and zinc content in grain (39.48 mg kg-1) and straw (55.87mg kg-1). However, application of Zn @ 5 kg ha-1 alone was at par with the soil application followed by foliar spray. Hence, it is concluded that soil application of Zn 5 kg ha-1 at the time of final land preparation along with the soil test based NPK is optimum for higher productivity and profitability of rice in zinc deficient Inceptisol.

Role of ZnCl2 in the Uptake and Translocation of Cd to Different Parts of Wheat Plant and Risk Assessments for Cow and Human

ABSTRACT In this study, we assessed the effect of zinc (Zn) when present in form of zinc chloride (ZnCl2) on translocation and accumulation of cadmium (Cd) in different parts of wheat plants (Triticum aestivum). Along with that, health risks to organisms of higher trophic levels (cows and humans) that consume these polluted wheat plants were also calculated. For the experiments, the soil was spiked with CdCl2 at rate of 3, 6, 12, 24, and 48 mg Cd kg−1 soil and ZnCl2 at a rate of 50, 100, 200, and 300 mg Zn kg−1 soil. In the combination treatment, all Cd concentrations used in single exposure were mixed in the soil that spiked with 200 mg kg−1 of Zn. According to the data, concentration of Zn and Cd in all parts of wheat plants increase with the increase of their concentration in the soil. However, soil application of Zn reduced Cd concentration in all parts of wheat plants (approximately two-fold in root and shoot, and more than 13-fold in the grains). The highest bioaccumulation of both metals was recorded in the roots and least in grains and leaves. The translocation factor also showed that roots store most of the metals and did not translocate them to the grains. The data showed that Zn application in the soil did not decrease ecological risk factor. However, daily intake metal (DIM) and health risk index (HRI) of cows showed that the Cd intake was higher than the permissible limit, but this quantity was not a health risk for cows. In humans, DIM values were higher than the permissible limit and caused severe health risk. However, a two-fold decrease in health risk of human due to Cd was recorded in the presence of Zn. This study revealed that ZnCl2 can be used to suppress the Cd uptake in wheat even at high pollution levels. It may decrease the risk of toxicity to higher tropic levels that consume different parts of wheat plants. In future further investigation about the role of ZnCl2 in the mitigation of other metals phytotoxicity is required to use it in agroecosystem.

Application of Zinc, Iron and Boron Enhances Productivity and Grain Biofortification of Mungbean

Deficiencies of essential vitamins, iron (Fe), and zinc (Zn) affect over one-half of the world’s population. A significant progress has been made to control micronutrient deficiencies through supplementation, but new approaches are needed, especially to reach the rural poor. Agronomic biofortification of pulses with Zn, Fe, and boron (B) offers a pragmatic solution to combat hidden hunger instead of food fortification and supplementation. Moreover, it also has positive effects on crop production as well. Therefore, we conducted three separate field experiments for two consecutive years to evaluate the impact of soil and foliar application of the aforementioned nutrients on the yield and seed biofortification of mungbean. Soil application of Zn at 0, 4.125, 8.25, Fe at 0, 2.5, 5.0 and B at 0, 0.55, 1.1 kg ha−1 was done in the first, second and third experiment, respectively. Foliar application in these experiments was done at 0.3% Zn, 0.2% Fe and 0.1% B respectively one week after flowering initiation. Data revealed that soil-applied Zn, Fe and B at 8.25, 5.0 and 1.1 kg ha−1, respectively, enhanced the grain yield of mungbean; however, this increase in yield was statistically similar to that recorded with Zn, Fe and B at 4.125, 2.5 and 0.55 kg ha−1, respectively. Foliar application of these nutrients at flower initiation significantly enhanced the Zn contents by 28% and 31%, Fe contents by 80% and 78%, while B contents by 98% and 116% over control during 2019 and 2020, respectively. It was concluded from the results that soil application of Zn, Fe, and B enhanced the yield performance of mungbean; while significant improvements in seed Zn, Fe, and B contents were recorded with foliar application of these nutrients.

Microsatellite markers-aided dissection of iron, zinc and cadmium accumulation potential in Triticum aestivum.

Wheat is a staple cereal food around the globe. It provides a significant source of proteins, carbohydrates, and other micronutrients to humans. When grown on cadmium (Cd) contaminated soils, the uptake of trace elements e.g., iron (Fe) and zinc (Zn) has also been affected drastically that in turn affected the wheat grain. In this study, wheat accessions were used to investigate the impact of soil application of Zn (5 mg/kg, 20 mg/kg) and Cd (0 mg/kg, 10 mg/kg) on accumulation of these elements in wheat grains. A total of 45 Fe, Zn, and Cd transporter-related genes were used to design 101 gene-specific SSR (simple sequence repeat) markers. In response to Cd stress, application of 20 mg/Kg Zn improved Fe (64.6 ug/g) and Zn (48.3 ug/g) accumulation in wheat grains as well as agronomic traits. Marker trait association revealed that SSR markers based on NAM-B1 gene (PR01 and PR02) were associated with Zn accumulation. Similarly, SSR markers based on TaVTL5-2B_5 (PR19 PR20), TaVTL5-2B_2 (PR25, PR26), TaVTL5-2D_3 (PR30), TaVTL2-2A (PR31), TaVTL1-6A (PR32), and TaVTL2-2D_1 (PR37) were significantly associated with Fe accumulation, while HMA3-5B1 (PR62) and TaNRAMP3-7D (PR89) were linked to Cd accumulation in grains. The highly associated markers may be used in marker-assisted selection of suitable wheat genotypes for breeding bio-fortified varieties with low Cd accumulation.

Dynamics of Zinc Fractions in Soil as Affected by Zinc Fertilization in a Maize-maize Cropping Sequence in Upper Brahmaputra Valley Zone of Assam, India

Zinc is considered as an important micronutrient for maize which is a promising emerging cash crop for the state of Assam, India. A field experiment was conducted at the experimental farm of Krishi Vigyan Kendra, Jorhat, Assam Agricultural University during 2018-19 and 2019-20 to study the dynamics of zinc fractions in soil in a maize-maize cropping sequence as affected by zinc fertilization. The experiment was laid down in a randomized block design (RBD) with twelve treatments combinations of basal and foliar application of zinc through zinc sulphate and zinc oxide nanoparticles (ZnO NPs). The results revealed that zinc fertilization significantlyinfluenced the studied zinc fractions in soil during both the years under investigation. The distribution of different zinc fractions in soils at harvest was found in the following order: water soluble plus exchangeable-Zn < complexed-Zn < crystalline sesquioxide bound-Zn < amorphous sesquioxide bound-Zn < residual-Zn. Among the zinc treatment combinations, soil application of Zn @ 3.75 kg ha-1 in combination with foliar application of 500 ppm ZnO NPs exhibited the highest concentration of water soluble plus exchangeable-Zn content (1.10 ppm) in soil. The highest concentration of complexed-Zn (2.95 ppm), amorphous sesquioxide-bound-Zn (4.11 mg kg-1), crystalline sesquioxide-bound-Zn (3.76 ppm), residual-Zn (125.65 ppm) and total-Zn (137.33 ppm) were recorded in the treatment receiving soil application of Zn @ 7.5 kg ha-1. Among the zinc fractions studied, the concentration and percent contribution of water soluble plus exchangeable-Zn to total-Zn was the lowest while residual-Zn fraction contributed the highest to the total soil zinc pool. Furthermore, path coefficient analysis revealed that the water soluble plus exchangeable-Zn had the highest contribution towards the plant available DTPA extractable-Zn in soil. Moreover, all the fractions of zinc were found to be significantly and positively correlated with each other indicating existence of dynamic equilibrium of zinc in soil.

Nutritional enrichment of tomato (Lycopersicon esculentum L.) through Zinc (Zn) and Boron (B) Fertilization

The influence of micronutrients namely zinc (Zn) and boron (B) with or without farmyard manure (FYM) on growth, yield and quality parameters viz. ascorbic acid and carotene content of tomato was evaluated. A field experiment was conducted with graded doses of Zn (soil and soil + foliar application) and B (soil application) application with or without FYM for the two consecutive years (2012 and 2013). Results revealed that application of Zn and B significantly enhanced fruit yield and different growth parameters as well as plant tissue concentration of Zn and B in tomato. The highest increase in fruit yield over control (27.6%) was observed with the conjoint application of Zn (soil + foliar), B (2.0 kg ha−1) and FYM. Soil application of Zn at higher doses (10 kg ha−1) as well as its application through both soil + foliar method has an edge over control or its application at comparatively lower doses in increasing the fruit yield of tomato. Results further revealed that combined application of Zn and B can significantly increase the important quality parameters viz. carotene and ascorbic acid content in tomato. Such increase in carotene content to the tune of 25 and 35% and ascorbic acid content to the tune of 7 and 30% over control were observed with soil + foliar application of Zn and 2 kg ha−1 B, respectively. Therefore, optimization of Zn and B doses can improve the yield and quality of tomato as well as helps in correcting the micronutrients malnutrition vis-à-vis nutritional disorders in humans by enriching the antioxidants.

Iron and Zinc Bio-fortification through Agronomic Intervention in Chickpea (Cicer arietinum L.)

Essential micronutrients are required for humans to sustain proper physiological body processes and a healthy health condition. Micronutrient deficiencies, such as iron, zinc, and iodine, create global health concerns for people. Zinc and iron deficiency are frequent in chickpea growing regions across the world. Bio-fortification of pulse grains, especially with Fe and Zn by agronomic bio-fortification, is the simplest, most practical, and quickest method. During the Rabi season of 2019–20, a field experiment was done at the Bairiya Dhab Research Farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, India, to find out effect on chickpea genotypes when Zn and Fe were added to the soil and the leaves. Two genotypes (GCP-105 and GNG-2264) and seven fertilization treatments (control, 0.5% Zn, 0.5% Fe, soil application of Zn and Fe, 25 and 15 kg/ha, respectively) were used in a split plot design with three replications. The GNG-2264 variety had a significantly higher plant height, yield and yield characteristics, such as number of pods per plant, test weight, seed and straw yield and economics viz. gross return, net return (62860 and 37986 ₹/ha), and B: C ratio (2.52) than GCP-105. Among the fertilization treatments, RDF + Zn (0.5%) and Fe (0.5%) foliar spraying at the pre-flowering and pod development stage recorded significantly higher growth and yield parameters viz., plant height (59.89 cm), number of pods/plant (22.31), seed yield (1283 kg/ha) and straw yields 2433 kg/ha), and quality parameters such as zinc and iron content in seed (31.84 and 17.40 ppm) and straw (72.26, 21.79 ppm, respectively) and economics in term of gross return, net return, and B: C ratio.