Available Concentrations Of Zn Research Articles

Synergistic improvement of soil organic carbon storage and wheat grain zinc bioavailability by straw return in combination with Zn application on the Loess Plateau of China

Organic amendment can increase soil zinc (Zn) availability and its uptake in cereals. Conversely, Zn transformation in soil may modify soil organic carbon (SOC) dynamics. To date, the effects of the simultaneous addition of organic material and Zn fertilizer on soil SOC storage and crop Zn enrichment have received little attention. Here, with a view to clarifying this problem, a 2-year wheat-based field study was conducted on the Loess Plateau in China with the following treatments: control, SR alone (SR7.5, 7.5 Mg·ha−1), ZF alone (ZF15, 15 kg Zn·ha−1), and SR plus ZF (ZF15SR7.5). The results indicate that loss of SOC after 2 years was 0.6 Mg·ha−1 in the control soil, and an input of 2.2 Mg C·ha−1·y−1 was needed to maintain the pre-experimental SOC stock. However, the increase in SOC storage after 2 years was 1.0 Mg·ha−1 in soil with SR7.5 and 2.6 Mg·ha−1 in soil with ZF15SR7.5, which accounted for 9.3% and 24% of residue-C input, respectively. On the other hand, the concentration of available Zn in soil with ZF15 was 3-fold higher than that in the control soil, but lower than that in soil with ZF15SR7.5 in both years. The Zn uptake by wheat and the grain Zn concentration also increased as the soil Zn availability increased, especially in the second year. Most importantly, in soil with ZF15SR7.5, the wheat grain Zn concentration reached 38 mg·kg−1 after 2 years, and the estimated dietary-absorbed Zn was 3.65 mg·d−1, which met the recommended Zn intake of 3 mg·d−1 for adults. Therefore, combining SR and ZF shows a promising synergistic effect for the enhancement of both SOC storage and wheat grain Zn bioavailability on China’s Loess Plateau and other drylands.

Pre-monsoon spatial distribution of available micronutrients and sulphur in surface soils and their management zones in Indian Indo-Gangetic Plain.

The efficient (site-specific) management of soil nutrients is possible by understanding the spatial variability in distribution of phyto-available nutrients (here after called available nutrients) and identifying the soil management zones (MZs) of agricultural landscapes. There is need for delineating soil MZs of agricultural landscapes of the world for efficient management of soil nutrients in order to obtain sustainability in crop yield. The present study was, therefore, undertaken to understand the spatial distribution pattern of available micronutrients (zinc (Zn), boron (B), iron (Fe), manganese (Mn) and copper (Cu)), available sulphur (S), and soil properties (soil acidity (pH), electrical conductivity (EC) and organic carbon (SOC) content) in soils of intensively cultivated Indo-Gangetic Plain (IGP) of India and to delineate soil MZs for efficient management of soil nutrients. Totally, 55101 soil samples from 0–15 cm depth were obtained from 167 districts of IGP during 2014 to 2017 and were analysed for different soil parameters. Soil pH, EC and SOC content varied from 4.44 to 9.80, 0.02 to 2.13 dS m-1 and 0.10 to 1.99%, respectively. The concentration of available Zn, B, Fe, Mn, Cu and S varied from 0.01 to 3.27, 0.01 to 3.51, 0.19 to 55.7, 0.05 to 49.0, 0.01 to 5.29 and 1.01 to 108 mg kg-1, respectively. Geostatistical analysis resulted in varied distribution pattern of studied soil parameters with moderate to strong spatial dependence. The extent (% area) of nutrient deficiencies in IGP followed the order: S > Zn > B > Mn > Cu > Fe. Principal component analysis and fuzzy c-means clustering produced six distinctly different soil MZs of IGP for implementation of zone-specific soil nutrient management strategies for attaining sustainability in crop yield. The developed MZ maps could also be utilized for prioritization and rationalization of nutrients supply in IGP of India.

Spatio-Temporal Variability and the Factors Influencing Soil-Available Heavy Metal Micronutrients in Different Agricultural Sub-Catchments

Information on the spatial variability of soil-available micronutrients is important for farming and soil management practices. As current knowledge of factors influencing soil available micro-nutrients in the long-term scales is limited, we analyzed 821 and 812 representative surface (0–20 cm) soil samples from five sub-catchments in the Ping Gu intermontane basin in Beijing, China in 2007 and 2017. The objectives of this study were to assess the temporal and spatial distribution characteristics of soil-available micronutrients (Cu, Zn, Fe and Mn) and their relationships with soil’s chemical properties. The concentration of available Cu ranged from 1–2 mg∙kg−1 distributing over a large area in 2007, but it was more than 2 mg∙kg−1 in the hilly regions in 2017. The concentration of available Zn (>5 mg∙kg−1) increased significantly from 2007 to 2017, and showed an uneven distribution. The distribution of available Fe and Mn decreased from the northeast to the southwest region of the study area between 2007 and 2017, this being consistent with the topography in this area. Soil’s available P (AP) had a higher contribution to available Cu and Zn in different sub-catchments. In addition, soil pH had a significant negative influence on available Fe in sub-catchments 1, 2 and 3, and on available Mn in all sub-catchments, except for sub-catchment 4. Moreover, the effects of soil chemical properties on soil-available micronutrients increased in each sub-catchment from 2007 to 2017. We conclude that differences in soil properties and land-use types were the main reasons for the spatial variability of soil-available micronutrients in the Ping Gu intermontane basin.

Temporal Variation and Ecological Risk Assessment of Metals in Soil Nearby a Pb⁻Zn Mine in Southern China.

Metal contamination in soil from tailings induces risks for the ecosystem and for humans. In this study, the concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil contaminated by a tailing from Yangshuo (YS) lead and zinc (Pb–Zn) mine, which collapsed for more than 40 years, were determined in 2015. The mean concentrations of Zn, Pb, Cu, and Cd were 1301.79, 768.41, 82.60, and 4.82 mg/kg, respectively, which, with years of remediation activities, decreased by 66.9%, 61.7%, 65.4%, and 65.3% since 1986, but still exceed the national standards. From 1986 to 2015, soil pH increased significantly, with available concentrations of Zn, Pb, Cu and Cd decreasing by 13%, 81%, 77%, and 67%, respectively, and potential ecological risk indexes (Er) of the determined metals decreasing by more than 60%. Horizontally, total contents and percentages of available concentrations of Zn, Pb, Cu, and Cd decreased with the distance from the tailing heap in SD village, while pH values showed the reverse pattern. Vertically, Zn and Cd, Pb, and Cu showed similar vertical distribution patterns in the soil profiles. There was a slight downward migration for the determined metals in soil of M and H area and the mobility was in the order of Cd > Zn > Pb > Cu. It can be concluded that although concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil decreased significantly, SD village is still a high risk area, and the priority pollutant is Cd.

The Effects of Cow Manure and Vermicompost on Availability and Desorption Characteristics of Zinc in a Loamy Calcareous Soil

ABSTRACTThe application of organic fertilizers in soils not only increases soil organic matter but also introduces essential nutrients to soil. Therefore, applying these fertilizers can affect the availability and desorption characteristics of nutrients. The main objective of this research is to study the effects of cow manure (CM) and vermicompost (VC) on availability and desorption characteristics of zinc (Zn) in a loamy calcareous soil. In this study, concentration of available Zn (using DTPA-TEA, AB-DTPA, and Mehlich 3) and desorption characteristics of Zn (using successive extraction with DTPA-TEA For 1–504 h at 25 ± 1°C) in amended soil with 0, 0.5, and 1% (w/w) of CM and VC were investigated in a completely randomized design. Results of this research showed that concentration of Zn extracted by using three methods was higher in amended soils with 1% CM and VC than those with 0.5% of these fertilizers. Furthermore, the difference between concentration of available Zn in amended soils with CM and VC was not found to be significant (p > 0.05). The results of kinetics study illustrated that the effect of organic fertilizers on Zn desorbed after 504 h was found to be significant (p < 0.01). Amount of cumulative of Zn desorbed in amended soils was significantly (p < 0.05) higher than unamended soil. Concentration of Zn desorbed after 504 h in 0.5 and 1% of CM and VC compared with unamended soil increased 26, 54, 12, and 46%, respectively. In addition, Zn desorption rate in amended soils with CM was higher than those with VC. It can be concluded that organic fertilizers applied to loamy calcareous soils enhance source of available Zn for the plant. Moreover, the results of this study showed that the ability of amended soils with VC to supplying Zn for plants was lower than those with CM.

Inhibition of the bioavailability of heavy metals in sewage sludge biochar by adding two stabilizers.

Agricultural application of sewage sludge (SS) after carbonization is a plausible way for disposal. Despite its benefits of improving soil fertility and C sequestration, heavy metals contained in sewage sludge biochars (SSB) are still a concern. In this study, two types of heavy metal stabilizers were chosen: fulvic acid (FA) and phosphogypsum (with CaSO4, CS, as the main component). The two stabilizers were incorporated into SS prior to 350°C carbonization for 1 h at the rates of 1%, 2%, or 4%. The obtained SSBs were then analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Total and available concentrations of four heavy metals, i.e., Zn, Pb, Cd, and Ni, in the SSBs were determined. In addition, a series of pot soil culture experiments was conducted to investigate the effects of stabilizers incorporation into SSB on heavy metal bioavailability and the uptake by plants (corn as an indicator) and plant biomass yield, with SS and SSB (no stabilizers) as controls. The results showed that incorporation of both FA and CS increased functional groups such as carboxyl, phenol, hydroxyl, amine and quinine groups in the SSBs. The percentage of heavy metals in sulfuric and oxidizable state and residual state of SSBs were significantly increased after carbonization, and hence the mobility of the heavy metals in SSBs was decreased. The introduction of the stabilizers (i.e., FA or CS) significantly lowered the total and available concentrations of Zn, Pb, Cd, and Ni. The reduction in available heavy metal concentration increased with incorporation rate of the stabilizers from 1% to 4%. In the treatments with FA or CS incorporated SSB, less heavy metals were taken up by plants and more plant biomass yields were obtained. The mitigating effects were more pronounced at higher rates of FA or CS stabilizer. These findings provide a way to lower bioavailability of heavy metals in SS or SSB for land application or horticulture as a peat substitute.

Assessing the ecotoxicological effects of long-term contaminated mine soils on plants and earthworms: relevance of soil (total and available) and body concentrations.

The interactions and relevance of the soil (total and available) concentrations, accumulation, and acute toxicity of several essential and non-essential trace elements were investigated to determine their importance in environmental soil assessment. Three plant species (T. aestivum, R. sativum, and V. sativa) and E. fetida were simultaneously exposed for 21 days to long-term contaminated soils collected from the surroundings of an abandoned pyrite mine. The soils presented different levels of As and metals, mainly Zn and Cu, and were tested at different soil concentrations [12.5, 25, 50, and 100% of contaminated soil/soil (w/w)] to increase the range of total and available soil concentrations necessary for the study. The total concentrations in the soils (of both As and metals) were better predictors of earthworm uptake than were the available concentrations. In plants, the accumulation of metals was related to the available concentrations of Zn and Cu, which could indicate that plants and earthworms accumulate elements from different pools of soil contaminants. Moreover, Zn and Cu, which are essential elements, showed controlled uptake at low concentrations. The external metal concentrations predicted earthworm mortality, whereas in plants, the effects on growth were correlated to the As and metal contents in the plants. In general, the bioaccumulation factors were lower at higher exposure levels, which implies the existence of auto-regulation in the uptake of both essential and non-essential elements by plants and earthworms.

Copper and zinc concentration in soil and plants used for feed on different locations in Serbia

In 2013 an investigation was conducted on 15 different localities on the territory of Serbia (12 on territory of Vojvodina province and 3 in west Serbia - Kolubara count) in order to overview content of copper and zinc in soil and plants. The total and available content of Cu and Zn were determined and compared to the limits concentration in order to determine the level of the supply with these elements in soil and their effect on the plants quality. In the examination of the plant material only plants used for feed (alfalfa, pasture and grassland) were considered. In the aboveground plant mass the content of Cu and Zn was determined and put in correlation with soil content of analyzed elements. Soil samples showed that content of the available Cu was high in all locations, while the content of Cu in plant material was insufficient on three locations. The concentration of available Zn in soil was sufficient on almost all locations, but the analysis showed that the plants was insufficiently provided with Zn on the most locations, thus certain agricultural methods need to be applied in order to increase its content in plants.

Residual effects of organic Zn fertilizers applied before the previous crop on Zn availability and Zn uptake by flax (Linum usitatissium)

AbstractThe objective of this study was to compare the residual effect of zinc (Zn) from three Zn chelates (Zn‐aminelignosulfonate, Zn‐AML; Zn‐polyhydroxyphenylcarboxylate, Zn‐PHP; and Zn‐ethylenediaminedisuccinate, Zn‐EDDS), applied at two rates (5 and 10 mg Zn [kg soil]–1, respectively) to a previous crop, for a flax crop (Linum usitatissimum L.). For the greenhouse experiment, two different soils were used: a weakly acidic soil, classified as Typic Haploxeralf (Soilacid), and a calcareous soil, classified as Typic Calcixerept (Soilcalc). Plant availability of soil Zn was evaluated using the DTPA‐triethanolamine (TEA), Mehlich 3, and low‐molecular‐weight organic acids (LMWOAs) methods. Easily leachable Zn was determined, and soil Zn status was characterized based on the Zn distribution in different fractions obtained by a sequential extraction. The Zn reserves after the previous crop were substantial and ranged from 2.85% to 5.61% of available Zn (Mehlich 3‐extractable) with respect to the applied Zn. Plant parameters such as dry‐matter yield, total Zn, and soluble Zn concentrations were measured, and Zn utilization by plants was calculated. In both soils, the highest concentrations of available Zn were associated with the application of Zn‐AML at a rate of 10 mg Zn kg–1. In Soilacid the largest quantity of easily leachable Zn was also observed with Zn‐AML fertilizer. Similarly, Zn‐AML resulted in the highest Zn concentration in flax seeds (229 mg Zn kg–1 and 72 mg Zn kg–1 for the highest rate of Zn application to Soilacid and Soilcalc, respectively). The results suggest that these Zn chelates resulted in a residual effect in soils with appropriate concentrations of the most labile fractions of Zn and available Zn, particularly when Zn‐AML was applied at the highest rate. This chelate was more effective in Soilacid than in Soilcalc. In the weakly acidic soil at the lowest Zn level it was associated with the highest percentage of Zn utilization by the flax plant and the most effective Zn transfer from soil to the plant.

Influence of Soil Type on the Mobility and Bioavailability of Chelated Zinc

The objective of this study was to compare the distribution, mobility, and relative effectiveness of Zn from Zn-amino acids (Zn-AA) and Zn-DTPA-HEDTA-EDTA (Zn-CH) (DTPA, diethylenetriaminepentaacetate; HEDTA, N-2-hydroxyethyl-ethylenedinitrilotriacetate; and EDTA, ethylenedinitrilotetraacetate) sources by applying different Zn levels to weakly acidic and neutral soils in laboratory (incubation and soil column studies) and greenhouse conditions. The experiments were carried out for 60 days in incubation and column experiments and for 45 days in a greenhouse experiment. The zinc soil behavior was evaluated by DTPA-TEA and Mehlich-3 extractions and sequential speciation. The incubation experiment showed that the highest concentrations of available Zn in weakly acidic soil occurred with Zn-AA treatments, whereas in the neutral soil Zn-CH treatments produced the highest quantities of available Zn. The column experiment showed that in neutral soil, with slow to moderate permeability in the Ap and Bt horizons, only Zn-CH significantly increased the mobility of Zn through the column with respect to the control and the Zn-AA source: 31% of the Zn applied as synthetic chelate was leached from the column. The greenhouse experiment showed that, at different rates of Zn application, the Zn carriers increased Zn uptake by maize (Zea mays L.). The use of applied Zn by maize, or Zn utilization, was greatest when the Zn treatments were Zn-CH (3.3%) at 20 mg kg-1 and Zn-CH (4.9%) at 10 mg kg-1, in weakly acidic and neutral soils, respectively.

Use of a Zinc Fluorophore to Measure Labile Pools of Zinc in Body Fluids and Cell-Conditioned Media

Here we describe a rapid and sensitive zinquin-based fluorometric assay that enables one to monitor levels of labile Zn(II) in body fluids, buffers, and cell-conditioned culture media as well as changes in these pools in disease. Labile pools of Zn(II) are free or loosely bound pools and more tightly bound but zinquin-accessible pools in contrast to the fixed pools of Zn(II) within metalloproteins. In human plasma, mean labile Zn(II) was 8.1 microM (SEM 0.53; n = 81) and constituted about 70% of the total plasma Zn(II) and >90% of human plasma albumin Zn(II). Plasma labile Zn(II) was significantly depleted after 7 days of Zn(II) deprivation in mice, despite only small changes in body weight. Labile Zn(II) concentrations were also measured in the induced sputum plugs, saliva, and urine of normal adults and were 1.30 microM (SEM 0.27; n = 73), 0.11 microM (SEM 0.11; n = 6), and 0.23 microM (SEM 0.08; n = 8), respectively. Urinary labile Zn(II) concentration was significantly increased in some patients with type II diabetes mellitus (overall mean was 0.90 microM, SEM 0.30; n = 12). The technique may be particularly useful in assessing extracellular Zn(II) levels in diseases associated with altered Zn(II) homeostasis, identifying those subjects most in need of Zn(II) supplementation, and defining the optimum concentrations of available Zn(II) in buffers and culture media.