Diethylenetriaminepentaacetic Acid-extractable Zn Research Articles

Correction and standardization of critical limit of zinc for maize (Zea mays L.) crop: Bangladesh perspective

Critical limit (CL) determination of zinc (Zn) is very important for predicting response of maize crop to its application in soils and for the crop’s actual fertilizer requirement. This study was conducted at Bangladesh Agricultural Research Institute, Gazipur, to determine the CL of Zn for maize grown in 20 soils collected from the five Agro–Ecological Zones during January to March, and April to June of 2017. The available Zn content of soils and maize biomass were estimated utilizing the extraction method with 0.005 M diethylene triamine pentaacetic acid (DTPA). During January to March and April to June 2017, the amount of DTPA extractable Zn in different soils ranged from 0.60–3.25 mg kg−1 and 0.50–1.68 mg kg−1, respectively. During both periods of crop growth (January to March and April to June, 2017), the soil available zinc was negatively significantly correlated with soil pH, available P, exchangeable Ca, exchangeable Mg and positively significantly correlated with relative dry matter (DM) yield. Soil Zn also positively significantly correlated with maize tissue Zn content (r = 0.521*). However, the CL of Zn were estimated to be 0.84 mg kg−1 in soils and 26.1 mg kg−1 in maize tissue for maize cropping as determined by Cate and Nelson’s (1965) graphical procedure. Maize crop may respond to Zn application in soils containing Zn at/below the above level. This data may be used for predicting plant response to Zn fertilizer and development of crop Zn nutrition guide for maximum production.

Can Edaphic Variables Improve DTPA‐Based Zinc Diagnosis in Corn?

Core Ideas DTPA‐extractable Zn is often used to predict corn response to Zn application. Can DTPA–Zn‐based diagnosis be improved by considering other soil properties? Soil properties did not contribute to explain corn grain yield response. DTPA–Zn allowed to discriminate sites based on their response to Zn fertilization. We determined a Zn‐critical range from 0.86 to 1.30 mg kg−1 (n = 64). Current zinc (Zn) diagnostic methods for corn (Zea mays L.) are often based on soil DTPA (diethylenetriamine‐pentaacetic acid) extractable Zn (DTPA‐Zn). However, calibration of the DTPA‐Zn test may be influenced by other soil properties such as pH, organic matter (SOM) and available Bray‐P (PBray‐1). Our objective was to assess the contribution of soil properties to a DTPA‐Zn model used to predict corn response to Zn fertilization. We conducted 64 field trials with two Zn‐fertilization treatments: with and without Zn fertilization. In all sites, we measured SOM, PBray‐1, pH, and DTPA‐Zn at 0‐ to 20‐cm depth before sowing. Yield difference between Zn‐fertilized and unfertilized treatments (Ydifference) was significant in 33% of the experimental site‐years. In responsive site‐years, the average Ydifference was 0.98 Mg ha‐1 (11.4%). Soil organic matter was the only property that was a significant addition to the DTPA‐Zn model for predicting the corn relative yield (Model R2 including SOM = 0.27). However, the improvement was nominal (Partial R2 of SOM = 0.06). Use of DTPA‐Zn alone was suitable to discriminate Zn responsiveness among site‐years based on the Ydifference by correctly diagnosing 81% of the outcomes. We determined three soil DPTA‐Zn ranges with different probability of resulting in a Ydifference greater than zero when fertilized with Zn: high (<0.9 mg kg‐1), medium (0.9–1.3 mg kg‐1), and low (>1.3 mg kg‐1). These soil‐test‐based Zn recommendations improve the identification of Zn‐deficient soils allowing prevention of yield loss from Zn deficiency and more rational use of Zn fertilizers.

Micronutrients distribution in salt-affected soils of the Punjab in relation to soil properties

Salt-affected soils in arid and semi-arid tracts of the Indian Punjab are prone to deficiency of micronutrients. Nine profiles from alluvial terraces, sand dunes and palaeochannels in the southwestern Punjab were investigated for total and diethylenetriamine-penta-acetic acid (DTPA) extractable Zn, Cu, Mn and Fe. Soil physiography exerted significant influence on the spatial distribution of micronutrients. Total contents varied from 20–78 for Zn, 8–32 for Cu, and 88–466 mg kg−1 for Mn and 0.82–2.53% for Fe. DTPA-extractable contents varied from 0.10–0.98 for Zn, 0.14–1.02 for Cu, 0.54–13.02 for Fe and 0.82–9.4 mg kg−1 for Mn. Total contents were higher in fine-textured soil than in coarse-textured soils. Concentration of micronutrients in the surface layer was low and there occurred more accumulation in the Cambic horizon. Organic carbon, pH, clay, silt and calcium carbonate exerted strong influence on the distribution of micronutrients. DTPA extractable Zn, Cu, Mn and Fe increased with increasing organic carbon but decreased with increase in pH and calcium carbonate content. Total micronutrient contents increased with increase in clay, silt and calcium carbonate contents and decreased with increase in sand content.

The Accumulation of Zinc and Nickel in Irankoh Indigenous Plant Species on a Contaminated Land

The accumulation of heavy metals by plants determines both the micronutrient content and the toxic metal content of our food. A field survey of higher terrestrial plants growing on a metalliferous site of the Iranian arid mountain in Isfahan was conducted to identify species accumulating exceptionally large concentrations of Zn and Ni in shoots and roots. Plant samples were collected from Irankoh areas near the Bama Pb and Zn mine. Sampling was carried out in Spring 2004 and analyzed for DTPA (Diethylene triamine pentaacetic acid) extractable Zn and Ni by atomic absorption spectrophotometry. Mean total and available Zn in the studied soils were 259.7 μgg−1 and 5.067 μgg−1, respectively. Soil total and available Ni were relatively low (58.9 μgg−1 and 0.143 μgg−1 respectively). Zinc concentrations were considerably high in shoots of Stachys inflate, Ebenus stellata, and Astragalus glaucanthus (556.88, 508.8, and 449.53 μgg−1, respectively). Nickel concentrations were markedly high in shoots of Teucrium polium, Alyssum bracteatum, and Ebenus stellata (13.21, 10.98, and 8.84 μgg−1, respectively). Zinc translocation factor (TF or shoot/root concentration ratio) was higher than Ni TF in most plant species. Zinc and Ni enrichment factors and shoot/root concentration ratios were also significantly high in Stachys inflate, Ebenus stellata, Astragalus glaucanthus Teucrium polium, Stipa barbata, Bromus tectorum, and Alyssum bracteatum. Results suggest that these plants could be good candidates for use in the revegetation and phytoremediation of Zn and Ni contaminated lands in arid regions.

Distribution of Forms of Zinc and Their Association with Soil Properties and Uptake in Different Soil Orders in Semi‐arid Soils of Punjab, India

Profiles of semi‐arid–zone soils in Punjab, northwest India, were investigated for different forms of zinc (Zn), including total, diethylenetriamine penta‐acetic acid (DTPA)-extractable, soil solution plus exchangeable (Zn), Zn adsorbed onto inorganic sites, Zn bound by organic sites, and Zn adsorbed onto oxide surfaces. Irrespective of the different fractions of Zn present, its content was higher in fine‐textured Alfisols and Inceptisols than in coarse‐textured Entisols. In general, the higher content of Zn was observed in the surface horizon and then decreased in the subsurface horizons. However, none of the forms of Zn exhibited any consistent pattern of distribution. Organic matter and size fractions (clay and silt) had a strong influence on the distribution of different forms of Zn. Based upon the linear coefficient of correlation, the soil solution plus exchangeable Zn, adsorbed onto inorganic sites, and DTPA‐Zn increased with increase in organic carbon but decreased with increase in pH and calcium carbonate content. Total Zn increased with increase in clay and silt content. Among the different forms, Zn bound by organic sites, water soluble plus exchangeable Zn and Zn adsorb onto oxide (amorphous surfaces) were all correlated with DTPA extractable Zn. The uptake of Zn was more in recent floodplain Entisols than very fine textured Alfisols and Inceptisols. Among the different forms soil solution +exchangeable and DTPA‐extractable Zn was positively correlated with total uptake of Zn.

EFFICIENCY OF MULTINUTRIENT EXTRACTANTS FOR THE DETERMINING OF AVAILABLE ZINC IN SOILS

The increasing use of the ICP-AES (inductively coupled plasma atomic emission spectrophotometry) as a multielement analytical technique has stressed the preference for the use of multinutrient extractants in routine soil analysis. However, few studies relating the extraction of zinc (Zn) from soil with such extractants and the absorption of the element by plants have been published. Two experiments under greenhouse conditions were carried out in order to determine the efficiency of some multinutrient extractants for the determination of available Zn in 44 soils from the State of São Paulo, Brazil, for corn and soybean. All soil samples were limed to increase the CEC's base saturation at pH 7 to 70%. Twenty-two soil samples with DTPA (diethylenetriaminepentaacetic acid) extractable Zn concentration lower than 0.6 mg dm−3 received either the application of B, Cu, Mn, Zn or of these micronutrients excluding Zn. The remaining 22 soil samples, with Zn concentration above 0.6 mg dm−3, received application of three micronutrients (B, Cu and Mn). Macronutrients were applied to all pots as needed for crop development. Zinc was extracted from the soils before each planting using the extracting solutions, DTPA, Mehlich 1 (M-1), Mehlich 3 (M-3) and AB-DTPA (ammonium bicarbonate-DTPA) and determined by ICP-AES. The results showed significant correlations between plant Zn concentration and soil Zn concentration. The correlation values between soil-Zn and plant-Zn were of 0.74 (M-3), 0.73 (DTPA), 0.62 (AB-DTPA) and 0.61 (M-1) for corn, and of 0.71 (DTPA), 0.63 (M-1), 0.58 (M-3) and 0.46 (AB-DTPA) for soybean. Thus, the DTPA solution was the most efficient extractant for the determination of bioavailable Zn when both crops are considered together.

Mehlich 3 or modified olsen for soil testing in Malawi

Soil nutrient extraction methods, which are currently being used in Malawi, are time consuming and require too many resources. The use of a universal soil extractant would greatly reduce resource requirements. The objectives of the study were to (i) compare the universal soil extractants, Mehlich 3 (M3) and Modified Olsen (MO) with ammonium acetate (AA), Bray P1 (BPl), and diethylene triamine penta acetic acid (DTPA) in the amount of nutrients extracted, (ii) determine the relationship among the extractants for the nutrients they extract, and (iii) determine the critical soil‐test levels of phosphorus (P), potassium (K), and zinc (Zn) for a maize crop. Missing nutrient trials involving P, K, and Zn were conducted on thirty sites across Malawi using maize (Zea mays L.). Phosphorus application rates ranged from 40 to 207 kg P2O5 ha‐1. Potassium and Zn were applied at 75 kg K2O and 10 kg Zn ha‐1, respectively. Procedures of Cate and Nelson were used to identify soil nutrient critical levels. Results showed that the correlations between M3 and BP1, and MO and BPl were highly significant (r=0.93, 0.94, respectively). Mehlich 3 extractable K and AA extractable K (r=0.90), MO and AA extractable K (r=0.94) were highly significant (P<0.01) and the correlations between M3 and AA and MO and AA extractable calcium (Ca) (r=0.92, 0.90, and 0.94, respectively) were also highly significant (P<0.01). The correlations between M3, MO, and AA extractable magnesium (Mg) (r=0.99) were highly significant (P<0.01). Zinc, copper (Cu), and manganese (Mn) extracted with M3 and DTPA were significantly correlated (r=0.89, 0.87, and 0.95, respectively). Correlations between MO and DTPA extractable Zn, Cu, and Mn were also highly correlated (r=0.89,0.85, and 0.95, respectively). Maize grain yields ranged from 730 to 9,400 kg ha‐1. Mehlich 3‐P and MO‐P critical levels were 31.5 and 28.0 μg g‐1, respectively. Mehlich 3 and MO gave a similar critical level of 0.2 cmol kg‐1 for K while Zn critical levels were 2.5, and 0.8 μg g‐1 for M3 and MO, respectively. Mehlich 3 and MO were equally effective in separating responsive to none responsive soils for maize in Malawi.

EXTRACTABILITY OF ZINC, CADMIUM, AND NICKEL IN SOILS AMENDED WITH EDTA

Synthetic chelating agents are produced in large quantities for use in many industrial applications. Certain chelates, such as ethylenediaminetetraacetic acid (EDTA), are persistent in the environment. The presence of EDTA in soil may alter the mobility and transport of Zn, Cd, and Ni in soils because of the formation of water soluble chelates, thus increasing the potential for metal pollution of natural waters. Mobility of metals is related to their extractability. To investigate metal extractability affected by EDTA, Zn, Cd, and Ni were added to a portion of eight Georgia topsoil samples at rates of 75.9, 1.62, and 4.30 mg kg{sup -1}, respectively. Both natural and metal-amended soils were treated with Na{sub 2-}EDTA at rates of 0, 1.0, and 2.0 g kg{sup -1}. After 5 months of incubation, soil samples were extracted with Mehlich-1, DTPA (diethylenetriamine-pentaacetic acid) and 1 M Mg(NO{sub 3}){sub 2}, the latter of which extracts the exchangeable form of metals. Results showed that Zn and Ni in Mehlich-1 and DTPA extractions increased with increasing rates of EDTA. The increase for Cd was not as great as for Zn or Ni. Similar changes were found for the Mg(NO{sub 3}){sub 2} extraction. As a percentage of total metal concentration,more » the Mehlich-1 and DTPA extractable Zn was greater than Ni in the natural soils, and the order for the metal-amended soils was Cd > Zn > Ni. The results also suggested that EDTA significantly elevated the extractability of Zn and Ni in both natural and metal-amended soils. The order of mobility based on extractability was: Cd > Zn > Ni for metals added to soils, but when EDTA was present, added Ni was more extractable than Zn or Cd. 36 refs., 5 tabs.« less

Bioavailability of Zinc, Cadmium, and Lead in a Metal‐Contaminated Alluvial Soil

AbstractMetal mining activities can cause a variety of soil contamination problems including the deposition of sediments having high concentrations of heavy metals on alluvial soils. This study was conducted to investigate the effects of various soil amendments or combinations of amendments on Zn, Cd, and Pb bioavailability in a metal‐contaminated alluvial soil as indicated by a chemical fractionation procedure and soybean [Glycine max (L.) Merr.] growth and heavy metal composition. Total soil concentrations were 1165 mg/kg for Zn, 11 mg/kg for Cd, and 110 mg/kg for Pb, and evidence suggested that Zn phytoxicity was limiting soybean growth. In one greenhouse experiment, the addition of limestone, N‐Viro soil, and K2HPO4 significantly increased soybean yields; and the addition of limestone, limestone suspension, cattle manure, poultry litter, N‐Viro, and K2HPO4 significantly decreased soybean tissue Zn concentrations as compared to the control. The limestone, limestone suspension, cattle manure, N‐Viro, and K2HPO4 amendments also significantly reduced KNO3‐extractable Zn as compared to the control. In a second greenhouse experiment, the combination of limestone at 1.12 or 2.24 Mg/ha and 10 Mg/ha of cattle manure produced significantly higher soybean yields as compared to either amendment alone for the first cutting. For the same cutting, a significant limestone by manure rate interaction was found for concentrations of Zn, Cd, and Pb in soybean tissue and for Zn, Cd, and Pb uptake. Generally, the effects of increasing limestone rate were diminished as the manure rate increased. Root dry weights significantly increased and root tissue Zn concentrations significantly decreased with both rates of limestone application compared to 0 Mg limestone/ha for samples taken at the completion of experiment two. Root tissue Cd or Pb concentrations were not significantly influenced by limestone or manure rates. Significant increases in NaOH‐extractable Zn and Pb were found with increasing limestone rates whereas NaOH‐extractable Cd significantly decreased. Correlations between soybean tissue Zn concentrations and various Zn fractions and diethylenetriaminepentaacetic acid (DTPA)‐extractable Zn indicated significant relationships for KNO3‐Zn (r = 0.92), NaOH−Zn (r = 0.62), KNO3 + H2O−Zn (r = 0.82), KNO3 + NaOH−Zn (r = 0.88), KNO3 + H2O + NaOH−Zn (r = 0.54), and DTPA extractable Zn (r = 0.70).

Zn buffering capacity and Zn accumulation in Swiss chard for some sludge-amended soils

Zinc sorption by soils can greatly affect its availability to plants. This study was conducted to determine the relationship between the Zn sorption capacity and plant Zn accumulation in five sludge-amended soils using Swiss chard (Beta vulgaris L.) as an indicator plant. Zinc sorption as a function of Zn concentration and pH was determined for the soils which received no sludge amendment; also DTPA (diethylenetriaminepentaacetic acid) extractable Zn was determined in all soils. Whereas the responses of DTPA-Zn and plant Zn to pH and the quantities of Zn sorbed were similar, the logarithm of DTPA-Zn accounted for only 82% of the variability in the logarithm of Zn accumulation by the plants. The variability was better explained when pH was included with DTPA-Zn in stepwise multiple regressions. The Zn buffering capacity, defined as the ratio of the change in quantity of Zn sorbed (Δ Zns) to the change in Zn solution concentration (ΔZn1) (or ΔZns/ΔZn1), and the estimated quantity of Zn sorbed were used as a basis to measure Zn intensity. Zinc intensity, which reflects Zn solution concentration, was the predominant factor controlling Zn accumulation by Swiss chard, judging from the good fit of the values of both parameters to the Michaelis-Menten equation. The maximum Zn accumulation was approximately 9 mmol kg−1.