Chelates in agriculture

Clemens, D.F.; Whitehurst, Brooks M.; Whitehurst, Garnett B.

doi:10.1007/bf01095092

Cited by 24 publications

(10 citation statements)

References 3 publications

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“…). This has already been hypothesized by Clemens et al . This treatment also showed a decrease in the concentrations of Fe, Mn, Zn, and Cu in soybean tissues (Tables and 4).…”

Section: Discussionsupporting

confidence: 84%

“…These results are consistent with those reported by López‐Rayo et al ., where G7 presented a better complexing capacity than G6 for Mn in solution. Clemens et al . also hypothesized that G7 has a higher complexing capacity than G6 due to previous studies that demonstrated its effectiveness in correcting Fe chlorosis in calcareous soils.…”

Section: Discussionmentioning

confidence: 99%

“…also confirmed that the percentage of Fe remaining in solution for G6 in the pH range 5–7.5 was around 20%. In contrast, Clemens et al . suggested that the G7 would be a better complexing agent for Fe 3+ than EDTA and G6 in alkaline soils.…”

Section: Introductionmentioning

confidence: 91%

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Effect of Fe:ligand ratios on hydroponic conditions and calcareous soil in Solanum lycopersicum L. and Glycine max L. fertilized with heptagluconate and gluconate

et al. 2019

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BACKGROUND: The environmental risk from the application of synthetic chelates has led to the use of biodegradable complexes to correct Fe deficiency in plants. In this article, the Fe oxidation state, the Fe:ligand ratio, and the molecular weight distribution for heptagluconate (G7) and gluconate (G6) are considered as key factors for the efficacy of complexes as fertilizers. Complexes with different Fe:ligand ratios were prepared and analyzed by gel filtration chromatography (GFC). The ability of Fe:ligand ratios to provide Fe to tomato in hydroponics and soybean in calcareous soil was tested and compared with synthetic chelates (Fe 3+ :HBED and Fe 3+ :EDTA). RESULTS: G7 presented greater capacity to complex both Fe(II) and Fe(III) than G6, but the Fe(II) complexes exhibited poor stability at pH 9 and oxidation in solution.Gel filtration chromatography demonstrated the polynuclear nature of the Fe 3+ :G7 at various ratios. The effectiveness of the Fe fertilizers depend on the Fe 3+ :ligand ratio and the ligand type, the Fe 3+ :G7 (1:1 and 1:2) being the most effective. Fe 3+ :G7 (1:1) also presented a better response for the uptake of other micronutrients. CONCLUSION: Fe 3+ :G7 molar ratios have been shown to be critical for plant Fe uptake under hydroponic conditions and with calcareous soil. Thus, the Fe 3+ :G7 at equimolar ratio and 1:2 molar ratio can be an environmentally friendly alternative to less degradable synthetic chelates to correct Fe chlorosis in strategy I plants.

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“…). This has already been hypothesized by Clemens et al . This treatment also showed a decrease in the concentrations of Fe, Mn, Zn, and Cu in soybean tissues (Tables and 4).…”

Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Fe:ligand ratios on hydroponic conditions and calcareous soil in Solanum lycopersicum L. and Glycine max L. fertilized with heptagluconate and gluconate

et al. 2019

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“…Thus, the use of an appropriate Fe-specific chelate can result in increases in solution concentration. While glucoheptonate has been suggested to be an Fe chelate (Clemens et al, 1990), these results indicate that glucoheptonate has no apparent chelation ability in these soils. The stability constants of Fe glucoheptonate and Fe-EDTA are 1.1 and 15.3 (log K), respectively (Martell and Smith, 1974).…”

Section: Ironmentioning

confidence: 55%

Solubility of Iron, Manganese, and Magnesium Sulfates and Glucoheptonates in Two Alkaline Soils

Shaddox

Unruh

Kruse

et al. 2016

Soil Science Soc of Amer J

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Sulfate and glucoheptonate forms of Fe, Mn, and Mg are commonly applied to horticultural and agricultural crops. Once these metals enter the soil solution, their solubility may be limited. Glucoheptonate may prolong soil solubility, but its influence in alkaline soils has not been documented. The objective of this study was to determine the solubility of Fe, Mn, and Mg sulfates and glucoheptonates in two alkaline soils. A Tavares sand (a hyperthermic, uncoated Typic Quartzipsamment) and a Fuquay loamy sand (a loamy, kaolinitic, thermic Arenic Plinthic Kandiudult) were incubated with soluble Fe, Mn, or Mg applied as either the sulfate or the glucoheptonate. At 1 h, 4 h, 1 d, and 1, 2, and 3 wk, soils were extracted with 0.01 mol L −1 CaCl 2 and analyzed for Fe, Mn, or Mg. At 1 h, approximately 98 and 93% of applied Fe was insoluble in the Tavares sand and Fuquay loamy sand, respectively. The greatest differences between soils occurred with Mn solubility, with 54 and 20% rendered insoluble in Tavares sand and Fuquay loamy sand, respectively, at 1 h. Soluble Mg declined at 1 h by 10%, with no further reductions throughout the 3-wk incubation. Soil applications of Fe as sulfate or glucoheptonate should be avoided. Applications of Mn sulfate or glucoheptonate may lead to increased soil solubility immediately following the application but may rapidly decline. Magnesium, however, remains soluble for as much as 3 wks. Glucoheptonate did not increase the solubility of Fe, Mn, or Mg compared with sulfate in either soil. Abbreviations: EDDHA, ethylenediaminedi-o-hydroxyphenlyacetic acid; EDTA, ethylenediaminetetraacetic acid. I ron, Mn, and Mg are common components of both granular and foliar agricultural nutrient programs. In granular form, these elements are commonly applied as soluble salts (sulfates) blended with other components such as N, P, or K. In sulfate form, Fe and Mn may rapidly convert to insoluble compounds, which reduces plant uptake, leading to deficiency symptoms, particularly in high-pH soils (Petrie and Jackson, 1984; Snyder et al., 1979). Thus, metals are often applied in chelated forms that are designed to maintain solubility, especially in high-pH soils (Sommers and Lindsay, 1979). Glucoheptonate (Fig. 1) (National Center for Biotechnology Information, 2016) is a chelate relatively new to agricultural use. Glucoheptonate is typically recommended as a foliar spray. However, some applicators use glucoheptonate as a soil application or soil drench despite any evidence confirming the ability of glucoheptonate to sustain metal solubility in alkaline soils. The solubility of Fe, Mn, and Mg in soils is strongly influenced by soil pH and moisture. As transitional heavy metals, Fe and Mn respond similarly to soil pH and moisture, with both exhibiting reduced solubility as pH increases and moisture decreases (

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“…Chelates are very soluble in water, but only slightly dissociate. The gradual release of micronutrients increases their absorption by plants and prevents their excessive uptake [ 5 , 6 , 7 ]. Regulation (EC) No 2019/1009 of the European Parliament and of the Council of 5 June 2019 on fertilizers legalized fertilising chelators of synthetic origin and complexing substances of natural origin (lignosulfonic acid salts).…”

Section: Introductionmentioning

confidence: 99%

Chemical Stability of the Fertilizer Chelates Fe-EDDHA and Fe-EDDHSA over Time

et al. 2021

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In application conditions, the influence of environmental parameters on used fertilizer chelates and their distribution over time is important. For this purpose, the changes in the content of micronutrient ions and Fe-EDDHA and Fe-EDDHSA chelates in an aqueous medium at different pH values were studied. In the assumed time, changes in the ions content were analyzed using the voltammetry method at pH 3, 5 and 7. The content of isomers and chelate forms was analyzed by ion pair chromatography at pH 3, 5 and 7. These studies allowed us to determine the effect of pH on the stability of iron chelates over time.

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Chelates in agriculture

Cited by 24 publications

References 3 publications

Effect of Fe:ligand ratios on hydroponic conditions and calcareous soil in Solanum lycopersicum L. and Glycine max L. fertilized with heptagluconate and gluconate

Effect of Fe:ligand ratios on hydroponic conditions and calcareous soil in Solanum lycopersicum L. and Glycine max L. fertilized with heptagluconate and gluconate

Solubility of Iron, Manganese, and Magnesium Sulfates and Glucoheptonates in Two Alkaline Soils

Chemical Stability of the Fertilizer Chelates Fe-EDDHA and Fe-EDDHSA over Time

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