Assessment of iron availability in soilless potting media

Handreck, Kevin A.

doi:10.1080/00103628909368152

Cited by 28 publications

(15 citation statements)

References 17 publications

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“…Similar leaching characteristics of chelates have also been demonstrated in a study by Broschat and Donselman (1985). Regarding the lower Fe concentrations recovered in the current study compared with the previous study , it has been determined that substrates consisting of bark or sawdust immobilize more iron than peatbased substrates (Handreck, 1989). Because the substrate in the current study consisted of pine bark and wood chips, and the substrates of the greenhouse study consisted mostly of peat, it is possible that the greater amounts of Fe were immobilized in the current study than the previous study.…”

Section: Resultsmentioning

confidence: 61%

Effects of Prohexadione-Ca and GA4+7 on Scarf Skin and Fruit Maturity in Apple

McArtney¹,

Ferree²,

Schmid³

et al. 2006

HortSci

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Nutrient release characteristics of four different controlled-release fertilizers (Osmocote, Nutricote, Polyon, and Multicote) were monitored during an 11-month period in a simulated outdoor nursery production facility. Although no plants were used in the experiment, fertilization rates, irrigation regimes, and cultural practices simulated those typically used to produce fast-growing, high-nutrient-requiring containerized woody ornamentals. Fertilizer prill release characteristics were monitored through analyses of leachates, which were collected weekly. Concentrations of Mg, Mn, Zn, Cu, and Mo were relatively high during the first 5 to 10 weeks of the experiment, then declined and usually stabilized during the remainder of the study. However, Mn and Zn displayed erratic increases in concentrations several times throughout the study. Calcium concentrations did not increase until the fifth week, rapidly peaked to about 300 mgÁL -1 , and then decreased and leveled off to %80 to 100 mgÁL -1 during the remainder of the study. Several significant differences were observed between treatments. The Osmocote treatment had significantly greater Ca and Mg concentrations in the leachate than the other fertilizer types during the last 6 weeks of the study, whereas the Nutricote treatment often had significantly greater Fe concentrations than leachates from other treatments, especially during the last 26 to 35 weeks of the study, and significantly greater Zn concentrations than the other CRFs during the last 21 weeks of the study. Based upon U.S. Environmental Protection Agency guidelines, concentrations of Fe were often more than the allowable limit of 0.3 mgÁL -1 with all fertilizer types, but especially with Nutricote. Concentrations of Mn and Cu also exceeded federal guidelines, particularly during the first several weeks of the study.

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Section: Resultsmentioning

confidence: 61%

Effects of Prohexadione-Ca and GA4+7 on Scarf Skin and Fruit Maturity in Apple

McArtney¹,

Ferree²,

Schmid³

et al. 2006

HortSci

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“…Leachate Fe concentrations increased over time in the disorder induction and Fe source and pH experiments, and were higher with correspondingly higher Fe-DTPA treatments and the use of chelated vs. unchelated Fe sources. Availability of metals for plant uptake from solid phase sources of peats has been estimated by extraction methods adapted from those used in mineral soils (Markus et al, 1981) and peats vary widely in metal content, particularly Fe (Handreck, 1989;Mitchell, 1954;Walsh and Barry, 1958). Chelates extract Fe from peat and extractable Fe concentration varies widely with peat source (Broschat and Donselman, 1985;Handreck, 1989).…”

Section: Discussionmentioning

confidence: 99%

“…Availability of metals for plant uptake from solid phase sources of peats has been estimated by extraction methods adapted from those used in mineral soils (Markus et al, 1981) and peats vary widely in metal content, particularly Fe (Handreck, 1989;Mitchell, 1954;Walsh and Barry, 1958). Chelates extract Fe from peat and extractable Fe concentration varies widely with peat source (Broschat and Donselman, 1985;Handreck, 1989). DTPA is a more reliable indicator of medium micronutrient status than EDTA (Berghage et al, 1987).…”

Section: Discussionmentioning

confidence: 99%

Iron Toxicity Stress Causes Bronze Speckle, a Specific Physiological Disorder of Marigold (Tagetes erecta L.)

Albano¹,

Miller²,

Halbrooks³

1996

jashs

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A specific physiological disorder, bronze speckle (J.P.A.'s nomenclature), was consistently induced in `First Lady' and `Voyager' marigold with Fe-DTPA concentrations greater than 0.018 mm Fe-DTPA (1 ppm) applied to a soilless medium. The disorder was characterized by specific symptomology distinguished visually by speckled patterns of chlorosis and necrosis, and downward curling and cupping of leaves. The percentage of total leaf dry weight affected with symptoms generally increased with increasing Fe-DTPA treatments. Symptomatic leaf tissue had a greater Fe concentration than corresponding asymptomatic leaf tissue. Leaf Mn concentrations in symptomatic and asymptomatic tissue were similar. In `First Lady', older leaf tissue accumulated more total Fe and was associated with more severe symptoms than younger tissue. Media leachate Fe concentrations increased over 6 weeks and were larger at greater Fe-DTPA treatments. Adjustment of nutrient solution pH to 4.0, 5.25, or 6.5 did not alter media pH, nor did it prevent disorder symptoms. Application of Fe-DTPA containing nutrient solution to a soilless medium resulted in leachate Fe levels 3 times greater than for FeSO4 treatments. Chemical names used: ferric diethylenetriaminepentaacetic acid, monosodium salt (Fe-DTPA).

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“…Manganese extracted by this reagent shows little response to changes in pH over the range 4.5 to 6.0 (Table 3), and overestimates Mn availability when Mn oxides are present in the medium (5). However, 2 mM DTPA and CaCk/DTPA have been shown to be excellent for assessing the plant availability of most other nutrients (1,2,7,8,9,11,12), and even of Mn in low-Mn soilless media (10). DTPA has clear advantages over other extractants for estimating plant-available Fe (7), P (2,12), and Cu and Zn (11) in soilless media.…”

Section: Discussionmentioning

confidence: 95%