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Zinc sulfate (ZnSO4 · H2O) has traditionally been the “reliable” source of zinc (Zn) fertilizer, but other sources of Zn are also available. Some are derived from industrial by‐products, varying from flue dust reacted with sulfuric acid to organic compounds derived from the paper industry. The degree of Zn mobility in Zn sources derived from these various by‐products is related to the manufacturing process, the source of complexing or chelating agents (organic sources), and the original product used as the Zn source. Many claims are made regarding the relative efficiency of traditional inorganic Zn fertilizers and complexed Zn sources. The objective of this column study was to compare the mobility of several commercial Zn fertilizer materials (organic and inorganic) that are commonly used to correct Zn deficiencies in soils. The sources included three granular inorganic Zn sources, two granular organically complexed Zn sources, and liquid ZnEDTA. Soil columns were leached five times with deionize...

Zinc sulfate (ZnSO4) has traditionally been the “reliable” source of Zn fertilizer but other sources of Zn are also available. Some are derived from industrial by-products, varying from flue dust reacted with sulfuric acid to organic compounds derived from the paper industry. The degree of Zn availability in Zn sources derived from these various by-products is related to the manufacturing process, the source of complexing or chelating agents (organic sources), and the original product used as the Zn source. Many claims are made regarding the relative efficiency of traditional inorganic Zn fertilizers and complexed Zn sources. The objective of this greenhouse study was to determine the availability coefficients of several commercial Zn fertilizer materials (organic and inorganic) that are commonly used to correct Zn deficiencies in soils. We evaluated the dry matter production, total Zn uptake, and Zn concentration in corn (Zea mays L. cv. P3752) plants fertilized with six different commercial Zn fertilize...

Many industrial by-products containing Zn are being processed and sold as Zn fertilizers. Some baghouse dusts and flue dusts which contain ZnO may be used as fertilizers or may be partially acidulated with H2SO4 to form Zn oxysulfates (various mixtures of ZnO and ZnSO4). Spent H2SO4 by-products of several industries, especially the galvanizing industry, also may be processed into ZnSO4 fertilizers. The level of water-soluble Zn (as a percentage of total Zn) in these fertilizers is mainly related to the relative contents of ZnSO4 (water soluble) and ZnO (water insoluble). Other published results have shown that availability to plants of most nutrients in a granular fertilizer is related to their water solubility. Response of corn (Zea mays L.) to fine and granular Zn fertilizers varying in level of water-soluble Zn was determined on a limed Zn-deficient Crowley silt loam (Typic Albaqualf) in three greenhouse pot experiments. Dry matter production and Zn uptake by corn were similar with several finely ground (

Etude experimentale de l'absorption par du mais (Zea mays) et des bettes (Beta vulgaris) de Cd, Ni et Pb contenus dans des engrais au zinc prepares a partir de sous-produits industriels

A field experiment was conducted to determine uptake of Cd and other heavy metals by winter wheat (Triticum aestivum L.) from three diammonium phosphate (DAP) fertilizers containing 2, 74, and 153 ..mu..g Cd/g. A phosphorus-deficient Paden silt loam (Glossic Fragiudult, pH 4.7) was limed at two rates and treated with the DAP sources at a rate of 50 kg of P/ha (100 lb of P/sub 2/O/sub 5//acre). Grain yields were higher at pH 5.9 than at pH 5.1, were significantly increased by P applications, and results were similar using all DAP sources. Concentrations of Cd in both grain and straw were significantly increased only with application of high-Cd DAP to the low-lime soil. Cadmium concentrations in grain increased from 0.028 to 0.086 ..mu..g/g, and those in straw increased from 0.067 to 0.118 ..mu..g/g (dry weight basis) with application of low-Cd DAP and high-Cd DAP, respectively, and were lower on the high-lime soil. Concentrations of Cu, Mn, Ni, and Zn in both grain and straw were not significantly affected by DAP source. Results for a second year on the same plots limed to pH 5.8 and 7.0 and treated again with the same DAP sources were similar to those for themore » first year, except that heavy metal uptake was generally lower. Results suggest that Cd concentrations in wheat products are not significantly changed by the phosphate fertilization and crop production practices in general use in the United States at this time.« less

This study related Cd-Zn concentrations in plants to levels of Cd and Zn in soil recovered by several extractants soon after application of Cd and Zn sources to soil. Cadmium nitrate and ZnSO/sub 4/ or Zn(C/sub 2/H/sub 3/O/sub 2/)/sub 2/ were mixed with a Zn-deficient Crowley silt loam soil, cropped with corn (Zea mays L.), and then cropped with Swiss chard (Beta vulgaris). Applied Cd significantly increased the Cd/Zn ratio in both crops, especially in Swiss chard, which accumulates heavy metals. A previously published sequential-extraction procedure was used to fractionate Cd and Zn in soil after the corn harvest. Results of statistical analyses showed the highest correlation between Cd uptake by each crop and the carbonate and sulfide fractions of Cd in soil. Including other Cd fractions resulted in only slightly higher R/sup 2/ values. Zinc uptake by each crop was best related to the organic fraction of Zn in soil, and including the other Zn fractions did not affect the relationship. These results show that Cd and Zn uptake by corn or Swiss chard was not related to similar chemical fractions of these elements in soil, and that the Cd/Zn ratio in plant tops was significantly affected by bothmore » Cd and Zn applications to soil.« less

Two coarsely ground air-dried municipal sewage sludges and a garbage compost were mixed with Hartsells fsl (limed to pH 5.5) rates of 15, 75, or 300 g/3 kg of soil in two greenhouse pot experiments. Fine ZnSO₄ and Na₂Cr₂O₇ were each mixed with soil limed to pH 5.5 to 7.0 at rates up to 1,400 ppm of Zn and 320 ppm of Cr, equivalent to rates applied in the organic wastes. Three successive crops of corn (Zea mays L.) were planted 0, 7, and 18 months after waste application. Corn forage yields were increased only in Crops 1 and 3 by compost applications but were not affected by sludge applications. Concentrations of Zn in the corn forage increased with application rate and Zn content of the three waste products. In contrast, Cr concentrations in the corn were not affected by the 0.05% to 1.36% Cr in the wastes. Concentrations of both Zn and Cr in the corn forage were much higher from ZnSO₄ and Na₂Cr₂O₇ from each waste at similar Zn and Cr rates and soil pH. Levels of 0.5N HCl-extractable Zn and Cr in the soil after each harvest increased with application rate of Zn and Cr in each organic waste and inorganic salt, but were not proportional to plant concentrations. Trivalent Cr as Cr₂(SO₄)₃ was less toxic to corn than hexavalent Cr as Na₂Cr₂O₇ at a rate of 80 ppm of Cr, while both sources were very toxic at 320 ppm. Toxicity resulted from ZnSO₄ in pH 5.5 soil at 240 ppm Zn and at 960 ppm in soil above pH 6.5. Results of these experiments suggest that Zn and Cr contained in municipal wastes applied at high rates are not toxic to corn even after relatively long periods in the soil. Reduced plant uptake of these heavy metals in organic waste was not due entirely to their liming effect on the soil.

Dry matter production and uptake of Zn, N, and P by corn grown in greenhouse pots were higher with (NH₄)₂SO₄ than with anhydrous NH₃ or CO(NH₂)₂, whether ZnSO₄ was mixed, spotplaced, or not applied. These results are largely explained by the lower soil pH associated with application of (NH₄)₂SO₄ and hence, the increased availability of indigenous and applied Zn. Yields were lower when Zn was mixed, but higher when Zn was omitted or spot-placed 4 weeks prior, as compared to treatment just prior to planting. In general, Zn and N uptake varied directly with yield and inversely with P uptake, except where growth was extremely poor due to severe Zn deficiency.

Zinc oxide, ZnSO₄, and ZnS were tested as sources of Zn at rates of 1, 2, and 4 ppm Zn for two successive crops of corn (Zea mays) grown on Nolichucky sandy clay loam (pH 7.3). Each source was mixed throughout the soil as finely ground material, incorporated into granules of ammonium nitrate (AN) or ammonium polyphosphate (APP) by pressure granulation, and into granules of concentrated superphosphate (CSP) during the granulation stage of the manufacturing process. When mixed with the soil ZnO and ZnSO₄ were more effective than when incorporated with a macronutrient carrier. Both ZnO and ZnSO₄ were markedly superior to ZnS. Ammonium nitrate and APP were comparable carriers when ZnSO₄ was the source, but APP was superior to AN when ZnO was used. A higher concentration of Zn in the CSP granules resulted in poorer response to this carrier. Zinc oxide was pressure granulated with CSP, AN, APP, or Nolichucky soil to contain 0.5, 2.0, or 8.0% Zn. Soil granules and CSP were applied at 1, 2, and 4 ppm Zn while AN and APP were applied at 2 ppm only. Forage yields and Zn uptake varied inversely with concentration of Zn in all carriers.

Movement of Zn in Hartsells fine sandy loam (pH 5.2) from granules containing 2% Zn as ⁶⁵Zn labeled ZnSO₄ decreased in the order: ammonium nitrate (AN) > soil (no carrier) = concentrated superphosphate (CSP) > monoammonium phosphate (MAP) = triammonium pyrophosphate (TPP). In limed soil (pH 7.1) Zn movement was less from MAP than from all other carriers, and Zn movement from each carrier was less than that in acid soil. Zinc also moved further from MAP than TPP in other soil systems below pH 6.0, the same between pH 6.0 and 6.8, and less above this range. Most Zn movement from P carriers occurred during the first week, except in extremely acid soil. Carrier-Zn reactions affected the amount of Zn which moved out of the fertilizer granules, but soil-Zn reactions were also important in affecting Zn movement from the granule site. The recovery by various chemical extractants of Zn applied in granules of soil and in all macro-nutrient carriers to acid soils was similar. The amount of Zn recovered by 2N MgCl₂ from limed soil less than 0.5 cm from the granule varied with carrier after 1 week, but was similar for all carriers after 8 weeks. Uptake of Zn by corn (Zea mays L.) in a greenhouse pot experiment was greater from AN, but no clear relationship was evident with the P carriers.