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Factors Affecting Release and Plant Availability of Sulfur‐Coated Micronutrients
Author(s) -
Ryan John,
Prasad J. Devi
Publication year - 1979
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1979.03615995004300050045x
Subject(s) - micronutrient , incubation , chemistry , sorghum , calcareous , zoology , moisture , sucrose , dry matter , nutrient , human fertilization , agronomy , horticulture , food science , botany , biology , biochemistry , organic chemistry
The agronomic effectiveness of S‐coated micronutrients and factors influencing their dissolution were studied in the green‐house and laboratory. Grain sorghum ( Sorghum vulgare L.) was grown for 7 weeks on a calcareous soil incubated individually with S‐coated and uncoated FeSO 4 ·7H 2 O, MnSO 4 ·H 2 O, and ZnSO 4 ·7H 2 O for 0, 1, 2, 3, 5, and 8 weeks. Dry matter yield was not significantly affected, but Fe and Mn uptake decreased with time of incubation prior to cropping. Values from S‐coated materials were initially higher than from uncoated materials but showed little differences after 8 weeks of incubation. Coated materials were incubated for up to 9 weeks at varying moisture contents (8–32%), temperature (8–35°C), Ca(OH) 2 (1–10%) and sucrose (0.5–2 g). DTPA‐extractable Fe, Mn, and Zn in treated soils decreased with incubation time and with increasing moisture, temperature and Ca(OH 2 ) levels while the effect of sucrose additions was variable. With continuous extraction of the granules in water and in soil by DTPA at 4‐day intervals for 71 days, most of Fe, Mn, and Zn was released during the 1st month. Oxidation of the S‐coatings enhanced native micronutrient availability. Unless improvement in coating materials is made, S‐coated micronutrients are unlikely to have a significant impact in micronutrient fertilization.