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Reaction of MnEDTA Applied Alone or with Ammonium Polyphosphate Fertilizer to Soils
Author(s) -
Mortvedt J. J.
Publication year - 1980
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/sssaj1980.03615995004400030038x
Subject(s) - soil water , chemistry , manganese , fertilizer , phosphorus , ammonium , alkali soil , soil ph , environmental chemistry , geology , soil science , organic chemistry
Manganese ethylenediamine tetraacetate (MnEDTA) applied alone to some low‐Mn, high‐Fe soils generally is not an effective Mn source for plants; apparent substitution of other soil cations for Mn in MnEDTA decreases plant availability of applied Mn. A laboratory study was conducted to estimate cation substitution for Mn in MnEDTA by determining changes with time in H 2 O‐soluble cations in treated soil. Four moist soils (pH 5.4 to 7.7) were treated with MnEDTA at rates of 0, 25, and 100 ppm Mn; soils were aerobically incubated up to 148 days. In addition, MnEDTA was applied to these soils with 10‐15‐0 (10‐34‐0 oxide basis) fluid polyphosphate fertilizer at rates of 1,500 ppm P and 100 ppm Mn. The application rate simulated that in soil around a fertilizer band of 10‐15‐0 containing 1% Mn at a rate of 50 kg of P/ha (100 lb of P 2 O 5 /acre). Water‐soluble Mn increased with MnEDTA rate in all soils just after application but decreased with time to the level of untreated soils. In soils treated with MnEDTA alone, H 2 O‐soluble Fe increased with time in acid soils, and H 2 O‐soluble Ca increased in limed or calcareous soils, suggesting substitution of these cations for Mn in the EDTA molecule. Levels of H 2 O‐soluble Mg, Zn, and Cu in all soils were not affected by application of MnEDTA. Application of MnEDTA with 10‐15‐0 reduced the apparent rate of cation substitution for Mn in MnEDTA by precipitation of competing cations in soil. Thus, Mn in MnEDTA should remain available to plants for a longer time with band application in fluid polyphosphate fertilizers than with mixed application alone or with other fertilizers to soil.