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Comparison of Partially Acidulated Rock Phosphate and Concentrated Superphosphate as Sources of Phosphorus for Corn 1
Author(s) -
Lutz J. A.
Publication year - 1971
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1971.00021962006300060030x
Subject(s) - phosphorite , phosphorus , phosphate , chemistry , agronomy , sowing , phosphate fertilizer , human fertilization , zoology , fertilizer , zea mays , field corn , biology , biochemistry , organic chemistry
The data available measuring the relative efficiencies of acidulated rock phosphate at various levels of applied P are limited, and further investigation of this subject is warranted. Florida rock phosphate was acidulated with H 3 PO 4 at 20 and 100% of that required to convert rock phosphate to concentrated superphosphate. These two materials plus a check (0 P) were applied as treatments for corn ( Zea mays L.) during three consecutive years on an acid soil in field experiments. Rates of total P from each source were 0, 10, 20, 30, and 100 kg/ha, which was broadcast and disked in each year just prior to planting. There was an excellent response to P fertilization. Corn yields were similar from both sources of P at some rates of applied P, while at other rates, P from concentrated superphosphate appeared to be the superior source. Phosphorus content of the ear leaves was not affected by P source in 1968, but differences were evident in 1969 and 1970. Leaf K content in 1970 was significantly increased by the highest rate of applied P from both P sources. There was an increase in available soil P only at the highest rates of applied P. At low rates of applied P, CSP was the most economical source of P. At the highest rate of P application, the 20% acidulated rock phosphate appeared to be more economical