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Reaction Products of Polyphosphates and Orthophosphates with Soils and Influence on Uptake of Phosphorus by Plants
Author(s) -
Subbarao Y. V.,
Ellis Roscoe
Publication year - 1975
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/sssaj1975.03615995003900060022x
Subject(s) - polyphosphate , calcareous , chemistry , diammonium phosphate , phosphorus , ammonium , ammonium polyphosphate , phosphate , alkali soil , calcareous soils , soil water , ammonium phosphate , fertilizer , phosphorite , environmental chemistry , agronomy , nitrogen , solubility , dry weight , nutrient , botany , raw material , geology , soil science , organic chemistry , biology
Ammonium polyphosphate and diammonium phosphate were compared as sources of P for corn ( Zea mays L.) in a growth chamber experiment with an alkaline‐calcareous soil and a slightly‐acid soil. Reaction products of the two P sources in soils and soil extracts correlated with results obtained in the growth chamber. Applied P increased dry weights, uptake of P by the plants, and available soil P in the slightly acid soil. Both sources of P effectively supplied P for plant growth on this soil. Ammonium and magnesium orthophosphates, formed as reaction products in the laboratory experiments when the two P fertilizer materials were added, should furnish sufficient P for plant growth. Neither source of P increased dry weights, uptake of P by plants, or available soil P in the alkaline‐calcareous soil as much as with the slightly‐acid soil. Dry weights of plants and uptake of P were significantly less with polyphosphate than with orthophosphate, both at 36 ppm applied P. Polyphosphate also failed to increase the available soil P. A reaction product, Ca(NH 4 ) 2 P 2 O 7 ·H 2 O, that is highly stable in alkaline‐calcareous soil was formed when ammonium polyphosphate was added. Its stability and low solubility explain the limited availability of P. The compounds, Mg 2 KH(PO 4 ) 2 ·15H 2 O and Ca 4 H(PO 4 ) 3 ·2.5 H 2 O, formed when diammonium phosphate was added. They provided more P for plants at the highest rate of application, but uptake of P was limited for both sources of P in this soil.