Premium
Applicability of the morgan test for determining available soil phosphate
Author(s) -
Yuen S. H.,
Pollard A. G.
Publication year - 1951
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740020503
Subject(s) - phosphate , phosphorus , acre , extraction (chemistry) , potassium , chemistry , soil water , soil test , environmental chemistry , reagent , magnesium , ammonium , zoology , environmental science , agronomy , soil science , chromatography , biology , biochemistry , organic chemistry
Abstract An examination of the Morgan ‘quick’ test showed that the amount of phosphate extracted from soils increased with the widening of the ratio, soil/extractant, and with the period of extraction; the maximum extraction was obtained in most soils by shaking the soil with the extractant for I hr. Of the likely phosphorus‐bearing constituents of soil Morgan's reagent dissolves mainly calcium (and probably magnesium) phosphates; organic forms of phosphorus dissolve only to a small extent. In the soil examined, Morgan's test failed to distinguish the effect of 17 successive annual applications of superphosphate at the rate of 100 lb. per acre. However, it did detect, decisively, corresponding applications at the rates of 200 and 400 lb. per acre. The Morgan test further demonstrated the depression of phosphate availability by repeated application of ammonium sulphate, the opposite effect of liming, the very substantial increase in availability after the application of dung, the absence of any effect of treatments with potassium sulphate and an apparent seasonal variation in phosphate status in the soil examined.