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Phosphorus Fixation and the Assimilation of Fixed Phosphates
Author(s) -
Moser Frank
Publication year - 1940
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/sssaj1940.036159950004000c0032x
Subject(s) - citation , assimilation (phonology) , fixation (population genetics) , south carolina , computer science , phosphorus , library science , political science , sociology , chemistry , demography , philosophy , linguistics , organic chemistry , population , public administration
A NNUAL applications of phosphate fertilizer to / i lateritic soils have not appreciably affected the available phosphorus content, but each soil tends to approach a constant level of available phosphorus. Fixation is evident as the phosphorus removal by the increased crop growth does not account for the difference between the fertilizer additions and the available supply in the soil. Recent (11) studies on several soil types used for cotton fertilizer experiments in South Carolina corroborate the fact that the available phosphorus content, determined by the Truog and rapid test methods, remains approximately at the same level where normal fertilizer applications have been used annually. Fixation of phosphorus by soil is the conversion of the soluble phosphate to a less soluble form. The process is influenced largely by the pH of the soil and by active cations predominating in the colloidal complex, while the mass-law equilibrium reaction is undoubtedly responsible for maintaining a constant level of available phosphorus. Numerous methods have been proposed for studying phosphorus fixation in soil. Chemical methods have been employed by such workers as Fraps (4), Ford (5), Heck (7), Scarseth and Tidmore (13), and Hibbard (8), while electrodialysis has been suggested by McGeorge (9), Harper (6), and Dean (3). Inasmuch as all of the methods are rather empirical and no method has been definitely accepted, this study was begun to obtain further information on electrodialysis as a means of determining the nature of the phosphorus complex of soils through the release of phosphorus and accompanying cations. Plant and fungi cultures were grown and analyzed for total phosphorus assimilated during their growth period to determine the available plant phosphorus supply of the soil.