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Evaluating Plant‐available Phosphorus with the Electro‐Ultrafiltration Technique
Author(s) -
Simard R. R.,
Tran T. Sen
Publication year - 1993
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/sssaj1993.03615995005700020020x
Subject(s) - avena , chemistry , fertilizer , soil water , phosphorus , extraction (chemistry) , ultrafiltration (renal) , calcareous , agronomy , environmental chemistry , zoology , environmental science , chromatography , soil science , botany , organic chemistry , biology
The electro‐ultrafiltration (EUF) technique successfully evaluated the short‐term and long‐term supplying power for many essential plant nutrients of European and Asian soils but has not been evaluated for P in North America. The objective of this study was to compare the capacity of EUF with other extraction techniques to predict the plant availability of soil P and P fertilizer responsiveness of oat ( Avena sativa L.) and corn ( Zea mays L.) grown in the greenhouse. Increasingly higher average concentrations of soil P were extracted by EUF at 50 V and 20 °C (1.53 mg kg ‐1 ), water 2.28 mg kg ‐1 ), EUF at 200 V and 20 °C (4.76 mg kg ‐1 ), 0.5 M NaHCO 3 (13.0 mg kg ‐1 ), HCO ‐ 3 resin (41 mg kg ‐1 ), EUF at 400 V and 80 °C (44.2 mg kg ‐1 ), and Sr citrate (51 mg kg ‐1 ). The P desorbed by EUF at 20 °C was smaller than the 0.5 M NaHCO 3 P in acidic soils while comparable amounts were desorbed by the two methods from neutral to calcareous soils. The total amount of P desorbed by EUF between 30 and 55 min at 400 V and 80 °C was equivalent to chemical methods but less precise than HCO ‐ 3 resin in predicting the amount of P uptake by oat and corn as well as the fertilizer responsiveness of oat grown to Zadoks 71 stage. The prediction of P availability by the different EUF fractions could not be improved by the inclusion of selected additional physical and chemical characteristics of the soils studied. The desorption of soil P by EUF provides an evaluation comparable to chemical methods of the P‐supplying power of northeastern North American soils. The large amount of time involved in the EUF extraction limits its applicability as a soil‐testing procedure.