HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Schwab, A. P. Search for Related Content PubMed Articles by Schwab, A. P. Agricola Articles by Schwab, A. P.

Manganese-Phosphate Solubility Relationships in an Acid Soil

Dep. Agronomy. Kansas State Univ., Manhattan, KS 66506

*Corresponding author.

ABSTRACT

The chemistry of Mn and P is often complicated by apparent undersaturation with respect to mineral phases. The role of Mn phosphates in controlling the solubility of Mn and PO₄ was studied in acid soils which had been fertilized annually for 40 yr with NH₄NO₃ and superphosphate. Soil pH ranged from 4.1 to 6.8 and available P varied greatly. Fresh, field-moist soil samples were equilibrated with 0.01 M CaCl₂ for 25 d and then analyzed for Mn and PO₄ activities. A method was developed to measure redox potential reliably with a Pt electrode to allow calculation of Mn³⁺ activities. In previous studies, activities of PO₄ in these soils were less than the solubilities of strengite (FePO₄) and variscite (AlPO₄), and Mn activities were less than Mn oxide solubilities. The measured activities of Mn³⁺ and PO^3-₄ were consistent with the presence of MnPO₄·1.5H₂O but were undersaturated with respect to Mn(II) phosphates.

Contribution no. 89-391-J from the Kansas Agric. Exp. Stn.

Received for publication April 3, 1989.