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 Halstead, R. L. Search for Related Content PubMed Articles by Halstead, R. L. Agricola Articles by Halstead, R. L.

Chemical Availability of Native and Applied Phosphorus in Soils and their Textural Fractions¹

ABSTRACT

In a study of several Canadian soils, the Al-P fraction (Chang and Jackson, 4) was correlated with the percent yield [(yield without P x 100)/yield with P] of oats grown in the greenhouse and with estimates of available P (NaHCO₃-soluble). Although Fe-P was related to NaHCO₃-soluble P and Ca-P to acid-soluble P (Troug, 20), neither the Fe- or Ca-P fraction was related to yield. NH₄Cl-soluble P, however, was correlated with both percent yield and percent P uptake. The four P fractions (NH₄Cl-soluble, Al, Fe, and Ca) comprised a major part (62 to 92%) of the total inorganic P in the soils. Ca-P was the main form in all but the Podzols, in which Fe-P predominated.

Organic P, Al-P, Fe-P, and NaHCO₃-soluble P increased with decreasing particle size, whereas Ca-P, total inorganic P, and acid-soluble P (Truog) increased with decreasing particle size in the Podzols but not in the other soils. When the P in the total amount of a given particle-size fraction present in the soil (F value) was considered, it was found that the coarser fractions contributed a relatively large proportion of the P in some of the soils. In five out of seven comparisons a major part (>50%) of the total inorganic P, Ca-P, and Al-P was associated with the coarser silt and sand, whereas Fe-P and organic P were associated with the fine silt and clay. The significant relation of F values for Al-P of the clay to percent yield and percent P uptake provided further evidence of the importance of Al-P as a source of P for plants. Other relationships between yield parameters and F values for NH₄Cl-soluble P and Ca-P of the clay indicate that the clay may be a primary source of plant P.

In incubation studies with soils and textural fractions, a major part of the added P was recovered in the Al- and Fe-P forms. Al-P was the primary form of recovery except in the fine silt and clay fractions of the Podzol soils where Fe-P predominated.

¹ Contribution No. 211, Soil Research Institute, Canada Department of Agriculture, Ottawa. Ontario.

² Research Scientist.

Received for publication October 24, 1966. Accepted for publication February 2, 1967.