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 Burns, G. R. Articles by Hill, W. L. Search for Related Content PubMed Articles by Burns, G. R. Articles by Hill, W. L. Agricola Articles by Burns, G. R. Articles by Hill, W. L.

Estimation of Particle-Size Effects of Water-Soluble Phosphate Fertilizer in Various Soils¹

ABSTRACT

A laboratory method was developed for estimating the relative availabilities to plants of the P applied to soil in fertilizer particles differing in size. The method is based on the concept that the total availability of fertilizer P applied in particles of a given size is equal to the product of (a) the number of particles of that size, and (b) the summation of the availabilities of fertilizer P in the hypothetical small volumes of soil that may be considered to comprise the total volume of soil affected by a single particle. The method was applied experimentally to NaH₂PO₄·H₂O particles of three sizes in each of six soils. In this application, appropriate quantities of a concentrated solution of P³²-tagged NaH₂PO₄ were used to stimulate the effects of fertilizer particles of different sizes, and particles of anion-exchange resin were used to provide indexes of availability of fertilizer P in segments of the soil affected by one fertilizer particle. These values were integrated to obtain an index of total availability of fertilizer P. The indexes of total availability obtained from the laboratory data were in qualitative agreement with the relative availabilities of fertilizer P to plants in five of the six soils tested.

¹ Joint contribution of the Department of Agronomy, Iowa State University, and the Soil and Water Conservation Research Division, ARS, USDA, Beltsville, Md. Journal Paper No. J-4449 of the Iowa Agr. and Home Econ. Exp. Sta., Ames, Project No. 1183.

² Former Graduate Assistant, Iowa State University, now Research Soil Scientist, Soil and Water Conservation Research Division, ARS, USDA, Beltsville, Md.; former Graduate Assistant, now Associate Professor, Department of Agronomy, Cornell University, Ithaca, N.Y.; Professor of Soils, Iowa State University; and Director, Fertilizer Laboratory, Soil and Water Conservation Research Division, ARS, USDA, Beltsville, Md., respectively.

Received for publication September 27, 1962. Accepted for publication January 7, 1963.