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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Allen, E. R. Articles by Henninger, D. L. Search for Related Content PubMed Articles by Allen, E. R. Articles by Henninger, D. L. Agricola Articles by Allen, E. R. Articles by Henninger, D. L.

Release Rates of Phosphorus, Ammonium, and Potassium in Clinoptilolite-Phosphate Rock Systems

P.O. Box 83, Mason City, IL 62664

L. R. Hossner

Dep. of Soil and Crop Sciences, Texas A&M Univ., College Station, TX 77840

D. W. Ming and D. L. Henninger

NASA Johnson Space Center, Houston, TX 77058

*Corresponding author (erallen{at}aol.com).

ABSTRACT

Controlled release of P, NH₄, and K can be accomplished in synthetic soils through dissolution and cation-exchange reactions by phosphate rock (PR) and the zeolite mineral, clinoptilolite (Cp). The power-function equation has previously been found to adequately describe transport kinetics of the nutrient release process. Research was conducted to evaluate factors affecting P, NH₄, and K release rates in Cp-PR systems. Data was collected using a continuous-flow thin-disk technique. Results were evaluated with the power-function equation. Materials included a Texas Cp and North Carolina and Tennessee PRs. Variables examined included the Cp/PR ratio, the mole fraction of NH₄ and K on the Cp, and the type of PR. The power-function model indicated that initial release rates and cumulative nutrient release in Cp-PR mixtures were increased by using a higher Cp-PR ratio and by using a more reactive PR. Nutrient release rates were also affected by changes in the proportion of NH₄ and K occupying Cp exchange sites and reflected ion-selectivity characteristics of Cp. The results indicate that Cp and PR may be used to obtain a controlled release of NH₄, P, and K in a synthetic soil.

Received for publication April 17, 1995.

This article has been cited by other articles:

				M. C. Smith, D. R. Shaw, J. H. Massey, M. Boyette, and W. Kingery Incubation Time Effects on Imazaquin Desorption as Determined by Nonequilibrium Thin-Soil Disc Flow J. Environ. Qual., March 1, 2004; 33(2): 581 - 593. [Abstract] [Full Text] [PDF]