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 Cox, F. R. Articles by McCollum, R. E. Search for Related Content PubMed Articles by Cox, F. R. Articles by McCollum, R. E. Agricola Articles by Cox, F. R. Articles by McCollum, R. E.

A Descriptive Model of Soil Test Nutrient Levels Following Fertilization¹

ABSTRACT

For efficient utilization of fertilizer, a practical means of expressing the residual effect of certain plant nutrients is needed. A descriptive model was developed to show the change in extractable nutrient levels with time assuming a rapid increase after fertilization followed by a slower exponential decrease. The information needed or parameters for the model include (i) the equilibrium soil test level, (ii) the magnitude of the initial sorption reaction, and (iii) a loss constant. These were determined for seven long-term fertilizer studies with phosphorus (P). There was a large difference in P-sorption capacity of the soils; all parameters reflected this difference. The initial sorption reaction was linearly related to rate of fertilization in some soils and quadratically in others. The model was applied to conditions in which fertilizer was applied at various time intervals. Good agreement between observed and predicted values was obtained. The main value of this model is to be able to calculate the amount of fertilizer needed to establish and maintain a given soil test level.

¹ Contribution from the N. C. Agric. Res. Service, Raleigh, NC 27650. Paper no. 6215.

² Professors and Associate Professor, respectively, Dep. of Soil Sci., N. C. State Univ., Raleigh, NC 27650.

Received for publication November 26, 1979. Accepted for publication August 8, 1980.

This article has been cited by other articles:

				X. Shuai and R. S. Yost State-Space Modeling to Simplify Soil Phosphorus Fractionation Soil Sci. Soc. Am. J., July 1, 2004; 68(4): 1437 - 1444. [Abstract] [Full Text] [PDF]

				T. V. Karpinets, D. J. Greenwood, and J. T. Ammons Predictive Mechanistic Model of Soil Phosphorus Dynamics with Readily Available Inputs Soil Sci. Soc. Am. J., March 1, 2004; 68(2): 644 - 653. [Abstract] [Full Text] [PDF]

				J. A. Stecker, J. R. Brown, and N. R. Kitchen Residual Phosphorus Distribution and Sorption in Starter Fertilizer Bands Applied in No-Till Culture Soil Sci. Soc. Am. J., July 1, 2001; 65(4): 1173 - 1183. [Abstract] [Full Text] [PDF]