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 Sparks, D. L. Articles by Liebhardt, W. C. Search for Related Content PubMed Articles by Sparks, D. L. Articles by Liebhardt, W. C. Agricola Articles by Sparks, D. L. Articles by Liebhardt, W. C.

Effect of Long-term Lime and Potassium Applications on Quantity-Intensity (Q/I) Relationships in Sandy Soil¹

ABSTRACT

The effects of long-term lime and K applications on quantity-intensity (Q/I) relationships were investigated on the Ap and B21t horizons of a Kalmia soil (a fine-loamy over sandy or sandy-skeletal, siliceous thermic (Typic Hapludults) from the Delaware Coastal Plain. The predominant mineral suite of the <2µm clay fraction was mica, vermiculite, and chloritized vermiculite. Soil pH and exchangeable bases increased with depth and with lime additions. The equilibrium potassium activity ratio (AR^k_e) decreased with profile depth due to greater K fixation by specific sites for K in the B21t horizon. The AR^k_e decreased in the Ap horizon and increased in the B21t horizon with lime additions. The magnitude of AR^k_e [> 0.01 (moles/liter)] suggests that K adsorption in the Ap horizon occurred on planar positions while adsorption at specific sites was predominant in the B21t horizon [> 0.006 (moles/liter)]. The parameter K^o, which measures labile K, became more negative with increased lime and K additions, indicating a greater K release into soil solution. While the quantity of K extracted by NH₄OAc compared favorably to K^o in the Ap horizon, it exceeded K^o in the B21t horizon, suggesting K exchange involving specific sites in the B21t horizon. The number of specific sites (K_x) increased with K fertilization and with soil depth. The decreased K_x with increased lime additions could be ascribed to increased neutralization of hydroxyaluminum interlayer material, resulting in an increase in interlayer "islands." The potential buffer capacity (PBC^k) parameter increased with lime additions due to increased pH-dependent cation exchange capacity (CEC).

¹ Contribution from the Dep. of Plant Science, Univ. of Delaware, Newark, DE 19711. Published with the approval of the Director of the Delaware Agric. Exp. Stn. as Misc. Paper no. 907. Contribution no. 114 of the Dep. of Plant Science.

² Assistant Professor and Associate Professor, respectively.

Received for publication July 28, 1980. Accepted for publication March 10, 1981.