HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Wang, J. J. Articles by Bell, P. F. Search for Related Content PubMed Articles by Wang, J. J. Articles by Bell, P. F. Agricola Articles by Wang, J. J. Articles by Bell, P. F. Related Collections Sorption/Exchange Nutrient Management Soil Chemistry

DIVISION S-8—NUTRIENT MANAGEMENT & SOIL & PLANT ANALYSIS

Potassium Buffering Characteristics of Three Soils Low in Exchangeable Potassium

Agronomy Dep., 313 Sturgis Hall, Louisiana State Univ. Agricultural Center, Baton Rouge, LA. 70803

^* Corresponding author (jjwang{at}agctr.lsu.edu).

Plant availability of soil K is controlled by dynamic interactions among its different pools. Misunderstanding of these dynamics leads to mismanagement of soil fertility. This study was conducted to evaluate buffering characteristics of low exchangeable-K soils that showed different sugarcane (Saccharum spp. L.) responses to K amendment. Three silt loams, Crowley (fine, smectitic, hyperthermic Typic Albaqualfs), Dundee (fine-silty, mixed, active, thermic Typic Endoaqualfs), and Norwood (fine-silty, mixed, superactive, hyperthermic Fluventic Eutrudepts), were evaluated by using a modified quantity/intensity (Q/I) approach, which allows partitioning of K changes in the soil–solution system into exchangeable and nonexchangeable pools. Total potential buffering capacity (PBC_t) was found to correlate significantly (r = 0.97, P < 0.01) with the buffering capacity due to nonexchangeable K (PBC_n) rather with that due to exchangeable K (PBC_e). Impact factor (ß), a measure of effect of added K on nonexchangeable K, was inversely correlated with a soil's conversion magnitude () of converting added K to exchangeable K (r = 0.95, P < 0.01). Of the three soils, Dundee exhibited much smaller ß values than Crowley and Norwood but the soil converted much of added K to exchangeable K (60–65%) throughout its surface and subsurface soils. Both Crowley and Norwood possessed higher PBC_t as well as higher PBC_n and PBC_e than Dundee, but Crowley required relatively lower critical exchangeable K (EK_r) and solution K (CK_r) levels below which release of nonexchangeable K was initiated. The overall results indicated that the partitioned Q/I approach could be used to explicitly evaluate short-term K dynamics in soil–solution systems. The nonexchangeable K buffering characteristics along with the differences between critical levels (EK_r or CK_r and EK₀ or CK₀) have important implications in assessing the likelihood of nonexchangeable K release and could be calibrated for soil fertility management.

Abbreviations: AR, activity ratio • CEC, cation-exchange capacity • CK_i, initial solution K • CK₀, equilibrium solution K • CR, concentration ratio • CR₀, equilibrium concentration ratio • EK_o, equilibrium exchangeable K • EK_r, critical exchangeable K • K_G, Gapon selectivity coefficient • LPBC, linear potential buffering capacity • MHA, mobile humic acids • PBC_e, potential buffering capacity due to exchangeable K • PBC_n, potential buffering capacity due to nonexchangeable K • PBC_t, total potential buffering capacity • Q/I, quantity/intensity • , slope of linear regression between final exchangeable K (EK_f) and change in solution K (K) • , initial constraint • ß, slope of linear regression between change in nonexchangeable K (Non-Exch K) and initial constraint

This article has been cited by other articles:

				W. Nilawonk, T. Attanandana, A. Phonphoem, R. Yost, and X. Shuai Potassium Release in Representative Maize-Producing Soils of Thailand Soil Sci. Soc. Am. J., May 1, 2008; 72(3): 791 - 797. [Abstract] [Full Text] [PDF]

				J. J. Wang and D. L. Harrell Effect of Ammonium, Potassium, and Sodium Cations and Phosphate, Nitrate, and Chloride Anions on Zinc Sorption and Lability in Selected Acid and Calcareous Soils Soil Sci. Soc. Am. J., June 2, 2005; 69(4): 1036 - 1046. [Abstract] [Full Text] [PDF]