Effect of soil characteristics and potassium application rate on the plant-absorbable potassium forms and transport mechanisms in soil

Minako Yoshida, Yuki Mori, Shin Ichiro Wada

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Although the demand for saving potassium (K) fertilizer application is increasing, the evaluation of available K by exchangeable K that is operationally defined as 1 M ammonium acetate-extractable K has limitations. In order to investigate the contribution of soil K forms and transport mechanisms for K uptake, pot experiment was performed using two soils with varying K application rate. The spinach grown in vermicu-lite-rich soil absorbed considerable amount of K from nonexchangeable fraction and the transport mechanism was mainly by diffusion, whereas the plant cultivated in volcanic ash soil, which contain less vermiculite, mostly absorbed exchangeable K and the contribution of mass flow was substantially high. Exchangeable K and soil solution K in vermiculite-rich soil did not much increased at the high rate of K application. A part of applied K might become readily absorbable- nonexchangeable K. To evaluate K supplying capacity of soil, it is necessary to quantify not only exchangeable K but also the K fixation and the amount of K released from nonexchangeable sites. In soil whose K fixation capacity is low, the transport of K from soil might be modeled by solute transport and cation exchange.

Original languageEnglish
Pages (from-to)485-488
Number of pages4
JournalJournal of the Faculty of Agriculture, Kyushu University
Issue number2
Publication statusPublished - Sep 1 2012


All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Agronomy and Crop Science

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