M. Bahmani, M.h. Salehi, M.h. Salehi ,
Volume 15, Issue 57 (10-2011)
Abstract
Soil characteristics are affected by climate. Available potassium is one of the most important soil fertility indices. This study was conducted to determine the availability of potassium using Quantity- Intensity (Q/I) relationships in Vertisols of Isfahan and Chaharmahal-Va-Bakhtiari provinces with aridic and xeric moisture regimes, respectively. Soil mineralogy showed that smectite was the dominant clay in Chaharmahal-Va-Bakhtiari soil. The results showed that the activity ratio of K (AReK) in the soil solution of the surface soil in Isfahan and Chaharmahal -Va -Bakhtiari soils, ranged from 0.019 to 0.11 and 0.0037 to 0.0078 mmol.L-1 respectively. The labile K (∆K0) in Isfahan and Chaharmahal Va Bakhtiari soils ranged from 0.23 to 3.8 and 0.72 to 1.6 mmolkg-1, respectively. Potassium on specific sites (KX) in Isfahan and Chaharmahal-Va-Bakhtiari soils ranged from 2.8 to 7.1 and 2.6 to 3.7 mmolkg-1 respectively. The potential buffering capacity (PBCK) in Isfahan and Chaharmahal-Va-Bakhtiari soils ranged from 12 to 36 and 191 to 201 mmolkg-1/(mmolL-1)0.5 respectively. The results suggested that the Q/I parameters were affected by soil depth. In all of the soils studied, PBCK increased with soil depth.
