Evaluation of Potassium Quantity-Intensity in some Soils of El-Dakhla Oasis, New Valley, Egypt

Abstract

The current research was carried out in 2016 to evaluate potassium Quantity-Intensity parameters and the relation of these parameters to the characteristics of some agricultural soils of El-Dakhla Oasis, New Valley, Egypt. Six surface soil samples (0-30 cm) were collected from different sites in El-Dakhla Oasis. The values of equilibrium activity ratio of potassium (AR k o ) ranged between 0.0071 (soil 3) to 0.0320 (mol/L)

Use of Thermodynamic Parameters of Q−i Isotherms to Evaluate of K−availability in Some Egyptian Soils

“…In sandy soil, the lower K L value was 0.02 cmol kg −1 of 50% K level in soil 1, while the higher value was 0.45 cmol kg −1 by using a 150% K rate in soil 3. The high clay, silt, surface area, CEC values, and a number of loosely bound K + ions present at the exchangeable site may be linked to the increased K L values (Simard et al, 1992;Khamis, 2000;Krauss, 2000;Samadi, 2006;Al-Salam & AL-Kaysi, 2013;Hamed & Amin, 2017). Furthermore, high labile K levels resulted in an increase in K availability due to increased K release into the soil solution.…”

“…This could be due to the highest sand content in the soil. Because of their lower CEC or clay content compared to soil 3, therefore most of the K supplied by mineral fertilizer or released from organic amendments in calcareous or sandy soils (soil 1, 4) is subjected to leaching (Hamed & Amin, 2017). In regard to soil 1, 2, 3 and 4, values of PBC K were 11.9, 13.6, 18.7, 13.90, 26.2 cmol kg −1 /(mol L −1 ) 0.5 , 26.2, 29.9, 29.4, 26.9 cmol kg −1 /(mol L −1 ) 0.5 , 21.4, 25.5, 26.5, 27.3cmol kg −1 /(mol L −1 ) 0.5 and 14.8, 15.1, 20.1, 14.4 cmol kg −1 /(mol L −1 ) 0.5 for 0, 50, 100, 150%K, respectively.…”