Potassium Fixation Capacity in some Selected Soils in Albania.

JULITA SULA, FATOS HUQI, ILIR KRISTO*

Department of Agro-environment and Ecology, Faculty of Agriculture and Environment, Agriculture University of Tirana, Tirana, Albania

*Corresponding author e-mail: ilirkristo@yahoo.com

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Abstract

Although a lot of studies are conducted in Albania, little is known and published about soil potassium status. Most of studies have been to know the level of exchangeable forms of potassium. Up to now, there are no publications about the capacity of soils in Albania for K fixation. The objective of this study is to make an assessment of the capacity of some soils for K fixation.

Capacity for K fixation of soils is an important indicator affecting the status of soil K and its availability to crops.

Potassium fixation characteristics were studied in 7 selected soil samples collected in the western regions of Albania. Soils have exchangeable K extracted by 1M NH₄OAc in range from 109 mg K kg^-1 soil to 238 mg K kg^-1 soil and nonexchangeable K extracted by 1 N HNO₃ in range from 467 mg K  kg^-1 soil to 830 mg K  kg^-1 soil. To determine K fixation 5 g of each soil sample were weighed into 50-mL plastic bottles and equilibrated for 24 h at room temperature after adding 1000 mg K kg^-1soil. A known volume of standard K solution was added to each bottle to make the final soil – solution ratio of 1 : 5. Another set of soil samples was similarly treated with distilled water (control set). After equilibration soil samples were analyzed for K in 1M NH₄OAc extract. The K fixation was calculated as follows:

K fixed = applied – K + NH₄OAc-extractable K of control sample – NH₄OAc-extractable K.

Results shown a K fixation capacity of studies soils in range from 57 mg K kg^-1 soil to 334 mg K kg^-1 soil.

Keywords: Potassium, K fixation, Exchangeable and Nonexchangeable forms,