Comparison of several extraction methods to extract absorbable potassium in soils of arid and semi-arid regions: case study; Sistan Plains

Potassium is an essential element for plant growth and the major cation for physiological and biochemical activities. Therefore، the knowledge of in the soils will help better application of potassium fertilizers. This study investigates the status of soil potassium in the soil to be used by sorghum and evaluate the common extraction methods. The study was performed on all soil series (12 series) in Sistan plains. The study was designed on factorial experiment in a completely random design with three levels، 100 and 200 mg per kg of potassium in three replicates. Six different methods were used for the extraction of potassium. Results indicated that K application increased yield، concentration and K uptake in sorghum. Based on the values of K extracted، the extraction methods were divided into two groups and in each group، the extraction methods correlated significant. Correlation studies showed that the extraction with ammonium acetate can be introduced as an available K extraction solution.