Potassium Fractionation and its Relationship with Other Soil Characteristics in the Uplands of Balochistan

Abstract

Potassium (K) stands as a vital nutrient for plant growth and reproduction, ranking second only to nitrogen in importance among essential plant nutrients. Often heralded as the cornerstone of quality nutrition for plants, its significance extends to influencing various attributes such as plant shape, size, color, taste, and overall health. Plants primarily uptake potassium in its ionic form, K+. In the pursuit of high crop yields and superior agricultural produce, achieving a balanced and sufficient mineral nutrition, including potassium, is paramount. However, in many rain-fed regions of developing countries, imbalances in potassium nutrition have emerged as a significant impediment to optimal crop production. This study aimed to assess the potassium status in diverse soils across the uplands of Balochistan and elucidate the relationship between potassium fractions and other soil characteristics. Various soil profiles were meticulously examined, and samples were systematically collected, processed, and subjected to comprehensive analysis. The findings indicate that soils in the Quetta district exhibit higher levels of water-soluble, exchangeable, and non-exchangeable potassium compared to soils in the Pishin and Mastung regions. The readily available (water-soluble + exchangeable) and non-exchangeable potassium fractions constituted 0.02-0.07% and 0.1-0.9% of the total potassium content in soils, respectively. Mineral potassium accounted for approximately 92-97% of the total potassium, with concentrations ranging between 27.6-54.5 cmol/kg. The maximum soluble potassium content was recorded in Beleli location (0.039 cmol/kg), while the minimum was observed in Yaro location (0.015 cmol/kg). These variations in potassium levels were primarily attributed to the presence of potassium-rich minerals within the soil. The study concluded that a variability of potassium fractions exists across different soil profiles, with soils in Quetta district exhibiting higher levels compared to Pishin and Mastung regions.