Distribution of potassium fractions in relation to landforms in a Himalayan catena

Abstract

Spatial distribution of potassium in mountain soils is governed by landforms, as the operational intensity of factors and processes of soil formation vary with landforms. Therefore, we aimed to find out the relationship between potassium (K) fractions with landforms and the association of K fractions with soil properties. For this, horizon-wise soil samples were collected from pedons, one each from six topographic positions in a catena in the Punjab Himalayas. Samples were analysed for physical and chemical properties and for K fractions. The soils were alkaline and calcareous. The water soluble-K ranged between 4.0 and 18.5 mg kg⁻¹, exchangeable K between 27.3 and 292.2 mg kg⁻¹, fixed K from 392 – 240 mg kg⁻¹, and total K from 1.1 – 3.1%. All forms of K were positively related to silt and negatively to sand. Exchangeable and total forms of K were positively correlated with clay and CEC. The trends could be corroborated with mineralogy, which are rich in K-bearing minerals like micas and feldspars in coarse fractions and illites in clay fractions. The positive coefficients of correlation amongst the forms of K suggest that K forms are present in dynamic equilibria. The spatial distribution of K fractions was closely associated with landforms.

Keywords:

• Himalayas
• landforms
• potassium forms
• potassium in topo-sequences
• potassium-profile distribution
• soils
• Punjab