Forms and Distribution of Potassium in Soils under Paddy (Oryza sativa L.) Cover of Bhadra Command in Karnataka, India

Abstract

In order to know the status of potassium in soils under paddy cover of Bhadra Command in Karnataka, 145 surface soil samples 15 cm dept, were collected from soils of seven taluks coming under Bhadra Command, processed and analyzed for chemical properties, K fractions and their distribution in soils. Results revealed that pH of soils ranged from acidic to alkaline (4.57-9.22) and organic carbon (OC) content was found in the range of 2.10 to 25.80 g kg-1. Available K status in soils varied from 49.06 to 646.87 kg K2O ha-1. Further, out of 145 soil samples, 39.31, 45.52 and 15.17 per cent soils were recorded low, medium and high in available K status, respectively. Different forms of K and their distribution in soils followed the order of Lattice K > Non-exchangeable K > exchangeable K > Water soluble K. Among the fractions of K, lattice K was found as a dominant fraction and its contribution to the total K was 88.30 to 99.75 per cent and also it had a positive and significant correlation with total K. The variation in available K status and distribution of K fractions in soils may be attributed to the variation in soil properties such as soil pH, EC and OC status of soils and fertilizer management practices followed during crop production. Further, it was noticed that total K in soils under paddy cover of Bhadra Command varied from1230 to 30760 mg kg-1(0.12-3.08 %).