Forms and distribution of carbon and potassium in soils under mechanized harvest system of paddy in Bhadra command area of Davanagere District

A study was carried out in order to know the carbon and potassium status in soils as influenced by mechanized harvest of paddy in Bhadra command area of Davanagere district during the year 2023-24 at College of Agriculture, KSNUAHS, Shivamogga. Under this investigation, 70 and 10 composite soil samples were collected randomly from mechanized and manual harvested fields respectively under paddy cover of Davanagere and Channagiri taluks of Davanagere district. Soil samples were further processed and analysed for available K2O, potassium fractions and soil organic carbon and its fractions. The results revealed that soil reaction varied from slightly acidic to slightly alkaline and EC was normal in soils under both mechanized and manual harvest systems. The soils under mechanized harvest system recorded low to high organic carbon content. Carbon fractions viz., water soluble, active and total carbon recorded the mean of 48.33 mg kg-1, 561.37 mg kg-1 and 17.19 g kg-1 respectively. Available K2O was found to be 319.46±158.39 kg K2O ha-1, and potassium fractions such as water soluble, exchangeable, non-exchangeable, lattice and total K recorded the mean of 22.82, 119.15, 353.42, 10981.01 and 11476.41 mg K kg-1 respectively. Whereas in case of soils under manual harvest, organic carbon was low to high ranging from 4.20 to 6.16 g kg-1 with mean value of 4.87±0.60 g kg-1, available K2O was found to be 127.45±27.73 kg K2O ha-1 and total K was found to be 3775.46 mg K kg-1. Overall, soil organic carbon and its fractions, available K2O and potassium fractions were recorded higher in the soils due to stubble incorporation through mechanized harvest system compared to manual harvest.