Evaluation of Soil Test Methods for Potassium in Acidic Brown Hill Soils for Recommending Fertilizer Doses for Potatoes

Green-house experiments were conducted on 24 soils representing acidic brown hill soils of Simla region, to find suitable method for the estimation of available K in the soils and its critical limits for the potato crop. Soil K extracted with neutral 1N NH₄ OAc or Morgan's reagent was highly correlated with yield and K uptake of potato (Solauum tuberosum L.). NH₄ OAc-extractable K in these soils explained 79 per cent variation in tuber yield while Morgan's K accounted for 67 per cent of the variation in tuber yield due to K application. The critical limits of available K in these soils for getting economic response to K application were 120 ppm by NH₄OAc method and 65 ppm by Morgan's method.