Evaluation of Soil Tests for Predicting Potato Response to N,P and K in Acidic Soils

摘要

Suitability of conventional and recently developed rapid soil tests at the institute for available nitrogen,phosphorus and potassium determination were evaluated on cultivator's fields at Fagu (Shimla)in high hills of Himachal Pradesh with potato as a test crop.Among the physical properties,silt was positively related to potato yield responses whereas an adverse relationship was found with that of clay content.The soil nutrient availability indices for N and P were positively related to absolute yield and yield responses at all the fertilizer levels i.e.50,100 and 150% of NPK dose.Soil K tests on other hand showed negative association with yield response.The correlations for nutrient uptake followed similar trend.Among soil N tests,CrO_3-oxidisable N and KMnO_4-N gave best results for judging potato response to N.In case of P and K,organic carbon and NH_4OAc-K,respectively,were the best indicators.