Soil Potassium Fractions as Influenced by Integrated Fertilizer Application Based on Soil Test Crop Response under Maize-Wheat Cropping Systems in Acid Alfisol

Field experiments were conducted during 2014-15 to 2015-16 at the Experimental Farm of Department of Soil Science, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, HP as a part of long-term fertilizer experiment initiated in kharif, 2007 in a maize-wheat sequence.The experiment consisted of eight treatments viz., (1) control; (2) general recommended dose; (3) soil test based; (4) farmers' practice; (5) target yield of 25 and 30 for rabi and kharif, respectively without FYM; (6) target yield of 25 and 30 for rabi and kharif, respectively with FYM @ 5 t ha -1 (7) target yield of 35 and 40 q ha -1 for rabi and kharif, respectively without FYM; (8) target yield of 35 and 40 q ha -1 for rabi and kharif, respectively with FYM @ 5 t ha -1 ) which were replicated thrice in a randomized block design.The fertilizer adjustment equations were developed based on target yield concept and accordingly nutrient doses were calculated.The results revealed that soil available K was significantly increased in both the target yields with IPNS over general recommended dose and soil test based treatments.The different forms of potassium i.e. water soluble K, exchangeable K and non-exchangeable K were highest under STCR (IPNS) treatment for target yield of 35 q ha -1 .The status of non-exchangeable potassium was significantly inferior in unfertilized plots in comparisons to all other treatments.Regression analysis showed that exchangeable K was the most important variable contributing about 94% in the total variation in available-K.The present study was undertaken as a part of long-term fertilizer experiment initiated in kharif, 2007 in a maizewheat sequence at the Experimental Farm of Department of Cropping sequence, IPNS, maize, potassium, STCR, wheat