Central Research Institute for Dryland Agriculture, Santoshnagar, Hyderabad, 500 059, Andhra Pradesh.
*Present address: Global Theme-Agroecosystems, International Crops Research Institute for the Semi-Arid Tropics, Patancheru, 502 324, Andhra Pradesh.
**Present address: Potash and Phosphate Institute of Canada – India Program, Gurgaon, 122 016, Haryana.
†Present address: AICRP for Dryland Agriculture, MPKV, Solapur, 413 002, Maharashtra.
‡Present address: AICRP for Dryland Agriculture, ARS, Anantpur, 515 001, Andra Pradesh.
§Present address: AICRP for Dryland Agriculture, UAS, GKVK, Bangalore 560 065, Karnataka.
Twenty one profiles representing wide variety of soils and rainfed production systems were characterized for potassium supplying characteristics such as step K, constant rate K and cumulative K using boiling 1 N HNO3 as an extractant. Among production systems, groundnut and fingermillet system showed extremely low level of profile mean step K below 500 mg kg−1. Among other production systems some locations under pearlmillet and maize also showed relatively lower step and cumulative K release. Among soil types, Alfisols at Bangalore and Anantapur, Vertisols at Akola and Aridisols at S.K. Nagar showed lower K release parameters. Clay and CEC showed positive correlation in most of the soils while pH showed mainly positive relation in Alfisols and Inceptisols.
Step K, constant K, cumulative K, soil types, rainfed regions
