Satyanarayana, Dr. T.HEBSUR, N.S.2019-10-242019-10-241998-08-19Th-4941http://krishikosh.egranth.ac.in/handle/1/5810132779Ten soil pedons belonging to orders viz., Vertisol, Inceptisol and Alfisol derived from diverse parent materials from major sugarcane growing areas of North Karnataka were considered to study distribution of different forms of potassiium, K content In various textural fractions, its fixation and release parameters like cumulative K, CR-K and step-K, mineralogy of clay and transformation of added K In these soils. The range in contents of various forms of K in soil samples was 0.025 to 0.620 me of water soluble, 0.35 to 1.10 c mol (p+) kg-1 of exchangable, 150 to 1250 ppm of non-exchangeable, 0.47 to 3.25 per cent of lattice and 0.53 to 3.70 per cent of total potassium. Available K ranged from 275 to 900 kg ha-1. The water soluble, exchangeable, non-exchangeable and lattice potassium constituted 0.02 to 0.21, 0.64 to 4.01, 0.87 to 10.9 and 86.0 to 98.4 per cent of total K, respectively. Potassium contents in soil textural fractions viz., coarse sand, fine sand, silt and clay were in the range of 0.23 to 2.72, 0.40 to 3.23, 0.15 to 9.85 and 0.48 to 2.80 per cent, respectively in different profiles. The semi-quantitative estimate revealed the dominance of smectite in the clays of black soils and kaolinite in the clays of mixed black and red and red soils with associated minerals like mica, chlorite, kaolinite and vermiculite. The K fixation of surface soils ranged from 0.39 to 1.32 c mol (p+) kg-1. In transformation studies, water soluble K content increased in all soils with increasing levels of added K and decreased with time of Incubation. On the other hand, exchangeable K Increased with time of incubation. The added K @ 1.25 and 2.50 c mol (p+) kg-1 reacted to the tune of 223.0 to 458.7 and 448.0 to 931.2 ppm, respectively in different soils after 60 days of incubation. The cumulative K release, step-K and constant rate K values ranged from 378 tol 175, 306 to 770 and 8 to 45 ppm, respectively. Considering these parameters, the soils under study may not respond to the application of potassic fertilizers.ennullThesis