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ThesisItem Open Access Taxonomy and fertility capability of soils in the kole areas of Trichur(Department of Soil Science and Agricultural Chemistry College of Horticulture, Vellanikkara, 1995) Ambili, C; KAU; Venugopal, V KIn the present investigation, attempt has been made to evaluate the morphological, physical and chemical characteristics of seven soil series indentified in the areas of Thrissur, viz., Manalur, Ayyanthole, Anthikkad, Kizhapallikkara, Kattoor, Konchira and Perumpuzha. All these soils were fluxial rice lands situated in lower topographic positions. Profile pits were dug at these different locations and examind for their morphological features. Soil samples representing different horizons were collected for laboratory studies. The physic-chemical characteristics of the soil profiles were analysed using standard procedures with a view to classify the soils under Taxonomy, and to relate the characteristics to the genesis of these soils. Surface samples collected from different locations under each series were also analysed for available N, P and K and micronutrients and other fertility parameters to arrive at fertility capability classification. The soils generally had brown surface soils and grey coloured subsoils. The structure ranged from subangular blocky to massive. All series were predominantly clayey in texture except for Manalur which was sandy. The soils were highly weathered as indicated by the silt/clay ratios. The available water content of soils clearly followed the trends in clay and organic matter content. The apparent density and absolute specific gravity values showed no much variation. These soils had reasonable pore volume and low water holding capacity. All the soils under investigation were acidic. The surface horizons had high organic matter content. The total nitrogen, P, K, Ca, Mg and Na contents were low. The cation exchange capacity values varied over a narrow range. Calcium and magnesium predominated in the exchangeable bases. The general distribution of exchangeable bases were in the order Mg>Ca>Na>K. All the soils except Perumpuzha and Konchira were of high base saturation. The dithionite extractable iron, Fed, formed the major portion of total iron and it followed the variations in total iron. The ammonium oxalate extractable iron, Feo, was much lesser. The Feo/Fed values were also very low. When classified upto the subgroup level, Ayyanthole and Kattoor come under Alfisols and all the other soils under Inceptisols. The available nitrogen content was medium to high, available phosphorous content was low to medium and available potassium was medium to high for surface samples. The P fixation capacity was high. The DTPA extractable iron, manganese and copper recorded values greater than the critical level while in some samples zinc recorded values less than the suggested critical level. From the fertility capability classification it is observed that all the soils have high P fixing capacity, demanding proper management of phosphorous. Manalur and Ayyanthole soils have low inherent fertility and chances of aluminium toxicity in well aerated soils. Konchira soils are potential acid sulphate soils. Konchira and Perumpuzha soils have clayey top soils with shrink – swell properties. The quantity of fertilizer to be added, sources and methods of application are to be decided based on site specific characteristics and soil test data.