Evaluation and suitability rating of ten major soil series of the command area of Kallada Irrigation project

Abstract

The present study was undertaken covering the ten identified important soil series of the command area of Kallada Irrigation Project, with the objective of evaluating the soils based on their morphological and physico chemical characteristics. The soil series selected are Mannar, Adoor, Sooranad, Palamel, Mylom, Erath, Bharanikavu Kallada, Pooyappally and Kunnamkara. Profile pits were dug in the typical areas identified and the morphological features observed were recorded as per soil Survey Manual (1970). The salient features of the area in respect of location, physiography, drainage, vegetation and land use were also recorded. The physical and chemical properties of the soil samples collected were determined by standard analytical procedures. These soil series have been evaluated on the basis of land evaluation and rating of productivity parameters The productivity parameters considered in the present study include soil texture, depth, soil reaction, drainage, cation exchange capacity, base saturation, electrical conductivity, coarse fragments, slope and nutrient status. For each parameter, a range of scale is prepared, and numerical values assigned based on principles of land evaluation. Productivity of the soil has been calculated by multiplying the ratings of the individual parameters and expressed as percentage. The ten soil series selected for study have been classified as per the comprehensive soil classification system – Soil Taxonomy. Five soil series namely Kallada, Mannar, Erath, Pooyappally and Kunnamkara are grouped under Entisol. four series namely Bharanikavu, Palamel, Mylom and Sooranad under Inceptisol and Adoor series under Ultisol. The land capability classification of these soils shows that the Kallada soil series comes under class IIe, Sooranad, Mylom, Erath, Pooyappally and Kunnamkara series under class IIw, Palamel, Bharanikavu, major part of Adoor and a portion of Kallada under class IIIe and Mannar serious under class IIIsc. A portion of Adoor series is grouped under class IVe. The irrigability classification of these soils revealed that the Mannar series comes under class 2s, Kallada under class 2t, Sooranad, Mylom, Erath, Pooyappally and Kunnamkara under class 2d, Adoor, Palamel, Bharanikavu and a portion of Kallada series under class 3t. A portion of Adoor series in grouped under the irrigability class 4t. The productivity rating of these soil series gives the following results. The Kunnamkara soil series with a rating of 38.7 percent rank first for paddy. The study shows that the Earth soil series is the least productive for paddy. Coconut, tapioca and banana. The Palamel series having a rating of 31.4 percent, with good rating class is the most suitable for coconut. The kallada soil series ranks top both for tapioca and banana with rating of 27.6 and 38.8 percent respectively.