PG Thesis

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Subject: search.filters.subject.Soil texture

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    Characterisation of soil organic matter in different soil types of Kerala
    (Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1982) Usha, P B; Jose, A I
    Large number of surface soils representing the different districts of the state were analysed in order to work out precise relationships between organic carbon, total nitrogen and available nitrogen in these soils. The soils were categorized into different groups based on soil texture and content of organic matter. Relationships between different soil properties applicable to the different categories of soil were then examined. Fractionation of soil organic matter was carried out in a limited number of soils. Also the distribution of elemental components of soil organic matter was studied in soils selected for the fractionation of organic matter. Observations on the general characteristics of soil revealed that the content of organic carbon, total nitrogen and available nitrogen showed an increasing trend with increase in acidity of soil. In general more organic carbon was seen in fine textured soils. The total and available nitrogen content of soil increased with increase in content of organic matter. The content of available nitrogen showed significant and positive correlation with total nitrogen. Since the C/N ratio increased with increase in content of organic carbon it was necessary to predict the total and available nitrogen content of soil based on precise regression equations rather than depending on a conversion factor. On an average 10.82 per cent of the nitrogen in soil was extracted as available nitrogen. The C/aN ratio was positively and significantly correlated with organic carbon and total nitrogen while it was negatively correlated with available nitrogen. On an average the percentage of humic acid, fulvic acid and humin in soil organic matter were 28.28, 36.51 and 35.21 respectively. Of the 28.28 per cent humic acid, 9.60 per cent (of organic matter) was represented by hymatomelanic acid and the remaining 18.68 per cent by the insoluble fraction of humic acid. Humic acid was found to be significantly and positively correlated with total organic carbon, total nitrogen, clay and fulvic acid. Of the total fulvic acid 12.35 per cent (of organic matter) was represented by beta humus and the remaining by the soluble fraction of fulvic acid. Fulvic acid was positively and significantly correlated with organic carbon, total nitrogen, humic acid and clay. Humic acid and fulvic acid maintained a constant proportion irrespective of the variation in content of total organic matter. Humin was also positively and significantly correlated with organic carbon and total nitrogen. The mean phosphorus, sulphur and potassium content of organic matter were 0.051, 6.96 and 0.32 per cent respectively. The C/org.P, C/org.K, C/org.S, N/org.P, N/org.K, N/org.S, Org.P/org.K, Org.P/org.S and Org.K/org.S ratios were 1672.8, 94.1, 19.23, 205.81, 9.77, 2.91, 0.07, 0.008 and 0.0073 respectively.
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    Distribution fixation and availability of phosphorus in the kole soils of Kerala
    (Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 1988) Sheela, S; Koshy, M M
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    Evaluation and suitability rating of ten major soil series of the command area of Kallada Irrigation project
    (Department of Soil Science and Agricultural Chemistry, College of Agriculture, Tavanur, 1992) Premachandran, P N; Aiyer, R S
    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.
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    Subsurface drip irrigation of ladies finger in sandy loam soil
    (Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2007) Nisha, T V; Asha Joseph
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    Fertility investigations and taxonomy of the soils of regional agricultural research station, Pattambi
    (Department of soil science and agricultural chemistry, College of Horticulture, Vellanikkara, 1995) Deepa, K P; Chinnamma, N P
    The Regional Agricultural Research Station, Pattambi has entered it seventh decade of activities. The total area of the station is 63.64 ha and it includes both upland and low land. A detailed survey of the soil in the area of the station has not been made by the Soil Survey Department and hence a taxonomic classification of the soil and fixing of the soil serious as per the soil taxonomy has not been done so far. Therefore the present study was formulated to find out of the morphological and Physico-chemical characteristics of soil profiles of selected blocks, to analyse the surface soil samples from all the blocks for fertility parameters, to classify the soils under taxonomy and to prepare the soil fertility map of the station. The soils had predominantly red hues. Good structural development was noticed in all soils except in ill drained areas. Coarse fragments formed a predominant part in the soil samples collected. In general the soils were acidic in nature. Organic carbon content was low irrespective of crops grown. The nitrogen content of all soils were also low. No regular pattern of distribution with depth was obtained for total reserves of N, P2 O5, K2 O, CaO, MgO and Na2O which were low. Total Fe2 O3 content was fairly high. The cation exchange capacity calculated by NH4 OAC method was low for all the soils. Among the exchangeable bases, Ca formed the predominant cation. With regard to the available nutrient content of soils, nitrogen status of the soul worked out based on the organic carbon content showed that it was high in C block, low in blocks I and IX and medium in the remaining 19 blocks. Nutrient index worked out for available P content showed that it was medium in 12 blocks i.e., E, M, K, I, II, III, IV, V, VI, VII, IX, X and high in the remaining 10 blocks. For available K, the nutrient index values indicated that it was low in 10 blocks and medium in 12 blocks. Based on the nutrient indices, the fertility map of the station was prepared. Based on the profile soil sample analysis, classification of the soils under soil Taxonomy was attempted upto the subgroup level. Among the nine profiles, only 3 i.e., F, I and V fell under Inceptisols and the remaining 6 i.e., F, I and V fell under Inceptisols and the remaining 6 i.e., B, C, I, VIII, IX and X were under Entisols.