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Author: KAU × End date: 1977 × Start date: 1977 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Investigations on the salinity problems of pokkali and kaipad areas of Kerala state
    (Department of Soil Science & Agricultural Chemistry, College of Agriculture, Vellayani, 1977) Samikutty, V; KAU; Aiyer, R S
    The saline soils of the State viz., Pokkali, Kaipad and Orumundakan are coastal saline soils, which cover an area of about 30,000 hectares, cropped to a single crop of paddy. The profile characteristics of the soil reveal that they are Entisols. They contain varying levels of soluble salts depending upon their nearness to sea, backwater, or their situation on the flood plains of rivers and their nearness to the river mouths. The electrical conductivity of the saturation extract (ECe) of these soils range between 7.6 to 226.3 mmhos/cm showing differences in the magnitude of salinity encountered, prior to the soils being leached in summer months. Though the soils are exhibiting extremely high levels of salinity in the summer months, they get decreased rapidly below critical levels for growing a successful saline resistant paddy crop by July-August. The observed SAR and ESP values ranging to the maximum values of 25.0 and 26.3 in the months of February-March rapidly get decreased to 1 to 3 by between August and November. These low levels of salinity are maintained till December-January with an occasional spurt in salinity levels dependent on the opposing hydrological situation caused by the flood and rain waters on the one hand from east to west and the tidal waters from the west to the east on the other. The long period of nearly six months, when salinity in the soils are below critical levels, indicate the possibility of introducing a two crop system instead of one, provided nurseries are raised in non – saline uplands and transplanting resorted to in the raised mounds: previously leached free of soluble salts during the monsoon. The cationic-anionic composition of the soils reveal that they are Na-Mg-Cl-SO4 type of coastal saline soils. About 50 per cent of the soils studied have a pH below 5.5 and 15 to 20 per cent of the soils have lime requirement of more than 5 tons per hectare. In general the soils are extremely poor in phosphates and rich in potash. Application of non-magnesium containing lime materials at the time of mounding and subsequent leaching together with basal application of phosphate prior to planting are likely to enhance the yields of paddy in these areas. In short, the methods of management are highly location-specific calling for intensified research. The occurrence of saline water in the pits between the mounds even during the cropping period indicates the possibility of mixed rice culture with pisciculture
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    ThesisItemOpen Access
    Studies on the control of bacterial wilt of tomato with reference to organic soil amendments and chemicals
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1977) Jayaprakash, M G; KAU; Rajan, K M
    The pot culture and field experiments were conducted to assess the effort of organic soil amendments and chemicals on the incidence of bacterial wilt of tomato. The population dynamics in relation to the causal organism, total fungi, bacteria and actinomycetes were also studied. Theresult of the investigation revealed that organic materials did not chook the disease incidence to a satisfactory level . However , the application of organic material followed by the treatment with chlorotomycin and streptocycline gave a satisfactory control of the disease.
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    ThesisItemOpen Access
    Studies on the grey leaf blight disease of Coconut palm caused by Pestalotia palmarum Cooke.
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1977) Francis, A J; KAU; Paily, P V
    An investigation was carried out in the palms at the Coconut Research Station, Balaramapuram during the months of May, June, July, August and September of 1976 to study the influence of different nutrients on the intensity of disease caused by Pestalotia palmarum. The experiment was conducted on the palms which were treated with different combinations of NPK in a 3 confounded factorial design . Morphological characters of different species of Pestalotia were also studied along with this investigation. Highest degree of infection was noticed in the month of June and the lowest in September. Higher disease intensity was noted in the palms which were treated with 1 level of nitrogen, 2 levels of phosphorus and 2 levels of potassium than in these that were treated with 0 level of nitrogen, 1 level of phosphorus and 0 level of potassium.
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    ThesisItemOpen Access
    Studies on the leaf spot and post harvest diseases of banana, and their control
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1977) Suharban, M; KAU; Paily, P V
    Varietal susceptibility of different cultivars to the leaf spot diseases of banana was studied in an existing plantation, consisting of 18 varieties in the Instructional Farm, Vellayani. It was found that Robusta and Chakkarakeli were the most susceptible while Venattumonthan and Mass being the least susceptible. Different types of leaf spots viz., Cordana leaf spot, Deightoniella leaf spot, Helminthosporium leaf spot, Septoria leaf spot and Cercospora leaf spot were studied, and the fungi associated with them were also isolated, Growth and sporulation of all these fungi were studied in different media. Power oil was observed to be the best fungicide eventhough there was no significant difference between power oil, Difolatan and Bavistin in the fungicidal control of leaf spot diseases. It was found that carbondioxide does not have any role in enhancing the keeping quality. Both partial filling and complete filling of the gas were seem to enhance deterioration. When higher concentrations of benomyl were tried it was found that 600 ppm was superior to all other treatmentsIn 500 gauge polythene bags. Eventhough different fungicides like Bordeaux mixture, benomyl and lime water were tried in different gauges of polythene bags viz., 150, 200, 250, 300, 350, 400, 450 and 500, 600 ppm benonyl in 200 gauge polythene bags was found to be the best in preserving the fruits followed by lime water, and Bordeaux mixture
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    ThesisItemOpen Access
    Studies on the root-knot nematode of pepper (Piper nigrum L.)
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1977) Arthur Jacob, J; KAU; John Kuriyan, K
    Nematodes have recently been observed to constitute a major threat and limiting factor to the pepper production in Kerala State, Among the nematodes, neloidecyne spp, causing root-knots on pepper is one of the most important. Investigation on this nematode in pepper was not done in this state, Therefore, to gather some information on the extent of damage done by this nematode and pepper and to evolve control measures the present work was carried out