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Kerala Agricultural University, Thrissur

The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively. Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively. On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs. In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc. During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU). Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.

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Author: KAU × End date: 2003 × Start date: 2003 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Availability indices for stressed nutrients for coconut (Cocos nucifera L) in an ultisol
    (Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2003) Priya, P; KAU; Sureshkumar, P
    The present study was conducted with an objective to analyse the soil-plant system, the levels and interactions of nutrient ions in soil, soil solution and plant thereby / finding out the contributing factors to yield. The importance of the term relative intensity lies in the fact that the contribution of mineral elements to growth and yield of plants depend much on the relative amount of one element with respect to the others rather than the absolute content of individual elements. To study the ionic interactions and to unravel the role of Net Ionic Equilibrium based on Ratio Law on soil plant system, a sample of fifty phenotypically identical palms varying in yield from 14.4 to 84.4 nuts palm" year"! grown under an Ultisol were selected. Index leaf samples were collected during pre and post monsoon seasons from 25 palms each from high yielding and low yielding groups. Soil samples were also collected from the basins of these palms during the same seasons at 30 cm (surface) arid 60 cm (subsurface) depths. Soil solutions at saturation point were extracted from the surface samples by centrifugation technique. These leaf, soil and solution samples were analysed / . for different nutrient ions, and the NIE ratios in these three phases were worked out with respect to K and Na. The soil samples were acidic in nature and the variation in rhizosphere pH must have definitely influenced the solubility as well as absorption of different nutrient ions. In the case of available nutrients, the micro nutrients showed significant direct relation with yield both for high and low yielding populations. This might be due to their restricted availability due to aerobic oxidised condition where Fe and Mn might have been precipitated and got into unavailable forms. The BaCh exchangeable ions and the CEC derived from summing up of these exchangeable ions influenced yield directly. Exchangeable K had got a significant dominance in deciding the NIE ratio in soil, solution and in index leaves. Exchangeable K controlled the soil solution concentration of K which in turn controlled the NIE ratio in solution and the ratios in plant. Exchangeable K directly controlled the plant K content and plant K was positively and significantly correlated with the NIE ratios in plant and these ratios were positively and significantly correlated with yield. The negative significant correlation of exchangeable K with plant Mn and Zn revealed the antagonistic effect of exchangeable K in restricting the absorption of Mn and Zn by plants. Among the ionic concentrations in soil solution, Fe was positively and significantly correlated with yield in both the seasons. Soil solution concentrations of Ca and Mg were antagonistically and significantly related with plant Mn content. Potassium content and the NIE ratio in index leaves were found to have a significant direct relation with yield in the pre-monsoon season. Potassium, Ca and Mg were the dominant cations in plant deciding the total cation concentration in index leaves. The NIE ratios between the exchangeable ions, the ions in soil solution and the ions in index leaf samples were mutually, .positively and significantly correlated among themselves. This lead to the conclusion that there exists a constancy in the relative proportion of nutrient ions in the entire soil-plant system which followed Ratio Law. The study lead to the conclusion that the soil test values of the individual ions alone or the plant content of individual ions alone can't give a clear picture of optimum nutrient requirements for the plant. The relative concentration of K in soil through the ~ concentration in soil solution was found to govern the relative concentration in plant which in turn influenced the yield.
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    ThesisItemOpen Access
    Diversity of small mammals in the Parambikulam wildlife sanctury
    (Department of Wild Life Sciences, College of Forestry, Vellanikkara, 2003) Lekshmi, R; KAU; Ambika Varma, B
    A detailed study was conducted in the Parambikulam Wildlife Sanctuary during 1999-200 I to prepare an inventory and to estimate the abundance of small mammal fauna in diverse ecological habitats of the Parambikulam Wildlife Sanctuary. In this study, a total of twenty seven species of small mammals belonging to eight orders were recorded from the Parambikulam Wildlife Sanctuary. Among the eight orders Rodentia was represented maximum with eleven species followed by Carnivora with ten species, remaining orders represented only by a single species. While comparing the rodents trapped from different habitats, natural forest account for more number of species than plantation and vayal. The most common rodent species in the three habitats was Rattus rattus, whereas Golunda ellioti (Indian bush rat) was found only in the moist deciduous natural forest because of the favourable ecological conditions prevailing there. Maximum diversity was more in the natural forest than in plantation and vayal whereas species richness was more in vayal followed by plantation and natural forest. The relative dominance was also high in natural forest than plantation and vayal. Correlation between floral diversity and rodent species indicates that natural forest with more number of plant species possessed high rodent species richness. The ideal conditions prevailing in the natural forest would have helped the survival of rodent species. The lack of ideal conditions in the plantation and vayal would have been the reason for lesser number of rodent species.
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    ThesisItemOpen Access
    Management of phytophthora disease of black pepper (piper nigrum L. walp) using plant growth promoting microbial inoculants
    (Department of Plant Pathology, College of Agriculture, Mannuthy, 2003) Beena Nair, S; KAU; Anith, K N
    The study, "Management of Phytophthora disease of black pepper (Piper nigrum L. Walp) using plant growth promoting microbial inoculants" was conducted at the Department of Plant Pathology, College of Agriculture, Vellayani to investigate the effect of plant growth promoting rhizobacterial strains belonging to fluorescent pseudomonads and Bacillus spp. and the root endophytic fungus, Piriformospora indica on the suppression of nursery wilt of black pepper incited by Phytophthora capsici. Two strains of fluorescent pseudomonads viz., Pseudomonas putida strain 89B61 and P. jluorescens strain RCL3R4, two strains of Bacillus viz., BY -1 and BY -2 and P. indica were included in the study to explore their potential in plant growth promotion and disease suppression. P. capsici inoculated control, uninoculated healthy control, chemical control (0.20 per cent COC drenched at 15 days intervals) and combined application of Trichoderma harzianum and an AMF, Glomus fasciculatum were maintained for comparison. In the dual culture assay, conducted in vitro for preliminary screening, though P. indica exhibited a slight mycelial growth inhibition initially, the pathogen later overgrew the antagonist. Among the bacteria, fluorescent pseudomonad strains exhibited better mycelial growth inhibition 'on both PDA and Carrot Agar. The influence of different biocontrol agents on growth promotion of the black pepper cuttings was not statistically significant. However, the fluorescent pseudomonad, P. putida strain 89B61 exhibited maximum growth promotion. In the experiment conducted to test the potential of vanous plant growth promoting microbial inoculants in suppressing nursery wilt, the plants treated with spore suspension of P. indica exhibited the highest wilt percentage of 93.22 per cent which was more than that in the inoculated control (37.48). The plants treated with the fluorescent pseudomonad, P. jluorescens strain RCL3R4 recorded a wilt percentage of 6.70. All other treatments were highly effective and checked the infection completely. The Bacillus strain, BY -2 exhibited better disease suppression in vivo. The fluorescent pseudomonad, P. putida strain 89B61 also showed disease suppression in vivo, which indicated that it has the dual function of plant growth promotion and disease suppression.
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    ThesisItemOpen Access
    Zonation,leaf phenology and litter dynamics of mangrove forest at Puduvyppu
    (Department of Tree Physiology and Breeding, College of Forestry,Vellanikkara, 2003) Ajay Dattaram, Rane; KAU; Asokan, P K
    As species distribution along the sea-land interface to the land interior IS attributed to gradients in soil electro-chemical properties and tidal frequency and nutrient cycling in a system is dependent on litterfall and decay dynamics. Hence, the study for estimating zonation pattern and regeneration status of species along the ocean-land interior trans~cts, along with litter dynamics (literfall and litter decay) was carried out at Puduvyppu mangrove forest. Zonation pattern of species was revealed by carrying out phytosociological analysis along the land-ocean transect and correlating with gradients in electro-chernical properties of soil. Litterfall was studied by evaluating interzonal and monthly variations in litterfall between species for one year. Leaf fall and production was inturn correlated with weather parameters. Decay dynamics was studied by involving six predominant species of the forest namely, Avicennia officinalis, Bruguiera cylindrica, Rhizophora mucronata, Sonneratia caseolaris, Acanthus ilicifolius and Excoecaria agallocha and by estimating interzonal and monthly variations in mass loss and nutrient concentrations of decomposing leaf samples for 12 months. Results show that the area can be divided into three zones (zone I: 0-300 m, zone U: 301-800 m, zone Ill: 801-1200 m from the sea) based on species distribution pattern. Species diversity along the zones decreased from zone I to zone I I, whereas, phytosociological para~1eters of species increased. It was also observed that species like R. mucronata and S. caseolaris were restricted in zone I, whereas, A. officinalis and B. cylindrica were abundant towards the landward side, due to the tidal sorting of the species. Electrical conductivity and soil nutrient (N, K, Na) concentrations increased towards the landward side, whereas, pH decreased. Furthermore, soil P concentrations and in situ redox potential positively affected stand density and E. agallocha stand density respectively. Regeneration was profuse in the central zone of the forest (700-800 111 from the sea) and decreased towards the landward side and the seaward side, implying that monospecifity and tidal inundation affected regeneration. Among the species, A. officinalis seedlings were abundant in the lower height class «50 cm) and B. cvlindrica in upper height class (>50 cm), implying that shade tolerance of the species decided its establishment potential. Litterfall did not vary among the zones suggesting that the dominant A. officinalis determined litterfall of the forest. Leaf fall peaked during winter season (November-December), whereas, leaf production was initiated by rainfall, implying that rainfall and temperature controlled phenological cycles in species. Mass loss followed an exponential pattern in A. ilicifolius, A. officinalis. E. agallocha and S. caseolaris, whereas, it followed a linear pattern in B. cylindrica and R. mucronata. Similarly decay rates were inversely related with initial lignin and lignin: nitrogen ratio of the decomposing leaves. And also, interzonal variations in decay rates were observed, implying that site and species affected decay rates. Nutrient concentrations decreased with Nand K concentrations decreasing and P moderately increasing in the litter bags during the course of decomposition, implying that tidal frequency and mineralization-immobilization frequencies decided nutrient release patterns in these species. In general this is a low diversified, juvenile with an efficient nutrient input-out put mechanism.
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    ThesisItemOpen Access
    Response of Papaya (Carica Papaya L.) to Major Mineral Nutrients
    (Department of Pomology and Floriculture, College of Agriculture , Vellayani, 2003) Bindu, B; KAU; Jayachandran Nair, C S
    An experiment was conducted in the Department of Pomology and Floriculture, College of Agriculture, Vellayani during 2001-2002, to study the response of major plant nutrients viz., nitrogen, phosphorus and potassium on growth, yield and quality of papaya under Kerala conditions and to standardise the optimum dose of these nutrients. The experiment was conducted in 33 confounded factorial RBD, confounding NPK in replication 1 and Np2K2 in replication 2. The present study revealed that application of nitrogen, phosphorus and potassium increased plant height, girth and number of leaves. The highest plant height was obtained with the combined application of 200 g N, 300 g P and 500 g K plan' year-', while the highest plant girth was obtained with application of 250 g N, 300 g P and 500 g K. Combined application of 300 g N, 250 g P and 500 g K p lant' year-' resulted in the maximum number of leaves. Plants receiving a dose of nitrogen at 250 g, 300 g phosphorus and 500 g potassium plant" took the shortest time for flowering. Combined application of nitrogen at 250 g plant.", phosphorus at 250 g plant" and potassium at 500 g planr' considerably shortened the time for harvesting the first fruit. Fruit weight, number of fruits plant", yield planr' and papain yield increased by application of nitrogen, phosphorus and potassium. Application of 250 g N, 250 g P and 500 g K planr' year-' gave highest yield. Maximum fruit girth was obtained from 200 g N, 200 g P and 500 g K, whereas maximum fruit volume and pulp percentage was obtained from 250 g N, 250 g P and 500 g K. Levels of nitrogen and phosphorus tried had no significant influence on TSS and ascorbic acid content of fruits. Nitrogen at 200 g, phosphorus at 250 g planr' produced. fruits of low acidity, while potassium had no significant influence. The combination of 200 g nitrogen, 300 g phosphorus and 500 g potassium plane 1 year" increased carotenoids, total sugars, reducing sugars and organoleptic qualities of fruits. Most of the treatments had light yellow peel colour, orange pulp colour and firm flesh. Nitrogen at 200 g, phosphorus at 250 g and potassium at 500 g plant" was found to increase the shelf life of fruits. Application of nitrogen, phosphorus and potassium increased soil and leaf petiole content of the respective elements. Highest benefit: cost ratio was obtained from the combination of 250 g N, 250 g P and 500 g K I -I -I P ant year . Over all assessment indicated that application of N, P and K at the rate of 250 : 250 : 500 g plant" year-I in six equal splits was economically viable and improved growth, yield and quality of papaya.
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    ThesisItemOpen Access
    Bio-ecology and management of perianth infesting mealy bugs dysmicoccus brevipes(Cockerell) and Pseudococcus Longispinus (Targioni-Tozzetti) on coconut
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2003) Bindu Radhakrishnan; KAU; Premila, K S
    A study was conducted at the College of Agriculture, Vellayani from January 2001 to December 2001 to study the biology, species composition and symptomatology of perianth infesting mealybugs, D. brevipes and P. longispinus infesting the coconut palm and to assess the yield losses caused by the pest and to evolve management measures. The biology of the two species was studied after reanng them on pumpkin fruits. The mean larval period and adult longevity of D. brevipes and P. longispinus when reared on pumpkin were 36 and 103.3 and 26 and 57 days respectively. The mean sex ratio of D. brevipes was 3.17 and of P. longispinus was 3.54. Pumpkin appeared to be a good host material for mass rearing PMBs. Studies on the yield loss assessment revealed an annual yield loss of Rs 139.20/ palm in the highly susceptible palms whereas in the medium and low susceptible palms the yield losses were Rs. 85.80/palm and Rs. 40.80/ palm respectively. When the influence of bunch age on the extent of damage by mealybugs was studied, highest mean per cent damage was observed in the fifth bunch followed by fourth and sixth bunches. Maximum population of PMBs were observed in the fifth nutlet. The mean population of D. brevipes was maximum during May (1.31) whereas the mean population of P. longispinus was maximum during March (1.13). Studies on the susceptibility of stage of bunch to mealybug damage indicated that the peak level of damage was in the fifth bunch. Consequently the maximum damage was observed in the month of June. Rainfall was observed to be the most important factor adversely affecting mealybug population. Development of symptoms as a consequence of feeding injury by PMBs include drying of nut without drying of calyx, stunting, deformities in the buttons such as development of cavities in place of embryo and gummy exudation. The mean population of other perianth infesting arthropods found associated with highly infested category of palms was low when compared to medium and low category palms. A positive relation between number of flowers per spikelet and susceptibility to mealybugs was observed. A study on the reaction of nutlets of WC'T variety to PMBs in terms of tepal colour revealed that orange and green coloured tepals were the most preferred by PMBs. Ant species C. nuda, T. albipis and A. longipes were seen closely associated with PMBs. Among the various pesticides evaluated against PMBs, triazophos (0.05) and profenofos (0.05) were found to be effective in controlling the pest.
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    ThesisItemOpen Access
    Bioherbicidal potential of fungal pathogenes of water hyacinth [Eichhornia crassipes (Mart.) Solms]
    (Department of Plant Pathology, College of Agriculture,Vellayani, 2003) Ancy Salim, M; KAU; Naseema, A
    The study entitled "Bioherbicidal potential of fungal pathogens of water hyacinth [Eichhornia crassipes (Mart.) Solrns]", was conducted at College of Agriculture, Vellayani, Thiruvananthapuram during 2001-2003. Fourteen pathogenic fungi of water hyacinth obtained from the survey conducted as a part of the DST project on "Biocontro l of water hyacinth using mycoherbicides" were used for the study. Fungi which were not identified earlier were characterized and identified based on the cultural and morphological characters and was confirmed by sending to Agharkar Research Institute, Pune. These three fungi viz., Bipolaris tetramera, Drechslera sp. and Pestalotiopsis guepinii, were new records on water hyacinth. The fungi varied in the symptom development on water hyacinth with respect to nature of symptoms, parts affected and the time taken for the symptom development. The intensity of infection by the fungi varied from 9.94 to 58.80 per cent. Only five fungi viz., A.eichhorniae, F. moniliforme, F. oxysporum (isolate 2), F. pallidoroseum (isolate 3) and I M. advena gave more than 45 per cent intensity of infection. Cell free metabolites of the various fungi also varied in the symptom development. Intensity of damage varied from 8.03 to 89.00 per cent. Maximum was recorded by M. advena followed by F. pallidoroseum (49.80 per cent), A. eichhorniae (48.80 per cent) and F. oxysporum (47.20 per cent). Host range of A. eichhorniae, F. moniliforme and F. oxysporum was studied in detail. A. eichhorniae infected only three weed plants out of the 37 cultivated and 39 weed plants tested. F. moniliforme infected five 11 cultivated and 11 weed plants. F. oxysporum was found to be pathogenic to seven cultivated and nine weed plants. Combined application of A. eichhorniae and F. p allidorose um recorded higher intensity of infection than when sprayed alone. A. eichhorniae was found to give effective destruction of the weed at 107 spores per ml concentration. A. eichhorniae at 107 spores per ml and F. p all idoroseum at lOll spores per ml together recorded more intensity of infection of 89.84 per cent than when sprayed alone. Talc based combination product of A. eichhorniae and F. pallidoroseum when sprayed at 10.00 per cent concentration recorded an intensity of infection of 93.20 per cent, 10 days after spraying. The formulated product could retain the viability of spores of the pathogens at room temperature for 15 days.
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    ThesisItemOpen Access
    Response of chilly to plant growth promoting rhizobacteria fluorescent pseudomonads
    (Department of Agronomy, College of Agriculture, Vellayani, 2003) Anu, V; KAU; Elizabeth Syriac, K
    The research project entitled 'Response of chilli (Capsicum annuum L.) to plant growth promoting rhizobacteria fluorescent pseudomonads' was carried out as two investigations viz., a pot culture trial and a field study at the College of Agriculture, Vellayani, during July 2002 to April 2003. The study was conducted on chilli cultivar, Jwalasakhi. The pot culture study was aimed at evaluation of fluorescent pseudomonads isolates for growth promotion and yield in chilli. The treatments consisted of five different isolates of fluorescent pseudomonads (PI, P5, P14, P22and KKI6). The trial was laid out in completely randomised design with four replications. Among the five isolates tested, isolate P22 was adjudged as the best one for growth promotion and P I for disease resistance. As far as yield and economics are concerned, these two isolates were found to be on par. Thus a dual culture of Tsolate P22 and PI was selected for further field study. The objective of the field study was to assess the suitability of the best isolate of fluorescent pseudomonads as a biofertilizer either alone or in combination with Azospirillum along with different doses of NPK . fertilizers on growth and productivity of chilli. The field study was laid out in factorial randomised block design with three replications. The different treatments included three different levels of NPK (75 per cent (56.3 : 30 : 18.8 kg ha"), 100 per cent (75 : 40 : 25 kg ha') and 125 per cent (93.8 : 50 : 23.5 kg ha-I) of the recommended dose of NPK as per POP) and four biofertilizer treatments (Fluorescent pseudomonads, Azospirillum; Fluorescent pseudomonads + Azospirillum and no biofertilizers). The abstract of the result is furnished below. r I~ All the growth characters increased significantly with graded doses or PK. Combined inoculation of fluorescent pseudomonads and Azospirillum was the most superior one among biofertilizer treatments. Similar trend was also observed for yield attributing characters. However with regard to marketable fruit yield, all the levels of NPK fertilizers tested were statistically on par. With respect to biofertilizer application, combined inoculation (7.75 ha") was on par with fluorescent pseudomonads application (7.56 t ha-I). Compared to control of no biofertilizer treatment, Fluorescent pseudo monads + Azospiriflum increased fruit yield by 46.69 per cent. Among the treatment combinations, 75 per cent of the recommended dose of NPK (56.3 : 30 : 18.8 kg ha-I) + Fluorescent pseudomonads + Azospirillum produced significantly higher yield (8.74 t ha-I) and ensured a saving of 25 per cent of recommended dose of NPK. 100 per cent POP + Fluorescent pseudomonads application was on par with this treatment. At 125 per cent of the recommended dose of NPK (93.8 : 50 : 23.5 kg ha I) microbial count in the rhizosphere was significantly lower and fruit rot incidence was significantly higher. Biofertilizer application significantly increased microbial count and reduced disease incidence. 75 per cent of recommended dose of PK + Fluorescent pseudomonads + Azospirillum was rated as the most economically viable treatment combination, with a net profit and benefit-cost ratio of Rs. 59328 ha-I and 1.82 respectively.
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    ThesisItemOpen Access
    Integration of nutritional inputs for improving rice productivity in laterite soils
    (Department of Agronomy, College of Horticulture, Vellanikkara, 2003) Jinappa, Halingali; KAU; Usha, K E
    A study on "Integration of nutritional inputs for improving nee productivity in laterite soils" was taken up during 2001-2003 at the College of Horticulture, Vellanikkara The experiment consisted of 17 treatments including two sources of organic manure and two levels of nutrition with combinations of lime and silica to develop a cost effective, high yield and sustainable production technology for rice by identifying the components of good management. The treatment .receiving poultry manure with 90 kg ha" of fertilizer N and 500 kg ha" of silica recorded the maximum height productive tillers, •number of spikelets per panicle and thousand grain weight which . contributed to the maximum grain yield 0[7004 kg ha". An increase in 1680 kg grain yield and 1087 kg straw yield than the package of practices recommendation of Kerala Agricultural University appear to be due to the application of Silica, substitution of cow dung by the poultry manure and increased dose of N with an organic: inorganic ratio of 1 :2.25, increased dose ofK and reduced dose ofP. Cow dung contains Fe, Zn and Cu in toxic levels to rice. Poultry manure has the content of these elements in far less quantities but has higher Ca content . which helps in reducing the uptake of unfavourable elements by the rice plants. Increase in'the level of K application @120 kg ha' has recorded 1387 kg ha" more grain than the present recommendation of 35 kg ha" and the uptake of K by the plants are far above the applied levels. This suggests that the present recommendation of35 kg ha' ofK has to be enhanced up to 120 kg ha" to prevent the soil degradation. It is also seen that the rice plants absorb only around 20 kg P and hence the P recommendation can be reduced from 35 kg to 20 kg ha". There was no apparent effect when lime and silica were applied together but individually they could improve the yield. The number of weeds and the incidence of pests and disease were less in thetreatment plots, which revealed the influence of soil ameliorants in impa~ing resistance in the rice pants. TIle. results of the present study indicate that the failure of rice plants to respond to higher doses of fertilizer N, appears to be because of the unfavourable organic: inorganic' ratio. A ratio of 1 :2.25 was found to be beneficial to nullity the unfavourable chemical effects of fertilizer N.