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  • ThesisItemOpen Access
    Effect of Vermicompost on the yield and quality of tomato (lycopersicon esculentum Mill.)
    (Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1996) Pushpa, S; KAU; Prabhakumari, P
    An investigation was carried out at the Instructional Farm, attached to the College of Agriculture, Vellayani to evaluate the Effect of vermicompost on the yield and quality of tomato. The experiment was laid out in Randomised Block Design with ten treatments and three replications. Biometric observations viz. height of the plant, number of leaves and number of floweres were greately influenced by the application of vermicompost compared to farm yard manure. Yield attributes like mean fruit weight and girth of fruits were also found to be significantly influenced by the vermicompost application. Vermicompost application has got a significant influence on the yield of tomato. Plants receiving 25t vermicompost along with full dose of inorganic fertilizers produced maximum yield followed by the plants receiving 25 t farm yard manure along with full dose of inorganic fertilizers. Germination count and viability was maximum when vermicompost was used as the organic source. Maximum germination count and viability was observed when 100t ha-1 vermicompost was used. Vermicompost application has also got a significant influence on fruit qualities. Protein, and carbohydrate content were more in vermicompost treated plants compared to farm yard manure application. Chemical properties of the soil was significantly influenced by the application of vermicompost. pH, organic carbon, available N, P2O5, K2O, Ca and Mg was maximum when 25t vermicompost along with full dose of inorganic ferilizers was used. However availability of micronutrients Mn, Cu, Zn was more in 100t vermicompost applied plots. Application of vermicompost increased the uptake of nutrients by plants. Maximum uptake of all nutrients viz. N, P, K, Ca, Mg, Mn, Cu and Zn was found in plants treated with 25t vermicompost along with full dose of inorganic fertilizers. Correlation studies showed that nutrient uptake was significantly and positively correlated with availability of nutrients. Yield and nutrient uptake of plants were significantly and positively correlated with availability of nutrients and so vermicompost can be effectively used for increasing the fruit yield and quality of fruits in tomato.
  • ThesisItemOpen Access
    Behaviour of phosphorus in selected soil types of Kerala
    (Department of soil science and agricultural chemistry, College of horticulture,Vellanikara, 1993) Vijayan, A P; KAU; Sumam Susan, Varghese
    In order to study the distribution of inorganic P-fractions finding suitable chemical extractant for phosphorus, to study Q/1 relationship as a method of estimating available P and for studying adsorption- desorption characteristics of the soil types of Kerala, 100 surface soil samples were collected. These soil types were selected from different parts of the state belonging to five soil types viz., laterite, coastal alluvium, brown hydromorphic, Kuttanad alluvium and black soil. It is observed that all the soil types except black soil were acidic, clay content was comparable in case of black soil, Kuttanad alluvium, brown hydromorphic and lateritic but it was very low in coastal alluvium. Maximum content of sesquioxide and total phosphorus recorded in laterite soils and minimum in coastal alluvium. Dominant inorganic fraction in laterite and black soil was Ca- P while in coastal alluvium, brown hydromorphic, and Kuttanad alluvium dominant fraction was Fe- P. Coastal alluvium recorded maximum content of saloid- P, Al- P and Fe- P content were maximum in Kuttanad alluvium. Maximum content of Ca- P was recorded in black soil. Studies in black soil showed that total P is correlated to free carbonates significantly and positively. The different extractants studied in different soils showed that extractants should be selected according to soil types. Mathew’s triacid proved as a better extractant for available P in laterite and coastal alluvium. In case of Kuttanad alluvium soil Bray No.1 is better. Mathew’s P correlated significantly to uptake in laterite, coastal alluvium and Kuttanad alluvium. Olsen’s P correlated to uptake in laterite and Kuttanad soils. Phosphate potential negatively correlated to uptake in Kuttanad alluvium, coastal alluvium and brown hydromorphic soil. Where as equilibrium phosphate potential negatively correlated to uptake in coastal alluvium alone. DPBC values are not found as a suitable method for the estimation of available P. The P desorption adsorption studies showed that adsorption studies was not correlated to P uptake. While the desorbed P correlated significantly and positively to P uptake in laterite soil alone.
  • ThesisItemOpen Access
    Quality and fatty acid composition of coconut oil in relation to varietal variation and mineral nutrition
    (Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1994) Geetha Kumari, V S; KAU; Ranjendran, P
    Coconut is a perennial oil seed crop with a large number of cultivars having widely varying growth and yield characteristics. It is both an agricultural and industrial crop with immense economic importance. A variety of edible oils are available in the market today with wide variations in quality parameters and nutritional characteristics. Although product quality is influenced by many factors associated with production, harvesting, curing and processing; quality is influenced to a greater extent by the genetic parameters and chemical composition. Assessment of quality parameters and fixing standards for the nutritional aspects are to be considered with top priority for the development of new varieties/cultivars along with the yield attributes. Considering the afore mentioned facts in view, it was felt essential to study the effect of varietal variation and mineral nutrition on the oil content, quality and fatty acid composition of coconut oil. Nuts collected from different varieties/cultivars from RARS, Pilicode, Instructional farm, Vellayani and palms of an ongoing fertilizer trial of the CRS, Balaramapuram, were subjected to chemical analysis to study the above aspects. The results of the analysis were summarised and appropriate conclusions drawn. The effect of varietal variation on the oil content and quality parameters like acid value, saponification value and iodine value were found to be significant. Minor quality parameters like Reichert – Meissel and Polenske value also showed considerable differences among the varieties. The fatty acid composition of oil from selected varieties also had shown considerable variation. The effect of mineral nutrition on the oil quality and fatty acid composition of coconut oil were found to be insignificant. The oil content was not influenced by nitrogen and phosphorus while potassium had a significant but negative effect on oil content. The influence of N, P and K fertilizers on the quality parameters like acid value, saponification value and iodine value was not significant in general. Minor quality parameters like Reichert – Meissel and Polenske value showed variation due to fertilizer treatments. The fatty acid composition of oil from selected treatments. The fatty acid composition of oil from selected treatments were also influenced by mineral nutrition. From the results of the study it can be concluded that quality parameters of coconut are much influenced by varietal differences than by mineral nutrition. Thus it is evident from the study that the genetic variability has got a greater role to play in modifying quantity parameters and chemical composition of the most important tropical adible oil namely coconut oil. Selection and breeding should be directed towards tailoring new varieties with higher oil content, quality indices and fatty acid composition.
  • ThesisItemOpen Access
    Characterisation of the gravels in the major soil series of Trivandrum district
    (Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1996) Suraj, John; KAU; Subramonia Iyer, S
    Soil gravels are different in their morphological, physical, chemical and mineralogical features; as well as in their origin. In the major soil series of Trivandrum district, soil gravel inclusions make up a considerable part of the soil mass. Presence of soil gravels interferes with the cultivation operations, reduce soil volume and quantity of available water. In soil textural determinations and the soil fertility evaluation, presence of soil component greater than 2mm is usually disregarded and ignored. In order to gather information on the nature and properties of soil gravels, their genesis and distribution and their specific contribution to soil fertility; an integrated and systematic morphological, physical, chemical, mineralogical and micromorphological characterisation and interpretation of soil gravels of the representative profiles of the major soil serious of Trivandrum district namely Palode, Nedumangad, Varkala, Thonnackal and Trivandrum series were attempted. All the series except Thonnackal were gravelly throughout; Palode, Varkala, and Trivandrum series showed an increase in gravel content with depth but no specific profile pattern was observed at Nedumangad and Thonnackal. Palode series is unique with all the different gravel fractions (2mm to 2.5 cm, 2.5 to 7.5 cm and 7.5 to 25 cm). Another uniqueness of the Palode series is the presence of gneissic cobbles. Cobbles were absent in all the other series. Combination of grayels different in morphology and genesis are present at Palode and Trivandrum series. Gravel consolidation and soil hardening were observed maximum at Varkala series and least at Thonnackal series. Higher total phosphorus and potassium content of gravels indicate that gravels are the potential source of phosphorus and potassium for crop production. Acid insoluble content of gravels are in the increasing order Varkala< Trivandrum Quartz content of the finer gravels are in the increasing order at Varkala Palode and Nedumangad series contain multiglaebular microgravels and multimicrogravelly coarse gravels and cobbles. The gravels of Varkala are dominantly nodular than concretionary. The uniqueness of the Thonnackal series is the presence of rubefied less hard kaolinitic gravels. The gravels of the Trivandrum series are nodular, plinthic to petroplinthic with bigger angular skeletons. The preponderance of gravels with geodic internal morphology in the lower horizons and pseudomorphic in the surface horizons are direct expressions of geogenic and pedogenic origin of gravels. The observation of nucleic type of gravels in the last horizon of Thonnackal series is indicative of its detrital origin from microgravels of nearby landscapes. The preponderance of quartz both in the soil and gravels is obviously due to the acid igneous and metamorphic parent material. The hardened plinthite gravel ie., the petroplinthite gravel is proposed in the soil taxonomy to differentiate Entisols and Inceptisols from Oxisols and Ultisols. The comparative gravel contribution to available nitrogen content of the soil is in the increasing order Palode A multilocational field experiment based on the information gathered in the present study is desired to be taken up to reveal the effect of gravels on the performance of crops in the actual field situation.
  • ThesisItemOpen Access
    Soil temperature and moisture characteristics as influenced by inter-cropping of fodder crops in coconut garden
    (Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1993) Asok, P I; KAU; Pushkala, S
    An investigation was undertaken to study the effect of fodder grasses grown as inter crop in coconut garden on the soil characteristics. The observations were carried out from the already laid out experimental plot in the farm area of college of Agriculture. The layout was in randomised block design with six treatments and four replications. The treatments included guinea grass, congo, signal grass, setaria grass, molassess grass, hybrid napier and contrest. Soil samples were collected from two depths namely 15 cm and 30 cm from the surface. The samples were collected during March-April, July-August and December-January. The soil analysis was done for moisture, porosity, bulkdensity, particle density and water holding capacity. The infiltration rate and hydraulic conductivity were carried out at the close of the experiment. Chemical analysis was done for nitrogen, phosphorous, potassium, calcium and magnesium. The effect of growing fodder crops on soil moisture content was not significant. The thick canopy of guinea and congosignal grass could retain moisture in the field. The water holding capacity in the control plot was less than the fodder plot. So the competition for water would be minimum for coconut and fodder crops. The soil moisture was negatively correlated with soil temperature. Setaria and molasses grass could conserve moisture on the surface while other grasses could retain moisture on the subsurface layer. Fodder grass roots improved the structure of the soil. Bulk density values were reduced. The changes on particle density and porosity values were negligible. The hydraulic conductivity value observed for setaria grass was highest and the lowest value was recorded by guinea grass. Infiltration rate showed no significant difference among treatments. Soil temperature values were brought down by fodder grass cultivation during daytime, insulated the soil when it was cooled. There was no significant effect on the chemical properties of the soil namely, soil reaction , available nitrogen, available potassium, exchangeable calcium and exchangeable magnesium. Soil phosphorous level shown by the setaria grass was high, which was positively correlated with the soil temperature. Inter-cultivation with fodder grass in coconut garden, is not deteriorating the physical properties, but it can improve the hydraulic characteristics and thermal properties thereby leading to an increase in the coconut yield.
  • ThesisItemOpen Access
    Classification of the upland soils of Kerala
    (Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1993) Bindu Kumari, A; KAU; Subramonia iyer, M
    Soil taxonomy is one of the well accepted popular system of soil classification through which soil information can be communicated globaly. Inorder to have the soil Taxonomy information of the uplands of Agricultural Rsearch Station and Centres under Kerala Agricultural University and CWRDM, Calicut one representative profiles were examined described analysed for physical chemical and mineralogical properties and with the available site and climatic parameters and from the results of the present study the soil were classified as per Soil taxonomy (1975). All the soils are gravelly, clay loam to clayey texture with kaolinitic to mixed mineralogy with expanding 2:1 minerals at Pampadumpara, Ambalavayal and Kannara. At Calicut the clay fraction is more than non clay fraction. Irrespective of the profiles, the profiles are with ustic moisture regime and isohyperthermic temperature regime. The temperature regime at Pampadumpara and Ambalavayal is hyperthermic. Based on the degree of weathering revealed by silt/clay ratio the profiles can be arranged with a decreasing degree of weathering Calicut > Kottarakara > Balaramapuram > Vellayani > Pampadumpara > Ambalavayal > Thiruvalla > Pillcode > Vellayani II > Tavanur > Odakkali > Vellanikkara > Kannara Based on the available information and results of the present study, keys the profile in to the following taxa as per soil Taxonomy (1975). 1. Balaramapuram Fine loamy kaolinitic isohyperthermic family of kandic Haplustalf. 2. Vellayani Fine loamy kaolinitic isohyperthermic family of Typic Kandiustults. 3. Thiruvalla Fine loamy mixed isohyperthermic 4. Odakkali family of Tropustults. 5. Kottarakara Clayey skeletal kaolinitic 6. Vellanikkara isohyperthermic family of Typic 7. Pilicode Kandiustults 8. Pampadumpara Fine loamy mixed isohyperthermic family Haplustalf. 9. Kannara Fine loamy mixed isohyperthermic 10. Ambalavayal family of Haplustalf. 11. Calicut Clayey skeletal kaolinitic isohyperthermic family of kandiudlts 12. Tavanur Fine clayey kaolinitic isohyperthermic family of petroferric Dystropepts. The family charactors reveal that thesee soils are with less availables water capacity, low cation exchange capacity. Soil temperature is not a problem in these soils. The typic subgroup indicates lesser problems of water logging. The argillic and kandic endopedon indicates low nutrient holding capacity and presence of low active clays (LAC) warranting special soil management measures for increase crop production like split application of fertilizers. Ustic moisture regime is indicative of prevalent water stress in these profiles sites. The order Ultisol , Alfisol and even inceptisol is indicative of highly weathered soil of varied horizon development and less fertility because of lower percentage bases saturation (PBS) The present study gives a “soil basis” for the global communication and appreciation of the valuable research results of these research institutions. The research results, the crop performance from all these research institution are to be gathered and critically analysed with the “soil basis” as a future line of work.
  • ThesisItemOpen Access
    Behaviour of potassium in selected soil series of Thiruvananthapuram district
    (Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1993) George, Joseph; KAU; Saifudeen, N
    An experiment was conducted at the Department of Soil Science and agricultural Chemistry, College of Agriculture, Vellayani with 50 surface soil samples each from Trivandrum, Kazhakuttom and Kottor series to assess the behaviour of soil potassium. Water soluble, available, exchangeable, nitric acid soluble and non – exchangeable potassium in these soils were determined. Sample observations on total potassium from soils with low, medium and high available potassium were also undertaken. In addition, the physical and chemical properties of all the samples were studied through observations on soil separates, pH, electrical conductivity, organic carbon, cation exchange capacity, base saturation and exchangeable forms of calcium, magnesium and sodium. Neutral ammonium acetate (1.0 N) extractable potassium (available form) was found to be positively influenced by water soluble, exchangeable and nitric acid extractable forms of potassium. The organic carbon content positively influenced the available potassium where the soil organic carbon was low viz., Trivandrum and Kazhakuttom series. Cation exchange capacity also had a positive influence on available potassium. Percentage base saturation influenced available potassium positively, except in forest soils. In Trivandrum series 71 percent of nitric acid potassium was available to crops; while the corresponding values were 46 and 51 percent in Kazhakuttom and Kotoor series respectively. The total potassium content was also relatively high in Trivandrum series. The relationship between various forms of soil potassium and also between potassium fractions and other soil components expressed varying trends in soils falling under different fertility classes. This aspect needs further investigation. Quantification of the contribution of different fractions of soil potassium towards crop uptake is suggested as a future line of work. Basic studies on the ionic equilibria in soil solutions which affect potassium exchange and availability in these soils also warrants attention.
  • ThesisItemOpen Access
    Soil nutrirent dynamics in cocoa
    (Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Smitha, B; KAU; Wahid, P A
    An investigation on the dynamics of soil nutrients in the rootzone of cocoa (Theobroma cacao) was conducted during 1993 – 94 at the College of Horticulture, Vellanikkara. Soil and leaf samples were taken from cocoa trees under the Cadbury – KAU Co – operative Cocoa Research Project, Vellanikkara. Cocoa variety used for the study was forastero. The soil of the site was laterite (Oxisol). The treatments consisted of factorial combinations of N, P and K fertilizers each at two levels (with and without), two levels (with and without) of irrigation and shade and seven age groups namely 1, 3, 4, 5, 6, 9 and 12 years. Soil samples were also collected from an uncropped and unfertilized area nearby. The impact of long – term inorganic fertilization, irrigation and shade and age of the tree on soil chemical characteristics as well as foliar nutrition of cocoa influenced by long – term inorganic fertilization, irrigation and shade were assessed. Continuous application of urea for a period of nine years increased soil acidity and availability of P, S, Fe and Mn. It also increased total soil P and Fe. But it resulted in depletion of available K, Ca, Mg, Zn and Zn and Mn reserves of the soil. Long – term application of superphosphate resulted in the build – up of available and total P in soil. It also improved the status of soil available Ca, S and soil reserves of Ca and S. But it depleted soil available and total K, available and total Zn, available Mg and Cu and total Mn. Muriate of potash application increased the available and total K content of the soil. On the other hand it caused depletion of available P, Ca, S, Mn, Cu and soil Ca and Mg reserves. Interactions among urea, superphosphate and muriate of potash were also significant with regard to the fertility of the cocoa rootzone is concerned. Increasing soil acidity due to urea application, enrichment of S and Ca due to superphosphate application, and decrease in available P and S due to muriate of potash application were highly influenced by depth. Regular irrigation over a period of five years resulted in reducing the availability of P, Ca, Mn and Cu. It also reduced the total P and Mn in soil. But available K, Zn, S and total S tended to increase with irrigation. In the irrigated plots, total and available P were significantly lower in the surface layers compared to that in unirrigated plots. Provision of shade for a period of 13 years resulted in the build – up of soil organic carbon, available P, Fe and soil reserves of P, Ca, S, Fe, Zn and Mn. On the other hand it decreased the concentrations of available and total K, available S, and Zn and total Mg. Irrigation x shade interaction significantly influenced the available P content of soil. Urea application increased the foliar concentrations of N, Fe, Mn and Cu, but it decreased the leaf K content significantly. Long – term superphosphate application reduced Zn content of cocoa leaf. Application of muriate of potash increased leaf K content, but depressed foliar mg content significantly. Leaf N and K contents of cocoa were highly influenced by N x K interactions. N x P interaction significantly affected foliar Zn concentration of cocoa. Foliar Zn recorded higher values in plants receiving no nitrogen and phosphorus. Irrigation resulted in increased foliar concentrations of almost all nutrients except that of Ca and Mg. Foliar Ca content was higher in unirrigated plants. Effects of irrigation on leaf Mg was not significant. Cocoa trees under shade recorded higher concentrations of N, P, Mg, Fe and Mn and Cu in their foliage while K content was higher in open grown plants. Irrigation x shade interaction significantly influenced foliar N content. Shaded and irrigated conditions resulted in highest foliar N content. Nutrient dynamics in rootzone of cocoa over a period of 12 years of crop growth and fertilization could be described by linear or quadratic model. The linear model was found to be a better fit for available and total K, available and total Mg, available Cu and total Zn. In the case of available and total P, available and total Ca, available Zn, total S and total Cu the changes in concentrations with time could be described by a quadratic model. Available Mn content of the soil showed steady increase with age up to nine years followed by a sharp decrease.
  • ThesisItemOpen Access
    Fertility investigation and taxonomy of the soils of banana research station Kannara
    (Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Sreerekha, L; KAU; Marykutty, K C
    Taxonomy and fertility investigation of the soils of Banana Research Station, Kannara, was the main intension of the present investigation. Representative surface soil samples were collected from each block of this research station, namely A, B, C, D, E and F for investigating the fertility status of soil. Profiles considered for the study were P1 and P2 in A block, P3, P4 and P5 in B block, P6 and P7 in C block, P8 in D block, P9 in E block, and P10 in F block. Profiles were excavated to study the characteristics of each of the horizons in the soil profile and classify the soils of each block. After the collection and preparation of soil samples, laboratory analyses were carried out as per the standard methods. With an increase in depth, profile samples showed an increasing intensity of colour of the horizons and increase in clay content whereas a decreasing trend was noticed for apparent density, absolute density, water holding capacity and pore space. Soils were acidic and low electrical conductivity values were observed. Organic carbon and total nitrogen decreased with depth. Total P2o5 content was lower than total K2o. Low reserves of total nutrients were observed for other elements also. Sesquioxide content was very high and intermediate layers showed maximum accumulation. In surface as well as profile samples the predominant cation was calcium followed by magnesium. A general increase of CEC and ECEC with depth was observed. Oxalate extractable iron content was lower than the dithionite extractable iron. Distribution of total iron was irregular. Surface soil showed wide variation in texture. Clay content showed significant positive correlation with water holding capacity whereas silt and organic carbon failed to impart any influence upon the same. Phosphorus fixing capacity was high for all the samples. DTPA extractable micronutrients were more than the adequate amount. Based on the soil test values fertilizers were recommended for various blocks. Nitrogeneous fertilizers can be reduced by 5 to 10 per cent. Applications of phosphatic fertilizers can be reduced by 75 per cent in most of the blocks. Potassium fertilizers can also be reduced considerably. Nutrient indices were calculated and a soil fertility map was drawn. Classification of pedons of various blocks according to soil taxonomy has been attempted and found that P1 of A block belongs to the order Entisol. P2 (A block), P3, P4 and P5 (B block), P6 and P7 (C block), P9 (E block) and P10 (F block) belong to the order Alfisol. P8 of D block belongs to the order Inceptisol. By this investigation, the classification of soil profiles were done and the fertility status of each block was found out. In accordance with the soil test values, fertilizer recommendations were made. Thus, by reducing the inputs, cost of cultivation could be reduced considerably.