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ThesisItem Open Access Management of acidity by combined application of lime and gypsum in a low activity clay soil of Kerala(Department of soil Science and Agricultural Chemistry, College of agriculture, Vellanikkara, 1992) Jessy, Jacob K; Venugopal, V KThesisItem Open 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, PAn 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.ThesisItem Open 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, VargheseIn 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.ThesisItem Open 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, PCoconut 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.ThesisItem Open Access Influence Of Iron Toxicity On Growth Yield And Plant Composition Of Major Rice Varieties Cultivated In Kerala(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1993) Sheela, R; Ramasubramonian, P RA study was made to identify rice cultivars tolerant to iron toxicity situation culture using Hoagland solution. Thirty cultivars popular among the Kerala farmers were screened under the toxic level of 500 ppm iron and toxicity symptom displayed was scored on 1 - 9 scale. The varieties included high yielding and local ones. The varieties viz., Asha, Annapoorna, Aruna, Aswathi, Jaya, Jyothi, Karthika, Neeraja, Onam, Ptb – 2, Ptb – 10, Ptb – 20, Pavizham, Sabari and Santhosh exhibited severe toxicity symptoms with high scores, exceeding five. The plant iron content of these varieties at AT stage was found relatively higher than that of the remaining ones. Asha, Jaya and Jyothi were seriously affected with scores more than 8 and was therefore treated as highly susceptible. In varieties Bhagya, Bhadra, Bharathy, IR – 36, Kanakam, Makam, Rasi, Red Triveni, Remya and white Triveni, the intensity of visible symptom was lesser with scores ranging between 3 and 5. The iron content of the varieties was lower than in the susceptible varieties. These varieties were classified as moderately tolerant since they had the capacity to resist iron toxicity to a reasonable extent. Display of the least symptoms of iron toxicity and scoring were noticed in five varieties viz., H4, Mahsuri, Cherady, Kochuvithu and Keerthy. Plant analysis of these varieties at the At stage indicated the least iron content. In view of the comparatively better performance, these varieties were further examind to find out the comparative effect of increased iron levels at 400, 500 and 600 ppm on their growth and yield. The study indicated that, in general, growth and yield attributing characters as well as the yield decreased with progressive increase in iron level. H4 and Mahsuri recorded relatively higher grain and straw yields as compared to Cherady, Kochuvithu and keerthy. In all the varieties, the nitrogen content increased with increase in levels of iron whereas the uptake decreased. Keerthy recorded the highest content of nitrogen while H4 recorded the highest uptake of nitrogen. The content and uptake of P, K, Ca and Mg decreased in all the varieties as the level of iron was progressively increased. H4 and Mahsuri recorded significantly higher content and uptake of these elements in grain and straw while Keerthy recorded the lowest. The content of iron in all the varieties increased with increase in levels of levels of iron in growth medium. Relatively lower content of iron was recorded in the aerial parts of H4, Mahsuri and Cherady compared to other varieties, whereas roots of these varieties had higher iron content. The uptake of iron increased upto 500 ppm level and thereafter decreased in all the varieties. The study revealed that the varieties H4, Mahsuri, Cherady Kochuvithu and keerthy exhibited better performance even with toxic concentrations of iron. Among these varieties H4, Mahsuri and Cherady performed reasonably well and H4 performed better with regard to tolerance to iron toxicity. These varieties contained higher P, K, Ca and Mg and lesser iron as revealed by plant analysis. Better performance can be attributed to their genetic superiority such as better root development, improved root oxidation capacity and higher nutrient absorbing ability.ThesisItem Open 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, SSoil 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.ThesisItem Open 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, SAn 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.ThesisItem Open 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, MSoil 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.ThesisItem Open 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, NAn 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.
