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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 Land evaluation and suitability rating of the major soils of Onattukara region(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1998) Premachandran, P N; KAU; Subramonia Iyer, MThe need for a scientific approach in inventorying and utilizing land resources most economically and efficiently is now universally accepted. Agricultural prosperity, to a great extent, depends on judicious use of soils and rational application of soils data. A reconnaissance soil survey of Onattukara region was undertaken to study the extent and distribution of the different soils for soil classification, land capability and irrigability classification and for subsequent land evaluation. The study reveals that Onattukara region extends over an area of 40,948 ha. The soil map showing the distribution of the identified twenty soil series has been prepared. The climatological data reveals that the soil moisture regime is , ustic and the soil temperature regime is isohyperthermic. The soils have been classified as per Soil Taxonomy (U.S. Soil Survey Staff, 1975) and Keys to Soil Taxonomy( U.S. Soil Survey Staff, 1994 and 1996). Ten series were classified under Entisols, SIX under Inceptisols, three under Ultisols and one under Alfisols. Based on the inherent soil characteristics and landscape features, the soils have been grouped into three land capability classes, nine capability subclasses and land capability map prepared. The soils were classified into five land irrigability classes, eight land irrigability subclasses and land irrigability map prepared. The soils were evaluated based on principles of land evaluation and rating of productivity parameters. The productivity rating of the soil propertIes agamst the productivity index for nee, coconut, sesamum ,cassava and banana were made and conclusions arrived at. Productivity rating shows that Kottakakam series is best suited for rice, Palamel, best for coconut and banana, Artuva and Mahadevikad, for sesamum and Palamel and Vallikunnam, for cassava. On the basis of the studies carried out, a land use is proposed for the twenty soil series of Onattukara region based on crop suitability ratings and crop suitability map prepared for the five crops taken for study. A proper soil survey interpretation provides information on soil potential, productivity and limitations in their sustained use. Soil survey information forms the major basis for land evaluation. A thorough knowledge of the potentialities and limitations of every piece of land is a prerequisite in its efficient utilization. A systematic survey is essential for the evaluation and classification of the soils based on their inherent soil characteristics, land capability, land irrigability and land suitability. A systematic survey and evaluation of the soils of Onattukara region was taken up to study, interpret, classify and to show their location and extent on base maps. It is hoped that the present study would open up avenues for further investigations on land evaluation, crop suitability and other management aspects for sustained use of soil resource data to the best advantage. This will also form the basis for microlevel planning for integrated and sustainable development of the region under Panchayat raj.ThesisItem Open Access Distribution of extractable in soils of selected major land resource area of Kerala(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1997) Sathyanarayanan, R; KAU; Abdul, HameedThe investigation was carried out to assess the total and available micronutrients in soils of selected major land resource areas (MLRAs) of' Kerala. The micronutrients investigated in the present study were iron, manganese, zinc, copper and boron. The study was intended to establish the pattern of the distribution of micronutrients both vertically and spatially in eight MLRAs viz, Palode, Vellayani, Trivandrum, Mannar, Kottarakkara, Thakazhy, Ramankary and D-Block soil series of Kerala. Three extractables viz DTPA, EDTA and ammonium acetate were used in the analysis. The available boron content in these soils was also determined by hot water extraction method. All the micronutrients showed great variation in their distribution in the various horizons of the profiles. The micronutrients content of the soils estimated were correlated with soil properties like pH, organic carbon, CEC and clay content. They were found to be positively and significantly correlated with organic carbon, CEC and clay content while it was significantly and negatively correlated with pH. The significant correlations revealed that the micronutrient availability in these soils were influenced greatly by the soil properties mentioned above. From the results obtained, it was observed that micronutrients like iron and manganese were well supplied in all the profiles studied. The micronutrients were found to decrease with depth except in Ramankary, D-Blockand Thakazhy series where it showed an irregular trend with depth due to the peculiar hydrologic and oxidation-reduction conditions existing in these soil series. The available and total micronutrients content in the surface soils from places around the profile sites did not show any significant variation among places. In almost all the samples very high iron content was recorded.ThesisItem Open Access Leaf litter dynamics in acacia and eucalyptus plantations(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1997) Moossa, P P; KAU; Venugopal, V KAn investigation entitled “Leaf litter dynamics in Acacia and Eucalyptus plantations” was undertaken to study the leaf litter production, litter decomposition and nutrient release characteristics, and impact of Eucalyptus and Acacia monoculture plantations on the soil physico-chemical and biological characteristics during 1994-97. One hectare each of Acacia auriculiformis, Eucalyptus tereticornis and a moist deciduous forest coming under the Kulathupuzha range of Kerala Forest Department were selected for the study. Field experiment were conducted to determine the leaf litter production and decomposition characteristics of plantation and natural forest. Leaf litter collected at monthly intervals showed that highest litter production was in Acacia (9.4 t ha-1 year-1) followed by natural forest (6.67 t ha-1 year-1) and Eucalyptus (4.68 t ha-1 yaer-1). Pattern of litter production was unimodal in Acacia and natural forest while in Eucalyptus it was bimodal. Chemical analysis of litter samples of plantations and natural forest revealed that with respect to nutrient content fresh and leaf litter of Acacia and Eucalyptus is superior to natural forest whereas litter quality in terms of water soluble components, polyphenols, lignin and cellulose were superior in natural forest. Annual dry matter loss of leaf litter by decomposition followed the order natural forest > Acacia > Eucalyptus. Nutrient release pattern of major and micro nutrients were also worked out for the leaf litter during the process of decomposition and natural forest litter recorded the highest mobility for all the nutrients on decomposition. Improvement in soil physico-chemical properties were noticed due to leaf litter decomposition in the monoculture plantation and natural forest. Biological activity in terms of earthworm and nematode under monoculture plantation was significantly lower than that of adjacent natural forest. Microbial content of soil below the litter bag during different months of decomposition were low in Eucalyptus and Acacia. Chemical analysis of the profile samples of various plantations revealed lower nutrient status in respect of major and micronutrients compared to natural forest. The physical properties of the soil also recorded as unfavourable change in the monoculture plantations as compared to the adjacent natural forest. Proximate anlysis of soil organic matter and humus characterization of the soil organic matter separated from various plantations indicated a low rate of humification and condensation under Eucalyptus. Low humic acid and fulvic acid content in humus and dominance of fulvic acid over humic acid was also noticed in Eucalyptus plantations. Functional group analysis of humic acid and fulvic acid showed that humic material separated from natural forest contained higher quantity of total acidity, contributed by COOH and phenolic group compared to plantation soils. UV, IR, DTA and TGA analysis of humic acid and fulvic acid separated from various plantations showed no variation with respect to natural forest. Allelopathic effect of fresh leaf and leaf litter extract of various plantations on the germination and growth of rice and cowpea followed the order Eucalyptus > Acacia > natural forest and as the concentration decreased from 1: 2 to 1: 10, the allelopathic inhibition also decreased significantly. Allelopathic effect of soil extract also followed the order Eucalyptus > Acacia > natural forest. Thus it can computed that though the leaf litter production and litter quality of monoculture plantations are comparable with that of natural forest, leaf litter decomposition and nutrient released were significantly lower than that of natural forest. Soil physico-chemical properties, soil fertility and biological activities were also adversely affected by monoculture plantations.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.