Browsing by Author "Venugopal, V K"
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ArticleItem Open Access Available nutrient status of some red soils (Alfisols) from different regions in Kerala(Kerala Agricultural University, 1986) Betty Bastin; Venugopal, V K; KAUA study was made on the available nutrient status of sixty surface samples collected from red soil (Alfisols) series identified in different regions in Kerala. Among the major nutrients, Bray 1 extractable phosphorus recorded high values for all the soil series. Nitrogen was low to medium in Vellayani, Cheriniyoor and Beypore, while it was medium in Chirakkal, Bharanikkavu and Kunhimangalam series. Low to medium levels of available potassium was observed in Chirakkal, Bharanikkavu, Beypore and Cheriniyoor series while Kunhimangalam and Vellayani series showed low levelsof available potassium. All the soils showed high phosphorus fixing capacity. DTPA extractable iron and manganese were more than adequate in the surface soils of all the soils investigated. Zinc was deficient to adequate in Vellayani, Bharanikkavu and Kunhimangalam series and marginal to adequate in Cheriniyoor, Beypore and Chirakkal series. Copper was deficient to adequate in Vellayani, Cheriniyoor and Kunhimangalam series while, adequate levels were observed in Bharanikkavu, Beypore and Chirakkal series.ArticleItem Open Access Cadmium content of plants as affected by soil application of cadmium and farm yard manure(Kerala Agricultural University, Vellanikara, 2002) Usha, Mathew; Venugopal, V K; Saraswathy, P; KAUArticleItem Open Access Cation exchange capacity and chemical composition of clay fraction of some important soil groups of Kerala(Kerala Agricultural University, 1978) Venugopal, V K; Koshy, M M; KAUArticleItem Open Access Cation exchange capacity in relation to the mechanical composition and organic matter status of some soil profiles of Kerala(Kerala Agricultural University, 1976) Venugopal, V K; Koshy, M M; KAUA study was made of the cation exchange capacity of forty soil samples representing fourteen soil profiles of Kerala in relation to the mechanical composition and organic matter status of the soil. The important findings are summarised below: (1) The cation exchange capacity of the different soil groups exhibited wide variations, the sandy soil recording the lowest and the black soil the highest value. With the exception of black, kari and some alluvial soils all other soil groups gave very low values for this property. (2) Correlation between cation exchange capacity and clay for all the samples taken together was positive and highly significant. The same positive relationship was observed when the individual soil groups were considered. (3) The relationship between organic matter and cation exchange capacity for all the samples together was positive but not significant.ThesisItem Open Access Cation exchange studies in Kerala soils(Division of agricultural Chemistry, Agricultural College & Research institute Vellayani, Trivandrum, 1969) Venugopal, V K; KAU; Joshy, M MThesisItem Open Access Characterisation of laterite soils from different parent materials in Kerala(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1987) Stella Jacob; KAU; Venugopal, V KIn the present investigation, an attempt has been made to evaluate the morphological, physical, chemical and mineralogical characteristics of laterite soils occurring in different regions of Kerala in relation to the parent rock. Six soil series representing laterite soils identified by the Soil Survey Unit of Department of Agriculture, Kerala State were selected for the investigation. The soil series identified were Thonnackal, Kootala, Anjur, Kanjikulam, Mannur and Nenmanda located in Trivandrum, Trichur, Palghat and Calicut districts. Soil samples representing the different horizons were collected for laboratory studies. The physico-chemical characteristics of the soils, behaviour of iron and phosphorus fractions of samples were investigated with a view to study the interrelationship between various properties and to relate these characteristics to the genesis of the soils. Mineralogy of the fine sand fraction was also carried out. Placement of these soils under soil taxonomy was also attempted based on the available data. The salient findings are summarized below. The soils from different locations had striking similarity in colour with reed hues predominating. Coarse fragments formed a predominant portion of the soil and was mainly concentrated in the subsurface horizons. Most of the elements were found to be concentrated to the gravel as compared to the soil. Sand formed the predominant size fraction but the textual class of the soils was mostly clay. Increasing clay content with depth was a characteristic feature. The slit/clay ratios were very low indicating the highly weathered nature of the soils. The available water capacity was poor and the variations observed closely followed the distribution of clay. Kootala series had the highest available water capacity while Thonnackal recorded the lowest. The soils were in general acidic with very low electrical conductivity. The content of C, N and C/N ratios were very low. Silica formed the predominant fraction followed by Fe2O3 and AI2O3. The total reserves of CaO, MgO, K2O, P2O5 were very low and is a reflection of the mineralogy of the fine sand fraction which was dominated by quartz. The cation exchange capacities of the soils were very low. The CEC5 recorded still lower values as compared to NH4OAc method. The exchangeable bases were in the order Ca> Mg>K>Na in the case of Anjur, Mannur and Nenmanda series while in Thonnackal, Kootala and Kanjikulam series. Exchangeable Na was slightly higher than K. Among the acid generating ions extractable aluminium was very low. The percentage base saturation was low and did not show appreciable variation between soil series. The Fed formed the predominant iron fraction and based on the degree of freeness of iron in soils, Kanjikulam series was the oldest followed by Anjur, Kootala, Mannur, Nenmanda and Thonnackal. The active iron ratio (Feo/ Fed) recorded very low values for all the soils. Among the inorganic P fraction Fe-P was dominant in all the soils except Thonnackal series. Nenmanda series had the lowest content of Ca-P. All the soils were highly weathered based on the behaviour of P fraction. Silica was the dominant fraction of clay. Based on Sio2/Ai2o3 ratio, Thonnackal and Nenmanda were designated as ferralitic or true laterites. The Sio2/R2o3 ratio was the lowest among the molar ratios. The rocks were siliceous in nature with poor content of bases. The fine sand fraction of the soil also revealed a predominance of quartz and very little weatherable minerals. The heavy graction consisted of mainly opaques, zircon, sillimanite, mica, rutile and sphene. The soils did not reveal contrasting characteristics in their composition that can be attributed to the parent material. Under the influence of the high temperature and heavy rainfall conditions existing in the state, the effect of parent material has been obliterated and properties of the soils appear to be mainly governed by the dominating climatic factor conditioned by the relief of the area. Based on the available data Thonnackal series was classified under fine loamy kaolinitic isohyperthermic family of Typic Haplorthox while others belong to the clayey, kaolinitic isohyperthermic family of Typic Haplorthox.ArticleItem Open Access Comparative chemical composition of soil and gravel in some oxisols(Kerala Agricultural University, 1987) Stella Jacob; Venugopal, V K; KAUA study was made on the comparative chemical composition of soil and coarse fragment gravel in some Oxisol series identified in different regions in Kerala. The chemical composition of gravel showed a depletion of SiO, and accumulation of constituents especially Fe20s and AI203. Between sesquioxides, accumulation of Fea03 appeared to be more compared to AI203. The mean values for the profiles showed the highest accumulation of Fe203 in Thonnackal series followed by Anjur, Kanjikulam, Mannur and Kootala. High gravel/fine earth ratios of the constituents have been observed for Fe2O3. AI203, MgO, P2O5 and Na20. The gravel from the upper layers of the profile showed accumulation of constituents to a greater extent than the lower layers.ArticleItem Open Access Effect of lime in combination with gypsum on soil acidity parameters and uptake of nutrients in soybean(Kerala Agricultural University, 1994) Tessy Jacob, K; Venugopal, V K; KAULiming results in significant increase in plant heigh t, nodule number, dry weight of pod, grain yield, haulm yield, total dry weight and NPK uptake. Soil pH, effective CEC, total Ca, exchangeable Ca and available N were increased significantly due to liming. Significant reduction in Al saturation, exchangeable Al and available P and K occurred due to liming.ArticleItem Open Access Exchangeable cations of some important soil profiles of Kerala(Kerala Agricultural University, 1976) Venugopal, V K; Koshy, M M; KAUA study was made of the exchangeable cations of forty soil samples representing fourteen soil profiles of Kerala. The exchangeable base content of the different soils was generally in the order calcium > magnesium > potassium > sodium. In the case of kari and black soils the exchangeable sodium showed a higher content over potassium. The maximum amounts of exchangeable calcium, magnesium and potassium was observed in the black soil. The heighest value of exchangeable hydrogen was observed in the case of kari soil which also recorded very low values of pH.Institutional PublicationsItem Open Access Kole lands of Kerala(Kerala Agricultural University, 1993) Johnkutty, I; Venugopal, V K; KAUThesisItem 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 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 Horticulture, Vellanikkara, 1992) Tessy Jacob, K; KAU; Venugopal, V KAn investigation was conducted at the College of Horticulture, Vellanikkara in the period 1989-'91, with a view to identify the most appropriate and economic lime recommendation method and the most suitable combination of lime and gypsum for profitable management of upland latent e (LAC) soils. The first study was to characterise the low activity clay soils of Kerala m respect of acidity contribution factors. Another laboratory experiment was also conducted with PVC columns to study the mobility of Ca and Mg using different liming materials m combination with gypsum. A potculture experiment was also carried out using soybean to study the effect of liming in combination with gypsum on the growth, yield and uptake of various nutrients. The characterisation study revealed that the soils in the Vellanikkara series come under the textural class ranging from silty loam to silty clay loam. The soils m general were acidic in reaction with fairly high content of exchangeable Al and low CaO and MgO contents. Sesquioxide, and Al2O3 contents were high. The soils were low m organic carbon and CEC. The leaching experiment revealed that CaCO3 and MgCO3 can be used as an ameliorant for acid surface soils as it neutralised exchangeable Al and increased pH in the surface layer only. CaS0.2H20, however can be used as an ameliorant for acid subsoils as it neutralised exchangeable Al and supplied Ca throughout the length of the profile. The combination treatment with MgCO3 + 75 per cent CaSO4 2H2O can be suggested as an ameliorant for acid surface as well as subsoils as it resulted in uniform distribution of exchangeable Ca and Mg throughout the length of the column and neutralised exchangeable Al in the whole length of the profile. Liming resulted m significant increase in plant height, nodule number, dry weight of pod, g r a m yield, haulm yield, total dry weight and N, P, K uptake. , Soil pH, effective CEC, total Ca, exchangeable Ca and available N were increased significantly due to liming. However significant reduction in total Mg, exchangeable Al, Al saturation and available P and K resulted due to liming. Liming at the rate of 1.5 times exchangeable Al content of soil was found to be the most appropriate and economic lime recommendation method for the highly weathered and leached acid soils of Kerala.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 KArticleItem Open Access Micronutrient status of soil and leaf of coconut palms growing on reclaimed marshy soil(Kerala Agricultural University, 1985) Jose, A I; Venugopal, V K; Sushama, P K; Gopi, C S; Saifudeen, N; KAUArticleItem Open Access Morphology and particle size distribution in the soil profiles from a catena in Kerala(Kerala Agricultural University, 1985) Venugopal, V K; Koshy, M M; KAUInvestigations on the morphology and mechanical composition were carried out in a toposequence located in the mid-upland laterite region of Kerala. The sequential profiles in the toposequence showed a striking gradation in colour from reddish in the crest to different shades of grey in the valley. The structural development showed a decrease down slope. Another significant observation was the striking decrease in the content of coarse fragments down the slope. Among the size fractions, sand tended to accumulate in the nearly level lower slope position, while clay fraction decreased down slope. The formation of the diverse group of soils have been attributed to the variations in topography, causing erosion colluviation, sedimentation and other pedogenic processes modified by water table.ThesisItem Open Access Pedologic studies on lateritic catenary sequences occuring in Kerala(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1980) Venugopal, V K; KAU; Koshy, M NThree toposequences were identified at Varkala, Poruvazhy and Kalliaserry in the midland laterite regions of Kerala using soil maps prepared by the Soil Survey Wing of the Department of Agriculture. A systematic study of these catenary sequences along transects extending from crest to valley was made. Profile pits were dug at the different physiographic positions of the transects, viz., crest, upper midslope, nearly level lower slope and valley at each of these sites are examined for their morphological features. Soil samples representing the different horizons were also collected for laboratory studies. The physicochemical charecteristics, mineral assemblage of fine sand fraction and the minerology of the clays in the profile samples were studied with a view to relating these properties to the genesis of the four diverse groups of soils formed in the transects . Patterns of similarity or otherwise between the three locations of widely different conditions and the four physiographic positions were brought out .ArticleItem Open Access Phosphorus fractions in relation to the genesis of some oxisols in Kerala(Kerala Agricultural University, 1987) Stella Jacob; Venugopal, V K; KAUA study was made on phosphorus fractions from six profile collected from laterite soil (Oxisols) series identified in different regions in Kerala. Fe-P formed the predominant among the active fractions on all the soils investigated except Nenmanda and Thonnackal series indicating their highly weathered nature. This was followed by Ca-P and AI-P respectively in the case ©f Anjur, Kanjikulam and Mannur series. In Kootala series, Fe-P was followed by AI-P and then Ca-P. Thonnackal series showed a predominance of Ca-P followed by Fe-P and then AI-P.ThesisItem Open Access Physico-chemical characterisation of red soils in different regions of Kerala(Department of soil science and agricultural chemistry, College of Horticulture, Vellanikkara, 1985) Betty, Bastin; KAU; Venugopal, V KIn the present study an attempt has been made to evaluate the morphological, physical and chemical characteristics of red soils occurring in different regions of Kerala. Six soil series representing red soils identified by the soil survey unit of the department of Agriculture, Kerala state were selected for the investigation. The series identified were Vellayani, Cherniyoor, Bharanikkavu, Beypore, Chirakkal and Kunhimangalam located in Trivandrum, Quilon, Calicut and Cannanore districts. Profile pits were dug at these different locations and examined for their morphological features. Soil samples representing the different horizons were collected for laboratory studies. The physico-chemical characteristics of the soils and chemical composition of clays of the profile samples were investigated with a view to study the interrelationship between the various properties and to relate these characteristics to the genesis of these soils. Surface samples collected from different locations under each series were also analysed for available nutrients. The morphological features of the soil profiles revealed prominent red hues with increase in redness with depth. All the soil profiles were well drained, with ill defined horizons, exhibited good structural development and were devoid of coarse fragments. The soils were all sandy in nature, with the fine sand fraction predominating. Clay illuviation was observed in all the profiles. In respect of available water content appreciable variation was not observed between soil series. The highest available water content was recorded in Kunhimangalam series while beypore series had the lowest. All soils were acidic with very low electrical conductivity. The organic carbon, nitrogen and C/N ratios were low and showed little variation between soil series. Silica recorded very high values for all the soils while total Fe2 O3 and AI2 O3 did not reveal much variations between soil series. The total reserves of CaO, MgO, K2 O and P2 O5 were very low and is mainly a reflection of minerology of sand fraction which was dominated by quartz. In respect of total micronutrients iron and manganese recorded high values while Zinc and copper were low and did not reveal much variations between the different soils. Iron, Zinc and copper showed positive relationship with finer fraction while in the case of manganese, the relationship holds good in the case of fine sand fraction only. The e. c. e. c. values obtained were very low and less than the c. e. c. values determined by neutral N NH4 OAc method. Effective c. e. c. showed positive significant relationship with organic matter. The content of exchangeable bases were in the order Ca Mg Na K. Exchangeable hydrogen was more than exchangeable aluminium. Cherniyoor series recorded the highest percentage base saturation while the lowest value was obtained for Kunhimangalam series. The dithionite extractable iron was the predominant iron fraction in all the soils and based on the ‘degree of freeness of iron’ Kunhimangalam series was the oldest in respect of age followed by Chirakkal, Cherniyoor, Vellayani, Beypore and Bharanikkavu. The Ammonium oxalate extractable iron and iron oxide ratio, recorded very low values for all the soil series. The available nutrients of the surface samples showed high levels of phosphorus in all the soils. Nitrogen was low to medium in Vellayani, Cherniyoor and Beypore while it was medium in Bharanikkavu, Chirakkal and Kunhimangalam series. In the case of available potassium loe to medium levels were observed in Chirakkal, Bharanikkavu, Beypore and Cherniyoor series while Kunhimangalam and Vellayani series showed low levels of available potassium. The phosphorus fixing capacity for all the series was high. The DTPA extractable iron and manganese were more than adequate in the surface horizons of all the series. Zinc was deficient to adequate in Vellayani, Bharanikkavu and Kunhimangalam series and marginal to adequate in Cherniyoor, Beypore and Chirakkal series. Copper was deficient to adequate to Vellayani, Cherniyoor and Kunhimangalam series, while adequate levels were observed in Bharanikkavu, Beypore and Chirakkal series. Silica formed the predominant element of the clay fraction. The Si O2/AI2 O3, Si O2/Fe2 O3 and Si O2/R2 O3 ratios recorded for all the soils were higher than the values reported for typical laterite soils.