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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, 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.
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, 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.
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, 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.
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, M
The 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.
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, Hameed
The 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.
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 K
An 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.
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, 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.
Open Access
Evaluation of maton rockphosphate in the acid rice soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1997) Suja, Thomas; KAU; Sushama, P K
A study conducted at College of Horticulture during the period 1994 – 96 so as to assess the effectiveness of Maton rockphosphate (MTRP) as a source of P compared with single super phophate (SSP), diammonium phosphate (DAP) and Mussoorie rockphosphate (MRP). In addition to the above sources a control treatment (with no P fertiliser) and another treatment with SSP at the rate of 45 kg P2o5 ha-1 given twice (conventional practice) were also included. The P release from all the sources were monitored with an incubation experiment. In order to evaluate the response of fertilisers two continuous pot culture experiments were undertaken using Jaya variety of rice. Two acid rice soils of Kerala, viz., Kuttanad alluvium and laterite were used for the study. The variations in pH of the soil types indicated that there was increase with advancement of periods under waterlogging irrespective of the treatments including the control. Available N was high in Kuttanad alluvium as compared to laterite and was found to decrease with periods of incubation. The content of available P gradually increased with period of incubation, reached a peak at 120 days for water soluble phosphates (SSP and DAP) and 180 days for rockphosphates, irrespective of the soil types. Comparing the two extractants, Mathewstriacid extracted more available P than that of the Bray solution in both the soil types. Available K decreased with periods of incubations. In general, Kuttanad alluvium recorded higher content of available nutrients as compared to laterite. In both the soil types the most dominant P fraction was Fe – P followed by AI – P and Ca – P. While evaluating the pot culture experiment it was observed that available nutrient content decreased with advancement of crop growth. Even after the harvest of second crop, the residual effect of MTRP was recorded to be high. There was maximum uptake of P at the second crop season as compared to the first crop irrespective of the soil types. The leachate loss decreased with crop growth in both the soil types. But the maximum leachate loss was recorded for N followed by K and P. The grain yield as well as the relative yield was found to be maximum for the laterite soil on comparison to Kuttanad alluvium for the first and second crop of rice. In Kuttanad alluvium, DAP and MTRP yielded better in the first and second crop respectively. While in laterites SSP was found to be better in grain yield as compared to other sources, The source, DAP was superior to others in straw yield for both the soil types with increase in levels of P application, there was increase in grain and straw yield.
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, 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.

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