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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
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
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
Soil nutrirent dynamics in cocoa
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Smitha, B; KAU; Wahid, P A
An investigation on the dynamics of soil nutrients in the rootzone of cocoa (Theobroma cacao) was conducted during 1993 – 94 at the College of Horticulture, Vellanikkara. Soil and leaf samples were taken from cocoa trees under the Cadbury – KAU Co – operative Cocoa Research Project, Vellanikkara. Cocoa variety used for the study was forastero. The soil of the site was laterite (Oxisol). The treatments consisted of factorial combinations of N, P and K fertilizers each at two levels (with and without), two levels (with and without) of irrigation and shade and seven age groups namely 1, 3, 4, 5, 6, 9 and 12 years. Soil samples were also collected from an uncropped and unfertilized area nearby. The impact of long – term inorganic fertilization, irrigation and shade and age of the tree on soil chemical characteristics as well as foliar nutrition of cocoa influenced by long – term inorganic fertilization, irrigation and shade were assessed. Continuous application of urea for a period of nine years increased soil acidity and availability of P, S, Fe and Mn. It also increased total soil P and Fe. But it resulted in depletion of available K, Ca, Mg, Zn and Zn and Mn reserves of the soil. Long – term application of superphosphate resulted in the build – up of available and total P in soil. It also improved the status of soil available Ca, S and soil reserves of Ca and S. But it depleted soil available and total K, available and total Zn, available Mg and Cu and total Mn. Muriate of potash application increased the available and total K content of the soil. On the other hand it caused depletion of available P, Ca, S, Mn, Cu and soil Ca and Mg reserves. Interactions among urea, superphosphate and muriate of potash were also significant with regard to the fertility of the cocoa rootzone is concerned. Increasing soil acidity due to urea application, enrichment of S and Ca due to superphosphate application, and decrease in available P and S due to muriate of potash application were highly influenced by depth. Regular irrigation over a period of five years resulted in reducing the availability of P, Ca, Mn and Cu. It also reduced the total P and Mn in soil. But available K, Zn, S and total S tended to increase with irrigation. In the irrigated plots, total and available P were significantly lower in the surface layers compared to that in unirrigated plots. Provision of shade for a period of 13 years resulted in the build – up of soil organic carbon, available P, Fe and soil reserves of P, Ca, S, Fe, Zn and Mn. On the other hand it decreased the concentrations of available and total K, available S, and Zn and total Mg. Irrigation x shade interaction significantly influenced the available P content of soil. Urea application increased the foliar concentrations of N, Fe, Mn and Cu, but it decreased the leaf K content significantly. Long – term superphosphate application reduced Zn content of cocoa leaf. Application of muriate of potash increased leaf K content, but depressed foliar mg content significantly. Leaf N and K contents of cocoa were highly influenced by N x K interactions. N x P interaction significantly affected foliar Zn concentration of cocoa. Foliar Zn recorded higher values in plants receiving no nitrogen and phosphorus. Irrigation resulted in increased foliar concentrations of almost all nutrients except that of Ca and Mg. Foliar Ca content was higher in unirrigated plants. Effects of irrigation on leaf Mg was not significant. Cocoa trees under shade recorded higher concentrations of N, P, Mg, Fe and Mn and Cu in their foliage while K content was higher in open grown plants. Irrigation x shade interaction significantly influenced foliar N content. Shaded and irrigated conditions resulted in highest foliar N content. Nutrient dynamics in rootzone of cocoa over a period of 12 years of crop growth and fertilization could be described by linear or quadratic model. The linear model was found to be a better fit for available and total K, available and total Mg, available Cu and total Zn. In the case of available and total P, available and total Ca, available Zn, total S and total Cu the changes in concentrations with time could be described by a quadratic model. Available Mn content of the soil showed steady increase with age up to nine years followed by a sharp decrease.
Open Access
Fertility investigation and taxonomy of the soils of banana research station Kannara
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Sreerekha, L; KAU; Marykutty, K C
Taxonomy and fertility investigation of the soils of Banana Research Station, Kannara, was the main intension of the present investigation. Representative surface soil samples were collected from each block of this research station, namely A, B, C, D, E and F for investigating the fertility status of soil. Profiles considered for the study were P1 and P2 in A block, P3, P4 and P5 in B block, P6 and P7 in C block, P8 in D block, P9 in E block, and P10 in F block. Profiles were excavated to study the characteristics of each of the horizons in the soil profile and classify the soils of each block. After the collection and preparation of soil samples, laboratory analyses were carried out as per the standard methods. With an increase in depth, profile samples showed an increasing intensity of colour of the horizons and increase in clay content whereas a decreasing trend was noticed for apparent density, absolute density, water holding capacity and pore space. Soils were acidic and low electrical conductivity values were observed. Organic carbon and total nitrogen decreased with depth. Total P2o5 content was lower than total K2o. Low reserves of total nutrients were observed for other elements also. Sesquioxide content was very high and intermediate layers showed maximum accumulation. In surface as well as profile samples the predominant cation was calcium followed by magnesium. A general increase of CEC and ECEC with depth was observed. Oxalate extractable iron content was lower than the dithionite extractable iron. Distribution of total iron was irregular. Surface soil showed wide variation in texture. Clay content showed significant positive correlation with water holding capacity whereas silt and organic carbon failed to impart any influence upon the same. Phosphorus fixing capacity was high for all the samples. DTPA extractable micronutrients were more than the adequate amount. Based on the soil test values fertilizers were recommended for various blocks. Nitrogeneous fertilizers can be reduced by 5 to 10 per cent. Applications of phosphatic fertilizers can be reduced by 75 per cent in most of the blocks. Potassium fertilizers can also be reduced considerably. Nutrient indices were calculated and a soil fertility map was drawn. Classification of pedons of various blocks according to soil taxonomy has been attempted and found that P1 of A block belongs to the order Entisol. P2 (A block), P3, P4 and P5 (B block), P6 and P7 (C block), P9 (E block) and P10 (F block) belong to the order Alfisol. P8 of D block belongs to the order Inceptisol. By this investigation, the classification of soil profiles were done and the fertility status of each block was found out. In accordance with the soil test values, fertilizer recommendations were made. Thus, by reducing the inputs, cost of cultivation could be reduced considerably.
Open Access
Vertical movement of nitrogen in major rice soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1995) George Abraham, T; Kau; Pushkala, S
An experiment was conducted at the College of Agriculture, Vellayani, to assess the leaching and runoff losses of applied fertilizer nitrogen in typical, major rice growing soils of kerala, with varying physical and chemical properties. Undisturbed vertical columns were used for the leaching study. The runoff study was conducted as a pot experiment using surface soil samples. The study revealed that the Onattukara soil recorded the highest leaching loss of applied nitrogen (56.10%). Kayal soil showed the lowest leaching percentage of 24.21. The quantity of leachate collected per unit time was also found to be the maximum in the case of Onattukara soil (185.51 ml/hr) and least in the case of Kayal soil (155.60 ml/hr). Correlation studies revealed that the leaching loss of nitrogen was negatively correlated with organic matter (-0.5593), cation exchange capacity (-0.4560), clay (-0.5864), bulk density (-0.3213) and water holding capacity (-0.5544). The leaching loss was positively correlated with the quantity of leachate collected per unit time (+0.8876). In the case of Onattukara and kole soils, the loss of nitrogen through leaching was observed till the fifth day. For Kari soils, the loss stopped completely by the 10th day. The Karappadam and Pattambi soils showed leaching till the 15th day. However, in the case of Kayal soils, the leaching loss continued through the whole period of the study. In all cases, maximum amount of leaching occurred during the first five days after fertilizer application and after that the loss was in negligible quantities. In the case of runoff study also, Onattukara soil showed the highest runoff loss of applied nitrogen (40.41). The least loss was shown by karappadam soil (15.70%). The runoff loss was found to decrease with increase in number of days. Even though, Karappadam soils showed the lowest runoff loss of applied nitrogen, it had the highest percentage difference in runoff loss (77.8%) and the least was shown by Onattukara and Pattambi soils (63.5%). Correlation studies revealed that the runoff loss of fertilizer nitrogen was found to be negatively correlated with the oprganic matter (-0.1248), cation exchange capacity (-0.0324), clay (-0.4135), water holding capacity 9-0.6723) and bulk density (-o.4659).
Open Access
Vermicomposting of vegetable garbage
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1995) Anina Susan, Zachariah; KAU; Prabhakumari, P
An economically feasible method of composting, utilizing earthworms and beneficial micro organisms was standardized to produce an enriched organic manure and its efficiency was tested on a vegetable crop (Chilli). Comparison of the biomass production potential of earthworms and the composts produced by them were carried out in an experiment in CRD with three treatments and seven replications. The efficiency of the epigeic earthworm species, Eudrilluseugeniae in composting was well established. They had a greater biomass production potential and produced 11 cocoons and 22 young ones per 100g of compost in 41 days, Eudrilluseugeniae reduced the time required for composting and increased the rate of degradation and degree of humification. Eudrillus composts had a reduced oxidisable organic carbon content and increased humic acid and alkali soluble carbon content. HA : FA ratio was increased in Eudrillus compost and C:N ratio was narrowed down to a greater extent. Carbon content of humic acid and fulvic acid fractions of the three composts were found to be had comparable values. Vermicomposts showed a pH ranging from neutral to alkaline. Eudrillus compost showed a higher percentage of N, P, K, Mg, Mn, Zn and Cu in them. But Ca content was more in local earthworm compost. Inoculation of beneficial micro organisms increased nutrient levels of vermicomposts to a greater extent. Inoculation of both Azospirillum and P solubilising organisms along with one per cent rock phosphate gave maximum N, P, K and micro nutrients. Ca and Mg were highest in composts treated with P solubilising micro – organisms and one per cent rock phosphate. Various growth parameters were increased due to the application of Eudrillus compost enriched with both Azospirillumand P solubilising organisms. Application of Eudrillus compost increased the uptake of nutrients by plants. Uptake of N, P, Mg, Mn, Zn and Cu were higher for plants treated with Eudrillus compost enriched with both Azospirillum and P solubilising organisms. Yield was maximum for plants treated with Eudrillus compost enriched with both Azospirillum and P solubilising organisms. Yield and nutrient uptake of plants were significantly and positively correlated with nutrient content of compost and so vermitechnology using earthworms as biological agents is found to be the best for bio-degradation of organic wastes. Also Eudrilluseugeniae was found to be the superb effective agent for the operation of this technology.
Open Access
Dynamics of nutrient release and transformations from slow release fertilizers in acid rice soils
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Nisha, P T; KAU; Sushama, P K
A study was conducted to assess the pattern of release and transformation of major plant nutrients from slow release nitrogen fertilisers (SLNF) and to evaluate the efficiency of SLNF at the College of Horticulture, Vellanikkara, during 1992 – 94. Urea formaldehyde (UF), NP tablet (NP tab), NPK tablet (NPK tab), gypsum coated urea (GCU), blended urea ammonium sulphate (UAS) and magnesium ammonium phosphate (MAP) were compared with no (NF) and recommended dose of fertilisers (C). Evaluations were conducted with four acid soils viz., laterite, kari, Kuttanad alluvium and costal sandy kept under incubation for six months and a pot culture study using laterite soil and rice variety Jyothi during puncha season. The release of ammoniacal nitrogen (NH4 – N) was found maximum in kari soil, followed by kuttanad alluvium and laterite and the lowest in sandy soil. Release of nitrate nitrogen (NO3 – N) was maximum in the earlier periods in the case of sandy and laterite soils with lower release at later stages. In the case of kari and Kuttanad alluvium the trend was opposite with higher release at later intervals and lower release at early periods. In general nitrification was found to be low in all the soils. Irrespective of the soil types, the maximum content of NH4 – N was recorded by the NPK tab which was closely followed by MAP, whereas the maximum NO3 – N was registered by MAP. For these two different forms of nitrogen, the minimum values were always found in the NF treatment. The available P content of the soil recorded significant variation throughout the period incubation. Among the treatments MAP and UAS recorded the maximum values and NPK tab the minimum P content. Irrespective of the soil types, there was uniformity in the release of available K throughout the incubation period. In pot culture trial NH4 – N decreased as crop stages advanced. With NO3 – N, an initial decrease followed by an increase at harvest stage was noticed. The treatment GCU recorded maximum NH4 – N and NO3 – N content, while NF the minimum. There was decrease in available P and K contents of the soil as the crop growth proceeded. Significant influence on morphological observations were also recorded with MAP maintaining superiority over other treatments. Maximum dry matter, straw and grain yield were recorded respectively by the treatments UAS, C and MAP. Uptake of N, P and K were also influenced significantly with MAP registering the highest and NF the lowest values. Both NP and NPK tab recorded lower values. Maximum leaching loss of N and P were seen with the control and the minimum with MAP whereas it was respectively with UF and NPK tab for K. The total N recovery percentage, was recorded in the decreasing order : MAP > C > UF > GCU > UAS > NP tab > NPK tab. There was a decreasing order of MAP > UAS > UF > GCU > C > NPK tab NP tab for N response of different treatments under study.
Open Access
Partial substitution of muriate of potash by common salt for cassava (Manihot esculenta crantz) in oxisols of Kerala
(Department of Soil Science & Agricultural Chemistry, College of Agriculture, Vellayani, 1995) Sudharmai Devi, C R; KAU; Padmaja, P
Field experiments were carried out in the College of Agriculture, Vellayani during 1991 to 1994 to study the possibility and extent of substitution of K of Muriate of Potash with the Na of common salt in Cassava variety M4 used as the test crop. Substitution of K was tried at 4 levels viz. 25, 50, 75 and 100 per cent of the recommended dose. Muriate of potash, replaced by wood ash and a combination of KHCO3 and NaHCO3 (eliminating chlorine source) also were included in the experiment. Plant growth characteristics like plant height and number of leaves did not vary significantly as a result of substitution. The maximum LAI was observed in the case of 50% K as MOP + 50% Na as CS treatment at all the growth stages. An increase in chlorophyll content was observed with NaCl substitution. In the early growth stages there was no significant variation in the production of roots, but at the later stages there was significant difference in this aspect. The root volume at 2 MAP varied significantly between treatments. In general, there was an increase in total weight of plant with NaCI substitution upto 50% and thereafter a decrease with higher levels of substitution, at all growth stages. Significant treatment difference could be observed in tuber yield in both the years of the experiment. T3 (50% MOP +50% CS) registered the highest tuber yield and T5 the lowest. The bulking rate and Utilisation Index also differed significantly among treatments. The cooking quality of the tubers from T3 was as good as that of T1. Significant differences could be observed in total sugars, reducing sugars and sucrose content of fresh tubers under different treatments. With increasing levels of substitution, the content of total sugars increased. Sucrose content was found to increase with Na application upto 75% substitution of K by Na. Significant variation was observed in the crude protein, total amino acid and free amino acid content of tubers. Hydrocyanic acid, total phenols and crude fibre also differed significantly between treatments. The keeping quality studies revealed that tubers from T3 could be stored fresh up to 35th day in moist soil, whereas tubers from T1 could be stored only upto 12th day, without deterioration. Enzyme studies revealed significant difference in the activity of starch synthesising enzymes, but NRA at 6 MAP was not affected by different treatments. The uptake of N was highest in T1 and P and K in T3. Na uptake by T1 which received no Na was generally higher than other treatments receiving Na. Ca and Mg uptake also differed significantly between treatments. Changes in soil organic carbon, available P, available K and available Mg were statistically significant between treatments but that of Ca was significant only from 4 MAP onwards. Yield of tubers was positively and significantly correlated to the uptake of N, P, K, Na, Ca and Mg. Yield at harvest was positively and significantly correlated to the root weight and root volume and also to the bulking rate at 2 MAP. Path coefficient Analysis revealed that the maximum direct effect on yield was contributed by the drymatter of roots at 2 MAP. From the results, it can be concluded that in soils having low to medium status of K, the K of MOP can be substituted up to 50% by Na of commonsalt in cassava without affecting the quality and quantity of tubers.

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