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Open Access
Optimization of shade, nutrients and growth regulators for cut-flower production in anthurium
(Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 1997) Salvy, B R; KAU; Valsalakumari, P K
Experiments were conducted at the Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, during 1995-1997 to optimize the shade, nutrients and growth regulators for cut flower production in Anthurium andreanum var. 'Hawaiian Red'. The effects of three growth regulators, viz., GA, BA and Ethephon with two concentration each, 750 ppm and 1500 ppm, in combination with four nutrients, viz., 1 % fertilizer complex, Hoagland solution, Knop's solution and Ohio solution, were assessed at four levels of shade, viz., 80, 70, 60 and 50 per cent. Post harvest studies were also carried out with an objective to prolong the longevity of cut blooms, following different stage of harvest and giving different pulsing and hold- ing treatments. Results revealed that the different levels of shade and growth regulators significantly influenced all the morphological characters of the plant, viz., height, spread, number of leaves, leaf area, petiole length, number of branches and suckers. Plant height was significantly superior under 80 per cent shade (5.68 cm), 1 per cent fertilizer complex sprays (5.46 cm) and BA 750 ppm sprays (6.11 cm), were superior individually. The superior treatment combination was 70 per cent shade + Knop's solution + 750 ppm BA (7.60 cm). The maximum plant spread (EW - 20.13 cm and NS - 19.80 cm) was under 80 per cent shade. Eighty per cent shade + Ohio solution + 1500 ppm BA recorded the maximum EW spread (26 cm), while NS spread was maximum (28.70 cm) in the treatment combination involving 80 per cent shade + 1 per cent fertilizer complex + 750 ppm BA. The best values of growth parameters were recorded under 80 per cent shade and 750 ppm BA, viz., 14.03 and 14.02, respectively, for number of leaves (9.29 and 10.79 cm, respectively) for petiole length, leaf length (7.76 and 8.33 cm, respectively), leaf breadth (5.93 cm and 6.49 cm, respectively), index leaf area (50.75 cm- and 59.60 cm-, respectively). Total leaf area (423.25 cm? and 517.56 cm>, respectively) and LAI (0.43 and 0.51, respectively) were maximum under 70 per cent shade and BA 750 ppm. The superior combinations for these parameters were 80 per cent shade + Ohio solution + 750 ppm BA, for highest number of leaves (26.20); 80 per cent shade + Ohio solution + 1500 ppm BA for highest petiole length (14.00 cm); 60 per cent shade + Hoagland solution + 750 ppm BA for maximum leaf length (10.50 cm) and 60 per cent shade + 1 per cent fertilizer complex + 750 ppm BA for maximum leaf breadth (8.0 cm). The treatment combination involving 70 per cent shade + 1500 ppm BA with Hoagland solution was the best for maximum index leaf area (90.90 cm-) while same with 1 per cent fertilizer complex was the best for total leaf area (872.00 cm-) and LAl (0.89). Branching started only after 6 months from the commencement of the experiment. It was one month earlier under 80 per cent and 70 per cent shade levels. Significantly superior branching was observed under 80 per cent shade (2.29), fertilizer complex (2.13) and GA 750 ppm (2.37), individually. Treatment combination involving 80 per cent shade + 1 per cent fertilizer complex + 1500 ppm GA recorded the maximum branching (3.80). .' . Sucker production was the best under 80 per cent shade (1.35) and 750 ppm BA (1.35). Treatment combination involving 80 per cent shade + Ohio solution + 750 ppm BA produced the maximum number of suckers (2.5) per plant. Growth behaviour with respect to height, number of leaves, leaf area, number of suckers and branches showed a linear trend. The linear growth rate was consistent and positive under the treatment combination of 80 per cent shade + Ohio solution + 750 ppm BA. Dry matter production was significantly superior under higher shade intensity and lower concentration of BA. The dry weight ratio of shoot:root was the highest (2.15) under the treatment combination of 80 per cent shade + Knop's solu- tion + 750 ppm Ethephon. Leaf longevity was significantly highest (161 days) in the treatment combination, 70 per cent shade + 1 per cent fertilizer complex + 750 ppm BA. Stomatal distribution and size were not influenced significantly by the treatments. Leaf senescence, though was influenced significantly, no particular trend was observed. The aerial root production decreased significantly with decrease in shade intensity. Primary and secondary roots and root spread were the highest under 80 per cent shade and BA 1500 ppm. Maximum root length was observed under 60 per cent shade. Flowering with small stalkless flowers was first observed under 50 per cent shade with GA 750 ppm, at the age of 8 months. Inflorescence with normal size were produced at the age of 13 months, first under 80 per cent shade followed by 70 per cent, 60 per cent and 50 per cent. The time taken for various stages of flower development and the number of inflorescence produced per plant were not influenced significantly. Chlorophyll content in leaf was significantly influenced by shade levels. There was a decrease in chlorophyll content with decrease in intensity of shade. Eighty per cent shade and 1500 ppm Ethephon was superior with respect to the content of green pigments. The highest total chlorophyll content was observed in the treatment combination involving 60 per cent shade + Ohio solution + 750 ppm Ethephon (8.8 mg g -1 fresh weight). Anthocyanin content was not influenced by any of the treatments or combinations. The leaf nutrient content and uptake of nutrients was maximum under 80 per cent shade and BA 750 ppm, individually. Post harvest studies showed that the right stage of harvest of inflorescence was when 1/3 flowers were open on the spadix. Inflorescence harvested at this stage with medium to large size spathe lasted for a longer period (23.33 days). Among the pulsing treatments, BA 50 ppm for 12 hrs, recorded maximum vase life (20.00 days). Among the different holding solutions tried, 8-HQ 30 ppm, BA 20 ppm and Triadimefon 30 ppm recorded the optimum values of PL W, uptake of vase solution, change in pH and EC, and recorded late spathe blueing, late spadix necrosis and high gloss retention. Highest vase life period (27.00 days) was recorded in 8-HQ 30 ppm (25.00 days) and Triadimefon 30 ppm (25.00 days). Among the combinations tried, BA 20 ppm + Bavistin 0.1 per cent showed longest vase life (23.67 days). Maximum net profit per pot (Rs.204.60) was recorded by the treatment combination involving 80 per cent shade + Ohio solution + 750 ppm BA.
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
Response of cucumber (Cucumis melo L.) to drip irrigation under varying levels of nitrogen and potash
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Lakshmi, S; KAU; Sasidhar, V K
Two field experiments and one observational trial were conducted in the Instructional Farm, College of Agriculture, Vellayani during 1992 and 1993 to study the effect of drip irrigation and application of N and K fertilizers on the growth and yield of cucumber. In the preliminary observation trial (Experiment I a) three levels of drip irrigation, (2, 3 and 4 I plant-1 day-1) four timings of irrigation (1, 2, 3 and 4 hours) and two number of drippers per plant (1 and 2 dripper plant-1) were evaluated and based on the results of this experiment, the number of drippers per plant and duration of drip irrigation was standardised. Experiment 1 b was conducted to standardise the method of application of fertilizers in Experiment 2 and 3 for which cucumber plants raised under different levels of drip irrigation (2, 3 and 4 I plant-1 day-1). This was conducted during April 1992. The results of these experiments indicated the duration for drip irrigation as 3 hours per day and one number of dripper per plant to be the best. The spread and depth of root system of cucumber plants raised under drip irrigation pointed out that the fertilizers as a ring around the base of the plant at a distance of 20 cm will be within the root zone of the plant. The experiments 2 and 3 were laid out in the field with three levels of drip irrigation (2, 3, and 4 I plant-1 day-1), three levels of nitrogen (35, 70 and 105 kg ha-1) with three levels of potassium (25, 50 and 75 kg ha-1) with three drip irrigation controls (2, 3 and 4 I plant-1 day-1) and farmer's practice. The yield of cucumber was highest at the drip irrigation level of 31 planr-1 day-1. Irrigation at this level favourably influenced the vegetative characters, yield attributes and yield. But root dry matter was not influenced by the different drip irrigation level while the root spread and root depth were highest at the drip irrigation level of 41 plant-1 day-1. When different levels of nitrogen applied were observed, the vegetative characters yield attributes and yield were found to be favourably influenced at 70 kg N ha-1. The root spread of cucumber was highest at the highest level of N applied (l05 kg ha-1). Potassium at 50 kg ha-1 produced the highest yield due to its favourable influence on the vegetative and yield characters. There was no influence of potassium on my of the root characters studied. The soil moisture status was highest up to 30 cm depth in all drip irrigated treatments while in pot watered plots, the soil moisture was higher in the lower layers below 30 cm. The field water use efficiency was highest at the drip irrigation level of 3 I plant-1 day-1, 70 kg nitrogen ha-1 and 50 kg potassium ha-1. The nitrogen, phosphorus and potassium uptake by the plants and fruits were highest at the drip irrigation level of 31 plant day I, 70 kg N ha-I and 50 kg K ha-I. The physical optium levels of drip irrigation was 31 plant -1 day -1, 93 kg N ha-1 and 65 kg K ha-1 in the first season. When another crop is repeatedly grown in the same field, the Nand K levels can be reduced to 75 kg ha-1 and 60. kg ha-1 but drip irrigation is required at the rate of 31 plant-1 day-1. This resulted in higher benefit cost ratio of 2.83 and internal rate of returns of 23%. The payback period of this project worked out to 1.13 years.
Open Access
Soil test crop response studies in cassava in laterite soils of Kerala
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Kumari Swadija, O; KAU; Sreedharan, C
An investigation was undertaken at the College of Agriculture, Vellayani to establish soil test crop response correlation for soil test based balanced fertilizer prescription for cassava var. M-4 in laterite soils of Kerala. The field investigation consisted of fertility gradient experiment, STCR experiment and technology verification trial. The fertility gradient experiment was conducted during April- May 1994 in the Instructional farm, Vellayani. The desired gradient in soil fertility was created in one and the same field by applying graded doses of N, P and K fertilizers and raising fodder maize var. African Tall. The STCR experiment was conducted in the same field during June '94-March '95 using the test crop, cassava var. M-4. The treatments consisted of factorial combinations of four levels of N (0, 50, 100 and 150 kg ha-1), three levels of P (0, 50 and 100 kg P2O5 ha-1) and five levels of K (0, 50, 100, 150 and 200 kg K20 ha-1) along with three levels of farmyard manure (0, 6.25 and 12.50 t ha-1) fitted in a response surface design. Using multiple regression model, the fertilizer adjustment equation for N at varying soil test values for available N for maximum tuber yield (t ha-1) of cassava in laterite soil was derived as FN = 136.6 - 0.2 SN where FN is fertilizer N (kg ha-1) and SN is soil available N (kg ha-1). The equation becomes FN = 136.6 - 0.2 SN - R for economic tuber production where R is the ratio of cost of one kg of fertilizer N to price of one kg of tuber. At varying soil test values for organic carbon% (OC) the above equations become FN = 226.13 - 378.13 OC for maximum tuber yield and FN = 226.13 - 378.13 OC - 1.25 R for economic tuber yield. The behaviour of fertilizer P and K was found to produce responses other than 'normal' and hence optimisation could not be done for fertilizer P and K for maximum and economic tuber yield at varying soil test values. The nutrient requirements of cassava var. M-4 were estimated to be 6.58, 2.37 and 6.28 kg N, P2O5 and K2O respectively to produce one ton of tuber. In the laterite soil, the efficiencies of contribution of nutrients from the soil for cassava were calculated as 40.17, 41. 3 3 and 48.60% N, P2O5 and K2O respectively. The fertilizer efficiencies were worked out as 54.38, 47 and 52.650% N, P2O5 and K2O respectively. The efficiencies of contribution of nutrients from farmyard manure were calculated as 78.24, 57.33 and 69.66%) N, P2O5 and K2O respectively. From the above basic data, fertilizer prescription equations for specific yield targets of cassava var. M-4 in the laterite soil were derived as given below. Without FYM FN = 12.10 T - 0.74 SN FP2O5 - 5.04 T - 2.02 SP FK2O = 11.93 T - 1.10 SK With FYM FN = 12.10 T - 0.74 SN - 1.44 ON F P2O5 - 5.04 T - 2.02 SP - 2.79 OP FK2O = 11.93 T - 1.10 SK - 1.58 OK where FN, F P2O5 and FK2O are fertilizer N, P2O5 and K2O respectively in kg ha-1, T is the target of tuber yield in t ha-1, SN, SP and SK are soil available N, P and K in kg ha-1 respectively and ON, OP and OK are quantities of N, P and K supplied through organic manure in kg ha-1 The technology verification trial was undertaken during June '96-March. '97 in the laterite soil in three farmers' fields in Thiruvananthapuram district and also in the Instructional Farm, Vellayani. The treatments consisted of Package of Practices recommendation for fertilizer, fertilizer recommendation by the Soil Testing Laboratory and fertilizer doses for the yield targets of 15, 20 and 25 t ha-1 along with a uniform dose of 6.25 t ha-1 of farmyard manure for all treatments. The fertilizer doses based on targeted yield equations recorded higher tuber yield and net income, benefit cost ratio and net returns per rupee invested over the fertilizer recommendation by the Soil Testing Laboratory and Package of Practices recommendation emphasising the need for site specific recommendation based on soil tests. The yield targets of 15 and 20 t ha-1 recorded more than cent per cent achievement and the yield target of 25 t ha-1 recorded about 90% achievement. Higher tuber yield, benefit cost ratio and net returns per rupee invested could be achieved for the yield target of 20 t ha-1. The fertilizer dose for the yield target of 15 t ha-1 recorded the highest returns per rupee invested on fertilizers. The study has revealed the superiority of fertilizer application based on targeted yield approach over the semi-quantitative approach employed in the soil testing laboratories and generalised state level Package of Practices recommendation for the crop. In this approach, the fertilizer dose can be adjusted in accordance with the specific objective and available resources of the farmer.
Open Access
Effect of feeding onion (allium cepa var aggregatum g. don) and garlic (allium sativum linn) on lipid profile in Japanese quail (coturnix coturnix japonica)
(Department of Physiology and Biochemistry, College of Veterinary and Animal Sciences, Mannuthy, 1997) Girish Kumar, V; KAU; Surendranathan, K P
Poultry products are comparatively rich in cholesterol. WHO report indicates incidence of coronary heart disease and high dietary cholesterol level to be positively correlated. In such a situation, decreasing the cholesterol content in poultry products would be appropriate. Onion and garlic are ascribed with therapeutic effects such as hypocholesterolemia, hypolipidemia and immunosuppressant action in mammals, while no convincing reports are available on the effect of supplementation of these agents in reducing cholesterol level in egg and poultry meat. Hence, this study reports on the hypolipidemic effects and/or other effects of dietary onion and garlic on the lipid profile in the tissues of Japanese quails. Further, information on the physiological norms of tissues is essential for understanding any pathological entity. Although in recent years, the Japanese quail has gained increasing popularity as a biological model for various investigations, published reports on the lipid profile in the tissues of this species are very few. Essentially, all the previous studies on this aspect are based on observations in only a particular tissue or a particular lipid component or sex and age. Hence, the present investigation is also aimed at establishing a more or less complete picture of lipid profile in liver, plasma and muscle in both sexes at three different physiological stages of growth viz., three-week old (immature), six-week old (onset of sexual maturity) and in nine-week old (mature) birds. Likewise, the lipid profile that are analysed in the liver will also be: established in the egg yolk. The results revealed an increase in the liver and plasma total lipid content (Table II) due to onion and garlic. Although a trend of decrease in the cholesterol level in the liver and muscle was observed the results were statistically nonsignificant (Table III), indicating the hypocholesterolemic effect of onion and garlic to be of questionable biological significance. The plasma free cholesterol level (Table IV) was found to be decreased due to onion and garlic, while no effect of the same was observed with regard to plasma esterified cholesterol (Table IV). The effect of onion and garlic on the cholesterol content in different lipoproteins (Table IV) indicated that these alliums are causing recirculation of plasma cholesterol between different lipoproteins and/or tissues in such a way that the plasma LDL-C is not increased. There was an increase in the triglyceride content in the liver and plasma due to dietary alliums (Table V). The phospholipid level in the plasma was found to be increased with a decrease in the plasma free fatty acid (Table XII) level due to dietary alliums. The variations in the plasma esterified fatty acid content (Table XII) due to alliums are in accordance with the variations in the plasma content of esterified form of lipids. The iodine value of liver lipid was increased due to alliums in both sexes, while these alliums were found to have no influence on the saponification and acid value of the liver lipid. In all the above instances where onion and garlic were found to have significant effect, dietary garlic was found to have either a similar or significantly more alliaceous effect than dietary onion. No significant variations in the lipid profile of the muscle and yolk were observed due to dietary supplementation of onion and garlic. The influence of onion and garlic on the feed consumption by birds was found to vary with duration of feeding. In the first week of feeding alliums to both sexes and in the second week in the male birds, no change in the feed consumption was observed. Thereafter in both the sexes the feed consumption increased due to dietary onion and garlic. Dietary onion and garlic caused a nonsignificant increase in the body weight. Feed efficiency in both the sexes and egg production in the females were unaltered due to dietary supplementation of onion and garlic. The levels of total lipid, total cholesterol, triglycerides, total phospholipid and phospholipid fractions in liver, plasma and muscle were found to differ significantly due to effect of age within a sex and due to effect of sex within an age group. Similarly the level of plasma free cholesterol, esterified cholesterol, HDL-C, VLDL-C, HDL-C, free fatty acid and esterified fatty acid differed significantly due to age within a sex and due to sex within an age group. Iodine value and saponification value of lipid in liver were influenced due to age and sex, while the same was not observed in the muscle. The acid value of the lipid in the liver and muscle was unaltered due to age or sex. The feed consumption and body weight increased with age in both sexes and it was more in the females. The feed efficiency was unaltered due to age or sex. The egg production was also not influenced by age.
Open Access
Interaction of psychological economic, sociological and technological determinants of the entrepreneurial behaviour of agricultural students
(Department Of Agricultural Extension, College Of Agriculture, Vellayani, 1997) Seema, B; KAU; Babu, B
The study aimed to identify the factors which are conducive for the entrepreneurial behaviour of agricultural .students. The study was conducted among the students of the two Agricultural colleges of Kerala Agricultural University and the unemployed graduates who have passed out from these colleges. Two hundred and fifty respondents were selected for the main study which comprised of 100 undergraduate students, 100 postgraduate students and 50 unemployed graduates. The entrepreneurial behavior of agricultural students was measured with the help of a scale developed for the study. Based on relevancy rating twenty four independent variables were selected Data were collected through mailed, and distributed questionnaire. The maximum likelihood solution for entrepreneurial behavior extracted 12 factors About 43 per cent of the total variability in the extent of entrepreneurial behavior was accounted by twelve factors. Majority of the respondents in the undergraduate group and unemployed graduates were found to have high level of entrepreneurial behavior. Similarly majority of the male respondents were found to have high level of entrepreneurial behavior. Self esteem, sociability, innovation proneness, Self confidence, attitude towards competition, management Orientation, persuasiveness, and self reliance were found to * be significantly and positively related to entrepreneurial behaviour of undergraduate students. In the case of postgraduate students attitude towards competition, self esteem, innovation proneness, management orientation, self confidence, persuasiveness, sociability, self reliance and attitude towards self employment were found to be significantly and positively related. ■* • . As to the unemployed graduates significant positive relationship was observed between entrepreneurial behaviour and persuasiveness, management orientation, innovation proneness, self confidence and credit orientation. Sociability, self reliance, self confidence, attitude towards competition, self esteem, persuasiveness, management orientation, innovation proneness, attitude towards self employment and technical competency were found to be significantly and positively related with entrepreneurial behaviour of male students. In the case of female students, self confidence, self esteem, self reliance, attitude towards self employment, sociability, management orientation, persuasiveness, annual income, innovation proneness and attitude towards competition showed significant positive relationship with enfrepreneurial behaviour. Attitude towards self employment, innovation proneness, self confidence, credit orientation, self reliance, sociability, marks obtained in Pree-Degree, marks obtained in B Sc. and management orientation explained 36.74 per cent of the variation in entrepreneurial behaviour of undergraduate students. In the case of postgraduate students 49.19 per cent of variation in entrepreneurial behaviour was explained by attitude towards competition, self esteem, sociability, innovation proneness and O.G.P A. (work experience). Persuasiveness and innovation proneness explained 25.12 per cent of variation in entrepreneurial behaviour of unemployed graduates. » As much as 43.28 per cent of variability in entrepreneurial behaviour of male students was explained by sociability, self reliance, persuasiveness, attitude towards •self employment, O.G.P A ( work experience) management orientation, innovation proneness and attitude towards competition For variables viz., self esteem, sociability, innovation proneness and credit orientation were responsible fof 36.65 per cent of-variation in entrepreneurial behaviour of female students. Capital investment, availability of labour, availability of resource and infrastructural facilities were ranked high as factors influencing entrepreneurial behaviour of agricultural students as perceived by different category of respondents.
Open Access
Morphological, physical and chemical characterization of the soils of North Kuttanad
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1997) Manorama Thampatti, K C; KAU; Jose, A J
An investigation was carried out at the College of Horticulture, Vellanikkara during 1992 to 1995 to evaluate the morphological, physical and chemical characteristics of soils of North Kuttanad and to assess the extent of toxic factors that pertained in the soil due to restricted movement of water under the influ- ence of Thanneermukkom regulator. The study was carried out in three parts, viz., (1) Morpho- logy and physicochemical characteristics, (2) Fertility characteristics and (3) Toxicity chara- cteristics. Fifteen soil profile were drawn from North Kuttanad to study the morphology and physicochemical characteristics of the area. The fertility characteristics were studied by collecting 97 surface soil samples (0-15 cm depth) from 27 padasekharams of the area during rainy and summer seasons (before and after the closure of Thanneermukkom regula- tor). Toxicity characteristics of the area were studied by collecting bulk soil samples (0-25 cm depth), surface water and ground water from the above sites during the same period. Morphological and physicochemical properties of the soils showed great degree of variation. Soils were dark brown to black in colour, sticky and plastic, subangular blocky in structure and sandy to clayey in texture, with random deposits of lime shells and humus. Presence of faint to prominent reddish yellow or brown mottles, rice roots and root canals were some of the special characteristics observed in the soil profiles. Soils of the area were highly acidic and mildly saline. Both soil acidity and salinity increased with depth. Organic carbon, CEC and ECEC of the area were higher compared to other parts of Kerala, but the base saturation was comparatively lower. The area was rich in almost all the essential nutrients except P. Fe, Al and S were present in toxic concentrations. Potential acidity of the area was very high and more than 70 per cent of it was contributed by hydrolytic acidity and the rest by exchangeable acidity. All the acidity characteristics increased with depth. The profile IX was grouped under order Inceptisol and all others under order Entisol. On evaluating the fertility characteristics of the area it was observed that the area experienced an increase in soil acidity and availability of N, P, Fe and Zn and a decrease in salinity, CEC, ECEC and available K, Ca, Mg, \.10 and Cu. However, the availability of all nutrients except P was above the deficiency level. Fe was present in toxic quantities. On a general comparison with that of pre-barrage period, the area experienced a reduction in salinity and an enhancement in soil acidity and availability of K, Ca and Mg. The Na content was reduced considerably in response to the reduction in salinity. The exchangeable and water soluble cations followed the same trend as that of available cations. Among the exchangeable cations Ca was the dominant basic cation instead of Na which occupied the same place during pre-barrage period. Acidity characteristics of surface samples behaved similar to that of profile samples. Pot- ential acidity and hydrolytic acidity recorded higher values during rainy season while exchangeable acidity was greater during summer. Among the components of exchange- able acidity exchangeable Al3+ dominated during rainy season, and exchangeable H+ dur- ing summer. The overall influence was greater for exchangeable A13+ as evidenced from the higher correlation coefficient (0.862**). The general soil properties and acidity characteristics of the bulk soil samples were similar to that of surface samples, showing a reduction in pH, EC, CEC and available, exchangeable and water soluble cations during summer compared to the rainy season. Among the different fractions of Fe, free and available forms were present in large quantities while exchangeable and water soluble forms were present in negligible quantities. All the fractions expressed a higher concentration during summer indicating more chances for severe Fe toxicity during that period. Mn was also present in large quantities. Compared to Fe, the concentration of different fractions of Mn were very small. The availability of Cu and Zn were also above the critical levels. The area was rich in AI. Reverse to that of Fe the different fractions of Al showed a lower concentration during summer. The free Al content was three times lesser than that of free Fe, while in exchangeable form Al expressed a higher concentration. The water soluble AI was very low. Surface water and ground water of the area were mildly acidic and saline during rainy season and they showed an increase during summer. The acidity exceeded the permissible maximum but the salinity was maintained below the permissible limit for agricultural and domestic purposes. Among the various elements present in water, Na and Cl- were the dominant ions expressing greater concentrations during summer in both surface and ground water. Based on SAR they were rated as moderately unsafe for irrigation during summer. The concentrations of K, Ca and Mg were within the permissible maximum for agricultural and domestic purposes. P was present only in traces. The Fe content was greater for ground water than surface water and it exceeded the permissible limit for drinking water. Though Mn was absent in ground water, it has already reached up to the permissible maximum in surface water. Al content exceeded the permissible maximum for domestic purposes. Cu, Zn, Cd and Pb were not detected in water. SO4-S, NH4-N and NO2+NO3- N contents of both surface and ground water were well below the critical levels suggested, but Cl' contents of both were sufficient to cause specific toxicity effect. The chlorinated hydrocarbon pesticides identi _ fied in the area were (X-HCH, y-HCH and DDT. They showed higher concentration during summer. Among the chlorinated hydrocarbons, DDT was present in larger quantities, though it was banned for agricultural uses, followed by (X-HCH. The concentration of y-HCH was comparatively small. The accumulation of fertiliser residues in the area was not so negligible. The highest concen- tration was observed for NH4-N during addi- tional crop season, at the time of basal dressing, both in soil and water. During punja season, a decrease of 55 to 60 per cent in soil and 10 to 12 per cent in water for NH4-N was observed. The content of N02+N03-N was comparatively low in soil due to continuous submergence. In water it was not as low as that of soil, indicating a major portion of N02+NOrN retained in water. P content of the area was very low. Its loss through drainage water was nil. A sizable quantity of K was also subjected to loss through drainage water, though the extent of loss was well below the level of N. Here also highest concentration was noted during additional crop season at the time of basal dressing both in soil and water. The study indicated that the area is subjected to severe pollution due to the accumulation of native toxic factors as well as residues of pesticides and fertilisers. The closure of Thanneermukkom regulator aggravates the situation by restricting the water movement.
Open Access
Genetic analysis of seed dormancy and productivity in groundnut (Arachis hypogaea L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1997) Tessy Joseph; KAU; Namboodiri, K M N
Investigations on genetic analysis of seed dormancy and productivity in groundnut (Arachis hypogaea L.) were carried out in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara from 1992-95. The objective of the study was to find out the gene effects of biometric traits and seed dormancy in groundnut, so as to suggest appropriate breeding methodology and parental combinations to evolve domant, high yielding and early manuring varieties. The findings of the study are briefed below. Evaluation of 28 genotypes (14 domant and 14 non domant) for two seasons revealed that wide range of variability existed among them. Donors for specific traits were identified . The genotypes were also genetically diverse and could be grouped into four clusters. The line x tester analysis with three lines and five testers revealed that additive gene effects governed most of the characters except pod yield and number of mature pods , for which , non addictive gene effects were important. To harness both the types of gene effects pedigree method followed by selection in advanced generations will be fruitful.
Open Access
Characterisation and evaluation of indegenous ducks of Kerala
(Department of Poultry Science, College of Veterinary and Animal Sciences, Mannuthy, 1997) Mahanta, J D; KAU; Ramakrishnan, A
A basic study was conducted to characterise the two distinct indigenous types of ducks, namely Chara and Chemballi of Kerala and to evaluate their production potential. Five hundred sexed day-old female and 100 male ducklings each from Chara and Chemballi type were brought from M/s Susan Roy Hatchery of Chennithala. The ducklings were reared on deep litter system of management under identical conditions till 8 weeks of age. Thereafter they were switched over to semi- intensive system. The ducklings were wing banded and weighed individually at day-old, 4, 8, 12, 16, 20, 30, 40 and 52 weeks of age. After 18 weeks of age, 300.females and 30 males from each type were selected for further studies. The females from each type were divided into three groups of 100 birds each. At 18 weeks of age, ducklings were wing badged and provided with individual laying nests to facilitate recording of individual performance. Drakes of each type were maintained separately to study the external morphology and growth traits. At 20 weeks of age, individual body measurements and plumage colour patterns of different body parts of both Chara and Chemballi were recorded. The age at first egg (AFE) of all individual ducks, the weight of first egg, egg weight at 30, 40 and 50 weeks of age, shape index and shell colour of eggs, age at 5, 10 and 50 per cent egg production, total egg production upto 52 weeks of age, per cent duck-day and duck-housed egg production at eight 28-day laying periods and at weekly mean basis of the flocks were calculated and recorded. Morphologically, Chara and Chemballi drakes were squat in posture and gait and they differed in the colour of plumage of the head region. It was lustrous greenish black in Chara and dull greenish black in Chemballi. The Chara females were usually blackish brown in the back, tail and wing. The Chemballi females in general were brownish black and brownish grey in the back, tail and wings. The average body weights and growth pattern of Chara and Chemballi males were almost similar upto 52 weeks of age, whereas the Chara females tended to be heavier in body weights at all ages except 4 and 12 weeks. Significantly higher body weights at day-old and 20 weeks of age was recorded in Chara females over the Chemballi. The average age at first egg (AFE) in Chara and Chemballi was 148.59 and 147.50 days respectively. The ages at 5, 10 and 50 per cent egg production were 144, 153 and 187 days in Chara, while those in Chemballi were 141, 148 and 184 day respectively. The average egg number per duck upto 50 weeks of age was 116.09 in Chara and 124.95 in Chemballi. The corresponding mean per cent duck-day production in Chara and Chemballi was 44.49 and 48.68 respectively. The mean per cent duck-housed egg production to 50 weeks of age in Chara and Chemballi was 41.78 and 42.91 respectively. The mean weekly per cent egg production of Chara and Chemballi upto 52 weeks of age widely fluctuated from week to week. It was also found that during the production period upto 52 weeks of age there were two peaks in per cent egg production in both Chara and Chemballi type. The overall mean egg weight of Chara (69.69 g) was significantly (P<0.05) higher than that of Chemballi (68.08 g) . In the laying periods of Chara and Chemballi there were no discernible clutch size/pause. Broodiness as a trait was almost absent in both the types.

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