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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem 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 KTwo 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.ThesisItem 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, CAn 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.ThesisItem Open Access Development of diagnosis and recommendation integrated system (DRIS) in black pepper (Piper nigrum L.) in relation to yield and quality characteristics(Department of Agronomy, College of Horticulture, Vellanikkara, 1998) Sreekumaran, V; KAU; Neelakandan Potty, NAn investigative analysis was undertaken during 1993-96 to work out an objective and effective technology for nutritional management of black pepper based on cause and effect relationship. A critical and comparative evaluation of the available methods in this connection, viz. critical level concept, DRIS concept and management based on soil test data, soil analysis was envisaged. Approved standard procedures m estimating soil available and plant contents of nine elements, viz. N P K Ca Mg S Fe Zn and Mn and standard statistical methods were used in the study. A total of 1200 plants aged 14 years maintained at RARS, Ambalavayal were used as the test material in the study. A non-genic variability in yield ranging from 0.16 to 13.8 kg plant-1 was manifested by tile crop which indicated that variability shall be bridged upwards through managerial techniques. The range of available status of the elements in the soil analysis was very high. The lowest range of 0.9 to 4.5 ppm and the highest range of 144 to 1324 ppm were recorded by Zn and Ca, respectively. Soil pH ranged from 4.3 to 6.8. These were at the individual plant level. Foliar content as well as the range of the elements were much less and did not exactly related to soil available contents. Results also indicated that elements showed significant and specific interactions among themselves which varied with the elements. The pattern and magnitude of interactions at soil and plant level were different. Evaluation of soil test data of the study against approved soil test 0 - 9 scale classification showed that rhizosphere environments belonged to medium rich to very rich class and that it could not explain the yield variability and hence could not be a reliable basis of nutritional management in fertile soil. Examination of the foliar content of elements and their comparison with critical levels and ranges fixed by De Waard (1969) and Nybe (1986) respectively, showed that foliar content of all the elements in the study were above the critical levels which suggested that the critical level concept cannot be an adequate guiding principle in nutritional management of black pepper. It may be adequate only in situations where any element becomes specifically critical. Its inadequacy may also be due to the positive and negative interactions of elements in the plant system as well as due to the fact that yield is the resultant of a process involving several elements simultaneously. Negative relationship of P in the early stages and yield level of 6.5 and <1 kg berries at 2.33 and 2.35 per cent level and similar observations confirmed the above contention. DRIS concept was found to be more adaptable to explain the yield variability as it takes into account the content as well as interaction represented by ratios of every element with the others of the high yielding plants and tries to simulate them in low yielding plants. Results of the present study showed that by employing the DRIS concept and nutrient ratios, the content of every element can be identified at any time as absolutely deficient, relatively deficient, relatively sufficient, relatively excess and absolutely excess. This classification enabled to define the nature of recommendation as additive, deletive or ameliorative/corrective. Testing of the classification of the population into discriminative low and high - yielding sub-populations employing mean ± one SD showed that the system may be perfect when the magnitude of yield limiting factors in the entire range of low yield is the same. Possibility of variability in yield limiting factors could be accommodated by sub-dividing the lower yield group into smaller groups as was done in deciles in the study. The results appeared to show that the per plant variability can be accommodated with reasonable accuracy in such a system of micro level yield group identification and application of DRIS norms to them. The unique advantage of the DRIS system to reach the maximum realizable yield through progressive diagnosis based on progressive experimentation shall be substituted by the decile classification proposed in the study to a very good extent. Results of the present study showed that yield and quality factors are largely independent of each other and both can be improved by integrating the respective components even at the higher yield levels obtained in the present study. Analysis of inter-correlation matrix among elements at soil and plant level revealed the possibility of making specific recommendations to achieve progressive yield increases by working out quantity, intensity and rate of release characteristics. of elements in the soil in relation to absorption. Results in the present study showed that scientifically speaking the captions of DRIS indices or index values as " order of requirement" be modified as "order of limiting influences" - the former part of which is relative to metabolic deficiencies and the latter part to the metabolic excess. Imbalance indices have to be viewed as qualitative and not quantitative indices as they are relative, primarily based on the relative deficiencies and excesses which in turn are dependent upon the relative contents and valencies of the ions. The results of the study also revealed that with progressive increase in yield, causing .higher nutrient removal, will make the soil not only more deficient but also increase the frequency of application of nutrients more. The progressive increase in the number of limiting factors with yield improvement caused by higher rate of removal calls for more frequent monitoring and not treating the norm as static for a long period. The results of the experiment have brought to light a graded pattern of nutritional management for black pepper. The primary limiting factors were found to be high native content of Fe and Mn which will have to be ameliorated. Secondly, at the low yield level the yield is limited by a relative deficiency of Zn caused by high P calling for a temporary skipping of P; supplemented with N and K which can take the yield up to 5 kg plant-1. Excess S through the incidental application of prophylactic sprays of Bordeaux mixture and shortage of Ca and Mg appear to be the limiting factors at the higher yield class. Amelioration of acidity by supplying Ca + Mg carbonate, substitution of S containing fungicides and application of N and K shall constitute the recommendation, beyond which P may have to be applied.ThesisItem Open Access Developement of diagnosis and recommentation integrated system(Department of Agronomy, College of Horticulture, Vellanikkara, 1998) Sreekumaran, V; KAU; Neelakandan, Potty NAn investigative analysis was undertaken during 1993-96 to work out an objective and effective technology for nutritional management of black pepper based on cause and effect relationship. A critical and comparative evaluation of the available methods in this connection, viz. critical level concept, DRIS concept and management based on soil test data, soil analysis was envisaged. Approved standard procedures m estimating soil available and plant contents of nine elements, viz. N P K Ca Mg S Fe Zn and Mn and standard statistical methods were used in the study. A total of 1200 plants aged 14 years maintained at RARS, Ambalavayal were used as the test material in the study. A non-genic variability in yield ranging from 0.16 to 13.8 kg plant-1 was manifested by tile crop which indicated that variability shall be bridged upwards through managerial techniques. The range of available status of the elements in the soil analysis was very high. The lowest range of 0.9 to 4.5 ppm and the highest range of 144 to 1324 ppm were recorded by Zn and Ca, respectively. Soil pH ranged from 4.3 to 6.8. These were at the individual plant level. Foliar content as well as the range of the elements were much less and did not exactly related to soil available contents. Results also indicated that elements showed significant and specific interactions among themselves which varied with the elements. The pattern and magnitude of interactions at soil and plant level were different. Evaluation of soil test data of the study against approved soil test 0 - 9 scale classification showed that rhizosphere environments belonged to medium rich to very rich class and that it could not explain the yield variability and hence could not be a reliable basis of nutritional management in fertile soil. Examination of the foliar content of elements and their comparison with critical levels and ranges fixed by De Waard (1969) and Nybe (1986) respectively, showed that foliar content of all the elements in the study were above the critical levels which suggested that the critical level concept cannot be an adequate guiding principle in nutritional management of black pepper. It may be adequate only in situations where any element becomes specifically critical. Its inadequacy may also be due to the positive and negative interactions of elements in the plant system as well as due to the fact that yield is the resultant of a process involving several elements simultaneously. Negative relationship of P in the early stages and yield level of 6.5 and <1 kg berries at 2.33 and 2.35 per cent level and similar observations confirmed the above contention. DRIS concept was found to be more adaptable to explain the yield variability as it takes into account the content as well as interaction represented by ratios of every element with the others of the high yielding plants and tries to simulate them in low yielding plants. Results of the present study showed that by employing the DRIS concept and nutrient ratios, the content of every element can be identified at any time as absolutely deficient, relatively deficient, relatively sufficient, relatively excess and absolutely excess. This classification enabled to define the nature of recommendation as additive, deletive or ameliorative/corrective. Testing of the classification of the population into discriminative low and high - yielding sub-populations employing mean ± one SD showed that the system may be perfect when the magnitude of yield limiting factors in the entire range of low yield is the same. Possibility of variability in yield limiting factors could be accommodated by sub-dividing the lower yield group into smaller groups as was done in deciles in the study. The results appeared to show that the per plant variability can be accommodated with reasonable accuracy in such a system of micro level yield group identification and application of DRIS norms to them. The unique advantage of the DRIS system to reach the maximum realizable yield through progressive diagnosis based on progressive experimentation shall be substituted by the decile classification proposed in the study to a very good extent. Results of the present study showed that yield and quality factors are largely independent of each other and both can be improved by integrating the respective components even at the higher yield levels obtained in the present study. Analysis of inter-correlation matrix among elements at soil and plant level revealed the possibility of making specific recommendations to achieve progressive yield increases by working out quantity, intensity and rate of release characteristics. of elements in the soil in relation to absorption. Results in the present study showed that scientifically speaking the captions of DRIS indices or index values as " order of requirement" be modified as "order of limiting influences" - the former part of which is relative to metabolic deficiencies and the latter part to the metabolic excess. Imbalance indices have to be viewed as qualitative and not quantitative indices as they are relative, primarily based on the relative deficiencies and excesses which in turn are dependent upon the relative contents and valencies of the ions. The results of the study also revealed that with progressive increase in yield, causing .higher nutrient removal, will make the soil not only more deficient but also increase the frequency of application of nutrients more. The progressive increase in the number of limiting factors with yield improvement caused by higher rate of removal calls for more frequent monitoring and not treating the norm as static for a long period. The results of the experiment have brought to light a graded pattern of nutritional management for black pepper. The primary limiting factors were found to be high native content of Fe and Mn which will have to be ameliorated. Secondly, at the low yield level the yield is limited by a relative deficiency of Zn caused by high P calling for a temporary skipping of P; supplemented with N and K which can take the yield up to 5 kg plant-1. Excess S through the incidental application of prophylactic sprays of Bordeaux mixture and shortage of Ca and Mg appear to be the limiting factors at the higher yield class. Amelioration of acidity by supplying Ca + Mg carbonate, substitution of S containing fungicides and application of N and K shall constitute the recommendation, beyond which P may have to be applied.ThesisItem Open Access Sturcture analysis and system dynamics of agroforestry home gardens of southern Kerala(Department of Agronomy, College of Agriculture, Vellayani, 1997) Jacob, John; KAU; Achuthan, Nair MA study entitled "Structure analysis and system dynamics of agroforestry home gardens of southern Kerala" was undertaken during the period from 1994 - 1997 in Thiruvananthapuram district of Kerala State. The study comprised of a detailed agroforestry systems inventory description survey of the home gardens in the district, investigations on the system dynamics of two home gardens of the district, laboratory experiments to assess the allelopathic tendencies of some commonly grown multipurpose tree species and linear programming to develop integrated homestead models. The results of the survey revealed that the size of an overwhelming number of holdings was small. The species diversity and average number of plants per home garden was considerably high. Tuber crops ranked first among the crops, followed by fruits, oilseeds, rubber, spices, vegetables, timber and fuel trees and fodder crops. The tree intensity was found to increase as the size of the holding decreased. The frequency of occurrence was highest for coconut, followed by jack, mango, moringa, guava, wild jack and tamarind and lowest for the nitrogen fixing trees. Differences between the agroecological zones of the district with respect to the predominance of crop categories and tree species were also observed. The home gardens presented a multi-tier canopy configuration. There was no specific planting pattern or arrangement. The system, as a whole, was found to be profitable. The two year long field investigation on the dynamics of home gardens revealed that the tree components contributed considerable amounts of nutrients by way of litterfall, stemflow and throughfall. Nutrient addition took place mainly through organic manures at both locations. Harvested biomass accounted for removal of large quantities of nutrients from the systems. Coconut accounted for maximum biomass production and nutrient removal at both sites. The physical, chemical and microbiological properties of the homestead soil were better than that of the control. The soil in the homestead had a lower bulk density, high water holding. capacity, porosity and moisture "Content. An enhanced soil organic carbon content, available N, P and K status were also observed in the home garden. The soil microbial population (bacteria, fungi, actinomycetes and phosphorus solubilizing bacteria) was comparatively higher in the home garden. Nutrient cycling, recycling of crop residues and addition of organic manures helped in improving and maintaining the soil physico-chemical and biological properties of the system in a sustainable manner. The presence of trees lowered the soil temperature in the homestead, whereas relative humidity was maintained at an optimum level when compared to open condition. The light intensities at the floor of all the trees studied were invariably less than that in the open. Both the home gardens were found to be profitable. The tree-crop-livestock integration was a special feature which increased income considerably. Allelopathic inhibition of germination and growth of rice was caused by leaf extracts of all the tree species. Germination of cowpea was inhibited by the leaf extracts of acacia, eucalyptus, casuarina, ailanthus, tamarind, portia and cashew. Growth of cowpea was suppressed by leaf extracts of all the tree species except jack. The powdered leaf litter of all the trees inhibited rice germination and growth. However, jack did not suppress radicle growth. Cowpea germination was inhibited by the powdered litter of all the trees except jack and mange. Cashew, casuarina and jack did not suppress plumule growth of cowpea. Radicle growth of cowpea was inhibited all tree species. The integrated model for the 0.50 ha home garden with 23 enterprises was found to generate a profit of Rs. 10354.21 with an investment of Rs. 3262.30. The coconut-based mixed fanning model developed for the 0.40 ha home garden with 35 enterprises provided a net profit of Rs. 32464.32 on investing Rs. 45000/-.ThesisItem Open Access Nutrient- growth regulator interaction in snakegourd (Trichosathes anguina L.) under drip irrigation system(Department of Agronomy, College of Agriculture, Vellayani, 1998) Elizabeth K, Syriak; KAU; Raghavan Pillai, GTwo field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, to study the effect of varying levels of nitrogen (n), ethephon (g) and drip irrigation frequency (i) on the productivity of snakegourd. The influence of the treatments on the size, quality and shelf life of the produce and also on the physico-chemical properties of soil was investigated. The trials were conducted during the summer seasons (December to April) of 1994-'95 and 1995-'96. The experiments were laid out in 4 2x2 + 2 asymmetrical confounded factorial design with two replications and each replication included two blocks. Combinations of four levels each of N (35, 70, 105 and 140 kg ha'), ethephon (0, 50, 100 and 200 ppm) and two frequencies of drip irrigation (5 mm CPE and 10 mm CPE) constituted the treatments along with two controls (nogoiI and llogoi2) in each block. The highest order interaction NOI was confounded in both the replications. Results of the field experiments revealed that during both the years of experimentation, nitrogen, ethephon and irrigation frequency exerted significant positive influence on the fruit yield of snakegourd. During both the years, the higher levels of nitrogen (105 and 140 kg N ha') were found to be significantly superior to the lower levels (70 and 35 kg N ha'). Pooled analysis of the yield data also revealed a similar trend. Growth characters like internodal length, number of leaves plant" and dry matter production showed significant enhancement due to N application. The positive significant effect of N was manifested in the yield attributes viz., number of fruits plant" and average fruit weight. Significant increase in the WUE of the crop due to N application was also observed. The content and uptake of major nutrients also increased substantially due to applied N. Nitrogen improved the quality of fruits, significantly, in terms of crude protein, total sugars, reducing sugars and ascorbic acid content. However, the shelf life was adversely affected by it. The highest net profit and B:C ratio were recorded by 105 kg N ha' (Rs. 74,636/- and 2.37, respectively) compared to the other levels of N. Considerable improvement in the physico-chemical properties of soil due to applied N was also noticed. The results of the field experiments also indicated significant yield . increase in snakegourd due to ethephon application. The higher levels of ethephon ie., 100 and 200 ppm, were found to be significantly superior to the lower levels in this regard. Growth and yield attributes as well as quality of fruits were favourably influenced by ethephon. Through its indirect positive effect on fruit yield, the higher levels of ethephon improved the WUE of the crop significantly over its lower levels. The economic analysis also revealed the positive effect of ethephon on the net profit and B:C ratio and the highest values were registered by 200 ppm ethephon (Rs. 71,194/- and 2.31, respectively). With respect to irrigation frequency, il (irrigation at 5 mm CPE) registered significantly higher fruit yield compared to i2 (irrigation at 10 mm CPE): Growth characters and also the quality of fruits exhibited a similar trend. More frequent irrigation treatment (i.) exerted its positive significant effect on yield attributes viz., number of fruits plant:' and mean weight and girth of fruits. The physical optima for N at il were worked out to be 100 and 115 kg ha" during the first and second year, respectively. Economic analysis also revealed the favourable effect of frequent drip irrigation, with il registering substantially higher net profit and B:C ratio (Rs. 70,038/- and 2.28, respectively) compared to i2 (Rs. 61,615/- and 2.14, respecti vel y) .. A perusal of the data on fruit yield and economics of the treatment combinations elicited the favourable effect of n3g4il which registered the highest fruit yield, net profit and RC ratio (31.06 t ha", Rs. 1,04,271/- and 3.04, respectively) and hence this combination could be adjudged as the best one for snakegourd cultivation.ThesisItem Open Access Integrated nutrient management for rice based cropping systems of Onattukara tract(Department of Agronomy, College of Agriculture, Vellayani, 1998) Shalini Pillai, P; KAU; Muraleedharan Nair, VAn investigation was carried out at the Rice Research Station, Kayamkulam to identify the most suitable rice based cropping system for the Onattukkara tract and to evolve a suitable ecologically and economically viable integrated nutrient management practice for the system. The experiment was laid out in a 4x6 factorial strip plot design and was carried for two consecutive years extending from April, 1994 to May 1996. The treatments consisted of four cropping systems (rice-rice-sesamum, rice-rice-groundnut, rice-rice-cowpea and rice-rice-bhindi) and six nutrient management levels (N1 farmers' practice, N2 - Package of practices recommendations, N3 three-fourth recommended N as chemical + one-fourth as FYM, N4 - three-fourth recommended N as chemical + one-fourth as FYM + Azospirillum, N5 - three-fourth recommended N as chemical + one-eighth as FYM + one-eighth as vermicompost and N6 - three fourth recommended N as chemical + one - eighth as FYM + one - eighth as vermicompost + Azospirillum). During the third crop season the treatments N2 to N6 was package of practices recommendations (for the respective crops) while N1 was farmers' practice itself. Among the different nutrient management levels tested, the treatment wherein one-fourth recommended N was substituted with FYM and vermicompost along with Azospirillum recorded the maximum grain yield for first crop rice and second crop rice (irrespective of cropping system). The same treatment also supported a better straw yield by maintaining a favourable grain:straw ratio. In ricc-rice-'sesamum, the production efficiency was highp.st when one-fourth recommended nitrogen was supplied through farmyard manure and vermicompost along with Azospirillum. The BCR was maximum when the same treatment was applied without Azospirillum. In rice-rice-groundnut, rice- rice cowpea and rice-rice-bhindi, the same trend followed. Rice-rice-bhindi cropping system recorded the maximum production efficiency followed by rice-rice-groundnut during both the years, and rice-rice-sesamum recorded the minimum value. The overall mean returns was maximum with the cropping system,rice- rice-groundnut. It was followed closely by the rice-rice-bhindi cropping system. While rice-rice-cowpea recorded the meaning of economic returns during the first year, rice- rice sesamum recorded the same during the second year. Studies on the physico-chemical properties of the soil showed that the cropping system, rice-rice-sesamum resulted in a slight increase in bulk density, water holding capacity and water stable aggregates. The organic carbon, total nitrogen and available phosphorus content of the soil increased, while the soil pH, available nitrogen and available potassium contents decreased. The cropping system, rice-rice- groundnut resulted in an increase in bulk density, water holding capacity, water stable aggregates, organic carbon, soil pH, total nitrogen and available phosphorus and a decrease in the available nitrogen and available potassium contents. While there was an increase in the water holding capacity, water stable aggregates, organic carbon, total nitrogen, available nitrogen and available phosphorus there was a slight decrease in bulk density and soil pH in the cropping system, rice-rice- cowpea. The rice-rice-bhindi cropping system resulted in a decrease in the bulk density and soil pH and available potassium and an increase in the water holding capacity, water stable aggregates, organic carbon, total nitrogen, available nitrogen and available phosphorus. The balance sheet of nitrogen showed•a positive balance in the cropping systems rice-rice-groundnut and rice- rice-cowpea and a negative balance in the other two systems. All the cropping systems tested resulted in a negative balance for available phosphorus and a positive balance for available potassium. The cropping system, rice-rice-groundnut was observed to be the most efficient one. followed by rice-rice-bhindi based on the productive efficiency, benefit cost ratio and soil sustainability. The marginal benefit cost ratio for the different nutrient management practices showed that the treatment comprising three fourth recommended dose of N as chemical + one-eighth as FYM + one-eighth as vermicompost (for first and second crop rice) and package of practices 1ecommendations for groundnut (third crop) was the most economic. However, for the rice-rice-bhindi cropping system, the package of practices recommendations was observed to be more economical.ThesisItem Open Access Influence of high background radiation on coconut nutrition(Department of Agronomy, College of Horticulture, Vellenikkara, 1998) Rekha, C; KAU; Balachandran, P VAn investigation on the influence of high background radiation on coconut palms was conducted during 1994-97 at the College of Horticulture, Vellanikkara. This study was carried out in the high background radiation areas of the coastal Kollam district. A pot culture experiment was also conducted at the College of Horticulture, Vellanikkara. Soil collected from the high background radiation area (Chavara) was used for the study. The radiation exposure of coconut roots and its influence on the root activity of coconut palms, radiation profile of coconut rhizosphere, radionuclide accumulation by coconut palms and the influence of organic matter application on absorption of radionuclides by coconut palms were assessed. The main findings are given below. A wide variation in natural background radiation ranging from 200-8 200 nGy h-1 was observed in Chavara and adjoining areas. The radiation levels were generally higher in the coastal areas compared to the inland. 232 Th was the major radionuclide contributing to the high radiation and its content in soil ranged from 144 to 3580 ppm. The results from root exposure studies indicated that plant roots are continuously exposed to high radiation levels and a significant reduction in radiation exposure occurred only at a depth of 1 m. Correlation and regression analyses revealed a significant positive relation between surface radiation and the radiation exposure at different soil depths. The root activity studies employing 32P soil injection technique revealed that the root activity of coconut palms in the high radiation areas was comparable with that in the low radiation areas. The studies on 232Th uptake and its distribution within coconut palm pointed out that considerable accumulation of the absorbed 232Th occurs in roots and that only a small fraction of it is translocated up to the leaves and nuts. Application of organic matter, especially green leaf manure was found to be highly effective in reducing the 232Th uptake by coconut seedlings growing in monazite rich soil.ThesisItem Open Access Varietal reaction to nutrient and moisture stress in Cashew (Aracardium occidentale L.)(Department of Agronomy, College of Horticulture, Vellenikkara, 1998) Latha, A; KAU; Abdul Salam, MFive experiments were conducted at Cashew Research Station, Kerala Agricultural University, Madakkathara during 1996-98 to identify drought tolerant varieties of cashew, to study the response of cashew to applied N at different levels of drip irrigation and to assess the tolerance of cashew varieties to N, P and K deficiency in soil. The abstract of the experiments is given below. Exp. I. Varietal variation in drought tolerance The varieties H-1591, M-26/2, V-5 and M-44/3 are drought tolerant and K-22-1 is drought sensitive. Exp. II. Response of cashew to applied N at different levels of irrigation (drip) N application @ 1500 g per tree per year along with irrigation @ 80 litres per tree per day (through drip) is essential in the state of Kerala for obtaining best results from cashew. Exp . lIl. Tolerance of cashew varieties to N dificient soils The varieties H-1591 and M-2612 are efficient for N deficient soils. The N use efficiency of cashew seedlings grown under pot culture was 24.7 per cent. Exp. IV. Tolerance of cashew varieties to P deficient soils H-1591 is an efficient variety for P deficient soils. The P use efficiency of cashew seedlings grown under pot culture was 8.02 per cent. Exp. V. Tolerance of cashew varieties to K deficient soils The varieties H-1591, M-26/2 and H-1598 are efficient for K deficient soils. The K use efficiency of cashew seedlings grown under pot culture was 12.17 per cent. N, P and K absorption of a six month old cashew seedling was in the order of 151.95 mg N, 21.58 mg P and 49.48 mg K per plant with a nutrient absorption ratio of7: 1:2 (approximately). The variety H-1591 is a super variety capable of tolerating not only drought but also N, P and K deficient soils. The variety M-26/2 is capable of tolerating drought as well as N and K deficiency in soils. The variety K-22-1 is drought sensitive.
