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ThesisItem Open Access Time of application of pre-emergence herbicides in dry-sown rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1989) Suja, G; KAU; Abraham, C TThesisItem Open Access Spatial arrangement and nutrient management for maize- fodder cowpea intercropping in rice fallows(Department of Agronomy, College of Agriculture Vellayani, Trivandrum, 1989) Geetha Kumari, S; KAU; Mohamed Kunju, UAn investigation was carried out during the summer season of l987-88 in the instructional farm attached to the College of Agriculture Vellayani to determine the best crop arrangement for a grain maize fodder cowpea inter cropping in summer rice fallows under different fertility levels • The different crop arrangements. tried were pure crop of maize at normal row arrangement, maize at normal row arrangement, + one, row of cowpea in between the maize pure crop of maize at paired row arrangement two rows of cowpea in the interpair spaces maize at paired rows of cowpea.ThesisItem Open Access Response of modern varities of rice to nitrogen in kole lands(Department of Agronomy, College of Horticulture, Vellanikkara, 1987) Premkumar, J; KAU; Sreedharan, CAn experiment was carried out in Kole lands during the Kole season of 1985 (December-January to March-April) to ascertain and compare the nutritional requirement of short duration rice varieties and pre – release culture 10-1-1. The treatments consisted of factorial combination of 3 varieties ( Jyothi, Culture 10-1-1 and Triveni) and 5 levels of nitrogen (50,70,90,110 and 130kg N ha-1) in Randomised Block Design, replicated thrice. It was found that the pre-release Culture 10-1-1 had significantly higher plant height, tiller number, leaf area index, dry matter production, number of panicles per m2 and thousand grain weight over other varieties. Triveni recorded the highest filled grains per panicle and weight per panicle. There was no variation in grain yield among the cultivars tested. Culture 10-1-1 registered the highest straw yield and nutrient uptake. Culture 10-1-1 also recorded the highest net income over the varieties tested. Application of nitrogen increased the vegetative characters and yield attributes of rice viz., plant height, tiller production, number of panicles per m2, panicle length, panicle weight, filled grains per panicle and thousand grain weight. The highest grain yield and net income was obtained by Jyothi at 110 kg N ha-1 and that for culture 10-1-1 and Triveni at 90 kg N ha-1. Straw yield and dry matter production were increased upto 110 kg N ha-1. The uptake of nutrients were also influenced positively by nitrogen fertilization. The per day production of Jyothi, culture 10-1-1 and Triveni was found to be 42.65, 51.63 and 49.88 kg, respectively at 90 kg N ha-1. The present investigation revealed that the optimum level of nitrogen fertilization to be 103.74, 97.48 and 93.07 kg ha-1 for Jyothi, Culture 10-1-1 and Triveni, respectively. It was also observed that the field duration of culture 10-1-1 was only 77 days compared to that of 79 and 91 days of Triveni and Jyothi respectively. Benefit cost ratio was highest for Culture 10-1-1 thus indicating the scope of popularizing this cultivar as a short duration variety in Kole land.ThesisItem Open Access Nutrient management in bitter gourd under partial shade(Department of Agronomy, College of Agriculture, Vellayani, 1989) Ravikrishnan, M K; KAU; Sasidhar, V KA field experiment was conducted at the College of Agriculture, Vellayani during 1988 to study the influence of three levels of each nitrogen (50, 70 and 90 kg/ha), phosphorus (15, 25 and 35 kg/ha) and potassium (25, 50 and 75 kg /ha) on growth, yield, content and uptake of major nutrients in bittergourd VK-1 (Priya) under partially shaded conditions of coconut gardens. The trial was conducted as 33 + 1 partially confounded factorial experiment in Randomised Block design with two replications. Higher levels of nitrogen had profound influence on growth characters like days for opening of first male and female flowers and their node of emergence, internodal length, length of main vine and total dry matter production. Application of phosphorus of 35 kg/ha had significant positive effect on the node of emergence of first female flower and total dry matter production. Yield attributes like sex ratio, fruits per plant and harvest index were not influenced significantly by the main and interaction effects of the major nutrients. However the control plots registered a significant reduction in values for these parameters. The fruit set was maximum at 90 kg/ha of nitrogen, 25 kg/ha of phosphorus and 25 kg/ha of potash. Application of 90 kg N/ha, 25 kg P2O5/ha and 50 kg K2O/ha recorded the maximum yield. The response of bittergourd to nitrogen levels was linear and that to phosphorus levels was quadratic. Application of potassium at 75 kg K2O/ha was found to significantly increase the fruit weight. The length and girth of the fruits were positively influenced by the application of nitrogenous fertilizer. Potassium at the rate of 75 kg K2O/ha recorded the maximum girth of fruits signifying its effect on this character. The nitrogen and phosphorus content of fruits and plants and protein content of fruits were found to be unaffected by the main effects of nitrogen, phosphorus and potash. An increase in potash level increased the potassium content of fruits and plants. Nitrogen at 90 kg/ha significantly increased the nitrogen uptake by plants and fruits and phosphorus uptake by plants as compared to other levels. Maximum potassium uptake by fruits was obtained by application of 35 kg P2O5/ha and 75 kg K2O/ha and uptake of potassium by plants was maximum at 90 kg N/ha, 35 kg P2O5/ha and 75 kg K2O/ha. The study indicated that application of 90 kg N/ha 25 kg P2O5/ha and 50 kg K2O/ha recorded the maximum yield and net returns from bittergourd cv. VK-1 (Priya) under partially shaded conditions of coconut gardens in the red loam soils of Vellayani.ThesisItem Open Access Slow release nitrogen in cassava nutrition(Department of Agronomy, College of Agriculture, Vellayani, 1988) Vinod, G S; KAU; Muraleedharan nair, VAn investigation was undertaken at the College of Agriculture, Vellayani during the year 1985-86 to study the effect of slow-release nitrogen sources on cassava. The variety used for the trail was Sree Visakha. The treatments consisted of four sources namely urea, neemcake coated urea, urea super granule and rubber cake coated urea each at five levels of nitrogen (50, 75, 100, 125 and 150 kg/ha). The experiment was laid out in a 4 x 5 rectangular lattice design with three replications. Application of slow release sources of nitrogen like urea super granule and neem cake coated urea enhanced the growth characters of tapioca such as plant height, number of functional leaves, number of nodes and the leaf area index. Higher levels of nitrogen gave better results in the growth characters. The highest number of tubers, maximum tuber weight and the highest tuber yield were recorded by the urea super granule application, followed by neem cake coated urea. Among the levels of nitrogen tried, the level 150 kg/ha gave the highest yield. Starch content, crude protein content and the hydrocyanic acid contents were not affected by the slow-release source of nitrogen while higher levels of nitrogen application increased the hydrocyanic acid content and the crude protein content. Urea super granule recorded the highest nitrogen uptake and potassium uptake followed by neem cake coated urea. There was no significant difference in the total nitrogen content of the soil with the use of slor-release sources of nitrogen. The treatment combination of neem coated urea tried at 150 kg N/ha resulted in the maximum net return. Though urea super granule gave the maximum yield its cost of cultivation was higher than that of the other sources. So it is more economical to use neem cake coated urea than urea super granule. So in general, the slow-release sources of nitrogn like urea super granule and neem cake coated urea resulted in a better performance than prilled urea.ThesisItem Open Access Shade response of common rainfed intercrops of coconut(Department of Agronomy, College of Horticulture, Vellanikkara, 1981) Lalitha Bai, E K; KAU; Vikraman, RAn experiment was conducted at the College of Horticulture, Vellanikkara during 1980-81 to study the shade response of five common rainfed intercrop of coconut garden. The experiment was laid out in randomised block design with four levels of shade and five replications. The study revealed that sweet potato cannot be cultivated under shade as it is a ‘shade –sensitive’ crop,while coleus is suitable only where light infiltration is high. Colocasia, turmeric and ginger were found suitable for intercropped situations. Colocasia appears to be shade – tolerant while ginger and turmeric are indicated as ; shade – loving’. These two shade – loving crops are best suited under shaded situations up to 25 and 50 per cent shade, respectively . Photosynthetic mechanism appears to have a decisive role on the shade response of all these crops expecting sweet potato. Excepting colocasia, plant height (length of vine) in all the crops increased with increasing shade intensities. Number of branches (tillers) in all the crops significantly decreased with increasing intensities of shade. The content of total chlorophyll and its components were significantly influenced by shading in all the crop. The contents of nitrogen, phosphorus and potassium in all the plant components of all crops increased because of shading. The uptake of all the nutrients followed an identical pattern as that of dry matter accumulation in all the crops.ThesisItem Open Access Biomass productivity and nutrient accumulation in sesbania rostrata inoculated with rhizobium(Department of Agronomy, College of Agriculture, Vellayani, 1989) Murali, S; KAU; Muraleedharan Nair, VWith a view to study the biomass productivity and nutrient accumulation of Sesbania rostrata, a field experiment was initiated at college of Agriculture, Vellayani during summer of 1988-’89. The investigation was carried out as two separate experiments. The objective of Experiment I was to assess the biomass productivity and nutrient accumulation of Sesbania rostrata in relation to other green manures, viz. Sesbania aculeata and Crotolaria juncea. The second experiment was intended to determine the effect of Rhizobium inoculation, Liming and phosphorus application on the biomass productivity of Sesbania rostrata. The experiment (s) were laid out in randomized block design with three replications. The soil of the experimental site(s) was sandy clay loam, low in available nitrogen and phosphorus and medium in available potassium. An abstract of the results is given below. Optimum time of harvest of the green manures during the third crop season in rice fallows was at flowering stage(50 DAS), since all the parameters investigated showed a maximum value at this period. Among the green manures tried, Crotolaria juncea proved to be superior in terms of green matter yield, dry matter yield and nutrient up take followed by Sesbania aculeata. At final harvest (50DAS) Crotolaria juncea plant, yielded 14.98 t/ha of biomass, 5.36t/ha of dry matter and yielded 103.78kg/ha, nitrogen. The performance of Sesbania rostrata was not at all satisfactory under the agro-climatic conditions of Trivandrum during the summer season. The present study indicated the superiority of Crotolaria juncea as a green manure under Trivandrum conditions during the summer, as compared with the other two green manures tried. Highest level of lime application (500kg/ha) tried in the experiment together with inoculation positively influenced the growth parameters, nutrient uptaken , soil content of nitrogen, phosphorus, calcium and Rhizobium population . Net returns and cost-benefit ratio also showed higher values for the said treatments. Though phosphorus application at 30kg/ha positively influenced the said parameters, its effect was negligible and greatly nullified by the cost of fertilizer which resulted in a lower net profit and cost-benefit ration. Thus, it is revealed from the present study that phosphorus application is not absolutely necessary for growth of Sesbania rostrata under the agro-climatic conditions of Trivandrum district.ThesisItem Open Access Effect of different levels of nitrogen phosphorus & potassium on the growth & yield of vegetable cowpea var. kurutholapayar grown as an intercrop in the coconut gardens & in the open(Department of Agronomy, College of Agriculture, Vellayani, 1987) Rajesh, Chandran; KAU; Abdul Salam, MField experiments were conducted at the college of Agriculture, Vellayani during 1986 to study the effect of three levels of nitrogen (10,20 30 kg/ha), three levels of phosphorus (20, 40, 60 kg P2 O5 /ha) and three levels of potassium (10,20 and 30 kg K2 O/ha) on the growth, yield and quality of vegetable cowpea Var. Kurutholapayar grown in the coconut gardens and in the open. The experiment was laid out in a 33 factorial experiment with two replications confounding NPK in replication I and NP2 K2 in replication 2. The same experiment was simultaneously laid out, both in the open and in the coconut garden. The abstract of the results is presented below. Nitrigen application upto 30 kg/ha or phosphorus application upto 60 kg P2O5/ ha increased the vine length, leaf number per plant, dry matter production, number of pods per plant and number of seeds per pod. Application of 30 kg N/ha or 60 kg P2 O5/ ha resulted in the highest uptake of nitrogen and phosphorus. The highest potassium uptake was noticed with the application of 20 kg K2 O/ ha. The fresh bhusa yield of vegetable cowpea var. Kurutholapayar increased with N application upto 30 kg/ha or P application upto 60 kg P2 O5/ha. Application of potassium had no significant effect on the fresh pod yield of vegetable cowpea in the red loam soils of vellayani containing medium amounts of potassium. A maximum net income of Rs. 11,044.80 was obtained from the plants raised in the open by the application of “30 kg N along with 60 kg P2 O5 and 30 kg K2 O/ha”. In general, vegetable cowpea grown in the open showed a much better performance compared to those raised under the partial shade.ThesisItem Open Access Effect of shade and moisture regimes on the growth of cocoa seedlings(Department of Agronomy, College of Horticulture, Vellanikkara, 1981) Gopinathan, R; KAU; Vikraman Nair, RAn experiment was conducted at the College of Horticulture, Vellanikkara during 1979-80 on the effect of shade and moisture regimes on the growth of cocoa Theobroma cacao L.) seedlings. The investigations were carried out to arrive at the optimum shade and moisture requirement for the growth of cocoa seedlings. The experiment was laid out in a completely randomised design with four levels of shade and three levels of moisture with four replications. The study revealed that cocoa seedlings must be shaded and well watered for their better growth. 50 – 55% shade and irrigation at 75% available moisture was found best. Death of all the seedlings in the open by the third month of observation stresses that, cocoa seedlings cannot be grown without any shade irrespective of the frequency of irrigation. Expect net assimilation rate (NAR) and leaf area ratio (LAR) all the growth characters were increasing with increasing shade (up to 50 – 55%) and increasing frequencies of irrigation.
