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ThesisItem Open Access Combined application of granular preparations of pre-emergent herbicides and fertilizers in rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Bindu, N K; KAU; John, P SA field experiment was conducted at the Agricultural Research Station, Mannuthy under the Kerala Agricultural University during the first crop season of 1994 to find out the effect of pre-emergent herbicides and fertilizers in rice. The experiment was laid out in a randomized block design and consisted of fourteen treatments with three replications. Broadleaved weeds and sedges dominated the field. Among broadleaved weeds, Mono choria vaginalis and sphenocleazeylanica were predomint. Shoenoplectus lateriflorus and Cyperus difformis were the prominent sedges present in the field and Echinochloa colonum,saccolepis interrrupta and Isachne miliacea were the important grasses present. Butachlor, anilofos and oxyflourfen under different methods of application reduced the weed Population. Though oxyflourfen recorded high weed control efficiency, it was highly phytotoxic to the rice crop and resulted in poor crop stand. Butachlor and anilofos applied as homemade granular (GP) preparation or as spray alone, or in combination with fertilizer was safe to the crop. The available nutrient in the soil was not affected by the different methods of application of butachlor and anilofos, alone or when combined with fertilizer. Butachlor and anilofos as spray or as GP applied alone, or in combination with fertilizer recorded similar crop growth characteristics, yield and yield attributes. Nutrient up taken by weeds was lower in butachlor and anilofos treatment. Lower weed index values were recorded in butachlor and anilofos treatment. The highest return per rupee was obtained from anilofos treatments. The highest return per rupees was obtained from anilofos treatments. In general, combined application of anilofos or butachlor GP with fertilizer gave efficient control of weed, produced higher grain yields and high return per rupee invested. It also reduced cost, energy and time of weed control operation.ThesisItem Open Access Standardisation of fertilizer schedule for export oriented production of bhindi(Department of Agronomy, College of Agriculture, Vellayani, 1993) Sajitharani, T; KAU; Pushpakumari, RAn experiment was conducted at the instructional farm, College of Agriculture, Vellayani to find out the effect of different levels of fertilizers and their split application on the growth, yield, quality and nutrient uptake of bhindi. Abelmoschus esculentus (L) Moench. The treatments consisted of four levels of nutrients Viz. (330: 110: 220 kg N2 P2O5 & K2O), the present T & V recommendation, 2/3 of the T & V recommendation, 1/3 of the T & V recommendation and 50: 8: 30 kg NP2O5 & K2O per hectare the present package of practices recommendation and 3 methods of application viz. nutrients in 2 splits, 4 splits and 6 splits. The results revealed that nutrient levels significantly influenced most of the growth and yield contributing characters and yield of bhindi. Biometric characters like plant height, LAI, CGR, DMP and yield contributing characters like days to 50 percent flowering, number of flowers formed, number of fruits formed total yield of fruits and quality parameters like protein content and ascorbic acid content increased with increasing levels of nutrients, recording their maximum value at F1 level, (T and V recommendation). Uptake of nutrients by plants, fruits and total was also maximum for the same treatment. However yield attributes viz. setting percentage, length and girth of fruits etc. remain unchanged with increasing levels of nutrients. Application of fertilizer nutrients in different splits viz. 2,4 or 6 cause significant variation in some of the growth and yield characters. An increase in the plant height at 60 DAS, DMP, days taken for 50 percent flowering and uptake of nutrients was noticed when nutrients were supplied in two equal splits, viz half as basal and half 30 DAS (S1). On the other hand the ascorbic acid content in fruits was maximum when nutrients were applied in six splits. Application of nutrients in 6 splits caused a significant reduction in the crude fibre content also. From the economic point of view, the maximum net profit of Rs.13682.54 was obtained by F3 level (2/3 of T and V recommendation) and Rs.14710.8 by S1 (2 equal splits half as basal and half 30 DAS).ThesisItem Open Access Investigation on allelopathic influence and control of purple nuts edge(Department of Agronomy, College of Agriculture, Vellayani, 1999) Ameena, M; KAU; Sansamma, GeorgeLab and field experiments were conducted at the Instructional farm, College of Agriculture, Vellayani to study the allelopathic influence of Purple nutsedge (Cyperus rotund us L) on important field crops; to investigate the effectiveness of systemic herbicides for control of nutsedge and also to assess the effect of chemical weed control on growth and yield of subsequent field crops. In Ex. no. I, allelopathic influence of purple nutsedge on important field crops like rice, ragi, cowpea, green gram, bitter gourd and bhindi were studied. The treatments comprised of aqueous extracts and blended extracts of fresh and dry plant parts of nutsedge. The results revealed that aqueous extracts of nutsedge inhibited germination of rice, ragi, bitter gourd and bhindi while it had some stimulatory effect on germination of cowpea and green gram. The early growth characters of the field crops were found suppressed by the aqueous extract treatment while the blended extract showed no effect. In general, the dry plant parts showed greater effect than the fresh material. Under Ex.no.Il, field studies were made to investigate the effectiveness of systemic herbicides viz. Glyphosate and 2,4-D for control of nutsedge. The treatments included different doses of the herbicides with and without adjuvants and Glyphosate combined with sublethal dose of 2,4-D. The results revealed that lowest dose of the herbicides were sufficient for complete kill of the purple nutsedge plants in the experimental area and there was no regrowth upto 6 weeks. There was significant reduction in viability of tubers collected one month after herbicide application, but the tubers tested 45 days after spraying showed an increase in germinability over the record on 30th day. Tubers from treatments involving Glyphosate with sublethal dose of 2,4-D recorded the lowest sprouting percentage indicating the possibility for weed control for a longer period. In Ex. no. In, the persistence of the herbicides in soil were monitored and it was observed that early growth of cucumber sown on the same day of herbicide application was affected while that sown on soils collected 10 days after spraying recorded growth characters comparable to that of control. From Ex.no.IV, it could be inferred that chemical weed control did not show any deleterious effect on growth and yield characteristics of ragi and cucumber sown 15 days after the treatments. Application of 2,4-D for nutsedge control was found superior to other treatments in terms of net income and B:C ratio and the lower unit cost of the chemical was precisely the reason for its superiority.ThesisItem Open Access Economising nitrogen in rice production with sesbania rostrata(Department of Agronomy, College of Agriculture, Vellayani, 1992) Shalinipillai, P; KAU; Muraleedharannair, VWith a view to assessing the influence of in situ growing and incorporation of Sesbania rostrata on the growth and productivity of rice and to study the economy of nitrogen use by rice, a field experiment was conducted at College of Agriculture, Vellayani during the period from July 1991 to December 1991. The experiment was laid out in Randomised Block Design with three replications. Three levels of Rhizobium inoculation for Sesbania rostrata (i1-seed inoculation, i2 - stem inoculation, i3 – seed + stem inoculation), five levels of nitrogen to succeeding crop of rice raised after incorporation of Sesbania rostrata (n0 – no nitrogen, n1 – 25 percent of the recommended dose, n2 – 50 percent of the recommended dose, n3 – 75 percent recommended dose, n4 – 100 percent recommended dose) and one control plot of rice (treated as per KAU package of practices recommendations) were fixed as treatments. The rice variety used was Jyothi. The soil of the experimental site was sandy clay loam, medium in available nitrogen and phosphorus and low in available potassium. An abstract of the results is given below. Among the three different levels of inoculation, seed + stem inoculation was found to influence, the green matter and dry matter yields of Sesbania rostrata positively, though not significantly. The number and dry weight of root nodules and shoot nodules, nitrogen uptake, phosphorus uptake, potassium uptake, calcium uptake and magnesium uptake were not found to be influenced significantly by the different inoculation levels. From these results, it can be concluded that, the easiest method of inoculation viz. seed inoculation is sufficient for satisfactory growth and nitrogen fixation by Sesbania rostrata. The present study also revealed that the growth and nodulation of Sesbania rostrata is not satisfactory under conditions of continuous submergence, as that prevailed during the cropping period of the present experiment. Rhizobium being an aerobic bacteria might have got inhibited under the anaerobic conditions created by continuous water logging. Furthermore, the acidic condition of the soil of the experimental site might have also inhibited the activity of Rhizobium. Thus it shows that liming is absolutely necessary for the satisfactory growth of Sesbania rostrata in acid soils. Among the different treatments tried, though the control (KAU package of practices recommendations) gave the maximum yield, it was on par with the treatment comprising 50 percent of the recommended dose of nitrogen along with Sesbania rostrata incorporation. This shows that there is considerable scope for economising nitrogen by the substitution of chemical nitrogen applied to rice by Sesbania rostrata.ThesisItem Open Access Evaluation of low cost techniques in potted vegetables grown in roof gardens(Department of Agronomy, College of Agriculture, Vellayani, 1993) Roshni, C C; KAU; Geethakumari, V LA pot culture study was conducted at the College of Agriculture, Vellayani to evaluate the lowcost techniques in potted vegetables and to compare the efficiency of various techniques for economising water use in vegetables. The experiment was conducted with chilli cultivar ‘Jwalasakhi’ as test crops. The treatments included three levels of irrigation (I3-60, I2-80 and I1-100 per cent field capacity), two methods of irrigation (M1- indigenous auto irrigator using hospital drip and M2-pot watering) and three moisture conservation methods (c0-control without any conservation, C1-application of coir pith and c2-application of Jalasakhti). One absolute control viz., wick irrigation was compared with other treatments. Potting mixture prepared by mixing sand, soil and cowdung in 1:1:1 proportion by weight was used as the rooting medium. The medium was low in available nitrogen, high in available phosphorus and low in available potassium. The field capacity and permanent wilting point were 18.4 and 7.4 per cent respectively. The experiment was laid out in completely randomised design with six replications. The results of the investigation are summarised below. Plant height, branches, LAI at harvest, DMP, S: R ratio and root dry weight at different growth stages differed significantly with methods, levels of irrigation and conservation methods. All these parameters were better under wick irrigation, 100 per cent FC and coir pith mulching. Whereas drip irrigation recorded maximum LAI at initial stages and tap root length. All yield parameters like number of flowers plant-1, fruit plant -1, fruit girth, fruit volume and hundred fruit weight were better under wick irrigation followed by drip irrigation. Among the moisture regimes 100 per cent FC registered better values for all the yield attributes. Coir pith mulching top seeded with respect to these characters. Maximum yield was obtained for wick irrigation, 100 percent FC and coir pith mulching. With respect to WUE, coir pith mulching followed the same pattern as yield. Whereas drip irrigation recorded maximum WUE and 80 per cent FC resulted in higher WUE compared to the other two irrigation regimes. Uptake of N, P and K were maximum in wick irrigation and coir pith mulching. N and K uptake were maximum at 100 per cent FC, but P uptake was high at 80 per cent FC. Under all levels of irrigation, maximum yield and WUE were obtained by drip irrigation and coir pith mulching. Coir pith mulching revealed its superiority under both methods of irrigation with respect to yield and WUE. Maximum yield was obtained at drip irrigation at 100 per cent FC with coir pith mulching while maximum WUE was obtained at drip irrigation at 80 per cent FC with coir pith mulching. Maximum profit was realised by drip irrigation at 100 per cent FC with coir pith mulching. With drip irrigation and coir pith mulching 20 per cent water can be saved without much reduction in yield.ThesisItem Open Access Development of subsurface pad irrigation system for tomato(Department of Agronomy, College of Agriculture, Vellayani, 1995) Abdul Nassar, K; KAU; Jaikumaran, UAn experiment was conducted in the summer rice fallows of the Agricultural Research Station, Mannuthy during 1995 to develop and test subsurface pad irrigation system for tomato and to compare it with surface irrigation. The soil was sandy clay loam, medium in organic carbon and available potassium and high in available phosphorus. The eight treatments comprised of combination of four frequencies of irrigation (IW/CPE ratios of 1.2, 0.9, 0.6 and 0.3) and two irrigation systems (subsurface pad irrigation and surface irrigation). The experiment was laid out in randomized block design with three replications. Poly bags filled with saw dust placed 45 cm beneath the surface at the frequency of one pad for every four plants formed SSPI. Water was supplied to pads by laterals supplying 40 mm of water per irrigation. The study revealed that tomato responded very well to irrigation. Biometric characters like plant height, number of leaves and leaf area index and yield attributing characters like number of flowers, number of fruits and total weight of fruits per plant were favourably influenced by frequent irrigation under both the systems of irrigation. The fruit yield increased with frequency of irrigation and maximum at the IW/CPE ratio of 1.2. The plants irrigated by surface method grew taller, had more leaf area index, produced more number of green leaves, flowers, fruits and total fruit weight per plant compared to the plants irrigated under SSPI system at the irrigation frequencies of IW/CPE ratios 1.2, 0.9, and 0.6. But at the IW/CPE ratio of 0.3, the subsurface irrigated plants performed better than the surface irrigated plants both in terms of growth and yield attributing characters. The crop receiving irrigations through SSPI systems consumed lesser amount of water at all the frequencies of irrigation compared to surface method. This decline at the IW/CPE ratios of 1.2, 0.9, 0.6 and 0.3 were to the tune of 22,30,40 and 18 per cent respectively. The soil moisture extraction from 0-15, 15-30 and 30-60 cm layers in SSPI was 62-70, 24-29 and 6-12 per cent respectively whereas in surface irrigation the respective values were 62-64, 22-23 and 13-15 per cent. The soil moisture redistribution was rapid in the case of surface irrigation whereas it was gradual in the case of SSPI. Moisture content in the case of SSPI was maximum at the radial distance of 15 cm from the pad on either sides whereas in surface irrigation there was no remarkable difference in the moisture content with respect to radial distance from the plant.ThesisItem Open Access Influence of date of sowing and levels of irrigation on the growth and yield of water melon (citrullus lanatus) grown in rice fallows(Department of Agronomy, College of Horticulture, Vellanikkara, 1993) Siby Neendissery, T; KAU; Balakrishna Pillai, PAn experiment was conducted at the Rice Research Station, Mannuthy, Thrissur during the period from November 1990 to April 1991 to study the influence of date os sowing and levels of irrigation on the growth and yield of watermelon (Citrullus lanatus) grown in rice fallows. The experiment was laid out in split plot design with three replications. The treatment consisted of seven dates of sowing (November Ist, November 16th, December 16th, December 32st, January 15th and January 30th) in the main plot and four levels of irrigation (IW/CPE ratio of 1.0, IW/CPE ratio of 0.75, IW/CPE ratio of 0.50, pot watering -1 pot per day per pit) in the sub plot. Observations on various morphological characters, flowering and yield attributes were recorded during the course of investigation. Soil moisture observations were taken before, and 24 hours after irrigation to compute consumptive use and soil moisture depletion. The daily values of various weather elements recorded at the meterological observatory were collected to work out the crop weather relationship. The plants irrigated daily (10 litre/pit/day) were superior to others with regard to vine length, date of picking maturity, date and number of male and female flower production, number of fruits, fruit girth, weight, yield and total dry matter production, but was on par with IW/CPE ratio of 1.0. Irrigation at IW/CPE ratio of 1.0 was superior with regard to the number of nodes for female flower production and number of seeds per fruit. Irrigation treatment IW/CPE ratio of 0.50 recorded the highest sex ratio, hundred seed weight and T.S.S. content. The crop sown on November 16th was superior to others with regard to most of the crop characters. The crop weather relationship studies showed that the temperature range during flowering and early fruit development (3rd to 7th week), maximum temperature during fruit development (7th to 10th week) and relative humidity during maturity (11th to 13th week) negatively correlated with yield. While for total dry matter production there was a negative correlation between temperature range during flowering (3rd to 5th week), maximum temperature during fruit development and early maturity (8th to 11th week) and relative humidity during maturity (11th to 13th week). It was found that irrigation and sowing date has a significant effect on overall growth and yield of the crop. The highest yield was recorded in crop sown on November 16th irrigated daily (10 litre/pit /day). The best performance may be attributed to the optimum weather conditions during the crop period and the effective utilisation of water. From the soil moisture studies it is evident that the consumptive use increased with the frequency of irrigation. The top 15 cm of the soil layer accounted for the highest soil moisture depletion. The depletion was more from the deeper layers in the drier regimes. The water use efficiency was highest for the plants irrigated at IW/CPE ratio of 0.5. sown on November 16th. Results of the present experiment indica that at Mannuthy and surrounding water melon can be successfully raised in rice fallows if irrigated daily (10 litre/pit/day.) and sown in the middle of November.ThesisItem Open Access Nutrient management for intercropped colocasia esculenta var thamarakannan(Department of Agronomy, College of Agriculture, Vellayani, 1993) Rajasree, J; KAU; Oommen, MField experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani to study the effect of nitrogen and potassium on growth and yield of Colocasia and uptake pattern of major nutrients under open and intercropped situations in coconut gardens. The treatments in the experiment consisted of a combination of three levels of N) 40, 60 and 80 kg/ha) and three levels of K (80, 120 and 160 kg/ha). The experiment was laid out in 32 factorial RBD. Different growth attributes like plant height, number of leaves plant-1and LAI were maximum when N @ 60 kg/ha and K @ 160 kg/ha were applied under open condition. Under intecropped situations N @ 40 kg/ha and K @ 160 kg/ha recorded the maximum values for these characters. The yield attributes viz., number of cormels/plant, mean weight of cormels, cormel and corm yield/plant, and harvest index gave maximum values when N @ 60 kg/ha and K @ 160 kg/ha were applied under open condition. In the intercropped situation, the highest values were obtained when N and K were applied @ 40 and 160 kg/ha. Nitrogen @ 60 kg/ha and K @ 160 kg/ha gave the highest yield of marketable tubers under open condition while K @ 160 kg/ha gave the maximum yield under intercropped situation. Nitrogen had no influence on yield of marketable tubers under intercropped situations. Pottasium application increased the starch percentage of tubers and 160 kg K/ha resulted in the maximum value under open and intercropped situations. Plant uptake of N, P and K were influenced by increasing levels of K and was highest at the highest level of K in both open and intercropped situations. Available N and P content of the soil was not influenced by N and K levels under open condition, while the available K was maximum when 160 kg/ha was applied in both open and intercropped situations. Maximum benefit cost ratio and net returns were obtaining by the application of N and K @ 60 kg/ha and 160 kg/ha respectively under open conditions and 40kg/ha and 160 kg/ha respectively under intercropped situation with coconut.ThesisItem Open Access Agronomic evaluation of rice cultivars for rainfed conditions of Kerala(Department of Agronomy, College of Agriculture, Vellayani, 1993) Sheela, K R; KAU; Thomas, AlexanderTwo field experiments were conducted at the Cropping Systems Research Centre, Karamana and one pot culture trial at the College of Agriculture, Vellayani during 1991 and 1992, to select a suitable rice variety and nutrient level required for maximum rice production in the rainfed wetlands of Southern Kerala. The influence of seed hardening in inducing stress tolerance was also studied. In the study, experiment I included a pot culture trial with six varieties, viz., Jaya, Culture -4, M-102, Rasi, Ravi and Tulasi and six methods of seed hardening viz., water, triazole, NaH2PO4, KCI, cowdung extract treatments and a control in two moisture regimes. The significant results of the study were tested in the field. Experiment 2 included these six varieties and three nutrient levels, viz., 100, 75 and 50 per cent of recommended dose for medium duration varieties (90 : 45 : 45 kg N, P2o5 and K2o) and was conducted as a factorial experiment in RBD during the first crop season of 1991 and 1992. The results of the germination study revealed that KCI concentration of 2.50 per cent was ideal for seed hardening. Seed hardening improved germination of all the varieties and water treatment registered the highest vigour index values. In pot culture, Culture – 4 with water treatment registered the highest biomass production, grain and straw yields. The variety, Jaya had the highest root weight and root : shoot ratio. Among the seed treatments, water, KCI and triazole treatments favourably influenced the yield attributes, yield, root parameters and root : shoot ratio. Increasing the moisture regime from 50 to 100 per cent available water enhanced the growth characters, RWC, chlorophyll and decreased the proline content. The subsequent field trial with the highest grain yielding varieties and seed treatments confirmed the superiority of Rasi and Tulasi for increased grain yield, net income and benefit : cost ratio. The different seed treatments also had favourable influence on the above characters. The results of experiment 2 revealed that M – 102 recorded the highest plant height during both the years, while, Tulasi and Rasi had higher tiller number. The varieties, M-102 and Rasi registered higher straw yield than the others. Increased nutrient levels improved growth characters and straw yield. Pooled analysis of grain yield revealed that the varieties, Jaya, Rasi and Tulasi were good yielders and 75 per cent of the recommended nutrient level was sufficient to obtain high grain yield under rainfed conditions. Increased RWC values were observed in the drought tolerant varieties, Ravi, Tulasi and Rasi and at increased nutrient levels. Proline eontent was unaffected by varieties and nutrient levels. The variety, Jaya registered the highest uptake of major nutrients during 1991 while, Tulasi, Rasi and M-102 had higher uptake than the others during 1992. The highest nutrient level recorded the maximum uptake during both the years. Among the varieties, Jaya, Tulasi, Culture – 4 and Rasi recorded high net income and benefit : cost ratio. Among the nutrient levels, the variation between 100 and 75 per cent recommended nutrient dose was not significant with regard to net income and benefit : cost ratio. Under rainfed conditions, 75 per cent of the recommended nutrient dose was sufficient for the varieties, Jaya, Rasi and Tulasi to obtain commensurate yield, net income and benefit : cost ratio. Moreover, the yield and economic returns could be increased by resorting to seed hardening methods.