Browsing by Author "Prameela, K P"
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ThesisItem Open Access Compatibility of herbicides and insecticides for tank mix application in wet seeded rice(Department of Agronomy, College of Horticulture, Vellanikkara, 2017) Anjana Devaraj, G; KAU; Prameela, K PWeeds and insect pests are the major biotic constraints in rice production. Chemical methods of control of insects as well as weeds is very common in rice production. Separate application of the chemicals is expensive and labour intensive with the result that many farmers of Kerala adopt tank mix application of different chemicals without due consideration to efficacy and compatibility. The present study entitled “compatibility of herbicides and insecticides for tank mix application in wet seeded rice” was conducted in a farmer’s field at Alappad Kole lands of Thrissur district, from August 2016 to January 2017. The experiment aimed at studying the compatibility of two commonly used herbicides (bispyribac sodium and cyhalofop-butyl) with two new generation insecticides (flubendiamide and imidacloprid) for tank mix application in wet seeded rice. Another objective of the study was to assess the pest control efficiency of herbicides and insecticides. Out of 14 treatments, four treatments in the trial included sequential and mixed application of bispyribac sodium with two insecticides separately. The next four included cyhalofop-butyl substituted for bispyribac sodium. The remaining treatments were application of herbicides alone, hand weeding with and without application of insecticides and unweeded control. Weed spectrum of the experimental field included barnyard grass (Echinochloa crus-galli), hippo grass (Echinochloa stagnina) and red sprangletop (Leptochloa chinensis) among grasses. Major broad leaf weed was water primrose (Ludwigia parviflora). Yellow nut sedge (Cyperus iria) was the only sedge species which was the major weed of the experimental plot. Treatments were studied for their phytotoxic effects on rice and no toxicity symptoms were observed in tank mix or sequential application. Weed counts, weed dry matter production and weed control efficiency were estimated at different stages of crop growth. Comparing sequential application and tank mix application of bispyribac sodium and flubendiamide, the mixed application resulted in high weed dry weight and low weed control efficiency. Yield parameters and yield were recorded low in this treatment. For sequential and combined applications of bispyribac sodium and imidacloprid, weed control efficiency, weed dry weight, yield and yield attributes were on par. Weed dry weight was low and weed control efficiency was high for mixed application of cyhalofop-butyl and flubendiamide. Yield and yield attributes were also high for this treatment. Weed dry weight, weed control efficiency, yield attributes and yield were comparable for sequential and mixed applications of cyhalofop-butyl and imidacloprid. Insect pest infestation was very low in the experimental field. Rice leaf folder (Cnaphalocrocis medinalis), white backed plant hopper (Sogatella furcifera), red spotted earhead bug (Menida versicolor) and yellow stem borer (Scirpophaga incertulas) were the insect pests noted. Observation on insect count showed that there was no significant difference among treatments with respect to insect pest counts at 5, 7 and 11 days after spraying which was comparable to unweeded control. Hence efficacy of insecticides when tank mixed with herbicides could not be interpreted. Hand weeding was the best treatment in terms of weed control efficiency, yield and yield attributes. However, the highest B: C ratios were registered by the treatments cyhalofop-butyl + flubendiamide and bispyribac sodium + imidacloprid. Highest net return was recorded in bispyribac sodium + imidacloprid. Unweeded control recorded lowest values for yield and B: C ratio. With respect to efficacy of herbicides used, the study indicated that the two insecticides tried were compatible with cyhalofop-butyl. In the case of bispyribac sodium, the insecticide imidacloprid appeared to be compatible, but mixing of flubendiamide cannot be recommended since weed control efficiency was very low.ThesisItem Open Access Effect of biofertilizers on early rooting, growth and nutrient status of Black Pepper (Piper nigrum L.)(Department of Agronomy, College of Horticulture, Vellenikkara, 2001) Ashithraj, N; KAU; Prameela, K PWith an objective of studying the effect of vanous biofertilizers on establishment and growth of pepper cuttings, an experiment was conducted in the College of Horticulture, Vellanikkara during 1999-2000. Both lateral and runner cuttings were inoculated with five species of Glomus and three strains each of A.lipoferum and A.chroococcum. Observations were taken on germination and different growth parameters. Based on the early performance two species of Glomus and two strains each of A.chroococcum and Alipoferum were selected. Single, double and triple combinations of these selected microbes were studied further. Multiple inoculation was found to be supenor over single inoculations. Combinations involving AMF and nitrogen fixing bacteria were showing better results compared to two nitrogen fixing bacteria. Comparing the two species of AMF, Gfosciculatum was more effective in improving overall growth characters. Among nitrogen fixers, Alipoferum was more promising. Combination effect of Gfasciculatum and Alipoferum was appreciably good. However, addition of A.chroococcum with A.lipoforum and AMF further improved the growth performance of crop.ThesisItem Open Access Effect of weather on cocoa and improvement of bean size through seasonal crop orientation(Department of Agronomy, College of Horticulture, Vellanikkara, 1997) Prameela, K P; KAU; Vikraman Nair, RWith an objective of understanding the probable reasons for seasonal fluctuations in flowering and fruiting and also to orient the cocoa crop to a season favourable for bean size, a four year investigation was carried out at the College of Horticulture, Vellanikkara during 1993-96. The influence of weather variables on flowering was studied by correlating weekly flower production with weather parameters of previous one to twelve weeks. This was done using plants with and without fruit load. Flower production was also correlated with increase in fruit load of previous one to twelve weeks. The possible effects of soil moisture deficit and surplus on flowering was also studied. The influence of weather on fruiting was studied by correlating monthly pod yield with weather variables of previous one to seven months. The influence of fruit load on fruiting was also studied by correlating monthly pod yield with increase in fruit load of previous one to seven months. For crop orientation study two sets of plants were used, one as control and the other as treatment. The plants used as control were retained as such without disturbing pods. In the other set, defloration was done excepting during the period from April to July. The results revealed that maximum temperature and bright sunshine hours were positively correlated with flower production while rainfall, relative humidity and number of rainy days were negatively' correlated. However, summer rains had positive effect. Fruit load had negative influence on flowering. For pod production the seasonal difference was much pronounced. During monsoon season a comparatively dry condition with high temperature and low relative humidity caused high pod production after five to six months, while in a non-monsoon period production was favoured by high humidity and high rainfall. Pod load affected flower and fruit production adversely. Models were developed to predict flower and fruit production from weather variables and pod load. The crop orientation study showed that the crop could be oriented to the favourable season of October-November without affecting the total annual yield. However, during years of heavy incessant rains the practice may fail.ArticleItem Open Access Moisture retention characteristics of alluvial soils of Kerala(Kerala Agricultural University, 1985) Prameela, K P; Vikraman Nair, R; KAUAn investigation on the moisture retention characteristics of alluvial soils of Kerala was carried out in the College of Horticulture, Vellanikkara, during 1982-'83, using soil samples collected from different parts of the state. Moisture retention was measured at six tensions and a prediction model was developed for moisture characterisation. More than 70 per cent of the available water was found to be removed at a tension of 3 bars. The moisture contents of different tensions were correlated to the contents of organic carbon and textural components. Organic carbon content showed no significant correlation with moisture retention. The textural components were apparently the determining factors for moisture retention as indicated by the significant positive correlation with the fine fractions (clay and silt) and significant negative correlation with the coarse fractions {fine sand and coarse sand). Multiple regression equations were developed to predict the available water content and moisture contents at 0.3 and 15 bar suctions from the contents of organic matter and textural components.ThesisItem Open Access Nutritional interrelations in nendran banana (Musa AAB)(Department of Agronomy, College of Horticulture, Vellanikkara, 2003) Sulekha, D; KAU; Prameela, K PAn experiment on nutritional inter-relations in Nendran banana was coitducted during 2001-2002 in the farm attached to the Campus Development office, Vellanikkara. Objective of the study was to elucidate the interaction pattern between applied and native elements, which influenced the productivity of banana. The study also aimed at developing a sustainable management system that would bring about a balance between removal of nutrients and yield without depleting soil. The pattern of influences of different sources such as organic, inorganic and integrated forms on growth as well as productivity of banana was studied. Interacting influences of Nand P at two levels, one being the recommended dose and the other, a lower dose, were also studied. The results showed that treatments had a significant beneficial influence on growth characters as well as yield attributes. The integrated nutrient management system showed better response. Total yield as well as yield attributes like number of hands, total number of fingers per bunch, number of D fingers and D finger weight were the highest with integrated method. Foliar contents of Fe and Mn were reduced while those of other essential cations were increased. Application of Nand P at levels lower than the recommended one, gave better results. An analysis of foliar nutrient contents indicated that application of any element by itself was !lot a guarantee for its uptake, but was subjected to the influences of other elements, either applied or native. The highest yield was obtained when foliar K content as well as ratios of Ca+MglFe, Ca+Mg/Mn, S/Fe and S/Ml1 recorded high values. Integrated nutrient application, reducing Nand P levels, basal dressing with time as well as top dressing with S containing compounds like K2S04 are related to higher productivity and sustainability.ThesisItem Open Access Studies on the moisture retention characteristics of alluvial soils of Kerala(Department of Agronomy, College of Horticulture, Vellenikkara, 1983) Prameela, K P; KAU; Vikraman Nair, RAn experiment was conducted in the College of Horticulture, Vellanikkara during the period from September 1982 to July 1983 to study the moisture retention characteristics of alluvial soils of Kerala. Soil samples representing five series located at different districts were collected from fifteen profiles at five depths. Moisture contents were determined at six applied pressures, viz., 0.3, 1, 3,5,10 and 15 bars. The moisture retention was correlated with the organic carbon content and texture of the soil by simple and multiple regression analysis. The study revealed that 50 per cent of the available moisture was depleted at a tension just above one bar, and at 3 bar more than 70 per cent of the available water was extracted. The ranges in the field capacity and permanent wilting point were found to be 21.4 to 32.2 and 12.1 to 16.9 respectively, and the overall mean values 25.8 and 13.9. The correlation study showed that the fine fractions (clay and silt) have significant positive correlation with moisture retention. Both coarse and fine sand fractions gave significant negative correlation. The relationship of organic carbon content with moisture retention and available water was positive, but not significant even at five per cent level. Prediction equations were developed to determine the available moisture content from known value of textural components and organic carbon content. The coefficients of determination obtained were high indicating that the difference in the quality of soil organic matter and fine fractions in the alluvial soils are not substantial.ThesisItem Open Access Weed management in cabbage (brassica oleracea var.capitata L.)(Department of Agronomy, College of Horticulture, Vellanikkara, 2018) Akshatha, V; KAU; Prameela, K PCabbage is an important cool season annual vegetable crop belonging to the family Brassicaceae. In Kerala, its cultivation was earlier restricted to the hill tracts but with the introduction of tropical varieties and hybrids by the Kerala Agricultural University, cultivation of the crop has spread to the plains also. The heavy manurial and irrigation requirements of the crop create conducive conditions for germination and growth of weeds, which reduce cabbage yield by 45-80 per cent. Manual weeding is an effective method of weed control in cabbage, but due to the time, labour and cost factors involved, it is not very acceptable. The present experiment entitled “Weed management in cabbage (Brassica oleracea var. capitata L.)” was conducted at Centre for Hi-tech Horticulture and Precision Farming, Vellanikkara during November 2017 to March 2018 using the variety NS 183. The objective of the study was to evolve a weed management package for cabbage suited to the plains of Kerala. The treatments comprised of application of two pre emergence herbicides (oxyfluorfen 0.2 kg/ha and pendimethalin 1.5 kg/ha) both followed by a hand weeding at 30 DAP, high density planting (0.6m x 0.3m) plus one hand weeding at 25 DAP, two mulching treatments (coconut fronds and silver-black polythene), stale seed bed technique plus one hand weeding at 30 DAP, hand weeding (25 and 50 DAP) and an unweeded control. Broad leaf weeds were predominant (79%) in the field and the important among them were Trianthema portulacastrum, Oldenlandia sp., Cleome viscosa and Cleome burmanii.Polythene mulching of the field resulted in 100 per cent weed control efficiency. Weed dry matter production and N, P and K removal by weeds were higher in unweeded control, and dry matter production increased from 25DAP to 50DAP. Pre emergence application of pendimethalin at 1.5 kg/ha was more effective than oxyfluorfen at 0.2 kg/ha application (8% more effective at 25 DAP). Stale seed bed technique recorded a weed control efficiency of 97.83 per cent at 50 DAP and in high density planting weed control efficiency increased from 12.49 per cent at 25 DAP to 93 per cent at 50 DAP. Coconut frond mulching could not control weeds effectively and weed control efficiency reduced from 55.52 per cent at 25 DAP to 48.96 per cent at 50 DAP. Plant growth parameters were influenced by the different weed management practices. Polythene mulched plots recorded the highest plant height and spread and the lowest duration to 50 per cent head formation and maturity. The highest gross (1987.27g) and net (858.47g) head weights were recorded in polythene mulched plots, which was statistically superior to all other treatments. It was followed by pendimethalin treatment with a net head weight of 523.40g. Highest yield of 16.83t/ha was obtained from polythene mulched plots, followed by pendimethalin applied plots (10.26t/ha). Unweeded control recorded the lowest cabbage yield and values for yield attributes. Unweeded control recorded lower content of all the major nutrients (available N, P and K) in soil. Nutrient contents were highest in plots with minimum weed infestation. The population of soil microflora (bacteria, fungi and actinomycetes) increased after experiment as compared to pre experimental period, indicating no negative influence of herbicides on soil microbes. Polythene mulching, even with higher cost of cultivation, resulted in the highest net return and B:C ratio (2.17). Second highest B:C ratio was obtained with pendimethalin treatment (1.63). Coconut frond mulching cannot be recommended as a weed control measure as it was found ineffective in suppressing weed growth. Polythene mulch was found to be the best method of weed control in cabbage.