Browsing by Author "Abraham, C T"

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Biological and control of the weed Mikania micrantha HBK in Kerala
(Department of Agronomy, College of Horticulture, Vellenikkara, 1999) Mini Abraham; Abraham, C T
Biology and management of mimosa invisa mart. in Kerala
(Department of Agronomy, College of Horticulture, Vellanikkara, 2005) Jayasree, P K; Abraham, C T
Biology and management of weedy rice (Oryza sativa f. spontanea)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2015) Nimmy Jose; Abraham, C T
Effect of nitrogen and lime on the yield attributes and yield of dinanath grass (Pennisetum pedicallatum Trin.)
(Kerala Agricultural University, 1980) Abraham, C T; Raghavan Pillai, G; Sreedharan, C
Efficiency of thiobencarb in dry sown rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 1987) Jayasree, P K; Abraham, C T
A field experiment was conducted at the Agricultural Research Station, Mannuthy of Kerala Agricultural University during the first crop season of 1986 to find out the best time and method of application of thiobencarb in dry sown rice. The treatments included combinations of six time and two method of applications and two controls (un weeded and hand weeded), laid out in RBD with three replications. The results showed that the count, dry matter production and nutrient removal of weeds were appreciably reduced by the weed control treatments, particularly by the spray applications at 6 and 9 days after sowing. Effective control of the weeds during the critical stages of the crop was obtained for the spray treatment. , while the new flushes of weeds after each hand weeding posed some competition in the hand weeded plot. The weed control efficiency was highest during the critical stages for the spray applications at 6 and 9 days after sowing, even higher than that of hand weeding. The herbicide did not produce any phytotoxicity symptoms on the crop. Tiller production was found to be adversely effected by weed competitions whereas the crop plants tended to grow taller with increased weed density. A significant negative correlation was found to exit between the crop and weed dry matter productions. The spray treatments at 6 and 9 days after sowing produced higher crop dry matter and resulted in maximum uptake of nutrients during the critical stages. The spray applications at 6 and 9 days after sowing gave significantly higher values of the yield attributes viz., the productive tillers per hill, length of panicle and number of grains per panicle, resulting in higher grain yields on per with the hand weeding. These treatments recorded higher straw yields also. The weed index values were lower for 6 and 9 days treatments after sowing. In terms of return per rupee invested, the spray application of herbicide at 6 days after sowing was the best.
Enhancing the productivity of the rice- fish/prawn farming system in pokkali lands
(Department of Agronomy, College of Horticulture, Vellanikkara, 2004) Sasidharan, N K; Abraham, C T
Influence of nitrogen and lime on the k/(Ca + Mg) ratio of dinanath grass (Pennisetum pedicellatum Trin.)
(Kerala Agricultural University, 1980) Abraham, C T; Sreedharan, C; Raghavan Pillai, G
Integrated weed management in okra (Abelmoschus esculentus (L.) Moench)
(Department of Agronomy, College of Horticulture, Vellenikkara, 2000) Sainudheen, K; Abraham, C T
Field experiments were conducted during summer and kharif seasons of 1998 and 1999 at College of Horticulture, Kerala Agricultural University, Thrissur, with the objective of developing an integrated method for management of weeds, especially perennial weeds like Cynodon dactylon (L.) and Cyperus rotundus L. in okra. Broadspectrum herbicide glyphosate, solarization, smother croppmg with cowpea and monthly digging were compared with unweeded control in the summer season, for their effect on weeds. In the subsequent okra crop, during kharif season, different pre-emergence herbicides and farmer's practice of hand weeding were compared with black polyethylene mulching and unweeded control. The experiment was carried out in a split-plot design with three replications, taking summer season treatments as main plots and weed control methods in okra, as sub plots. Cynodon dactylon and Cyperus rotundus were the predominant perennial weeds in the field. Cyperus iria, Digitaria ciliaris, Dactyloctenium aegyptium, Eleusine indica and Ludwigia parviflora were the major annual weeds. In summer season.,) treatments solarization and glyphosate l.2 kg ha-1 were very effective in reducing the weed problems. They also resulted in reduction in the underground vegetative propagules of perennial weeds. Solarization resulted in increasing the soil temperature by 8.5 and 6. 7°C at 5 and 1 0 cm depths respectively, during April. In the subsequent okra crop, black polyethylene mulching gave complete prevention of any weed problems. Among the other combinations, glyphosate 1.2 kg ha" (twice at 45 days interval) during summer season followed by metolachlor l.0 kg ha-1 + HW at 45 DAS in okra crop (in 1998) as well as solarization followed by pendimethalin l.0 kg ha-1 + HW at 45 DAS (in 1999). The total returns was higher ill plots which received polyethylene mulching in the okra crop, irrespective of main plot treatments given in the summer season. Among them, highest total return was obtained from glyphosate 1.2 kg ha-I in the summer season followed by polyethylene mulching in okra crop (Rs.31,704 ha"), followed by solarization followed by black polyethylene mulching (Rs.30,594 ha"). However, the highest return per rupee invested on weed control was obtained from combinations of metolachlor 1.0 kg ha" (in okra) with glyphosate 1.2 kg ha" in summer season (Rs.2.41), solarization (Rs.2.28) and that of glyphosate 0.8 kg ha'. But all the combinations of weedy control in summer season, except that of polyethylene mulching resulted in loss as far as the cost of weed control and the total cost is concerned.
Integrated weed management under system of rice intensification (SRI)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2011) Musthafa, Kunnathadi; Abraham, C T
An experiment was conducted to assess the performance of system of rice intensification (SRI) vis-à-vis conventional system with special emphasis on weed problems under SRI and to develop an economic weed management strategy. Aiming at reducing drudgery while using manual cono weeder, it was also envisaged to develop the prototype of a self propelled cono weeder. The field studies laid out in randomized block design with 16 treatments in three replications were conducted at RARS, Pattambi in Palakkad district and in farmers’ fields at Alappad Kole in Thrissur district, during the Mundakan seasons of 2007 and 2008. The soil at Pattambi was lateritic sandy clay loam with pH 4.96 and medium fertility, and that at Alappad Kole was clayey in texture with pH 5.0 and of high fertility. At both locations, the density and dry weight of weeds at 45 and 60 days after transplanting (DAT) were higher in all the SRI treatments especially when weed control was done through repeated cono weeding. At Pattambi, weed density and weed dry weight were the lowest in conventional system with post emergence herbicides, which recorded lower nutrient removal by the weeds and the lowest weed index and also higher gross return, net return and B:C ratio. The weed density and dry weight in the SRI fields were the lowest with pre emergence herbicide followed by hand weeding at 30 DAT, but the use of post emergence herbicides showed higher B:C ratio. At Alappad Kole, the weed density and dry weight, both at 45 and 60 DAT, were the lowest in conventional system with cono weeding at 10 DAT followed by post emergence herbicides. Cono weeding followed by hand weeding, pre emergence herbicides followed by hand weeding as well as the use of post emergence herbicides were also equally effective in controlling the weeds 233 in the conventional system, and were on par in the B:C ratios. In the SRI plots cono weeding at 10 DAT followed by post emergence herbicides recorded the lowest weed density and dry weight, however, use of post emergence herbicides recorded the highest net return and B:C ratio among the SRI treatments. Thus, considering the acute shortage and high wages for the labourers in Kerala, weed management through post emergence herbicides will be the preferable option for the farmers in both conventional and SRI systems of rice cultivation. Comparison between the two systems of rice cultivation at two different rice growing ecosystems showed that SRI improved the performance of individual hills through higher number of tillers hill-1, root length and root dry weight hill-1. On the other hand, the tiller number, dry matter production, root dry weight and productive tillers per unit area were higher in the conventional treatments. Owing to higher number of productive tillers per unit area the grain yield of conventional treatments was significantly higher than that of the typical SRI. At Pattambi, conventional system with post emergence herbicides recorded higher number of productive tillers m-2, panicle length, number of filled grains panicle-1, 1000 grain weight and grain yield (2877 kg ha-1), which was 33 per cent higher than the grain yield in the typical SRI. This treatment also recorded significantly higher B:C ratio (1.27) compared to that (0.91) of the typical SRI. However, the highest straw yield (2510 kg ha-1) at Pattambi was observed in ‘SRI with cono weeding at 10 DAT followed by post emergence herbicides’, which was on par with the typical SRI treatment. At Alappad Kole, higher number of productive tillers m-2, more filled grain percentage, highest 1000 grain weight, highest grain yield (6073 kg ha-1) and highest straw yield (5109 kg ha-1) were recorded by conventional system with cono weeding followed by hand weeding, which showed an increase of 93 per 234 cent in grain yield, with an additional yield of 2934 kg ha-1, and 109 per cent in straw yield over the typical SRI and recorded the highest gross return, net return and B:C ratio (2.46). Thus, the study showed the superiority of conventional system of rice cultivation at a spacing of 20 cm x 10 cm over the SRI system at a spacing of 30 cm x 30 cm at both the two different rice growing ecosystems studied viz., the sandy loam soils at Pattambi and the clayey soils at Alappad Kole. Prototype of the self propelled cono weeder was developed and field tested. It works satisfactorily in a single forward pass, and covers an area of 0.1 ha h-1. The field study showed that the self propelled cono weeder is effective for inter row weeding in rice, however, further refinement is needed to improve its weeding efficiency.
Method and time of application of thiobencarb in dry-sown rice
(Kerala Agricultural University, 1993) Jayasree, P K; Abraham, C T
Natural enemies on Mikania micrantha H.B.K. in Kerala
(Kerala Agricultural University, Vellanikara, 2002) Mini, Abraham; Abraham, C T; Joy, P J
Laboratory and field investigations were conducted to identify the natural enemies of Mikania micrantha H.B.K. and to evaluate their efficacy as biocontrol agents. During a survey on the distribution of Mikania in Kerala, pests seen on this weed were collected. Nineteen species of insect pests and a species of mite belonging to 15 families and eight orders were identified. Nature and extent of damage caused by these different pests on Mikania were studied. Among them tea mosquito bug (Helopeltis theivora) caused serious damage on Mikania. All these pests are polyphagous in nature. So further scope for utilizing them as biocontrol agent is limited.
Sequential and combined application of herbicides in dry sown rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 1989) Jolly Chacko Palaikudy; Abraham, C T
Field experiments were conducted during Virippu (1st crop season) of 1967 ie. from June to September at Agricultural Research Station, Mannuthy under the Kerala Agricultural University, Vellanikkara, Kerala with the objective of evaluating the efficiency of repeated application of pre-emergence herbicides asa well as combined application of pre emergence and post emergence at early post emergence stage of rice so as to develop a cheaper and efficient herbicide sequence for season long weed controlin dry sown rice. Fifteen treatments were compared with farmers practice of hand weeding, unweeded control and post emergence application of propanil alone. The experiment was carried out in R,B,D with three replications.
Sequential and tank-mix application of herbicides in dry-sown rice
(Kerala Agricultural University, 1995) Jolly Chacko Palaikudy; Abraham, C T
Standardization of bioassay technique for determining butachlor residues in kole soils of Kerala
(Kerala Agricultural University, 1999) Durga Devi, K M; Abraham, C T; Prabhakaran, P V
Different plant species were grown in pots containing soil fortified with known quantities of butachlor and based on the response to the herbicide amaranth was selected as the indicator plant for the herbicide. Among the several growth parameters tested for assessing the plant response to soil residues of butachlor, CSGR (compound shoot growth rate) proved to be the best for quantitative determination of butachlor residues in kole soils of Kerala.
Time of application of pre-emergence herbicides in dry-sown rice
(Kerala Agricultural University, 1991) Suja, G; Abraham, C T
A field experiment was conducted at the Agricultural Research Station, Mannuthy under the Kerala Agricultural University during the first crop season of 1988 to find out the optimum time of application of the pre-emergence herbicides, butachlor and thiobencarb and to assess the scope of second application of these herbicides for efficient weed control in dry-sown rice. Major part of the weed flora of the experimental field was constituted by grasses and sedges. Control of Eehinochloa colons and other grasses was very effective in the treatments where thiobencarb was applied at 0, 3 or 6 days after sowing (DAS) and repeated at 25 DAS whereas almost all the butachlor treatments gave complete control of sedges. The population and drymatter production of weeds were appreciably reduced by the repeated application of thiobencarb and resulted in improvement of growth, yield attributes and yield of rice. These treatments also reduced the crop-weed competition for major nutrients N, I' and K.
Time of application of pre-emergence herbicides in dry-sown rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 1989) Suja, G; Abraham, C T
Weed dynamics in rice fields : influence of soil reaction and fertility
(Department of Agronomy, College of Horticulture, Vellanikkara, 2003) Vidya, A S; Abraham, C T
Weed flora and their relative dominance in semi-dry rice culture
(Kerala Agricultural University, 1997) George Thomas, C; Abraham, C T; Sreedevi, P
The weed flora in surgarcane fields of Palghat district
(Kerala Agricultural University, 1993) Girija Devi, L; Neelakantan Potty, N; Abraham, C T; George Thomas
Weed management in banana cv. nendran with cowpea as an intercrop
(Kerala Agricultural University, 1991) Nybe, E V; Abraham, C T; Suma, A