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20112
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Subject: Plant Physiology × Author: Pawanika × End date: 2019 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Physiological aspects of weed management and crop growth in rice under long term herbicide trial in rice-wheat cropping system
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2011-08) Pawanika; Guru, S.K.
    The present study was conducted in the Norman E Borlaug Crop Research Centre and the Department of Plant Physiology, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, with an objective to evaluate the physiological basis of weed management and growth physiology of rice crop under long-term herbicide trials in rice-wheat cropping system. The field experiments were conducted during rainy season of 2009 and 2010. The experiment was laid out in a split plot design with three replications with weed control methods in rice as main plots and weed control methods in previous crop wheat as subplot treatments. The treatments consisted of Weedy, Hand weeding, and the herbicides butachlor and anilofos applied at recommended doses and in previous crop wheat Weedy, Handweeding, Isoproturon, Isoproturon+tank mix 1% urea, Isoproturon+ tank mix .1% surfactant. Morpho-Physiological growth parameters as well as biochemical parameters and total dry matter production by rice were measured at different growth stages. Effect of weed management practices on weed seed bank and soil micro flora were also assessed. Both the herbicide treatments and hand weeding were found to be effective in controlling weeds over the unweeded control. Both butachlor and anilofos showed similar results in relation to suppression of weed density. It was found that, the first thirty to sixty days are critical during which weeds must be controlled to prevent yield losses. Among all the weed species, Leptochloa chinensis reported as a problematic weed. At all the growth stages, Physiological growth parameters were higher in hand weeding as compared to unweeded control. Both the herbicide treatments and hand weeding recorded significantly higher chlorophyll content and photosynthetic rate over the unweeded control but chlorophyll fluorescence was similar in all the treatments. There was non-significant difference among the weed management practices on fungal population but the bacterial population in soil was higher in the herbicide (butachlor and anilofos) treated plots as compared to hand weeding and weedy plots. Weed seed bank was affected by the weed management strategies adopted in the cropping system. Results of weed seed bank study showed that, total number of weed seeds were higher in hand weeding in combination with Iso. (0.75 kg/ha) + Surfactant (0.1%) during 2009 while in the year 2010, treatment combination weedy check in rice and hand weeding or Iso. (1 kg/ha) in wheat recorded highest weed seeds.
  • Thumbnail Image
    ThesisItemOpen Access
    Physiological aspects of weed management and crop growth in rice under long term herbicide trial in rice-wheat cropping system
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2011-08) Pawanika; Guru, S.K.
    The present study was conducted in the Norman E Borlaug Crop Research Centre and the Department of Plant Physiology, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, with an objective to evaluate the physiological basis of weed management and growth physiology of rice crop under long-term herbicide trials in rice-wheat cropping system. The field experiments were conducted during rainy season of 2009 and 2010. The experiment was laid out in a split plot design with three replications with weed control methods in rice as main plots and weed control methods in previous crop wheat as subplot treatments. The treatments consisted of Weedy, Hand weeding, and the herbicides butachlor and anilofos applied at recommended doses and in previous crop wheat Weedy, Handweeding, Isoproturon, Isoproturon+tank mix 1% urea, Isoproturon+ tank mix .1% surfactant. Morpho-Physiological growth parameters as well as biochemical parameters and total dry matter production by rice were measured at different growth stages. Effect of weed management practices on weed seed bank and soil micro flora were also assessed. Both the herbicide treatments and hand weeding were found to be effective in controlling weeds over the unweeded control. Both butachlor and anilofos showed similar results in relation to suppression of weed density. It was found that, the first thirty to sixty days are critical during which weeds must be controlled to prevent yield losses. Among all the weed species, Leptochloa chinensis reported as a problematic weed. At all the growth stages, Physiological growth parameters were higher in hand weeding as compared to unweeded control. Both the herbicide treatments and hand weeding recorded significantly higher chlorophyll content and photosynthetic rate over the unweeded control but chlorophyll fluorescence was similar in all the treatments. There was non-significant difference among the weed management practices on fungal population but the bacterial population in soil was higher in the herbicide (butachlor and anilofos) treated plots as compared to hand weeding and weedy plots. Weed seed bank was affected by the weed management strategies adopted in the cropping system. Results of weed seed bank study showed that, total number of weed seeds were higher in hand weeding in combination with Iso. (0.75 kg/ha) + Surfactant (0.1%) during 2009 while in the year 2010, treatment combination weedy check in rice and hand weeding or Iso. (1 kg/ha) in wheat recorded highest weed seeds.