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  • ThesisItemOpen Access
    PHYSIO-MORPHOLOGICAL APPRAISAL OF CROPS AND WEEDS AS INFLUENCED BY CONTINUOUS AND ROTATIONAL USE OF HERBICIDES IN RICE-WHEAT CROPPING SYSTEM.
    (CSK HPKV, Palampur, 2019-07) Singh, Gurpreet; Suresh, Kumar
    The present investigation was conducted in an ongoing long-term experiment on effect of continuous use of herbicides on weed shifts in rice- wheat system at the Research Farm of Department of Agronomy, Forages and Grassland Management, CSKHPKV, Palampur during 2016-17 and 2017-18. Nine treatments viz., Farmer’s practice, continuous use of herbicide in rice and continuous or rotational use of herbicide in wheat, continuous use of herbicide in rice with substitution of 25 percent N though Lantana and continuous or rotational use of herbicide in wheat, rotational use of herbicide in rice and continuous or rotational use of herbicide in wheat and rotational use of herbicide in rice with substitution of 25 percent N though Lantana and continuous or rotational use of herbicide in wheat were evaluated for two years (2016-17 and 2017-18) with three replications. Ammannia baccifera and Cyperus sp. were the most dominant weeds constituting (11.97 and 14.54%) of the total weed flora during Kharif 2016 and 2017, respectively. These were followed by Scirpus sp., Cyperus sp. and Monochoria vaginalis, during 2016 and Ammannia baccifera, Scirpus sp., and Monochoria vaginalis, during 2017. Avena ludoviciana was the most dominant weed constituting 20.22 and 18.61% of the total weed flora during Rabi 2016-17 and 2017-18, respectively followed by Phalaris minor (19.26 and 17.69%), Lolium temulentum (19.08 and 15.84%), Poa annua (16.02 and 17.51%), Vicia sativa (10.68% and 8.5%) and Polygonum alatum (1.5 and 6.94%). Significantly lower total weed count, total weed dry matter accumulation and NPK depletion by weeds was recorded in ‘continuous use of herbicides in both the crops with substitution of 25 per cent N through Lantana in rice’ and ‘rotational use of herbicide in both the crops with substitution of 25 per cent N through Lantana in rice’ during both the year of study in rice and wheat, respectively. In rice, significantly higher plant height, dry matter accumulation, leaf area, leaf area index, CGR, yield attributes, yield and nutrient uptake during both the years were recorded in ‘continuous use of herbicide in both the crops with substitution of 25 per cent N through Lantana in rice’. In wheat, significantly higher plant height, plant population, dry matter accumulation in root, shoot, leaves and CGR were recorded in ‘rotational use of herbicide in both the crops with substitution of 25 per cent N through Lantana in rice’ during both the years. Treatment effects were not significant for RGR and NAR for both rice and wheat. The system’s net return and net return per rupee invested were maximum in rotational use of herbicide in both the crops with substitution of 25 per cent N through Lantana in rice’ during both the years. On an average rotational use of herbicide in both the crops with substitution of 25 per cent N through Lantana in rice’ was found to be the best treatment for getting higher productivity and profitability.
  • ThesisItemOpen Access
    EFFECT OF DIFFERENT CROPPING SYSTEMS ON WEED DIVERSITY UNDER MID-HILL CONDITIONS OF HIMACHAL PRADESH
    (CSKHPKV, Palampur, 2018-07-20) Singh, Gurpreet; Pathania, Pawan
    The present study was carried out in a continuing experiment at the Bhadiarkhar farm of the university. Eight cropping systems [C1- „rice – wheat‟, C2- „rice – pea – summer squash‟, C3- „okra – radish – onion‟, C4- „turmeric – pea – summer squash‟, C5- „rice – lettuce – potato‟, C6- „rice – palak – cucumber‟, C7- „rice – broccoli – radish‟, C8- „colocasia – pea + coriander‟] were evaluated during 2016-17 in RBD with four replications for their effect on weed menace, production potential, economic feasibility, energy relations and yield and nutrient losses due to weeds under mid hill conditions of Himachal Pradesh. There were 24 weed species which invaded different cropping systems. During kharif, Ageratum sp. (28%) Cynodon dactylon (20%) and Commelina benghalensis (19%) were the predominant weeds. In rabi, Phalaris minor(63%) was the most dominating weedfollowed by Coronopus didymus (10%), Spergulla arvensis (6%) and Ageratum sp. (4%). In kharif, Commelina benghalensis was most abundant weed irrespective of the cropping system and was most dense in rice-based cropping systems. Ageratum sp. was most dense in other systems. Monochoria vaginalis was only present in rice-based cropping systems. Cynodon dactylon had highest important value index (IVI) irrespective of the cropping system followed by Commelina benghalensis, while Ageratum sp. was important in other cropping systems having higher IVI. Weed flora during rabi was richer than that during kharif. In rabi, Phalaris minor had highest abundance, density and important value index (IVI) irrespective of the cropping system. Coronopus didymus and Spergulla arvensis were the other important weeds having higher value of these indices. In traditional „rice-wheat‟ system 14 species in rabi and 8 in kharif season were found associated and species richness varied with diversification of systems. In rabi, highest diversity of weed species was in rice-wheat system and in kharif weed flora was more diverse in C3, C4 and C8 i.e. okra, turmeric and colocasia based systems and was lower in rice-based systems. C8 had highest RGEY, profitability, productivity, gross returns, net returns and B: C among all the cropping systems. C3 had highest land use efficiency. C1 had highest carbohydrate, protein yield and highest energy output with lowest input. C4 had highest cost of cultivation and lowest B: C and energy output: input. N depletion by weeds ranged from 16.2 in C6 to 48.5 kg/ha/annum in C3, P from 3.1 in C5 to 8.1 kg/ha/annum in C3 and K from 4.8 in C6 to 13.2 kg/ha/annum in C3. Weeds inflicted huge yield losses ranging from 30.6 in C1 to 59.2 % in C6.