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Authors: Fathima Umkhulzum, S
Advisor: Ameena, M
Title: Management of rock bulrush (schoenoplectus juncoides (roxb.) palla) in wet seeded rice
Publisher: Department of Agronomy, College of Agriculture, Vellayani
Language: en
Type: Thesis
Pages: 140
Agrotags: null
Keywords: Schoenoplectus juncoides, Ethoxysulfuron , Penoxsulam,Carfentrazone, Bensulfuron methyl, Pretilachlor, Echinochloa, Cyperus, Chlorimuron ethyl, Metsulfuron methyl
Abstract: An investigation entitled "Management of rock bulrush (Schoenoplectus juncoides (Roxb.)Palla) in wet seeded rice" was conducted at College of Agriculture, Vellayani during 2016 to 2018. The major objective were to study the biology of the weed rock bulrush (Schoenoplectus juncoides (Roxb.) Palla) and to develop an effecetive and economic method for its management in wet seeded rice. Field experiment was undertaken in farmer's field at Nemom block, Thiruvannathapuram during rabi season (November 2017 to march 2018). Weed biology was studied by observing sample plants in weedy check plots starting from the emergence of the weed. The experiment was laid out in Randomized Block Design with 8 treatments replicated thrice. The experiment was laid out in Randomized Block Design with 8 treatment replicated thrice. The weed management practices tested were:T1-bensulfuron methyl+ pretilachlor @ 60+600 g ha-1 at 4-7 days after sowing (DAS) followed by (fb) hand weeding (HW) at 35-40 DAS; T2-penoxsulam @ 22.5 g ha-1 at 15 DAS fb HW at 35-40 DAS;T3 - ethoxysulfuron @ 15 g ha-1 at 15 DAS fb HW at 35-40DAS;T4-carfentrazone-ethyl @20 g ha-1 at 15 DAS fb HW at 35-40 DAS;T5-metsulfuron methyl +cholimuron ethyl @ 4 g ha-1 at 20 DAS fb HW at 35-40 DAS;T7- HWtwice at 20 and 40 DAS and T8-weedy check. Pre-germinated seeds of var. Sreyas (M) 22) were broadcasted in the puddled soil following all cultural practices as per KAU PoP (KAU, 2011) except weed management. Study on weed biology revealed that the weed behaved as annual/perennial depending on field situation, with an average duration of 106 days in continuously cultivated fields. Phenology of rock bulrush revealed that the weed took 5 days for seed germination, 22 days for flowering, 33 days for spike maturity and 68 days for seed maturity after wet seedign of rice. The weed echibited a lodging behaviour after spike maturity . Seeds were observed to be the main propagule however, vegetative buds and rhizomes also helped in propagation. Lodging after spike maturity and spiny apex of seeds were found to facilitate seed dispersal. The weed was observed to be a prolific seed producer (862 seeds plant-1) with a biomass production of 0.96 t ha-1 as worked out from weedy check plots. The nutrient content of the weed was analyzed to be 0.90,0.33 and 1.14 per cent NPK respectively. Among th weed management practices tested, ethoxysullfuron @ 15 g ha-1 at 15 DAS fb HW at 35-40 DAS (T3) wa significabtly superior to all other treatments with respect to number of productive tillers m-2 (382), number of grains panicle-1 (134.27), filled grains panicle-1 (115.85), grain yield (5750 kg ha-1 and straw yield (9955 kg ha-1). Grain yield recorded in penoxsulam @ 22.5 hg ha-1 at 15 DAS fb HW at 35-40 DAS (5500.76 kg ha-1) was on par with T3. These treatments also recorded higher B: C ratios of 2.26 and 2.11 respectively. At 45 and 60 DAS, lower weed density (2.09 and 3.15 respectively) and weed dry weight (0.13 and 1.83 g m-2 ewspectively) were recorded for enthoxysulfuron @ 15 g ha-1 at DAS fb HW at 35-40 DAS. Higher weed control efficienceis of 99.82 and 98.07 per cent were obtained in plots treated wih ethoxysulfuron @ 15 g ha-1 at 15 DAS fb HW at 35-40 DAS during critical stages of crop weed competition (45 and 60 DAS). Penoxsulam @ 22.5 g ha-1 at 15 DAS fb HW at 35-40 DAS was on par with T3 at 45 and 60 DAS recording weed control efficeincies of 99.07 and97.90 per cent respectively. Uncontrolled weed growth in wet seeded broadcasted rice could cause a yield reduction of 52.18 percent. Higher crop uptake (kg ha-1 ) of N (219.01), P (39.32) ane K (228.55) were recorded in T3 and it was statistically on par with T2, T6 and T7. The weed removal of N, P and K (8.61, 3.13 and 10.95 kg ha -1 respeectively) were aslo lower with ethoxysulfuron @ 15 g ha-1 15 DAS fb HW at 35-40 DAS. Schoenoplectus juncoides was observed to be an emerging sedge weed in the cultivated wet lands with round upright culms having annual or perennial nature, reproducing by seeds or rhizhomes with a biomass production of 0.96 t ha -1, if uncontrolled. The weed could be effectively controlled by ethoxysulfuron @ 15g ha-1 or penoxsulam @ 22.5 g ha-1 both at 15 DAS fb HW at 35-40 DAS. Considering the economics, ethoxysulfuron @ 15 g ha -1 at 15 DAS followed by hand weeding at 35-40 DAS could be adjudged as the most effective strategy for the management of Schoenoplectus juincoides (Roxb.) Palla in wet seeded rice.
Description: PG
Subject: Agronomy
Theme: Management of rock bulrush
These Type: M.Sc
Issue Date: 2018
Appears in Collections:Theses

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