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Fertilizer Placement Affects Weed Growth and Grain Yield in Dry-Seeded Rice (Oryza sativa L.) Systems  [PDF]
Bhagirath S. Chauhan, Seth B. Abugho
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.46155
Abstract:

A study was conducted in a split-plot design to evaluate the effect of fertilizer placement method on weed growth and grain yield in a dry-seeded rice (DSR) system. Main-plot treatments were four fertilizer placement methods: between narrow rows (between 15-cm-wide rows of the pattern 25-15-25 cm), between uniform rows (between 20-cm-wide rows), within uniform rows, and surface broadcast. Subplot treatments were three weed control methods: herbicide-treated, nontreated, and weed-free. Weed biomass was greater in the nontreated plots than in the herbicide-treated plots. Herbicide application reduced weed biomass by 89% to 99% compared with the nontreated control. Fertilizer placement did not influence weed biomass in the herbicide-treated plots; however, it greatly influenced biomass in the nontreated plots. Fertilizer placement on the surface increased weed biomass (69 -71 g·m2) compared with the placement of fertilizer below the soil surface (37 -57 g·m–2). Fertilizer placement did not influence weed density and biomass at 60 days after planting. Nontreated plots yielded 700 to 2080 kg·ha–1. Grain yield was similar between the herbicide-treated (2660-3250 kg

Impact of Manual and Chemical Control Over Weeds in the Direct Wet-seeded Rice (Oryza sativa L.)  [PDF]
Inayatullah Awan,Mohammad Amjad Nadeem,Mohammad Qazafi
Asian Journal of Plant Sciences , 2002,
Abstract: Study on rice (Oryza sativa L.) trial on cultural and chemical weed control was carried out during Kharif 2000. Different weeds under the direct wet-seeded rice crop were controlled by using cultural techniques as well as by the use of chemicals (rice herbicides). Weedy check was also kept in both the factors. Weeds were effectively controlled with herbicides and culturing method. Maximum tillers per m2 (928.10), 1000-grains weight (27.67 g) and highest paddy yield (8.89 t ha -1) were recorded from Rifit. The said herbicide also controlled the weed and gave minimum dry weed biomass (9.58 g). While in the other case, hand weeding after 6 weeks of seeding showed the best results.
Weed Vegetation of Direct Seeded Ricefields in Muda Rice Granary Areas of Peninsular Malaysia  [PDF]
M. Begum,A.S. Juraimi,M. Azmi,A. Rajan
Pakistan Journal of Biological Sciences , 2005,
Abstract: A survey was carried out at heading stage of direct seeded rice to determine the major weed flora in Muda area, Kedah, Peninsular Malaysia. Thirty five weed species belonging to 17 families were identified in this area. Of these, 15 species were broadleaves, 10 sedges, 6 grasses and 4 aquatics. According to % field infestation and infestation rating score the six most widespread and abundant species were Oryza sativa complex (weedy rice), Leptochloa chinensis, Echinochloa crus-galli, Ischaemum rugosum, Fimbristylis miliacea and Ludwigia hyssopifolia. The hierarchy of weed type according to % field infested ratio was in the order of grasses (G)> broadleaved weeds (BL)> sedges (SG)> aquatics.
Response of direct dry seeded rice (Oryza sativa L.) to seeding dates and seed rates  [PDF]
JD Rangit, S Sharma, DD Gautam
Agronomy Journal of Nepal , 2010, DOI: 10.3126/ajn.v1i0.7538
Abstract: Field studies to access seed rate, seeding dates, and weed infestation in direct dry sseded rice (Khumal -4) were carried out under rice-wheat rotation system at Khumaltar during 2005/06 -2007/08. The broadleaf weeds: Ageratum conyzoides, Commelina diffusa, Eclipta prostrata, Amaranthus veridis , Coronopus didymus, Lactuca sp. the grassy weeds: Echinochloa colona, Cynodon dactylon , and Paspalum distichum and the sedges: Cyperus difformis and C iria were recorded. E colona was the dominant weed in the second year, however A conyzoides was pronounced in the first year. A conyzoides showed an increasing trend over years and became a dominant species ranging from 2-13/0.25m 2 in the 1st year and 53 -144/0.25m 2 in the 3rd year. Significant interaction effect on total weed number/0.25 m 2 was recorded in the 2nd seeding date in all seed rates. Significantly higher weed numbers were recorded in 2nd seeding date and 20 kg/ha seed rate in the 3rd year. There was no significant interaction between different seed rate and seeding date on the gall formation due to Meloidogyne graminicola . Plant height, tillers/m 2 , number of seeds/panicle, and grain yield were not significantly affected due to seeding dates except plant height in 2005/06. Number of tillers/m 2 was significantly different among seed rates and showed slightly increasing trend with higher seed rates. But there was no significant different in grain yield among seed rates except in the year 2005/06. Dry straw weight did not show consistent results among seeding dates. The present study showed that rice seeding can be done in mid May with the seed rates 30–50 kg/ha. DOI: http://dx.doi.org/10.3126/ajn.v1i0.7538 Agronomy Journal of Nepal (Agron JN) Vol. 1: 2010 pp.16-22
Production Efficacy of Six Rice Cultivars Against Various Herbicides Applied for Weed Control in Direct Wet-Seeded Rice (Oryza sativa L.) Culture  [PDF]
Inayat Ullah Awan,Tufail Abbass,Mohammad Amjad Nadeem
Journal of Biological Sciences , 2001,
Abstract: Six varieties namely IR-6, IR-9, KS-282, Bas-370, Bas-198 and Bas-385 were sown at seed rate of 100 kg ha-1.Two herbicides viz. Acelor @ 250 ml ha-1 and Rifit @ 1 l ha-1 were applied as post emergence (30 days after seeding) to all plots except weedy check (control). Weeds were affectively controlled with herbicides application. Maximum number of tillers m-2 (340.2), number of panicles m-2 (329.8), 1000-grain weight (25.50 g), highest paddy yield (7.50 t ha-1) and straw yield (19.24 t ha-1) were observed in KS-282. Acelor @ 250 ml ha-1 controlled weeds more effectively and gave minimum weed population m-2 (15.28), maximum number of tillers m-2 (330.7), number of panicles m-2 (319.0), number of spikelets per panicle (139.2), 1000-grain weight (21.99 g), paddy yield (6.48 t ha-1) and harvest index (31.39 %)
Influence of Integrated Weed Management Practices on Dynamics and Weed Control Efficiency in Dry Direct Seeded Rice  [PDF]
KP Bhurer,DN Yadav,JK Ladha,RB Thapa,KR Pandey
Nepal Journal of Science and Technology , 2013, DOI: 10.3126/njst.v14i2.10413
Abstract: Field experiment under dry direct seeded rice(O ryza sativa L.) was conducted during rainy season of 2010 and 2011 at Regional Agriculture Research Station (RARS), Parwanipur, Bara to develop appropriate weed management practices for dry direct- seeded rice. The trial was laid-out in randomized complete block design (RCBD) and replicated thrice. Observations were taken on weed, plant growth and yield attributing, yield, and socio-economic parameters. The weed density, dry weed weight and weed control efficiency resulted significantly different as influenced by integrated weed management practices. Low weed population density, low weed index and highest weed control efficiency resulted by pendimethalin followed by 2, 4- D followed by one hand weeding were at par with weed free check. Highest yield resulted from weed free plot followed by pendimethalin followed by two hand weeding and pendimethalin followed by 2, 4- D followed by one hand weeding. However, the net return per unit investment resulted highest in pendimethalin followed by 2, 4- D followed by one hand weeding. This proved that amid increasing wage rate and labour scarcity integrated weed management through pendimethalin 30 EC (Stomp) @1 kg a. i. /ha as pre- emergence herbicide application followed by 2, 4- D sodium salt 80 WP @ 0.5 kg a. i. /ha followed by one hand weeding or stale seed bed followed by pendimethalin 30 EC (Stomp) @1 kg a. i. /ha followed by bispyribac (Nominee gold) @25 g a. i. /ha 10% @200 ml/ha at 20 days of seeding resulted best alternative for manual hand weeding practices giving higher net return per unit investment. DOI: http://dx.doi.org/10.3126/njst.v14i2.10413 ? Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 33-42
Mungbean (Vigna radiata L.) Residue and Nitrogen Rate Affected Growth and Yield of Direct Seeded Rice (Oryza sativa L.) In Rainfed Riceland  [PDF]
P. Suriyakup,A. Polthanee,K. Pannangpetch,R. Katawatin
Asian Journal of Plant Sciences , 2007,
Abstract: An experiment was conducted in a farmer’s field in Ban Muong village, Muang district in Khon Kaen province in 2003. The objective of this study was to investigate the effect of mungbean (Vigna radiata L.) residue and nitrogen rates (0, 30 and 60 kg N ha-1) on growth and yield of direct seeded rice (Oryza sativa L.) in rainfed riceland. The results showed that mungbean residue had no effect on tiller number, leaf area index and total top dry weight of rice in rice-mungbean intercropping or sole rice cropping. Also, mungbean residue had no significant effect on panicle number m-2, spikelets number per panicle, 1,000 grain weight, percentage filled grain, harvest index or grain yield However, mungbean residue tendes to increase rice grain yield over sole rice by 0.33 t ha-1(13 %) with had no nitrogen application. Rice grain yield was significantly affected by nitrogen rates. The highest rice grain yield (2.7 t ha-1) was obtained with a nitrogen rate of 30 kg N ha-1. Nitrogen fertilizer application at a rate of 60 kg N ha-1 decreased grain yield, when compared with 30 kg N ha-1.
Integrated Use of Herbicide and Crop Mulch in Suppressing Weed Growth in a Dry-Seeded Rice System  [PDF]
Bhagirath Singh Chauhan, Seth Bernard Abugho
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.48195
Abstract:

Dry-seeded rice production systems are increasing in many Asian countries because of labor and water scarcities. However, weeds are the main biological constraints in these systems. Herbicides are widely used to manage weeds but they do not provide effective weed control. The use of crop residue as mulch can suppress weed emergence and weed biomass but mulch alone does not provide effective weed control. The integrated use of herbicide and mulch, however, could provide more effective and sustainable weed control in dry-seeded rice systems. A study was conducted in two consecutive rice growing seasons to evaluate the combined effect of herbicide (treated and nontreated) and rice straw mulch (0, 2, and 4 t.ha-1) on weed growth and rice yield in a dry-seeded rice system. In the nontreated plots, weed biomass decreased with increases in mulch amounts, whereas weed biomass in the herbicide-treated plots was similar at different mulch amounts. Overall, herbicide treatments provided better weed control than the mulch treatments. In the nontreated plots, grain yield was similar at different mulch amounts, whereas grain yield in the herbicide-treated plots was greater when the field was mulched with 4 t.ha-1 of rice straw than with no mulch or mulched with only 2 t.ha-1 of rice straw. The results suggest that integrated use of mulch and herbicides can help weed control and increase crop yield in dry-seeded rice.

Competitiveness of Winter Rice Varieties against Weed under Dry Direct Seeded Conditions  [PDF]
A. N. M. Atikur Rahman, A. K. M. Mominul Islam, Md. Altamas Arefin, Md. Rashedur Rahman, Md. Parvez Anwar
Agricultural Sciences (AS) , 2017, DOI: 10.4236/as.2017.812101
Abstract:
Aerobic rice or dry direct seeded rice is highly vulnerable to weeds because of lack of “head start” over weeds and standing water layer to suppress weeds. The risks of chemical control and the huge cost involvement in mechanical control demand an eco-friendly and cost-effective integrated weed management. Weed competitive rice cultivar may be considered as a viable tool for integrated weed management. In these circumstances, an experiment was designed to evaluate weed competitiveness of some selected winter rice varieties under aerobic soil conditions. The study was conducted during dry season (February to June) 2016 at the Agronomy Field Laboratory and Weed Management Laboratory, Bangladesh Agricultural University, Mymensingh. Fourteen rice varieties namely, BRRI dhan28, BRRI dhan29, BRRI dhan47, BRRI dhan50, BRRI dhan55, BRRI dhan58, BRRI dhan59, BRRI dhan67, Binadhan-5, Binadhan-6, Binadhan-8, Binadhan-10, BRRI hybrid dhan3 and Agrodhan-14 were grown under weedy and weed-free conditions. Plots with no rice were also maintained to observe the natural growth of weed in absence of rice. The experiment was conducted with split-plot design with three replications. Weeding regime was allocated in main plot and rice variety was allocated in sub-plot. Results showed that rice varieties varied widely in their yield performances and weed competitiveness. Among rice varieties, BRRI dhan59 allowed the minimum weed growth (19.2 g m-2) while Binadhan-5 allowed the maximum weed growth (62.8 g m-2). Grain yield ranged from 1.85 t ha-1 (BRRI dhan55) to 3.92 t ha-1 (Binadhan-5) under weed-free condition and between 0.41 t ha-1 (BRRI dhan55) and 2.06 t ha-1 (BRRI dhan59) under weedy condition. Weed inflicted relative yield loss ranged from 43.4% to 82.1% among the varieties. BRRI dhan59 allowed the least yield penalty (43.4%) while Binadhan-5 had the maximum yield penalty (82.1%) due to weed competition. Although Binadhan-5 is the most productive variety (3.92 t ha-1) for aerobic culture but its weed inflicted relative yield loss is higher (82.1%) than many other varieties with low yield potential. On the other hand, BRRI dhan59 appeared as the most weed competitive variety (only 43.4% relative yield loss) with productivity of 3.84 t ha-1. Therefore, weed competitive variety should be considered as a vital tool while designing integrated weed management system for aerobic rice.
Bio-Economic and Qualitative Impact of Reduced Herbicide use in Direct Seeded Fine Rice Through Multipurpose Tree Water Extracts Impacto Bioeconómico y Cualitativo del uso Reducido de Herbicidas en Arroz de Siembra Directa a través de Extractos Acuosos de árboles Multipropósito  [cached]
Abdul Khaliq,Amar Matloob,Yasir Riaz
Chilean Journal of Agricultural Research , 2012,
Abstract: Weed control program should be environmentally benign and cost-effective so that reduced herbicide use can help meet these goals. Field trials were conducted to assess the bio-economic and qualitative impact of reduced doses (25 and 50% of label dose) of a postemergence pyrimidinyloxybenzoic acid herbicide (bispyribac-sodium) applied alone or in combination with multipurpose tree (eucalyptus Eucalyptus camaldulensis Dehnh., mango Mangifera indica L., and mulberry Morus alba L.) water extracts in direct seeded rice (Oryza sativa L.) fields. The label dose of bispyribac-sodium and penoxsulam along with weed control were included for comparison. Tank mixing of multipurpose tree water extracts with reduced herbicide doses accounted for > 55% suppression in weed density and > 75% in dry weight; they were quite higher than those recorded for the same herbicide doses used alone. A combination of these extracts with 50% reduced dose of bispyribac-sodium improved rice yield and quality attributes similar to the label dose of this herbicide. Despite the higher net benefits associated with label herbicide dose, the maximum marginal rate of return was achieved with a tank mix of 25% label herbicide dose with multipurpose tree water extracts. Los programas de control de malezas deben ser respetuosos del medio ambiente y rentables, y la reducción del uso de herbicidas puede ayudar a cumplir estas metas. Los ensayos de campo se llevaron a cabo para evaluar el impacto bioeconómico y cualitativo de dosis reducidas (25 y 50% de la dosis etiqueta) de un herbicida de post-emergencia pirimidiniloxi benzoico (bispiribac-sodio) aplicado solo o en combinación con extractos acuosos de árboles multipropósito eucalipto (Eucalyptus camaldulensis Dehnh.), mango (Mangifera indica L.), morera (Morus alba L.) en campos de arroz (Oryza sativa L.) de siembra directa. Se incluyó dosis recomendada en la etiqueta de bispiribac-sodio y penoxsulam y un control de malezas para comparación. Mezcla de estanque de los extractos acuosos de árboles multipropósito con dosis de herbicida reducida causó supresión de > 55% en densidad de malezas y > 75% en peso seco, lo que fue superior cuando estas dosis de herbicida se utilizaron solas. La combinación de estos extractos con un 50% de reducción de la dosis de bispiribac-sodio registró granos por panícula, peso 1000 granos y rendimiento de grano similar a la dosis de etiqueta del herbicida superiores a la aplicación de dosis reducida de este herbicida. Este tratamiento también mejoró los atributos de calidad del grano sobre el control similar a la dos
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