Weed competition in maize crop under different timings for postemergence weed control

The effect of early weed competition was determined for a maize (Zea mays) crop grown in Waikato Maize was established in three different environments viz weedy (no herbicide) grass weeds (preemergence atrazine) and broadleaf weeds (preemergence metolachlor) Surviving weeds were controlled with postemergence nicosulfuron (60 g/ha) after different periods of competition and the plots kept weed free for the remainder of the trial Weeds left completely uncontrolled for 4 weeks after emergence significantly reduced crop yields When a preemergence herbicide was used surviving weeds began to reduce maize yields after about 6 weeks with grasses having greater effect than broadleaf weeds The actual period before the weeds started affecting crop growth and yield appeared to be related to the time taken by the weeds to achieve complete ground cover

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Weed management options in transgenic stacked and non transgenic maize (Zea mays) hybrids-A review

Agricultural Reviews ◽

10.18805/ag.r-1671 ◽

2017 ◽

Vol 38 (04) ◽

Cited By ~ 1

Author(s):

K. Sivagamy ◽

C. Chinnusamy ◽

P. Parasuraman

Keyword(s):

Weed Control ◽

Weed Management ◽

Crop Growth ◽

Control Programme ◽

Growth And Yield ◽

Growth Stages ◽

Management Options ◽

Maize Crop ◽

Weed Growth ◽

Vigorous Growth

Weeds are generally hardy species having fast growth, deep root system and capable of competing very efficiently with cultivated crops for the available resources and adversely affect the crop growth and yield. Weed management systems that rely on post emergence control assume that crops can tolerate competition for certain periods of time without suffering yield losses. Initial slow growth particularly at early crop growth stages and wider plant spacing of maize crop encourages fast and vigorous growth of weeds. It is of paramount importance that, competition from weeds must be minimized to achieve optimum yield. Among the different weed control methods, chemical method bears many advantages in suppressing weed growth and to get healthy and vigorous crop stand. Non-selective herbicide molecules with a variety of mode of action were discovered, developed and marketed for successful weed control programme.

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Weed competition in maize (Zea mays L.) as a function of the timing of hand-hoeing weed control in the southern Guinea savanna zone of Nigeria

Acta Agronomica Hungarica ◽

10.1556/aagr.60.2012.3.8 ◽

2012 ◽

Vol 60 (3) ◽

pp. 257-264 ◽

Cited By ~ 2

Author(s):

F. Takim

Keyword(s):

Grain Yield ◽

Weed Control ◽

Seedling Emergence ◽

Dry Weight ◽

Field Studies ◽

Growth And Yield ◽

Weed Competition ◽

Maize Crop ◽

Weed Interference ◽

The University

Field studies were conducted in 2010 and 2011 at the Teaching and Research Farm of the University of Ilorin, Nigeria (9°29′ N, 4°35′ E) to evaluate the effect of early weed competition on the growth and yield of maize. The experiment was designed as a randomized complete block (RCBD) with a split-plot arrangement and three replications. The main plots consisted of three weed control treatments included weedy (no herbicide), grass weeds (pre-emergence atrazine) and broadleaf weeds (pre-emergence metolachlor), while the sub-plots consisted of six durations of weed infestation (3, 4, 5, 6, 7 and 8 weeks after emergence). The pre-emergence herbicides had a greater effect on weed density and weed dry weight. Weed seedling emergence and weed dry weight increased significantly with an increase in the duration of weed interference. The grasses and broadleaf weeds had a similar influence on the growth and grain yield of maize. Three to five weeks of weed interference gave similar grain yields, which were significantly higher than those obtained in plots that had 6-8 weeks of weed interference. These results suggest that the maize crop must be kept free of weeds for 6-8 weeks after the application of pre-emergence herbicide to minimize weed-crop competition and harvest a good grain yield.

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Critical period for weed control in field pea

Legume Research - An International Journal ◽

10.18805/lr.v0iof.6787 ◽

2015 ◽

Author(s):

Mainpal Singh ◽

Rakesh Kumar ◽

Satish Kumar ◽

Virender Kumar

Keyword(s):

Weed Control ◽

Critical Period ◽

Yield Loss ◽

Field Studies ◽

Crop Growth ◽

Field Pea ◽

Control Measures ◽

Growth And Yield ◽

Weed Competition ◽

Weed Density

Field studies were conducted during 2008-09 and 2009-10 at Hisar, India to assess the effect of weed competition on crop growth and yield of field pea. Weed density increased up to 60 days and then decreased at later stages of crop growth. Seed yield of field pea was decreased by 50% when weeds were allowed to compete for the entire season. The critical period for weed control was 21-63 days in year 1 and 20-70 days in year 2 to achieve 95% of weed-free yield. It is therefore concluded that, to minimize yield loss due to weed competition in field pea, weed control measures should be targeted to avoid weed competition between 20-70 days after sowing.

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HERBICIDES FOR FORAGE CORN NO-TILL SEEDED INTO CEREAL STUBBLE

Canadian Journal of Plant Science ◽

10.4141/cjps83-023 ◽

1983 ◽

Vol 63 (1) ◽

pp. 235-241 ◽

Cited By ~ 1

Author(s):

J. A. IVANY ◽

J. R. ENMAN

Keyword(s):

Zea Mays ◽

Weed Control ◽

Prince Edward Island ◽

Zea Mays L ◽

Crop Yields ◽

Taraxacum Officinale ◽

Plant Population ◽

No Till ◽

Herbicide Treatment ◽

Forage Yields

Forage corn (Zea mays L.) was grown successfully in Prince Edward Island by no-till planting the corn into standing cereal stubble 15–20 cm tall using a Buffalo no-till seeder. Planting with the slot-type shoe in a preliminary experiment in 1978 gave better forage yields than planting with a slice-type shoe mainly because of better plant population achieved. Subsequent experiments in 1979–1981 using the slot-type shoe to no-till plant corn in cereal stubble gave good forage yields when adequate weed control was provided with herbicide treatment. Best control of quackgrass (Agropyron repens L. Beauv.) and dandelion (Taraxacum officinale Weber) and crop yields was achieved with glyphosate + atrazine (1.5 + 2.5 kg a.i./ha) or amitrole + atrazine (3.4 + 2.5 kg a.i./ha) applied preemergence after seeding corn and before corn emergence. Control of quack grass and dandelion with glyphosate or amitrole used alone ranged from 71–80%, but paraquat alone did not provide any weed control. Addition of atrazine to paraquat, glyphosate, or amitrole gave improved control of quackgrass and dandelion and higher forage corn yields. Addition of 2.5 kg a.i./ha atrazine gave better results than use of 1.0 kg a.i./ha of atrazine.Key words: Forage corn, no-till seeding, glyphosate, atrazine, aminotriazole, paraquat

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The Concept and Application of Early Economic Period Threshold: The Case of DCPA in Onions (Allium Cepa)

Weed Science ◽

10.1017/s0043174500081753 ◽

1995 ◽

Vol 43 (4) ◽

pp. 634-639 ◽

Cited By ~ 17

Author(s):

Claudio M. Dunan ◽

Philip Westra ◽

Edward E. Schweizer ◽

Donald W. Lybecker ◽

Frank D. Moore

Keyword(s):

Weed Control ◽

Critical Period ◽

Crop Yields ◽

Economic Feasibility ◽

Control Measures ◽

Economic Losses ◽

Weed Competition ◽

Critical Periods ◽

Control Efficacy ◽

The Impact

The question of when to control weeds traditionally has been approached with the calculation of critical periods (CP) based on crop yields. The concept of economic critical period (ECP) and early (EEPT) and late (LEFT) economic period thresholds are presented as a comprehensive approach to answer the same question based on economic losses and costs of control. ECP is defined as the period when the benefit of controlling weeds is greater than its cost. EEPT and LEFT are the limits of the ECP and can be used to determine when first and last weed control measures should be performed. Calculation of EEPT accounts for the economic losses due to weed competition that occur between planting and postemergence weed control. In this way it is possible to better evaluate the economic feasibility of using preplant or preemergence control tactics. The EEPT for DCPA application is analyzed in the context of onion production in Colorado. The EEPT for DCPA application was calculated from an empirical regression model that assessed the impact of weed load and time of weed removal on onion yields. The EEPT was affected by control efficacy, weed-free yield, DCPA cost, and onion price. DCPA application was economically advisable in only one of 20 fields analyzed because of the tow DCPA efficacy (60%).

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Maize/Weed Competition Experiments: Implications for Tropical Small-Farm Weed Control Research

Experimental Agriculture ◽

10.1017/s0014479700012801 ◽

1983 ◽

Vol 19 (4) ◽

pp. 341-347 ◽

Cited By ~ 10

Author(s):

R. Vernon ◽

J. M. H. Parker

Keyword(s):

Weed Control ◽

Critical Period ◽

Maize Yield ◽

Weed Competition ◽

Labour Demand ◽

Small Farms ◽

Yield Losses ◽

Small Farm ◽

Control Research ◽

Maize Yields

SUMMARYTwo sets of experiments examined the effects of weeds on maize yields using weeding methods typical of small farms in Zambia where oxen are used for cultivation. Maize yield losses of 30% due to weeds were evident with common weeding practices. A critical period of competition, during which the crop should be kept clean, was demonstrated from 10 to 30 days after emergence. This is a period of peak labour demand and the prospect of using chemical weed control to ease the situation is considered. The value of weed competition data, given its variability between sites, is discussed.

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Crop response to soils amended with biochar: expected benefits and unintended risks

Italian Journal of Agronomy ◽

10.4081/ija.2017.794 ◽

2017 ◽

Vol 11 ◽

Cited By ~ 5

Author(s):

Raghunath Subedi ◽

Chiara Bertora ◽

Laura Zavattaro ◽

Carlo Grignani

Keyword(s):

Soil Quality ◽

Crop Yield ◽

Crop Yields ◽

Soil Health ◽

Crop Growth ◽

Plant Diseases ◽

Growth And Yield ◽

Yield Response ◽

Small Scale ◽

Positive Effects

Biochar (BC) from biomass waste pyrolysis has been widely studied due to its ability to increase carbon (C) sequestration, reduce greenhouse gas (GHG) emissions, and enhance both crop growth and soil quality. This review summarizes the current knowledge of BC production, characterization, and types, with a focus on its positive effects on crop yield and soil properties versus the unintended risks associated with these effects. Biochar-amended soils enhance crop growth and yield via several mechanisms: expanded plant nutrient and water availability through increased use efficiencies, improved soil quality, and suppression of soil and plant diseases. Yield response to BC has been shown to be more evident in acidic and sandy soils than in alkaline and fine-textured soils. Biochar composition and properties vary considerably with feedstock and pyrolysis conditions so much that its concentrations of toxic compounds and heavy metals can negatively impact crop and soil health. Consequently, more small-scale and greenhouse-sited studies are in process to investigate the role of BC/soil/crop types on crop growth, and the mechanisms by which they influence crop yield. Similarly, a need exists for long-term, field-scale studies on the effects (beneficial and harmful) of BC amendment on soil health and crop yields, so that production guidelines and quality standards may be developed for BCs derived from a range of feedstocks.

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Response of maize (Zea mays L.) growth and yield to different fertilizer application in rainforest agro-ecological zone of Nigeria: Evaluation of CERES-maize crop model

Net Journal of Agricultural Science ◽

10.30918/njas.64.18.034 ◽

2018 ◽

Vol 6 (4) ◽

pp. 70-76

Author(s):

D. N. Arije ◽

◽

F. M. Akinseye ◽

B. S. Ewulo ◽

◽

...

Keyword(s):

Zea Mays ◽

Zea Mays L ◽

Fertilizer Application ◽

Crop Model ◽

Growth And Yield ◽

Ecological Zone ◽

Maize Crop

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Interference and Control of Large Crabgrass (Digitaria sanguinalis) and Southern Sandbur (Cenchrus echinatus) in Forage Bermudagrass (Cynodon dactylon)

Weed Technology ◽

10.1017/s0890037x00044584 ◽

1998 ◽

Vol 12 (4) ◽

pp. 707-711 ◽

Cited By ~ 5

Author(s):

Robert H. Walker ◽

Glenn Wehtje ◽

John S. Richburg

Keyword(s):

Weed Control ◽

Field Experiments ◽

Cynodon Dactylon ◽

Ground Cover ◽

Weed Competition ◽

Minor Importance ◽

Digitaria Sanguinalis ◽

Competitive Species ◽

And Control ◽

Large Crabgrass

Field experiments were conducted at two locations in central Alabama to evaluate competitiveness of large crabgrass and southern sandbur with ‘Tifton 78’ hybrid bermudagrass as influenced by diuron application and sprigging rate. Large crabgrass was the more competitive species. In late season, bermudagrass ground cover with no weed competition was 96% compared with 72 and 81% where large crabgrass and southern sandbur, respectively, were present. Similarly, large crabgrass and southern sandbur reduced the proportion of bermudagrass in the cumulative harvested forage by at least 59 and 38%, respectively. Application of diuron preemergence (PRE) at 1.1 kg ai/ha was more effective than postemergence (POST) application, both in terms of weed control and bermudagrass safety. With diuron applied PRE, large crabgrass and southern sandbur reduced the proportion of bermudagrass in the harvested forage only 32 and 25%, respectively. Increasing bermudagrass sprigging rate was beneficial for weed control but of relatively minor importance compared with diuron PRE.

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