scholarly journals Competition periods of crabgrass with rice and soybean crops

2014 ◽  
Vol 32 (1) ◽  
pp. 31-38 ◽  
Author(s):  
D. Agostinetto ◽  
L.C. Fontana ◽  
L. Vargas ◽  
L.T. Perboni ◽  
E. Polidoro ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Grain Yield ◽  
Weed Control ◽  
Critical Period ◽  
Rice Cultivar ◽  
Weed Competition ◽  
Flooded Rice ◽  
Reducing Costs ◽  
And Control ◽  
Impact Of Pesticides

Determining the periods of weed competition with crops helps the producer to choose the most appropriate time to use weed control practices. This strategy allows for the reduction of the number of herbicide applications, reducing costs and the environmental impact of pesticides. The objectives were to determine the period before the interference (PBI) of crabgrass (Digitaria ciliaris) competing with flooded rice, the critical period of interference prevention (CPIP) of crabgrass with soybean and the effects of competition on the grains yield and their components. Experiments were conducted with the coexistence of BRS Querência rice cultivar with crabgrass, for periods of 0, 7, 14, 21, 28, 35, and 110 days after emergency (DAE) and Fundacep 53RR soybean cultivar, whose periods of coexistence and control of crabgrass were 0, 7, 14, 21, 28, 35, and 156 DAE. Rice can grow with crabgrass infestation until 18 DAE, while soybean should remain free from the presence of crabgrass in the period between 23 and 50 DAE. The grain yield and its components, in the crops studied, are affected when grown with crabgrass.

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

Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 634-639 ◽  
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%).

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

1983 ◽  
Vol 19 (4) ◽  
pp. 341-347 ◽  
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.

scholarly journals Herbicide evaluation for rice

1969 ◽  
Vol 70 (4) ◽  
pp. 293-297
Author(s):  
Lii C. Liu ◽  
Luis Almodóvar-Vega ◽  
José M. Lozano
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Safety Margin ◽  
Rice Cultivar ◽  
The Other ◽  
Tert Butyl

Two herbicide experiments on rice were conducted at the Gurabo and Lajas Substations in 1979 and 1980. Rice cultivar Brazos was planted in 3.1 x 3.1 m plots. Herbicides butachlor [N-(butoxymethyl)-2-chloro-2' ,6' -diethylacetanilide], oxadiazon [2 tert-butyl-4(2,4-dichloro-s-isopropoxyphenyl)-∆2-1,3,4 oxadiazolin- 5-one] and propanil (3,4-dichloro-propionanilide) alone or in combination were evaluated for weed control and grain yield. Butachlor at 3.36 and 6.72 kg ai/ha; oxadiazon at 1.12 and 2.24 kg ai/ha; and propanil at 3.36, 6.72 and 13.44 kg ai/ha; and their mixtures gave good to excellent weed control. As a group, propanil provided a better safety margin to rice than butachlor and oxadiazon. All propanil-treated plots outyielded those of the other herbicides.

scholarly journals Impact of sowing methods and weed control practices on yield and economics of wet direct seeded rice

2021 ◽  
Vol 58 (3) ◽  
pp. 375-383
Author(s):  
BS Satapathy ◽  
B Duary ◽  
Sanjoy Saha ◽  
S Munda ◽  
D Chatterjee
Keyword(s):  
Field Experiment ◽  
Grain Yield ◽  
Weed Control ◽  
Direct Seeding ◽  
Weed Competition ◽  
Weed Species ◽  
Cyperus Difformis ◽  
Control Options ◽  
Direct Seeded ◽  
Crop Weed Competition

Wet direct seeding is proved as a viable alternate to conventional transplanting method of rice. Maintenance of optimum population by adopting an appropriate sowing method followed by judicious weed control practices ensures profitability of wet direct seeded rice (W-DSR). A field experiment was carried out to find out a suitable sowing technique and weed control options for enhancing productivity and economics of W-DSR. The W-DSR was infested with twelve numbers of weed species comprising of eight families under different sowing methods. The composition of sedges, broadleaved (BLW) and grassy weeds was 83.07, 11.0 and 5.93%, respectively. Irrespective of sowing methods, weeds such as, Echinochloa glabrescens and Leptochloa chinensis among grasses, Cyperus difformis and Scirpus juncoides among sedges and Lindernia anagallis among BLW were dominant. Drum seeding recorded 6.9 and 12.7% higher gross and net return, respectively than broadcasting, but it was at par with spot seeding. Highest B: C ratio of 2.07 was recorded with drum seeding, whereas spot seeding recorded lowest B: C ratio (1.99). Crop-weed competition caused 31.7% reduction in grain yield with W-DSR. Application of early post-emergent herbicide bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS, azimsulfuron @ 35 g/ha at 20 DAS, and bispyribac sodium @ 30 g/ha at 20 DAS recorded increase in grain yield 40.3, 40.1 and 39.8%, respectively over the weedy check. Ready mix bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS registered highest B: C ratio (2.16) but it did not vary significantly with bispyribac sodium @ 30 g/ha and azimsulfuron @ 35 g/ha.

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

1998 ◽  
Vol 12 (4) ◽  
pp. 707-711 ◽  
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.

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

2012 ◽  
Vol 60 (3) ◽  
pp. 257-264 ◽  
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.

Light Quality and the Critical Period for Weed Control in Soybean

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 86-91 ◽  
Author(s):  
Emily Green-Tracewicz ◽  
Eric R. Page ◽  
Clarence J. Swanton
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Light Quality ◽  
Morphological Changes ◽  
Management Strategies ◽  
Leaf Number ◽  
Integrated Weed Management ◽  
Weed Competition ◽  
Shade Avoidance

The critical period for weed control (CPWC) is an integral component of integrated weed management strategies. Several studies have defined the CPWC in soybean under varying agronomic conditions, yet none have described the mechanisms involved in crop yield losses caused by weed competition. We hypothesized that under nonresource-limiting conditions, morphological changes resulting from the expression of shade avoidance could be used to define a period of developmental sensitivity to low red-to-far-red ratio (R : FR) that would overlap with the defined CPWC in soybean. Two experiments (a sequential harvest and a weed addition/removal series) were conducted in 2008 and 2009 under controlled environmental conditions to address this hypothesis. Two light-quality treatments were used: (1) high R : FR ratio (i.e., weed-free), and (2) low R : FR ratio (i.e., weedy). The low R : FR ratio treatment induced shade avoidance responses in soybean, which included increases in height, internode length, and the shoot : root ratio, as well as a reduction in biomass accumulation and leaf number. Using the morphological changes in biomass and leaf number observed in the weed addition/removal series, a period of developmental sensitivity to low R : FR was defined between the first trifoliate (V1) and third trifoliate (V3) stages of soybean development. This period was found to be very similar to the CPWC previously defined by field studies of soybean–weed competition.

Determination of the Critical Period for Weed Control in Corn

2013 ◽  
Vol 27 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Geoffroy Gantoli ◽  
Victor Rueda Ayala ◽  
Roland Gerhards
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Field Experiments ◽  
Critical Time ◽  
Weed Competition ◽  
Growth Stages ◽  
Leaf Stage ◽  
Time Period ◽  
Weed Infestation ◽  
Hand Weeding

Field experiments were conducted in western Atakora, Benin, to determine the critical time period of weed competition in hand-weeded corn. Weeds were removed until different crop growth stages and then allowed to reemerge. Other treatments began weed control at different growth stages (four-, eight-, and ten-leaf stages and flowering) and were maintained until harvest. One treatment was permanently kept weed-free and one treatment was uncontrolled until harvest. Yields without weed competition ranged from 2.8 to 3.4 t ha−1. As expected, yield loss increased with duration of weed infestation and ranged from 38 to 65% compared to permanent weed-free plots. In three out of four site-years, the critical period for weed control started at the four- to six-leaf stage and continued until ten-leaf stage or flowering of corn. Approximately four hand-weeding applications were required in this critical period of weed control.

CRITICAL PERIOD OF WEED INTERFERENCE IN FIELD-SEEDED TOMATOES AND ITS RELATION TO WATER STRESS AND SHADING

1987 ◽  
Vol 67 (2) ◽  
pp. 575-583 ◽  
Author(s):  
S. E. WEAVER ◽  
C. S. TAN
Keyword(s):  
Water Stress ◽  
Lycopersicon Esculentum ◽  
Weed Control ◽  
Critical Period ◽  
Weed Competition ◽  
Yield Losses ◽  
Weed Interference ◽  
Light Levels

The critical period of weed interference in field-seeded tomatoes (Lycopersicon esculentum L. ’TH 318’) was determined in 1981, 1982 and 1983. The minimum weed-free period varied among years from 7 to 9 wk after sowing, while the maximum weed-infested period varied from 5 to 6 wk after sowing. A minimum of two weed control operations during the critical period was required to prevent yield losses. Reductions in tomato yields were correlated with weed dry weights and could be attributed both to reductions in light levels due to shading and weed competition for water which resulted in stomatal closure.Key words: Competition, critical period, weed, tomato, Lycopersicon esculentum L.

scholarly journals A REVIEW ON NON-CHEMICAL WEED MANAGEMENT IN MAIZE (ZEA MAYS L.)

2021 ◽  
Vol 1 (1) ◽  
pp. 46-51
Author(s):  
A. Duwadi ◽  
A. Acharya ◽  
S. Gautam
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Weed Competition ◽  
Chemical Application ◽  
Organic System ◽  
Sustainable Solutions ◽  
Weed Population ◽  
Mechanical Methods ◽  
Crop Weed Competition

Weed is omnipresent species that compete with major crops for light, nutrients, space, and water for their growth and development and ultimately deteriorate the ideal environment for crops growth. In the present context, herbicide application is the easiest and seemingly economical approach for weed control in south-Asian countries. In contrary, the side effects of herbicide on health and environment impose to adopt for the non-chemical method of weed management. This paper reviewed the menace of herbicide, crop weed association, the critical period of crop-weed competition, and different methods of organic weed control implemented especially for maize. The main objective of this review is to maneuver a weed control strategy for maize other than the chemical application. The findings of different research suggested that a critical period of crop-weed competition in maize lies between 2 to 8 weeks after crop sowing. Many mechanical methods for weed control in maize proved efficient but seemed labour intensive and biological methods provided maximum security against specific weed species. The cultural method in combination with other methods effectively reduced the weed population in the maize field. It was found that, if various components of non-chemical weed management are implemented systematically, we can control the weed population with higher economic return and achieve the goal of organic food production with sustainable solutions. Weed control in the organic system focuses on management techniques designed to prevent weed emergence, give a competitive advantage to the main crop, and act for sustainable solutions. The non-chemical integrated weed management system is recommended to reduce the use of herbicide and for sustainable production. A review of non-chemical weed management in maize could be helpful for researchers to provide useful, sustainable, and environmentally friendly solutions to farmers to solve the problem of weed infestation in the maize crop along with substantial yield improvement.

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