Penentuan Tempoh Kritikal Untuk Mengawal Rumpai dalam Kawasan Penanaman Padi Wangi MRQ 76, Q 88 dan Q 89

2014 ◽  
Vol 70 (6) ◽  
Author(s):  
Chong Tet Vun ◽  
Azimah Abd Kadir ◽  
Azmi Man ◽  
Chew See Eng ◽  
Baharudin Abas ◽  
...  
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Slow Growth ◽  
The Other ◽  
Fragrant Rice ◽  
Other Hand ◽  
Hot Climate ◽  
Competition Ability ◽  
Loss Level

A study on critical period (CP) for weed control in fragrant rice MRQ 76, Q 88 and Q 89 was conducted in main season 2012/2013 and off season 2013 at MARDI Seberang Perai. The results showed that the CPs (based on 5% acceptable yield loss level (AYL)) for weed control of MRQ 76, Q 88 and Q 89 planted in main season were from 5 to 64, 13 to 68 and 8 to 66 DAS (Days after sowing), respectively. On the other hand, CPs of MRQ 76, Q 88 and Q 89 planted in off season were from 6 to 73, 9 to 81 and 3 to 83 DAS, respectively. If based on 10% AYL, CPs of MRQ76, Q 88 and Q 89 planted in main season were from 19 to 38, 28 to 41 and 14 to 53 DAS, respectively. CPs (based on 10% AYL) of MRQ76, Q 88 and Q 89 planted in off season were from 15 to 55, 19 to 68 and 10 to 66 DAS, respectively. The study clearly demonstrated that CPs of off season were longer than CPs of main season. The dry and hot climate in off season probably caused the slow growth of fragrant rice and eventually affected the competition ability of rice against the weeds. 

The Critical Period for Weed Control in Corn in Turkey

2006 ◽  
Vol 20 (4) ◽  
pp. 867-872 ◽  
Author(s):  
Dogan Isik ◽  
Husrev Mennan ◽  
Bekir Bukun ◽  
Ahmet Oz ◽  
Mathieu Ngouajio
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Relative Yield ◽  
Field Studies ◽  
The Black Sea ◽  
Yield Data ◽  
Black Sea Region ◽  
Weed Interference ◽  
Loss Level

Field studies were conducted in 2001 and 2002 in the Black Sea Region of northern Turkey to determine the critical period for weed control (CPWC) in corn and the effects of weed interference on corn height. Treatments of increasing duration of weed interference and weed-free period were imposed at weekly intervals from 0 to 12 wk after crop emergence (WAE). The CPWC was determined with the use of 2.5, 5, and 10% acceptable yield loss levels by fitting logistic and Gompertz equations to relative yield data. With 5% yield loss level, the CPWC was 5 wk, starting at 0.2 WAE and ending at 5.2 WAE, which corresponded to the one- to five-leaf stage of corn. The CPWC increased to 8.9 wk, starting at 0 WAE and ending at 8.9 WAE, at the 2.5% yield loss level. At 10% yield loss level, the CPWC decreased to 1.7 wk, starting at 2.1 WAE and ending at 3.8 WAE.

The Critical Period of Weed Control in Faba Bean and Chickpea in Mediterranean Areas

Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 452-459 ◽  
Author(s):  
Alfonso S. Frenda ◽  
Paolo Ruisi ◽  
Sergio Saia ◽  
Benedetto Frangipane ◽  
Giuseppe Di Miceli ◽  
...  
Keyword(s):  
Weed Control ◽  
Faba Bean ◽  
Critical Period ◽  
Yield Loss ◽  
Grain Legume ◽  
Yield Reduction ◽  
Mediterranean Areas ◽  
Full Flowering ◽  
Legume Crops ◽  
Loss Level

Weeds are often the major biological constraint to growing legume crops successfully, and an understanding of the critical period of weed control (CPWC) is important for developing environmentally sustainable weed management practices to prevent unacceptable yield loss. Therefore, we carried out two field experiments to identify the CPWC for two grain legume crops traditionally grown in Mediterranean areas: chickpea and faba bean. The experiments were conducted at two sites both located in the Sicilian inland (Italy). In chickpea, when weeds were left to compete with the crop for the whole cycle, the grain yield reduction was on average about 85% of the weed-free yield, whereas in faba bean the reduction was less severe (on average about 60% of the weed-free yield). The onset of the CPWC at a 5% yield loss level varied by species, occurring later in faba bean than in chickpea (on average, 261 and 428 growing degree days after emergence for chickpea and faba bean, respectively). In both species, the end of the CPWC occurred at the early full-flowering stage when the canopy of each crop enclosed the interrow space. On the whole, the CPWC at a 5% yield loss level ranged from 50 to 69 d in chickpea and from 28 to 33 d in faba bean. The results highlight the fact that faba bean has a higher competitive ability against weeds than chickpea. This could be attributable both to more vigorous early growth and to the plant's greater height, both factors related to a greater shading ability and, consequently, to a better ability to suppress weeds.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

scholarly journals Antioxidant leaf pigments and variability in vegetable amaranth

Genetika ◽  
2018 ◽  
Vol 50 (1) ◽  
pp. 209-220 ◽  
Author(s):  
Umakanta Sarker ◽  
Tofazzal Islam ◽  
Golam Rabbani ◽  
Shinya Oba
Keyword(s):  
Ascorbic Acid ◽  
Yield Loss ◽  
Rich Source ◽  
The Other ◽  
Genotypic Correlation ◽  
Acid Versus ◽  
Leaf Pigment ◽  
Other Hand ◽  
Transgressive Segregant ◽  
High Yielding Varieties

Twenty-three vegetable amaranth genotypes were evaluated for variability, interrelationships among antioxidant leaf pigments and foliage yield. Five genotypes found to be a rich source of antioxidant leaf pigments and might be directly selected as antioxidant leaf pigments enriched high yielding varieties. Two genotypes had high content of antioxidant leaf pigments with low yield might be used as donor parents for antioxidant leaf pigments genes to develop transgressive segregant or pigment enriched transgenic vegetable amaranth varieties. The insignificant negative genotypic correlation was observed between total carotene versus all antioxidant leaf pigments, ascorbic acid versus all antioxidant leaf pigments and foliage yield versus rest of all traits. Improvement of vegetable amaranth regarding carotene and ascorbic acid might be possible without compromising yield loss. On the other hand, most of the interrelationships among antioxidant leaf pigments traits indicated that improving of one antioxidant leaf pigment significantly improved the other antioxidant leaf pigments.

Influence of a Rye Cover Crop on the Critical Period for Weed Control in Cotton

Weed Science ◽  
2015 ◽  
Vol 63 (1) ◽  
pp. 346-352 ◽  
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy
Keyword(s):  
Weed Control ◽  
Cover Crops ◽  
Cover Crop ◽  
Critical Period ◽  
Yield Loss ◽  
Growing Season ◽  
Weed Biomass ◽  
Weed Density ◽  
Presence And Absence ◽  
Weed Removal

Cover crops are becoming increasingly common in cotton as a result of glyphosate-resistant Palmer amaranth; hence, a field experiment was conducted in 2009 and 2010 in Marianna, AR, with a rye cover crop used to determine its effects on the critical period for weed control in cotton. Throughout most of the growing season, weed biomass in the presence of a rye cover crop was lesser than that in the absence of a rye cover crop. In 2009, in weeks 2 through 7 after planting, weed biomass was reduced at least twofold in the presence of a rye cover compared with the absence of rye. In 2009, in both presence and absence of a rye cover crop, weed removal needed to begin before weed biomass was 150 g m−2, or approximately 4 wk after planting, to prevent yield loss > 5%. Weed density was less in 2010 than in 2009, so weed removal was not required until 7 wk after planting, at which point weed biomass values were 175 and 385 g m−2in the presence and absence of a cover crop, respectively.

scholarly journals The Critical Period for Weed Control (CPWC) in Potato (Solanum tuberosum L.)

2015 ◽  
Vol 43 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Dogan ISIK ◽  
Adem AKCA ◽  
Emine KAYA ALTOP ◽  
Nihat TURSUN ◽  
Husrev MENNAN
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Yield Loss ◽  
Cropping Systems ◽  
Control Period ◽  
Relative Yield ◽  
Yield Data ◽  
Weed Interference

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.

Critical Period of Quackgrass (Elytrigia repens) Removal in Potatoes (Solanum tuberosum)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 528-533 ◽  
Author(s):  
R. Baziramakenga ◽  
Gilles D. Leroux
Keyword(s):  
Critical Period ◽  
Yield Loss ◽  
Field Trials ◽  
Quebec City ◽  
Critical Periods ◽  
Marketable Yield ◽  
Elytrigia Repens ◽  
Medium Level ◽  
High Level ◽  
Loss Level

Field trials were carried out in 1989 and 1990 at St-Augustin, near Québec City, Canada, to determine the critical periods of quackgrass control in potato submitted to three levels of infestation. Potato yield losses due to quackgrass interference increased with quackgrass infestation and length of duration of interference. Quackgrass interference influenced marketable tuber yields more than total tuber yields. Duration of the critical period varied depending on the level of quackgrass infestation and year. Based on an arbitrary 5% level of marketable yield loss, the critical period started at ca. 15 days after emergence (DAE) of potato at low level of infestation, and at ca. 3 DAE at medium level of infestation. At high level of infestation, the critical period began prior to the emergence of potato. The end of the critical period of quackgrass removal was extremely variable across quackgrass infestation level and year and ranged from 23 to 68 DAE of potato at a 5 % yield loss level. It appears that onset of interference varied less than the end of it, indicating that early quackgrass control is necessary to prevent yield loss.

The Critical Period of Bengal Dayflower (Commelina Bengalensis) Control in Peanut

Weed Science ◽  
2007 ◽  
Vol 55 (4) ◽  
pp. 359-364 ◽  
Author(s):  
Theodore M. Webster ◽  
Wilson H. Faircloth ◽  
J. Timothy Flanders ◽  
Eric P. Prostko ◽  
Timothy L. Grey
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Plant Pathogens ◽  
Yield Loss ◽  
Maximum Yield ◽  
Field Studies ◽  
Yield Losses ◽  
Competitive Effects ◽  
Peanut Crop ◽  
The Relationship

Bengal dayflower (also known as tropical spiderwort) is one of the most troublesome weeds in peanut in Georgia, United States. Field studies conducted in 2004 and 2005 evaluated the relationship between the duration of Bengal dayflower interference and peanut yield in an effort to optimize the timing of weed control. In 2004, the critical period of weed control (CPWC) necessary to avoid greater than 5% peanut yield loss was between 316 and 607 growing degree days (GDD), which corresponded to an interval between June 8 and July 2. In 2005, the CPWC ranged from 185 to 547 GDD, an interval between May 30 and July 3. Maximum yield loss in 2005 from season-long interference of Bengal dayflower was 51%. In 2004, production of peanut pods was eliminated by interference with Bengal dayflower for the initial 6 wk (495 GDD) of the growing season. Robust Bengal dayflower growth in 2004 shaded the peanut crop, likely intercepting fungicide applications and causing a reduction in peanut yield. Therefore, the competitive effects of Bengal dayflower are likely complicated with the activity of plant pathogens. In spite of higher Bengal dayflower population densities, greater Bengal dayflower growth, and greater peanut yield losses in 2004 than in 2005, the CPWC was a relatively similar 4-wk period that ended during the first week of July, for peanut that was planted in the first week of May.

OPTIMIZATION OF PARAMETRIC YIELD: A TUTORIAL

1992 ◽  
Vol 03 (01) ◽  
pp. 95-136 ◽  
Author(s):  
STEPHEN W. DIRECTOR ◽  
PETER FELDMANN ◽  
KANNAN KRISHNA
Keyword(s):  
Manufacturing Process ◽  
Yield Loss ◽  
The Other ◽  
Parametric Yield ◽  
Other Hand ◽  
Different Types

Yield loss can be characterized as either catastrophic or parametric. Catastrophic yield loss is primarily due to local disturbances, such as spot defects, that occur in a manufacturing process. On the other hand, parametric yield loss is due to global disturbances, such as mask misalignment. In this paper we briefly explore these two different types of yield loss and then review some methods that have been developed to maximize parametric yield.

Milton and Mirabeau

PMLA ◽  
1934 ◽  
Vol 49 (4) ◽  
pp. 1116-1128 ◽  
Author(s):  
Don M. Wolfe
Keyword(s):  
Critical Period ◽  
Civil Liberty ◽  
The Other ◽  
Political Leader ◽  
Other Hand ◽  
Significant Interest ◽  
Close Study ◽  
Food And Drink ◽  
The Revolution

Though Milton and Mirabeau were devoted to almost identical ideals of civil liberty, their personalities offer a peculiar contrast. Milton was an idealist, a theorist, a poet; he was abstemious in food and drink, inclined to seclusion, religious by nature. Mirabeau, on the other hand, was a soldier, an orator, a political leader. Whereas Milton was thoughtful and reserved, Mirabeau was animated, impulsive, ever seeking the center of action, forever restless and impatient. Sensual and gluttonous, he was as much a slave to his passions as any of the Englishmen Milton condemned for being so; and in his last moments he turned away, more in kindness than in derision, the priest who sought to shrive him. Notwithstanding these essential differences, Mirabeau found in Milton a kindred spirit; he found in him that flaming love of liberty, that passion for essential freedoms, that lofty and unselfish devotion to country to which he himself aspired. Milton's influence on Mirabeau, many times suggested but never evaluated, is one of significant interest to students of Milton's politics. A close study of two Mirabeau tracts, Théorie de la Royauté après la Doctrine de Milton and De la liberté de la Presse, reveals not only that Mirabeau's reading of Milton strikingly verified his own political conclusions: it presents evidence that Milton's voice at a critical period of the Revolution became the weapon of its most powerful leader. French cries for liberty found expression in the tracts of the Puritan poet.

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