Atrazine Reduces the Critical Period of Weed Interference on Narrow Row Corn

ABSTRACT The objective was to determine whether a change occurs in the critical period of weed interference prevention in narrow row corn with the use of atrazine and whether there is influence of the herbicide on crop yield components. The treatments consisted of periods without or with an initial weed control (0, 21, 35, 49, 63, 77, and 91 days after emergence), with or without application of atrazine in spikely post-emergence. The experiment was carried out in a 2 x 7 randomized blocks design (with and without weed control and seven periods with three replications). The use or not of atrazine was arranged in a split plot design. The most important weed species were Senecio brasiliensis, Urochloa plantaginea, Conyza bonariensis, Sida rhombifolia, and Solanum spp. Corn yield reduced by 15% and 18% with and without application of atrazine, respectively. The number of grains per spike and corn yield were negatively influenced by coexistence with weeds, while the number of rows per spike, the diameter and length of spike were not affected. Corn yield components were not affected by the use of atrazine. The critical period of weed interference prevention was 35 days without atrazine and 23 days with application of atrazine. There is a reduction of the critical period of weed interference prevention on narrow row corn by using atrazine, with no influence of the herbicide on crop yield.

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Integrating Economics in the Critical Period for Weed Control Concept in Corn

Weed Science ◽

10.1614/ws-d-13-00184.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 608-618 ◽

Cited By ~ 3

Author(s):

Martina Keller ◽

Geoffroy Gantoli ◽

Jens Möhring ◽

Christoph Gutjahr ◽

Roland Gerhards ◽

...

Keyword(s):

Weed Control ◽

Critical Period ◽

Logistic Models ◽

Crop Growth ◽

Growth Stages ◽

Corn Yield ◽

Leaf Stage ◽

Weed Interference ◽

Free Interval ◽

Crop Growth Stages

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.

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Revisiting the concept of the critical period of weed control

The Journal of Agricultural Science ◽

10.1017/s0021859621000939 ◽

2022 ◽

pp. 1-7

Author(s):

K. Ramesh ◽

S. Vijaya Kumar ◽

P. K. Upadhyay ◽

B. S. Chauhan

Keyword(s):

Weed Control ◽

Crop Yield ◽

Critical Period ◽

Management Practice ◽

Cumulative Effect ◽

Farming Systems ◽

Time Interval ◽

Weed Species ◽

Weed Density ◽

Critical Timing

Abstract Weeds are a major biotic constraint to the production of crops. Studies on the critical period of weed control (CPWC) consider the yield loss due to the presence of all weeds present in the crop cycle. The CPWC is the time interval between the critical timing of weed removal (CTWR) and the critical weed-free period (CWFP), and the weed presence before and after the extremes of CTWR and CWFP may not significantly reduce crop yield. The crop yield is taken into consideration and weed density or biomass of individual weeds (annual or perennial) is not so important while calculating the CPWC. Only weed density or biomass is considered for calculating weed control efficiency of a particular management practice for which the weed seed bank is also a criterion. However, weed biomass is the outcome after competition experienced by each weed species with the fellow crop and the weeds. Consequently, the weed pressure in the subsequent season will be the cumulative effect of the preceding season too, which is unaccounted for in CPWC. It is argued that in organic farming or low-input farming systems, where herbicides are not used, the concept of CPWC can be misleading and should be avoided. It is concluded that CTWR is more meaningful than the CPWC.

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Weed Interference Periods in Early Wheat in the Midwest of Paraná

Planta Daninha ◽

10.1590/s0100-83582016340200010 ◽

2016 ◽

Vol 34 (2) ◽

pp. 291-298 ◽

Cited By ~ 1

Author(s):

A.A.P. SILVA ◽

A.M. OLIVEIRA NETO ◽

G. NAIARA ◽

R.A.K. KARPINSKI ◽

C.D.G. MACIEL

Keyword(s):

Plant Height ◽

Weed Control ◽

Crop Yield ◽

Critical Period ◽

Spike Length ◽

Wheat Crop ◽

Critical Periods ◽

Raphanus Raphanistrum ◽

Weed Interference ◽

And Control

ABSTRACT Several factors can influence wheat crop yield, they include the interference imposed by weeds is one of the most important. The objective of this study was to evaluate the critical periods of weed interference in early wheat in the midwest of the state of Paraná, Brazil. The experiment was conducted in an experimental area located in Campo Mourão - PR, during the year 2013, using the BRS Pardela cultivar. The treatments consisted of periods of coexistence and weed control in wheat. Periods of coexistence and control were 0, 7, 14, 28, 35 and the whole cycle at days after crop emergence (DAE). Number of reproductive tillers per plant, spike length, number of spikelets per spike, plant height and wheat crop yield, were significantly affected by coexistence with prevailing infestation of Raphanus raphanistrum, therefore, a critical period of interference was determined at 16 to 24 DAE.

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Phosphorus Application Influences the Critical Period of Weed Control in Lettuce

Weed Science ◽

10.1614/ws-d-12-00107.1 ◽

2013 ◽

Vol 61 (3) ◽

pp. 410-414 ◽

Cited By ~ 6

Author(s):

Dennis C. Odero ◽

Alan L. Wright

Keyword(s):

Weed Control ◽

Weed Management ◽

Critical Period ◽

Management Practices ◽

Natural Populations ◽

P Fertilization ◽

Weed Species ◽

Weed Interference ◽

Fertilization Level ◽

Phosphorus Application

Field studies were conducted in 2010 and 2011 at Belle Glade, FL, to evaluate the influence of phosphorus (P) applications (98, 196, and 293 kg P ha−1) on the critical period of weed control (CPWC) in lettuce. Natural populations of mixed weed species were allowed to interfere with lettuce in a series of treatments of both increasing duration of weed interference and the duration of weed-free period imposed within 98, 196, and 293 kg P ha−1levels added to the soil. The beginning and end of the CPWC for each P fertilization level based on a 5% acceptable marketable fresh lettuce yield loss level was determined by fitting log-logistic and Gompertz models to represent the increasing duration of weed interference and the duration of weed-free period, respectively. The CPWC in lettuce was estimated to be 4.6, 3.4, and 2.3 wk at 98, 196, and 293 kg P ha−1, respectively. The beginning of the CPWC was delayed at the highest P fertilization level (293 kg P ha−1), whereas the end of the CPWC was hastened at the same P fertilization level. Our study shows that inadequate levels of P fertilization in lettuce result in the need for more-intensive weed management practices to attain acceptable yields.

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Evaluation of Imazethapyr for Weed Control in Leafy Vegetable Crops

Weed Technology ◽

10.1017/s0890037x00039907 ◽

1996 ◽

Vol 10 (2) ◽

pp. 253-257 ◽

Cited By ~ 4

Author(s):

Joan A. Dusky ◽

William M. Stall

Keyword(s):

Regression Analysis ◽

Weed Control ◽

Crop Yield ◽

Relative Sensitivity ◽

Leafy Vegetable ◽

Field Conditions ◽

Vegetable Crops ◽

Weed Species ◽

Common Lambsquarters ◽

Common Purslane

Imazethapyr was evaluated PRE and POST in five lettuce types and chicory under Florida field conditions. The relative sensitivity of leafy crop vigor (most sensitive to most tolerant) to imazethapyr PRE, based on 20% inhibition determined using regression analysis, was as follows: Boston > bibb > crisphead > romaine > leaf > escarole > endive. Leafy crop injury increased as the rate of imazethapyr applied POST increased, with all leafy crops responding in a similar manner. Surfactant addition increased imazethapyr phytotoxicity. Imazethapyr PRE treatments at 0.067 kg ai/ha provided greater than 80% control of livid amaranth, common purslane, flatsedge, and common lambsquarters. Imazethapyr POST at 0.067 kg/ha, with surfactant provided control greater than 85% of all weed species. Greater than 85% spiny amaranth control was provided by imazethapyr POST at 0.017 kg/ha. Use of surfactant with imazethapyr did not improve spiny amaranth control over imazethapyr with no surfactant. POST treatments did not decrease leafy crop yield compared with the hand-weeded check. Imazethapyr applied PRE reduced crop yield compared to the POST treatments and the hand-weeded control.

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Effects of Nitrogen Application Method and Weed Control on Corn Yield and Yield Components

Pakistan Journal of Biological Sciences ◽

10.3923/pjbs.2014.497.503 ◽

2014 ◽

Vol 17 (4) ◽

pp. 497-503 ◽

Cited By ~ 2

Author(s):

Pariya Sepahvand ◽

Nurali Sajedi ◽

Seyed Karim Mousavi ◽

Mohsen Ghiasvand

Keyword(s):

Weed Control ◽

Yield Components ◽

Corn Yield ◽

Nitrogen Application ◽

Application Method ◽

Yield And Yield Components

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

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha43210031 ◽

2015 ◽

Vol 43 (2) ◽

pp. 355-360 ◽

Cited By ~ 1

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.

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The Critical Period of Weed Control in Grain Corn (Zea mays)

Weed Science ◽

10.1017/s0043174500051882 ◽

1992 ◽

Vol 40 (3) ◽

pp. 441-447 ◽

Cited By ~ 236

Author(s):

Michael R. Hall ◽

Clarence J. Swanton ◽

Glenn W. Anderson

Keyword(s):

Zea Mays ◽

Leaf Area ◽

Weed Control ◽

Critical Period ◽

Field Studies ◽

Southern Ontario ◽

Leaf Stage ◽

Individual Leaf ◽

Logistic Equations ◽

Weed Interference

Field studies were conducted in southern Ontario to determine the critical period of weed control in grain corn and the influence of weed interference on corn leaf area. The Gompertz and logistic equations were fitted to data representing increasing durations of weed control and weed interference, respectively. The beginning of the critical period varied from the 3- to 14-leaf stages of corn development However, the end of the critical period was less variable and ended on average at the 14-leaf stage. Weed interference reduced corn leaf area by reducing the expanded leaf area of each individual leaf and accelerating senescence of lower leaves. In addition, weed interference up to the 14-leaf stage of corn development impeded leaf expansion and emergence in 1989.

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Live and Killed Hairy Vetch Cover Crop Effects on Weeds and Yield in Glyphosate-Resistant Corn

Weed Technology ◽

10.1614/wt-03-228r ◽

2004 ◽

Vol 18 (3) ◽

pp. 835-840 ◽

Cited By ~ 13

Author(s):

Krishna N. Reddy ◽

Clifford H. Koger

Keyword(s):

Weed Control ◽

Cover Crop ◽

Production Systems ◽

Wide Band ◽

Science Research ◽

Research Unit ◽

Corn Yield ◽

Hairy Vetch ◽

Weed Species ◽

Dry Biomass

A 2-yr field study was conducted from 2002 to 2003 on a Dundee silt loam soil at the Southern Weed Science Research Unit Farm, Stoneville, MS (33°26′N latitude), to examine the effects of hairy vetch cover crop (hairy vetch killed at corn planting [HV-K], hairy vetch killed in a 38-cm-wide band centered over the crop row at corn planting [HV-B], hairy vetch left alive [HV-L], and no hairy vetch [NHV]) and glyphosate postemergence (broadcast, banded, and no herbicide) application on weed control and yield in glyphosate-resistant corn. Two applications of glyphosate at 0.84 kg ae/ha were applied 3 and 5 wk after planting (WAP) corn. Hairy vetch dry biomass was higher in HV-L (4,420 kg/ha) and HV-B (4,180 kg/ha) than in HV-K (1,960 kg/ha) plots at 7 WAP. Hairy vetch reduced densities of pitted morningglory, prickly sida, and yellow nutsedge in HV-B and HV-L compared with NHV plots, but hairy vetch had no effect on densities of barnyardgrass, johnsongrass, and large crabgrass at 7 WAP regardless of desiccation. Total weed dry biomass at 7 WAP was lower in HV-B and HV-L than in HV-K and NHV plots. Corn yield was higher in HV-K (10,280 kg/ha) than in HV-B (9,440 kg/ha) and HV-L (9,100 kg/ha), and yields were similar between HV-K and NHV (9,960 kg/ha). Glyphosate applied broadcast resulted in the highest corn yield (11,300 kg/ha) compared with a banded application (10,160 kg/ha). These findings indicate that hairy vetch cover crop has the potential for reducing the density of certain weed species in glyphosate-resistant corn production systems; however, optimum weed control and higher yield were obtained when glyphosate was used.

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The effects of weed density and different weed control applications on yield and yield components of chickpea cultivars

Legume Research - An International Journal ◽

10.18805/lr-480 ◽

2019 ◽

Author(s):

Melih Yilar Omer Sozen ◽

Ufuk Karadavut

Keyword(s):

Weed Control ◽

Weed Management ◽

Yield Components ◽

Control Method ◽

Herbicide Application ◽

Weed Species ◽

Control Applications ◽

Weed Density ◽

Yield And Yield Components ◽

Plot Design

This study was conducted to determine the effects of weed density and different weed control treatments on chickpea yield and yield components. The experiment was carried out in split plot design with 3 replications in experimental fields of Kirsehir Ahi Evran University during 2016 and 2017 crop seasons. Total nine treatments (no weed control, permanent weed control, one-time hoeing, two-time hoeing, three-time hoeing, herbicide application after emergence, one-time hoeing with herbicide application, two-time hoeing with herbicide application and three-time hoeing with herbicide application) were compared to know the most effective weed control method. Vaccaria pyramidata Medik., Sinapis arvensis L., Acroptilon repens L. weed species were found to be the most intense in the experimental area. All weed control applications had significant effect on chickpea yield and yield components compared to weedy plots. Three-time hoeing with herbicide application increased the yield by 361.55-478.50% compared to weedy plots. Likewise, three-time hoeing application even increased the yield by 348.50-357.09% compared to weedy plots. The results revealed that three-time hoeing with herbicide and three-time hoeing applications stood out in weed management to obtain a good yield in chickpea cultivation at Kirsehir province.

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