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.

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

Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 608-618 ◽  
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.

scholarly journals Effect of duration of weed competition and weed control on the yield of Indian spinach

1970 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
MSA Khan ◽  
MA Hossain ◽  
M Nurul Islam ◽  
SN Mahfuza ◽  
MK Uddin
Keyword(s):  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Agricultural Research ◽  
Cyperus Rotundus ◽  
Weed Competition ◽  
Weed Species ◽  
Maximum Benefit ◽  
Hand Weeding ◽  
Crop Weed Competition

Field experiments were conducted at the research farm of Bangladesh Agricultural Research Institute, Joydebpur during kharif-1 (March to July) seasons of 2005 and 2006 to identify the critical period of crop-weed competition for Indian spinach. Major weed species were Paspalurn commersoni, Echinochlaa crusgalli. Lie nv/nc india. Cyanotis axillaris and Cyperus rotundus. The lowest weed dry matter was 76.3 g m-2 in 2005 and l01.60 g m-2 in 2006 from the plots weeded up to 40 days after transplanting (DAT). The highest yields were obtained (74.82 t ha in 2005 and 48.48 t ha in 2006) from the weed free plots. The fresh yield of Indian spinach did not vary among no weeding upto 20, 30 and 40 DAT in 2006. But weeded plot upto 30 and 40 DAT produced identical yield in 2005. Maximum BCR (4.52) was obtained from weeded plots upto 30 DAT in 2005 but BCR (2.60) was same from weeded upto 30 and 40 DA F in 2006. On an average, highest BCR (3.55) was recorded from weeding upto 30 DAT. Results revealed that the critical period of crop weed competition lies between 20 and 30 DAT and two times hand weeding would be necessary within 30 DAT for maximum benefit. Key Words: Crop-weed competitions, critical period, weed management and Indian spinach. doi: 10.3329/bjar.v33i4.2306 Bangladesh J. Agril. Res. 33(4) : 623-629, December 2008

scholarly journals The competitive ability of Chenopodium album and Echinochloa crus-galli in maize crops depending on the time of their occurrence or removal

2016 ◽  
Vol 69 (4) ◽  
Author(s):  
Hanna Golebiowska ◽  
Renata Kieloch
Keyword(s):  
Competitive Ability ◽  
Stem Elongation ◽  
Chenopodium Album ◽  
Weed Competition ◽  
Growth Stages ◽  
Competitive Effect ◽  
Leaf Stage ◽  
Weed Infestation ◽  
Small Plot ◽  
Weed Emergence

Small-plot experiments for two levels of infestation (20 and 40 plants per m<sup>2</sup>) with <em>Chenopodium album</em> L. and <em>Echinochloa crus-galli</em> (L.) P. Beav were conducted in the 2009–2011 seasons. In the first variant, the effect of time of weed removal on maize was investigated. Weeds were removed in the following growth stages of maize: one, three, five, and seven leaves, the beginning of stem elongation, and the stage from the fourth to sixth node. The second variant concerned the effect of time of weed emergence on maize and included the same maize growth stages as mentioned above. In both treatments, weed competition was compared to the control – the plot completely free from weeds, as well as to the plot fully covered with weeds. <em>Echinochloa crus-galli</em> in the amount of 20 plants per m<sup>2</sup>, which were not removed until the five-leaf stage or which emerged immediately after the seven-leaf stage of maize, did not show any competitive effect on the growth and development of maize. <em>Chenopodium album</em> was characterized by a similar effect at the same level of weed infestation severity and when not removed until the five-leaf stage as well as in the case of plants that emerged after the seven-leaf stage of maize. Both species present in an amount of 40 plants per m<sup>2</sup> needed to be removed no later than at the three-leaf stage of maize.

Broadleaf Weed Control in Winter-Sown Lentil (Lens culinaris)

2015 ◽  
Vol 29 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Hassan Karimmojeni ◽  
Ali Reza Yousefi ◽  
Per Kudsk ◽  
Amir Hossein Bazrafshan
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Lens Culinaris ◽  
Management Strategies ◽  
Effective Control ◽  
Weed Species ◽  
Leaf Stage ◽  
Free Treatment ◽  
Hand Weeding ◽  
Herbicide Management

Winter sowing of lentil results in higher yields than a spring-sown crop. However, when lentil is winter-sown, the critical period of weed control is extended and might require sequential herbicide management strategies to obtain maximum yields. The efficacy of POST alone or soil applied followed by (fb) POST herbicides or hand weeding were evaluated in 2002 and 2003. Trifluralin (PPI) or pendimethalin (PRE) were applied at planting, and pyridate or oxyfluorfen were applied POST at the three- to four-leaf stage of lentil. The lowest level of weed biomass was recorded with all treatments, except pyridate alone in both years, pendimethalin PRE fb pyridate in 2002, and oxyfluorfen in 2003. Application of pyridate or oxyfluorfen POST alone resulted in lower yields. In 2002, trifluralin PPI or pendimethalin PRE fb one hand weeding or pendimethalin fb pyridate resulted in yields similar to the weed-free treatment. In 2003, yields were similar to the weed-free treatment, except pyridate or oxyfluorfen alone and trifluralin PPI fb oxyfluorfen. Weed species observed in the present study required sequential management to achieve both effective control and maximum lentil yield.

Estimation of Critical Period of Weed Control

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 273-283 ◽  
Author(s):  
M. Singh ◽  
M. C. Saxena ◽  
B. E. Abu-Irmaileh ◽  
S. A. Al-Thahabi ◽  
N. I. Haddad
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Field Experiments ◽  
Control Strategies ◽  
Maximum Yield ◽  
Logistic Function ◽  
Weed Infestation ◽  
Using Data ◽  
Relationship Of ◽  
The Relationship

An estimation of the critical period of weed control is helpful in formulating appropriate weed-control strategies. A regression approach is presented to estimate the thresholds of critical period of weed control and time of equal interference (or time of onset of competition). In this approach, yields were either a linear or logistic function of the duration of weed-free and weed-infested periods. Confidence intervals of the thresholds of critical period and time of equal interference were determined for the linear model. An approximation to the standard error of critical period and associated confidence interval were given for any general form of the model. The method was applied to estimate the critical period of weed control in rainfed lentil using data from four field experiments conducted in Jordan. The relationship of yield with the duration of weed-free period was described by a linear function, whereas the relationship with the duration of weed-infested period showed a better fit with a logistic function. To maintain 90% of maximum seed yield, the maximum time allowed to let weeds grow after the crop emergence varied over locations from 4.8 to 5.8 wk. The same level could be achieved if the crop is kept free of weeds from its emergence until 12.1 to 14.1 wk; while the time when the same amount of yield would be achieved under both approaches varied from 7.7 to 9.3 wk after crop emergence. For straw yield, the time to get 90% of the maximum yield could vary over location from a maximum of 4.5 to 8.0 wk under weed-infestation and from at least 11.5 to 13.5 wk when weed-free. The time to achieve the same amount of straw under two systems of competition varied from 6.5 to 9.9 wk after crop emergence. One of the four experiments showed a longer critical period than the others for seed and straw yields.

scholarly journals Influence of pendimethalin and hand weeding on mineral composition of maize, cowpea and their intercrop

Bio-Research ◽  
2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Amudalat Ranti Lawal ◽  
Bolaji Umar Olayinka ◽  
Lukman Bola Abdulra’uf ◽  
Emmanuel Obukohwo Etejere
Keyword(s):  
Weed Control ◽  
Mineral Composition ◽  
Active Ingredient ◽  
Field Experiments ◽  
Cropping Systems ◽  
Block Design ◽  
Weed Competition ◽  
Mineral Contents ◽  
Randomized Block Design ◽  
Hand Weeding

Weed competition has been a major challenge limiting crop yield especially in intercropping systems. Information on the use of chemicals for weed control in intercropping systems appears scanty. The aim of this study was to investigate the efficacy of pendimethalin (P) at 1 kg active ingredient/ha, and hand weeding (HW) on mineral contents of the harvested grains and effects of various weed control treatments in maize, cowpea, and their intercrop. Field experiments were carried out during the 2017 and 2018 rainy seasons. The field layout followed complete randomized block design with three replicates. There were eight treatments: Sole Maize/Cowpea + P, Sole Maize/Cowpea + P + 1HW at 3 weeks after sowing (WAS), Sole Maize/Cowpea + P+ 2HW at 3 and 6 weeks after sowing (WAS), Sole Maize/Cowpea weedy check, Intercrop + P, Intercrop + P + 1HW at 3WAS, Intercrop + P + 2HW at 3 and 6 WAS and Intercrop weedy check. It was observed that, P+1HW and P+2HW in both cropping systems have significant effects (p<0.05) and effectively control weed and increase the mineral contents in maize, cowpea, and their respective intercrop. The study revealed that, the mineral composition of maize and cowpea grains were improved by using pendimethalin with supplementary hand weeding. The study recommends that farmers should adopt intercropping maize with cowpea using pendimethalin plus one supplementary hand weeding at 3 WAS.

Competition and control of weeds in soybean

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Rajender Singh Chhokar ◽  
Rajender Singh Balyan
Keyword(s):  
Weed Control ◽  
Broad Spectrum ◽  
Weed Management ◽  
Critical Period ◽  
Management Practices ◽  
Field Experiments ◽  
Growth Stages ◽  
Single Application ◽  
Reduced Rate ◽  
And Control

Two field experiments were carried out from 1993 to 1995 to evaluate the critical period of weed control and to develop suitable weed management practices for jungle rice, horse purslane, and cockscomb in soybean. Horse purslane was more competitive during early growth stages (up to 45 days after sowing [DAS]) and cockscomb was more competitive during later growth stages, whereas jungle rice was competitive throughout the growing season. The critical period of weed control was found to be 30 to 45 DAS. Weed-free maintenance up to 45 DAS resulted in a 74% increase in grain yield of soybean over the unweeded control. Keeping soybean weed free for 45 d or allowing weeds to remain in the crop for less than 30 d resulted in no significant yield loss. Sequential application of a reduced rate of soil-applied trifluralin 1.0 kg ha–1(0.67 ×) with postemergence fluazifop 0.75 kg ha–1(0.75 ×) or a reduced rate of soil-applied trifluralin or pendimethalin at 1.0 kg ha–1(0.67 ×) followed by hand hoeing 35 DAS provided better control of a broad spectrum of weeds than a single application of a postemergence herbicide applied at reduced or recommended rates. Integration of reduced rates of soil-applied herbicides with post-emergence herbicides or hand hoeing 35 DAS produced soybean yields similar to the hand-weeded treatment. Compared to the weed-free or integrated weed control, a single application of soil-applied or postemergence herbicide did not control a broad spectrum of weeds and reduced soybean yield.

scholarly journals The Effect of Irrigation on Terbacil Tolerance in Field-grown Strawberry

2005 ◽  
Vol 15 (3) ◽  
pp. 560-564 ◽  
Author(s):  
Steven B. Polter ◽  
Douglas Doohan ◽  
Joseph C. Scheerens
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Fruit Yield ◽  
Leaf Stage ◽  
Safe Option ◽  
Irrigation Treatments ◽  
Hand Weeding

Field experiments were conducted in newly planted strawberry (Fragaria ×ananassa) with terbacil applied at rates of 0 to 6.4 oz/acre a.i. either 4 days after planting but before appearance of new growth, or at the three-leaf stage. Irrigation of 0.4 inch was applied to half of the plots immediately after application of terbacil. Injury was greater when terbacil was applied before new growth than when applied at the three-leaf stage. Injury symptoms increased linearly with terbacil rate. Irrigation immediately following terbacil application reduced injury relative to non-irrigated plots. Weed control was reduced when terbacil was applied at the three-leaf stage than when applied before new growth. Irrigation did not reduce weed control. Herbicide injury symptoms were not detected the spring following terbacil application. Fruit yield was not affected by herbicide and irrigation treatments applied the previous year. The combination of low rates of terbacil, 0.8–1.6 oz/acre a.i., followed by irrigation to remove the herbicide from foliage is a safe option that growers can use to improve weed control and reduce hand weeding costs in the planting year.

Effect of herbicides on the weed infestation and grain yield of soybean (Glycine max)

2004 ◽  
Vol 52 (2) ◽  
pp. 199-203 ◽  
Author(s):  
G. Singh ◽  
R. S. Jolly
Keyword(s):  
Glycine Max ◽  
Grain Yield ◽  
Weed Control ◽  
Negative Correlation ◽  
Rainy Season ◽  
Dry Matter ◽  
Field Experiments ◽  
Sand Soil ◽  
Loamy Sand Soil ◽  
Weed Infestation

Two field experiments were conducted during the kharif (rainy) season of 1999 and 2000 on a loamy sand soil to study the effect of various pre- and post-emergence herbicides on the weed infestation and grain yield of soybean. The presence of weeds in the weedy control plots resulted in 58.8 and 58.1% reduction in the grain yield in the two years compared to two hand weedings (HW) at 30 and 45 days after sowing (DAS), which gave grain yields of 1326 and 2029 kg ha-1. None of the herbicides was significantly superior to the two hand weedings treatment in influencing the grain yield. However, the pre-emergence application of 0.75 kg ha-1 S-metolachlor, and 0.5 kg ha-1 pendimethalin (pre-emergence) + HW 30 DAS were at par or numerically superior to this treatment. There was a good negative correlation between the weed dry matter at harvest and the grain yield of soybean, which showed that effective weed control is necessary for obtaining higher yields of soybean.

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.

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