Alireza Hamdami; Hashem Hadi; Amir Rahimi
Abstract
In order to investigate the effect of different periods of weed control and interference on yield and yield components of fenugreek, an experiment was done with two series of treatments including weed control from emergence to the third true leaf, to the sixth true leaf , to the first flowering branch, ...
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In order to investigate the effect of different periods of weed control and interference on yield and yield components of fenugreek, an experiment was done with two series of treatments including weed control from emergence to the third true leaf, to the sixth true leaf , to the first flowering branch, to the third flowering branch, to flowering, to seed filling and the second series including weed interference up to the third true leaf, up to the sixth true leaf, up to the first flowering branch, up to the third flowering branch, up to the flowering and up to the seed filling at research farm of Urmia university during 2018. The results showed that the interference treatment up to the third true leaf had the lowest weed dry weight. In both series of treatments with increasing the presence period of weeds, a significant decrease was observed in grain yield per plant and per hectare of fenugreek, so that the beginning of the critical period was determined 140 and 158 GDD from plants emergence at two acceptable levels of 5 and 10% reduction of grain yield per hectare, respectively, and the end of the critical period of weed control was established 349 and 282 GDD from the emergence at the two levels of yield reductions, respectively. Therefore, the best time to control weeds was from the third true leaf to flowering and from the four-leaf stage until the appearances of flowers at the levels of 5% and 10% yield reductions, respectively.
seyedeh roghaye hosseini valiki; Rahmat Abbasi; Hemmatollah Pirdashti; Vahid Akbarpour
Abstract
Weed infestation in arable lands is much more than one species. Thus, it is important to pay attention to the interaction of multy species of weeds. To study the effect of redroot pigweed (Amaranthus retroflexus L.) and barnyardgrass (Echinochloa crus-galli (L.) P. Beauv) interference on yield and essential ...
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Weed infestation in arable lands is much more than one species. Thus, it is important to pay attention to the interaction of multy species of weeds. To study the effect of redroot pigweed (Amaranthus retroflexus L.) and barnyardgrass (Echinochloa crus-galli (L.) P. Beauv) interference on yield and essential oil of fennel (Foeniculum vulgare Mill.), an experiment has been done in Research field of Sari Agricultural Sciences and Natural Resources University during 2017. It has been arranged in a factorial arrangement based on randomized complete block design with three replications with the experimental factors being three densities of redroot pigweed (0, 4, and 8 plants m-2) and three densities of barnyardgrass (0, 4, and 8 plants m-2). The highest grain yield (2230 kg ha-1) and essential oil content (2 %) are obtained at weed free plots. The density of 8 redroot pigweed plants m-2 at simultaneous interference with 0, 4, and 8 barnyard grass m-2 reduce grain yield by 30.1%, 62.9%, and 75.7%, and essential oil content by 24.5%, 26.2%, and 29.5%, respectively, compared with weed free plots. The coefficient of redroot pigweed competitivity is predicted to be higher than barnyardgrass, and the interference of 14.5 barnyardgrass plants m-2 or 7.7 redroot pigweed plants m-2 decreases fennel grain yield by 50%.
Ahmad Raefizadeh; Mohammad Armin; Matin Jamaimoeini
Abstract
To determination of critical time of weed control in Cotton (Gossypium hirsutum L.) (Khordad cultivar) in conventional and ultra-narrow row spacing conditions, a field experiment was arrange as a factorial arrangement in a randomized complete block design with three replications in Sabzevar in 2015. ...
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To determination of critical time of weed control in Cotton (Gossypium hirsutum L.) (Khordad cultivar) in conventional and ultra-narrow row spacing conditions, a field experiment was arrange as a factorial arrangement in a randomized complete block design with three replications in Sabzevar in 2015. Factors were cultivation systems (conventional (70 Cm row spacing) and ultra narrow row (20 Cm row spacing) and duration of weed interference (0, 30, 45, 60, 7 days after emergence and weedy in full season. The results of the experiment showed that in ultra-narrow row condition, seed cotton yield losses of 2.5, 5 and 10 percent were estimated to occur on 27.4, 36.1 and 44.7 day after emergence, respectively and in conventional condition yield losses of 2.5, 5 and 10 percent were estimated to occur on 8.1, 13.5 and 24.4 day after emergence, respectively. The onset of seed cotton yield an lint yield loss was earlier (46.3 and 53.7 days after emergence, respectively) in conventional condition while in ultra-narrow row condition the onset of seed cotton yield and lint yield loss was postponed to 57.9 and 65.9 days after emergence, respectively, Overall, the results of the experiment showed that cultivation of cotton in ultra-narrow row spacing in weed interference conditions could provide a better seed cotton yield than conventional spacing.