Modeling the Germination Responses of Wild Barley (Hordeum spontaneum) and Littleseed CannaryGrass (Phalaris minor) to Temperature
Mohsen
Beheshtian
دانشگاه تهران
author
Hamid
Rahimain
دانشگاه تهران
author
Hassan
Alizadeh
دانشگاه تهران
author
sara
Ohadi
دانشگاه تهران
author
Ahmad
Zare
دانشگاه تهران
author
text
article
2013
per
Different models have been developed to describe the germination responses of seeds to temperature among which the thermal time (heat unit) model has received the greatest implications. Although biologically relevant, the thermal time model is confined to some assumptions which may not be met in some species (particularly in weed species) and thus can result in poor predictions. In this paper we address a novel Weibull-based model which is not only more biologically relevant but also provides the better predictions of germination compared to the conventional model. Therefore, in a laboratory experiment the seed germination of wild barley (Hordeum spontaneum) and little canary grass (Phalaris minor) was tested at various sub- and super-optimal temperatures including 8, 12, 16, 20, 24 and 28 oC. The both models were then fitted to the data and compared. The conventional thermal time model provided very poor fits to the germination data of both (particularly P. minor) (RMSE = 9% to 12%). However, the new model well fitted to the same datasets with only 4% error (i.e. RMSE). The Weibull-based model was also good at estimating the germination lag, germination rate and final percent germination in either of weeds studied. Separating the effect of temperature on germination rate and germination extent is suggested to be amongst the most significant ecological properties of the model. For example, the optimum temperature for the mid germination rate (21.8 oC in H. spontaneum and 23.5 oC in P. minor) was found to be higher than and beyond the optimum range of germination extent (7.5 to 20 oC in H. spontaneum and 7.5 to 16 oC in P. minor). This can give the two species a high degree of germination plasticity in response to the environmental temperatures.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
105
118
https://ijws.areeo.ac.ir/article_5755_900464fb63b8771fc64c41c4a03dc66e.pdf
Investigating Efficiency of Non-chemical Methods to Management of Weeds in Forage Sorghum (Sorghum bicolor)
Eskandar
zand
موسسه تحقیقات گیاهپزشکی
author
Fariba
Maeighani
موسسه تحقیقات گیاهپزشکی
author
Mohammad
Sarhadi
دانشجوی دانشگاه مشهد
author
Ali Reza
Barjasteh
مرکز تحقیقات شاهرود
author
text
article
2013
per
In order to investigate the efficiency of non-chemical methods management of weeds in forage Sorghum, an experiment was conducted in Varamin Research farm during 2010. The experiment was carried out in split factorial design with three replications. Treatments included cultivation at 3 leaf stage of sorghum, cultivation at 3 and 5 leaf stages of sorghum, weed free and weed infested as main plots and two levels of sorghum densities (190000 and 266000 plant/ha) and two levels of sorghum planting patterns (one and two row plant pattern) as factorial treatments in subplots. Weed density and biomass were measured 30 days after second cultivation and before second forage harvesting. Forage biomass was also measured at each harvesting. According to the results, weed density was decreased by cultivation (about 50%) but as the density of weed was very high, the effect of cultivation on weed biomass was not significant. Increasing density of sorghum+ two row planting pattern had positive effect on the final yield of sorghum. In general, integrating cultivation, density and planting pattern did not have significant effect on the final yield of sorghum and weed population, but the effects of cultivation at 3 leaf stage of sorghum + two row planting pattern and 19000 plant/ha+ two row planting pattern) on final yield were more favorable than other treaatment. It seemed that these treatments can be recommended in integrated weed management of sorghum.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
119
126
https://ijws.areeo.ac.ir/article_5819_88c27bd65eb20a0882848c0ee7e96608.pdf
Interactions between Herbicide Dose and Weed Leaf Area Damage Coefficient in a Multiple Weed Species Competition with Maize
mostafa
oveisi
دانشگاه تهران
author
hamid
Rahimian
دانشگاه تهران
author
Mohammad Ali
Baghestani
موسسه تحقیقات گیاهپزشکی
author
Hassan
Alizadeh
دانشگاه تهران
author
text
article
2013
per
Weed leaf area damage coefficient (λ) denotes the increase in weed competitiveness per unit increase in its leaf area. Although the variability of this parameter has been confirmed, it was assumed to be constant in many researches. The objective of this study was to determine the interactions between herbicide dose and λ. Field experiments were conducted to determine the relationship between competitive indices of maize, Xanthium strumarium and Amaranthus retroflexus during 2007 and 2008. Five doses of the herbicide nicosulfuron as main factor, and 16 density combinations comprised of 4 densities of A. retroflexus × 4 densities of X. strumarium as sub plots were arranged in a one-replicate split factorial. For A. retroflexus, the λ value was constant. For X. strumarium, the λ value was constant with no herbicide and 0.25 rate of the full dose. With increasing the dose up to half the recommended dose, the λ value increased and again with increasing dose to 0.75 rate, it returned to the level with no herbicide. This relationship was properly described by Gaussian model. Herbicide at half rate probably removed the apical dominance and increased the number of lateral shoots. Herbicide as an external factor was the most important determinant in the change of X. strumorium canopy shape. Deep understanding of the system behavior, relations and interactions with herbicide applications is of great help in improving the predictive power of weed management models
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
127
140
https://ijws.areeo.ac.ir/article_5820_eb2e3d0fedd30fa25c51f1a23a15b767.pdf
Investigating Resistance of Wild Mustard (Sinapis arvensis) Populations to Acetolactate Synthase Inhibiting Herbicides in Wheat Fields of Khoozestan, Gorgan and Kermanshah Provinces
Omid
Lotfifar
دانشگاه ابوریحان
author
Iraj
Alahdadi
عضو هیئت علمی دانشگاه ابوریحان
author
Eskandar
Zand
موسسه تحقیقات گیاهپزشکی
author
Gholam Abbas
Akbari
عضو هیئت علمی دانشگاه ابوریحان
author
text
article
2013
per
To study the resistance of wild musturd populations to acetolactate synthase inhibitors, 31 suspicious wheat fields to resistance (included of 14, 12 & 5 fields located in Golestan, Khoozestan & Keramanshah, respectively) were studied during 2012. Some important management information was analyzed in the first part of experiment. In the second part, the effect of three acetolactate synthase inhibitor herbicides (ALS) including of Tribenuron methyl (Granstar), sulfosulfuron + metsulfuron-methyl (Total) and Iodosulfuron methyl sodium+Mesosulfuron Methyl+Mephen payer (Atlantis) on the growth of suspicious populations was examined on the base of complete randomized block design. To study dose-response reactions, different doses of mentioned herbicides were sprayed on resistant populations (G3, G4 & G5 of Gorgan, Kh1, Kh5 & Kh7 of Khoozestan and Ker1 of Kermanshah) and three sensitive populations (G9, Kh3 & Ker1 of mentioned province) in the third part of this experiment. According to the results of the first part, the only crop sequence of herbicides was not observed in more than 80% of the fields and wheat was cropped as in 39% of these fields. In addition, Khoozestan had the weakest crop rotation with 50% single cropping. The results of second part showed that 20% and 10% of populations were resistant to Tribenuron methyl and sulfosulfuron + metsulfuron-methyl respectively, but, high resistance to Iodosulfuron methyl sodium+Mesosulfuron Methyl+Mephen payer. Also, 10% of populations were resistant to Tribenuron methyl and sulfosulfuron+metsulfuron-methyl. According to the results of dose-response experiment, G3, G4, G5 (Golestan) and Kh7 (Khoozestan) populations had low, Ker2 (Kermanshah) had medium and two populations of Kh1 and Kh5 (Khoozestan) had high resistance to Tribenuron methyl. In addition, Kh5, Kh7 (Khoozestan) and G3 (Golestan) had low, medium and high resistance to sulfosulfuron+ metsulfuron-methyl, respectively.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
141
157
https://ijws.areeo.ac.ir/article_5821_66497cc02b8ad667d3509523006f2f65.pdf
Effects of Nitrogen, Seeding Rate and Weed Interference on Growth and Yield of Wheat (Shiraz Cultivar)
Ayoub
Niknam Haghighi
دانشجوی دانشگاه شیراز
author
Seyed Abdolreza
Kazemeini
عضو هیئت علمی دانشگاه شیراز
author
Hossein
Ghadiri
عضو هیئت علمی دانشگاه شیراز
author
text
article
2013
per
In order to evaluate the effect of nitrogen, plant density and weeds on growth and yield of wheat cv. Shiraz, an experiment was conducted during 2009/2010 and 2010/2011 growing seasons at Agricultural College of Shiraz University. The experimental design was split-split plot with main plots arranged as an RCBD with three replications. Treatments included weed and weed free as main factor, three nitrogen levels (50,100,150 kg ha-1) as sub factor and seeding rate (180, 225, 270 and 315 kg ha-1) as sub factor. Wheat growth and yield as well as its components (1000-grain weight, grain number per spike and ear number m-2) were affected by weeds so that grain yield was significantly reduced by 34.23%. With increasing level of nitrogen (from 50 to 150 kg/ha), wheat grain yield (3840 Vs 4980 kg/ha)was significantly increased by 29/83%; however weed dry weight was also increased in weedy plots indicating that additional nitrogen cannot compensate for the effect of weed competition. Increasing seeding rate recorded significantly higher yield and yield components than control and a simultaneous reduction in weed competition with the lowest weed dry weight was achieved at 315 kg ha-1 seeding rate. A rise of nitrogen rate increased (0.57 gr m-2) weed dry weight. There was a negative and significant correlation between seed yield and weed dry weight, so that under different nitrogen levels, increasing weed dry weight decreased seed yield. Generally, it appears that compared to increased rate of nitrogen, higher seeding rate is a more effective strategy to compensate for yield losses caused by weeds. To achieve optimal wheat yield, application of 270 kg wheat seed and 150 kg nitrogen ha-1 is recommended.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
159
174
https://ijws.areeo.ac.ir/article_5822_1b118a5f7189577e0d85f2882c336141.pdf
Effects of Additive to Ease Hard Water Impacts as a Carrier on Glyphosate (Roundup SL 41%) Efficiency and its Effect on Some Growth Parameters of Camelthorn (Alhagi psedoalhagi)
mohammad
bazubandi
عضو هیئت علمی مرکز تحقیقات مشهد
author
majed
Abbaspour
عضو هیئت علمی مرکز تحقیقات مشهد
author
Hossein
Torabi
مرکز تحقیقات مشهد
author
Peyman
Keshavarz
مرکز تحقیقات مشهد
author
text
article
2013
per
This study was conducted to investigate enhancement effects of additives on efficacy of glyphosate at different levels of water hardness on camelthorn control at Abasabad Research Station (Mashhad) during 2009-2010. Two separate experiments were carried out. In the first experiment, Four doses of glyphosate (Rundup SL %41) i.e. 0, 4, 6 and 8 L.ha-1 were separately tank mixed with 0.1, 0.25, 0.5 percent of X-change at three levels of water hardness including 47.5, 95 and 190 mgL-1 of Mg+2 + Ca+2. In the second experiment, ammonium sulfate at three levels i.e. 0, 3 and 4 percent replaced X-change while other treatments remained intact. Treatments were applied during early May to camelthorn plants. Each treatment was replicated three times. Results revealed that without applying additives to herbicide solution, glyphosate efficacy to reduce plant height was significantly declined at higher levels of water hardiness as ED50 was increased from 2.478 to 31.407 L.ha-1. Maximum glyphosate efficiency was observed when X-change was used with concentration of 5%. It could reduce ED50 to 6.579 L.ha-1 compared to 31.407 L.ha-1 where no additive was applied at highest level of hardness. Under low and medium ED50, there was no significant difference between xchange and ammonium sulfate.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
175
185
https://ijws.areeo.ac.ir/article_5823_b3eed25737d60d1b0cea649b135248b5.pdf
Evaluation of Basil (Ocimum basilicum) and Cowpea (Vigna unguiculata) Intercropping at Different Nitrogen Fertilizer Levels and its Effect on Weed Density
Hoda
Abbadian
دانشجوی دانشگاه آزاد تبریز
author
Mehrdad
Yarnia
عضو هیئت علمی دانشگاه آزاد تبریز
author
Hematollah
Pirdashti
عضو هیئت علمی دانشگاه ساری
author
Rahmat
Abbasi
عضو هیئت علمی دانشگاه ساری
author
Farhad
Farahvash
عضو هیئت علمی دانشگاه آزاد تبریز
author
text
article
2013
per
To study the effect of different levels of nitrogen and intercropping systems of basil (Ocimum basiilicum L.) and cowpea (Vigna unguiculata L.) on weed population structure, an experiment was carried out as a split-split plot a randomized complete blocks design with three replications during 2010-2011 at Sari Agricultural Science and Natural Resources University. Treatments included weed control and weed infested as the main plots, levels of nitrogen (0, 50 and 100 kg/ha) as sub plots, Sole cropping of cowpea and basil, and additive planting ratios of 25, 50 and 75% basil as sub-sub plots. Under weed control conditions, the highest yield of cowpea (685 kg ha-1) and maximum dry matter yield of basil (430 kg ha-1) were obtained from 50% basil ratio with 50 and 100 kg ha-1N fertilizer application, respectively. The highest yield of basil (139 kg ha-1) was observed in weed infested plots of 25% basil planting ratio and 100 kg ha-1 nitrogen fertilizer with the highest invasive coefficient of 1.66 and competition coefficient of 3.42. The highest land equivalent ratio (1.43) belonged to 50% additive ratio of basil in weed free and the lowest (0.87) belonged to 75% ratio and without nitrogen fertilizer in weed infested condition. Generally, existence of cowpea in additive intercropping reduced the population and biomass of weeds compared to basil sole cropping. Increasing nitrogen fertilizer application caused faster closed canopy of plant species in intercropping which led to reduced weeds population and biomass.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
187
199
https://ijws.areeo.ac.ir/article_5824_c84bfc1f2489aca59e0c6e31abe89fe5.pdf
Evaluating of some Herbicides to Control Bermudagrass (Cynodon dactylon) and Field Bindweed (Convolvulus arvensis) in Established Alfalfa (Medicago sativa)
Ebrahim
Mamnoei
مرکز تحقیقات جیرفت
author
Mohammad Ali
Baghestani
موسسه تحقیقات گیاهپزشکی
author
text
article
2013
per
In order to evaluate the effect of some herbicides for weed control in established alfalfa, an experiment was conducted in a randomized complete blocks design with 4 replications in the Agricultural Research Center of Jiroft, for two years from 2009 to 2011. Treatments included Pursuit (imazethapyr SL 10%) at 0.4, 0.6, 0.8 and 1 Lit/ha plus cytogate at 1 Lit/ha, plus Focus (cycloxydim EC 10%) at 2 Lit/ha, Stomp (pendimethalin EC 33%) at 2.5 and 3 Lit/ha, Bazagran (bentazon SL 48%) at 3 L/ha plus focus at 2 Lit/ha, Senkor (metribuzin WP 70%) at 1 kg/ha, Butress (2,4,DB 42.3 % EC) at 2, 2.5, 3, 3.5 li/ha and weed- free as a check. The effect of herbicides on alfalfa biomass and weed biomass and density was studied from 3 harvests. Herbicides had significant effect on the density and biomass of bermudagrass (Cynodon dactylon) and field bindweed (Convolvulus arvensis). Herbicide cycloxydim, at 2 L/ha, was best to control bermudagrass, reducing density by 47-64% and dry weight by 47-62%. The best treatment to control field bindweed was 2,4-DB at 3.5 L/ha, reducing density by 38-42% and dry weight by 36-39%. The highest alfalfa yield was obtained with imazethapyr at 0.8 and 1 L/ha plus cytogate at 1 Lit/ha, plus cycloxydim at 2 Lit/ha.
Iranian Journal of Weed Science
Iranian Society of Weed Science
1735-3548
9
v.
2
no.
2013
201
211
https://ijws.areeo.ac.ir/article_5829_e72ea98a5f4b19aa3565cb21a5c863a4.pdf