The original article has been corrected. Publisher's Note Springer Nature remains neutral with re... more The original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
The reduction of herbicide applications is a main research priority in recent years. One way to a... more The reduction of herbicide applications is a main research priority in recent years. One way to achieve this goal is by using adjuvants that can increase the efficacy of foliar-applied herbicides by reducing surface tension. Previous studies have shown that the surface tension of distilled water decreases under the influence of a magnetic field. In order to compare the effects of a magnetic field and Frigate in clodinafop-propargyl and cycloxydim in controlling wild oat and evaluating the surface tension, a dose-response greenhouse experiment was conducted by using 0, 8, 16, 32, 48, and 64 g ai ha-1 of clodinafop-propargyl and 0, 15, 30, 60, 90, and 120 g ai ha-1 of cycloxydim with Frigate and/or by passing them through a magnetic field.The magnetic field and Frigate caused a significant reduction in the surface tension of the herbicide solutions. But, Frigate was more effective in reducing the surface tension of the herbicide solutions, compared with the magnetic field. The magnetic field and Frigate increased the efficacy of clodinafop-propargyl and cycloxydim remarkably. Frigate increased the efficacy of the herbicides more than did the magnetic field. The magnetic field and Frigate collectively had more of an effect on the herbicides' efficacy than when they were applied individually. The magnetic field and Frigate were more effective in increasing the efficacy of clodinafoppropargyl than that of cycloxydim.
In rational herbicide application technique, a critical management decision to minimize exo-and/o... more In rational herbicide application technique, a critical management decision to minimize exo-and/or endo-drift is the optimal nozzle selection to spray at wind speed authorized (< 1.5 m s −1) and unauthorized (> 1.5 m s −1). Two studies were conducted simultaneously to select the optimal nozzles for two windy conditions. In bioassay study, six doses of clodinafop-propargyl (0, 8, 16, 32, 48, and 64 g a. i. ha −1) were sprayed with 10 types of yellow color-coded polymer spray nozzle having a 110°spray angle against winter wild oat at 0.5 and 7.5 m s −1 wind speeds. In drift and deposition study, only the recommended dose of clodinafop-propargyl (64 g a. i. ha −1) was sprayed in the same manner above on the water sensitive papers which were installed in different positions. On the ground under the nozzle trajectory, the highest and lowest droplet density were observed with the Twin Fan Standard (45.0 droplet cm −2) and Turbo TeeJet Induction (11.0 droplet cm −2) nozzles at 0.5 m s −1 wind speed, respectively. With the exception of the Turbo TeeJet, Turbo Twin Jet and Air Induction Turbo Twin Jet nozzles, a significant droplet density was exo-drifted up to 10 m distance when other nozzle types were used to spray at 7.5 m s −1 wind speed. The highest and the lowest ED 50 values were obtained with the Turbo TeeJet Induction (9.84 g a. i. ha −1) and Twin Fan Standard (3.26 g a. i. ha −1) nozzles when clodinafop-propargyl was sprayed at 0.5 m s −1 wind speed, respectively. While, the highest and the lowest ED 50 values were obtained with the Turbo TeeJet Induction (12.35 g a. i. ha −1) and Turbo Twin Jet (9.23 g a. i. ha −1) nozzles when clodinafoppropargyl was sprayed at 7.5 m s −1 wind speed, respectively. The Twin Fan Standard nozzle having the lowest endo-drift at wind speed authorized and the Turbo Twin Jet nozzle having almost low exo-drift at wind speed unauthorized were found to be an optimal nozzle to obtain an optimal clodinafop-propargyl potency against winter wild oat.
Bulletin of Environmental Contamination and Toxicology, Aug 17, 2018
The current study examined whether soil pH could influence the toxicity of herbicides to soybean-... more The current study examined whether soil pH could influence the toxicity of herbicides to soybean-rhizobium symbiosis. This can be useful for farmers to minimize the toxicity of them to crop-rhizobium symbiosis via applying their reduced doses. The toxicity of bentazon, metribuzin, and trifluralin to soybean-rhizobium symbiosis was investigated in pH 6.4, 7.2, and 8 soils. Seed inoculation decreased shoot:root (S:R) ratio but increased height, shoot dry weight (SDW), root dry weight (RDW), shoot nitrogen content (SNC), root nitrogen content (RNC), and nitrogen fixation effectiveness (NFE) in the pH 7.2 soil without herbicide application. All herbicides decreased NFE in all soil pH regimes except metribuzin in the pH 6.4 soil. Unlike trifluralin, the toxicity of bentazon and metribuzin to soybean-rhizobium symbiosis was influenced by the soil pH. It can be concluded that soil acidification and alkalization, which can rapidly occur in agroecosystems, can decrease and increase the toxicity of bentazon and metribuzin to soybean-rhizobium symbiosis, respectively.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
All previous studies reporting the application time-of-day effect for herbicides have been conduc... more All previous studies reporting the application time-of-day effect for herbicides have been conducted with a single-orifice, flat fan nozzle. Whether an increased number of flat fans in the nozzle could affect the application time-of-day effect is unknown. A replicated outdoor pot experiment was conducted to determine the best application time for trifloxysulfuron from 05:00 (before sunrise), 07:00 (after sunrise), 09:00, 11:00, 13:00, 15:00, 17:00, 19:00 (before sunset), and 21:00 (after sunset) against velvetleaf when sprayed with a single-, dual-, or tripletorifice flat fan nozzles. Trifloxysulfuron sprayed with the single-orifice flat fan nozzle at 05:00 was the least effective treatment reducing velvetleaf fresh weight by 51%. When the single-orifice flat fan nozzle was used, velvetleaf fresh weight, expressed as a quadratic polynomial function with a parabola opening upward, decreased as the application time changed from 05:00 to 11:00 (70% control); thereafter, it increased until 21:00. When the dual-and triplet-orifice flat fan nozzles were used, velvetleaf fresh weight, expressed as a quadratic polynomial function with a parabola opening downward, increased from 05:00 to 07:00; thereafter, it increased as the application time changed until 19:00 (the best application time, reducing velvetleaf fresh weight by 82%). Foliar nyctinasty in velvetleaf is responsible for decreased efficacy of trifloxysulfuron sprayed with the single-orifice flat fan nozzle before sunset. This obstacle can be overcome using the dual-or triplet-orifice flat fan nozzles.
Journal of Agricultural Science and Technology, 2015
Wild barley has invaded wheat fields ever since flamprop-isopropyl was outdated in Iran. Newly de... more Wild barley has invaded wheat fields ever since flamprop-isopropyl was outdated in Iran. Newly developed herbicides such as sulfosulfuron or sulfosulfuron plus metsulfuronmethyl can control it at higher than recommended dosages, but causing significant wheat injury. Hence, two dose-response experiments were conducted to evaluate their efficacy when tank-mixed with thirteen different vegetable oils, at the Ferdowsi University of Mashhad, Iran, during 2013. Moreover, a wheat cultivar (Gaskogen) was also treated with effective dose of 90% (ED 90 ) of both herbicides (21.44 grams active ingredient (g ai) of sulfosulfuron ha -1 and 41.95 g ai of sulfosulfuron plus metsulfuron-methyl ha -1 ) with and without each vegetable oil to check selectivity. Averaged over vegetable oils, the effective dose of 50% (ED 50 ) was decreased 2.6- and 3.0-fold with sulfosulfuron and sulfosulfuron plus metsulfuron-methyl, respectively. Among the evaluated vegetable oils, cottonseed and coconut oil were the...
ABSTRACT: The efficacy of reduced (411.5 and 617.2 a.i. ha-1) and recommended (823.0 g a.i. ha-1)... more ABSTRACT: The efficacy of reduced (411.5 and 617.2 a.i. ha-1) and recommended (823.0 g a.i. ha-1) rates of phenmedipham + desmedipham + ethofumesate on the control of Amaranthus retroflexus, Amaranthus blitoides, Chenopodium album, and Tribulus terrestris in sugar beet field was investigated when they were tank-mixed with and without Adigor (0.5% v/v), Ammonium sulphate (2% v/v), Citogate (0.2% v/v), D-Octil (0.3% v/v), Hydro-Max (0.5% v/v), and Volck (0.5% v/v). When the herbicide was applied alone, there was no significant difference between the rates of 617.2 and 823.0 g a.i. ha-1 for reduction of total weed density and biomass. Significantly, the adjuvants decreased total weed density and biomass. However, there was no significant difference among the performance of adjuvants. The sugar beet root and sucrose yields were increased significantly by increasing herbicide rate as a result of an improvement in weed control. Although herbicide efficacy was influenced in a similar manne...
ABSTRACT Water is a vital limiting factor for agricultural production in certain areas. Thus, max... more ABSTRACT Water is a vital limiting factor for agricultural production in certain areas. Thus, maximizing crop water productivity has been a main research priority in recent years. Hence, a pot experiment under natural conditions, performed using a completely randomized factorial design, was conducted to investigate the influences of magnetically treated water on some biological properties and seed yield of five soyabean (Glycine max) varieties inoculated with Bradyrhizobium japonicum. A magnetic treatment device with magnetic field of 0.7 T was devised and used to treat water. With the exception of shoot:root ratio, the magnetic treatment of water had an enhancing effect on all measurements of the five soyabean varieties, shoot and root dry weight, shoot and root nitrogen content, shoot and shoot phosphorus content, and seed yield. The effect was variety-dependent. Although there were differences in the shoot:root ratio among soyabean varieties, there was no significant difference between magnetically treated water and non-magnetically treated water. In all tested varieties, the lowest nodulation (nodule number and weight) per plant was found in untreated water. The nodule number per plant increased from 40 to 61 in BtTellar, from 16 to 37 in Clark, from 28 to 47 in InterPrice, from 27 to 73 in Sari and from 16 to 34 in Williams after they were irrigated with magnetically treated water.
All previous studies reporting the application time-of-day effect for herbicides have been conduc... more All previous studies reporting the application time-of-day effect for herbicides have been conducted with a single-orifice, flat fan nozzle. Whether an increased number of flat fans in the nozzle could affect the application time-of-day effect is unknown. A replicated outdoor pot experiment was conducted to determine the best application time for trifloxysulfuron from 05:00 (before sunrise), 07:00 (after sunrise), 09:00, 11:00, 13:00, 15:00, 17:00, 19:00 (before sunset), and 21:00 (after sunset) against velvetleaf when sprayed with a single-, dual-, or triplet-orifice flat fan nozzles. Trifloxysulfuron sprayed with the single-orifice flat fan nozzle at 05:00 was the least effective treatment reducing velvetleaf fresh weight by 51%. When the single-orifice flat fan nozzle was used, velvetleaf fresh weight, expressed as a quadratic polynomial function with a parabola opening upward, decreased as the application time changed from 05:00 to 11:00 (70% control); thereafter, it increased u...
It is challenging to obtain proper leaf wetting. An angled spray could overcome this impediment, ... more It is challenging to obtain proper leaf wetting. An angled spray could overcome this impediment, but which spray angle is best suited to droplet size is still unknown. In an outdoor pot experiment, seven doses of cycloxydim and sethoxydim were sprayed with single-orifice standard, anti-drift, and air induction (having a fine, medium, and extremely coarse spray quality, respectively) flat fan nozzles, using spray angles of 10°, 20° backward, 0° (vertical), 10°, 20°, 30°, 40°, 50°, and 60° forward relative to the direction of nozzle trajectory on wild barley at the three-leaf stage. Generally, the forward angled spray was better than the backward angled spray. With a standard flat fan nozzle, the forward angling of spray from 0° to 20° reduced the ED 50 from 60.24 to 39.85 g a.i. ⋅ ha −1 for cycloxydim and from 150.51 to 81.13 g a.i. ⋅ ha −1 for sethoxydim. With an anti-drift flat fan nozzle, the forward angling of spray from 0° to 30° reduced the ED 50 from 72.57 to 50.20 g a.i. ⋅ ha −1 for cycloxydim and from 181.94 to 104.51 g a.i. ⋅ ha −1 for sethoxydim. With an air induction flat fan nozzle, the forward angling of spray from 0° to 40° reduced the ED 50 from 102.96 to 45.52 g a.i. ⋅ ha −1 for cycloxydim and from 209.91 to 92.80 g a.i. ⋅ ha −1 for sethoxydim. More angling did not improve the efficacy of these herbicides. Our results revealed that larger spray droplets needed more spray angle than smaller spray droplets to achieve an equal control.
The yield of many crops can be increased by irrigating them with magnetically treated water (MTW)... more The yield of many crops can be increased by irrigating them with magnetically treated water (MTW). The aim of our research was to determine if the efficacy of a soil-applied herbicide such as metribuzin against weeds could be affected by MTW. A split-plot randomized complete block experiment was designed with two main plots, including potato (Solanum tuberosum L.) irrigated with equal volumes of MTW and non-MTW. Sub-plots were weedy control, weed-free control (hand-weeded), and pre-emergence application of metribuzin at 420 and 525 g a.i. • ha-1. Generally, MTW induced the seed germination and vegetative growth of Amaranthus blitoides S.Watson and Convolvulus arvensis L., resulting in a reduction of the total tuber yield of potato from 1.47 to 1.18 kg • m-2. MTW improved the efficacy of weed control strategies, resulting in an improvement of the total tuber yield and the water use efficiency of potato. The total tuber yield when metribuzin was applied at 420 g a.i. • ha-1 with MTW (3.51 kg • m-2) was more than when metribuzin was applied at 525 g a.i. • ha-1 with non-MTW (2.76 kg • m-2). It can be concluded that the use of MTW can be a safer crop production method by reducing the required dosage of metribuzin to control weeds. Considering the fact that the use of MTW without herbicide application increased the density of weed species, this method should be limited to a scenario where weeds can be effectively controlled.
The original article has been corrected. Publisher's Note Springer Nature remains neutral with re... more The original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
The reduction of herbicide applications is a main research priority in recent years. One way to a... more The reduction of herbicide applications is a main research priority in recent years. One way to achieve this goal is by using adjuvants that can increase the efficacy of foliar-applied herbicides by reducing surface tension. Previous studies have shown that the surface tension of distilled water decreases under the influence of a magnetic field. In order to compare the effects of a magnetic field and Frigate in clodinafop-propargyl and cycloxydim in controlling wild oat and evaluating the surface tension, a dose-response greenhouse experiment was conducted by using 0, 8, 16, 32, 48, and 64 g ai ha-1 of clodinafop-propargyl and 0, 15, 30, 60, 90, and 120 g ai ha-1 of cycloxydim with Frigate and/or by passing them through a magnetic field.The magnetic field and Frigate caused a significant reduction in the surface tension of the herbicide solutions. But, Frigate was more effective in reducing the surface tension of the herbicide solutions, compared with the magnetic field. The magnetic field and Frigate increased the efficacy of clodinafop-propargyl and cycloxydim remarkably. Frigate increased the efficacy of the herbicides more than did the magnetic field. The magnetic field and Frigate collectively had more of an effect on the herbicides' efficacy than when they were applied individually. The magnetic field and Frigate were more effective in increasing the efficacy of clodinafoppropargyl than that of cycloxydim.
In rational herbicide application technique, a critical management decision to minimize exo-and/o... more In rational herbicide application technique, a critical management decision to minimize exo-and/or endo-drift is the optimal nozzle selection to spray at wind speed authorized (< 1.5 m s −1) and unauthorized (> 1.5 m s −1). Two studies were conducted simultaneously to select the optimal nozzles for two windy conditions. In bioassay study, six doses of clodinafop-propargyl (0, 8, 16, 32, 48, and 64 g a. i. ha −1) were sprayed with 10 types of yellow color-coded polymer spray nozzle having a 110°spray angle against winter wild oat at 0.5 and 7.5 m s −1 wind speeds. In drift and deposition study, only the recommended dose of clodinafop-propargyl (64 g a. i. ha −1) was sprayed in the same manner above on the water sensitive papers which were installed in different positions. On the ground under the nozzle trajectory, the highest and lowest droplet density were observed with the Twin Fan Standard (45.0 droplet cm −2) and Turbo TeeJet Induction (11.0 droplet cm −2) nozzles at 0.5 m s −1 wind speed, respectively. With the exception of the Turbo TeeJet, Turbo Twin Jet and Air Induction Turbo Twin Jet nozzles, a significant droplet density was exo-drifted up to 10 m distance when other nozzle types were used to spray at 7.5 m s −1 wind speed. The highest and the lowest ED 50 values were obtained with the Turbo TeeJet Induction (9.84 g a. i. ha −1) and Twin Fan Standard (3.26 g a. i. ha −1) nozzles when clodinafop-propargyl was sprayed at 0.5 m s −1 wind speed, respectively. While, the highest and the lowest ED 50 values were obtained with the Turbo TeeJet Induction (12.35 g a. i. ha −1) and Turbo Twin Jet (9.23 g a. i. ha −1) nozzles when clodinafoppropargyl was sprayed at 7.5 m s −1 wind speed, respectively. The Twin Fan Standard nozzle having the lowest endo-drift at wind speed authorized and the Turbo Twin Jet nozzle having almost low exo-drift at wind speed unauthorized were found to be an optimal nozzle to obtain an optimal clodinafop-propargyl potency against winter wild oat.
Bulletin of Environmental Contamination and Toxicology, Aug 17, 2018
The current study examined whether soil pH could influence the toxicity of herbicides to soybean-... more The current study examined whether soil pH could influence the toxicity of herbicides to soybean-rhizobium symbiosis. This can be useful for farmers to minimize the toxicity of them to crop-rhizobium symbiosis via applying their reduced doses. The toxicity of bentazon, metribuzin, and trifluralin to soybean-rhizobium symbiosis was investigated in pH 6.4, 7.2, and 8 soils. Seed inoculation decreased shoot:root (S:R) ratio but increased height, shoot dry weight (SDW), root dry weight (RDW), shoot nitrogen content (SNC), root nitrogen content (RNC), and nitrogen fixation effectiveness (NFE) in the pH 7.2 soil without herbicide application. All herbicides decreased NFE in all soil pH regimes except metribuzin in the pH 6.4 soil. Unlike trifluralin, the toxicity of bentazon and metribuzin to soybean-rhizobium symbiosis was influenced by the soil pH. It can be concluded that soil acidification and alkalization, which can rapidly occur in agroecosystems, can decrease and increase the toxicity of bentazon and metribuzin to soybean-rhizobium symbiosis, respectively.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
All previous studies reporting the application time-of-day effect for herbicides have been conduc... more All previous studies reporting the application time-of-day effect for herbicides have been conducted with a single-orifice, flat fan nozzle. Whether an increased number of flat fans in the nozzle could affect the application time-of-day effect is unknown. A replicated outdoor pot experiment was conducted to determine the best application time for trifloxysulfuron from 05:00 (before sunrise), 07:00 (after sunrise), 09:00, 11:00, 13:00, 15:00, 17:00, 19:00 (before sunset), and 21:00 (after sunset) against velvetleaf when sprayed with a single-, dual-, or tripletorifice flat fan nozzles. Trifloxysulfuron sprayed with the single-orifice flat fan nozzle at 05:00 was the least effective treatment reducing velvetleaf fresh weight by 51%. When the single-orifice flat fan nozzle was used, velvetleaf fresh weight, expressed as a quadratic polynomial function with a parabola opening upward, decreased as the application time changed from 05:00 to 11:00 (70% control); thereafter, it increased until 21:00. When the dual-and triplet-orifice flat fan nozzles were used, velvetleaf fresh weight, expressed as a quadratic polynomial function with a parabola opening downward, increased from 05:00 to 07:00; thereafter, it increased as the application time changed until 19:00 (the best application time, reducing velvetleaf fresh weight by 82%). Foliar nyctinasty in velvetleaf is responsible for decreased efficacy of trifloxysulfuron sprayed with the single-orifice flat fan nozzle before sunset. This obstacle can be overcome using the dual-or triplet-orifice flat fan nozzles.
Journal of Agricultural Science and Technology, 2015
Wild barley has invaded wheat fields ever since flamprop-isopropyl was outdated in Iran. Newly de... more Wild barley has invaded wheat fields ever since flamprop-isopropyl was outdated in Iran. Newly developed herbicides such as sulfosulfuron or sulfosulfuron plus metsulfuronmethyl can control it at higher than recommended dosages, but causing significant wheat injury. Hence, two dose-response experiments were conducted to evaluate their efficacy when tank-mixed with thirteen different vegetable oils, at the Ferdowsi University of Mashhad, Iran, during 2013. Moreover, a wheat cultivar (Gaskogen) was also treated with effective dose of 90% (ED 90 ) of both herbicides (21.44 grams active ingredient (g ai) of sulfosulfuron ha -1 and 41.95 g ai of sulfosulfuron plus metsulfuron-methyl ha -1 ) with and without each vegetable oil to check selectivity. Averaged over vegetable oils, the effective dose of 50% (ED 50 ) was decreased 2.6- and 3.0-fold with sulfosulfuron and sulfosulfuron plus metsulfuron-methyl, respectively. Among the evaluated vegetable oils, cottonseed and coconut oil were the...
ABSTRACT: The efficacy of reduced (411.5 and 617.2 a.i. ha-1) and recommended (823.0 g a.i. ha-1)... more ABSTRACT: The efficacy of reduced (411.5 and 617.2 a.i. ha-1) and recommended (823.0 g a.i. ha-1) rates of phenmedipham + desmedipham + ethofumesate on the control of Amaranthus retroflexus, Amaranthus blitoides, Chenopodium album, and Tribulus terrestris in sugar beet field was investigated when they were tank-mixed with and without Adigor (0.5% v/v), Ammonium sulphate (2% v/v), Citogate (0.2% v/v), D-Octil (0.3% v/v), Hydro-Max (0.5% v/v), and Volck (0.5% v/v). When the herbicide was applied alone, there was no significant difference between the rates of 617.2 and 823.0 g a.i. ha-1 for reduction of total weed density and biomass. Significantly, the adjuvants decreased total weed density and biomass. However, there was no significant difference among the performance of adjuvants. The sugar beet root and sucrose yields were increased significantly by increasing herbicide rate as a result of an improvement in weed control. Although herbicide efficacy was influenced in a similar manne...
ABSTRACT Water is a vital limiting factor for agricultural production in certain areas. Thus, max... more ABSTRACT Water is a vital limiting factor for agricultural production in certain areas. Thus, maximizing crop water productivity has been a main research priority in recent years. Hence, a pot experiment under natural conditions, performed using a completely randomized factorial design, was conducted to investigate the influences of magnetically treated water on some biological properties and seed yield of five soyabean (Glycine max) varieties inoculated with Bradyrhizobium japonicum. A magnetic treatment device with magnetic field of 0.7 T was devised and used to treat water. With the exception of shoot:root ratio, the magnetic treatment of water had an enhancing effect on all measurements of the five soyabean varieties, shoot and root dry weight, shoot and root nitrogen content, shoot and shoot phosphorus content, and seed yield. The effect was variety-dependent. Although there were differences in the shoot:root ratio among soyabean varieties, there was no significant difference between magnetically treated water and non-magnetically treated water. In all tested varieties, the lowest nodulation (nodule number and weight) per plant was found in untreated water. The nodule number per plant increased from 40 to 61 in BtTellar, from 16 to 37 in Clark, from 28 to 47 in InterPrice, from 27 to 73 in Sari and from 16 to 34 in Williams after they were irrigated with magnetically treated water.
All previous studies reporting the application time-of-day effect for herbicides have been conduc... more All previous studies reporting the application time-of-day effect for herbicides have been conducted with a single-orifice, flat fan nozzle. Whether an increased number of flat fans in the nozzle could affect the application time-of-day effect is unknown. A replicated outdoor pot experiment was conducted to determine the best application time for trifloxysulfuron from 05:00 (before sunrise), 07:00 (after sunrise), 09:00, 11:00, 13:00, 15:00, 17:00, 19:00 (before sunset), and 21:00 (after sunset) against velvetleaf when sprayed with a single-, dual-, or triplet-orifice flat fan nozzles. Trifloxysulfuron sprayed with the single-orifice flat fan nozzle at 05:00 was the least effective treatment reducing velvetleaf fresh weight by 51%. When the single-orifice flat fan nozzle was used, velvetleaf fresh weight, expressed as a quadratic polynomial function with a parabola opening upward, decreased as the application time changed from 05:00 to 11:00 (70% control); thereafter, it increased u...
It is challenging to obtain proper leaf wetting. An angled spray could overcome this impediment, ... more It is challenging to obtain proper leaf wetting. An angled spray could overcome this impediment, but which spray angle is best suited to droplet size is still unknown. In an outdoor pot experiment, seven doses of cycloxydim and sethoxydim were sprayed with single-orifice standard, anti-drift, and air induction (having a fine, medium, and extremely coarse spray quality, respectively) flat fan nozzles, using spray angles of 10°, 20° backward, 0° (vertical), 10°, 20°, 30°, 40°, 50°, and 60° forward relative to the direction of nozzle trajectory on wild barley at the three-leaf stage. Generally, the forward angled spray was better than the backward angled spray. With a standard flat fan nozzle, the forward angling of spray from 0° to 20° reduced the ED 50 from 60.24 to 39.85 g a.i. ⋅ ha −1 for cycloxydim and from 150.51 to 81.13 g a.i. ⋅ ha −1 for sethoxydim. With an anti-drift flat fan nozzle, the forward angling of spray from 0° to 30° reduced the ED 50 from 72.57 to 50.20 g a.i. ⋅ ha −1 for cycloxydim and from 181.94 to 104.51 g a.i. ⋅ ha −1 for sethoxydim. With an air induction flat fan nozzle, the forward angling of spray from 0° to 40° reduced the ED 50 from 102.96 to 45.52 g a.i. ⋅ ha −1 for cycloxydim and from 209.91 to 92.80 g a.i. ⋅ ha −1 for sethoxydim. More angling did not improve the efficacy of these herbicides. Our results revealed that larger spray droplets needed more spray angle than smaller spray droplets to achieve an equal control.
The yield of many crops can be increased by irrigating them with magnetically treated water (MTW)... more The yield of many crops can be increased by irrigating them with magnetically treated water (MTW). The aim of our research was to determine if the efficacy of a soil-applied herbicide such as metribuzin against weeds could be affected by MTW. A split-plot randomized complete block experiment was designed with two main plots, including potato (Solanum tuberosum L.) irrigated with equal volumes of MTW and non-MTW. Sub-plots were weedy control, weed-free control (hand-weeded), and pre-emergence application of metribuzin at 420 and 525 g a.i. • ha-1. Generally, MTW induced the seed germination and vegetative growth of Amaranthus blitoides S.Watson and Convolvulus arvensis L., resulting in a reduction of the total tuber yield of potato from 1.47 to 1.18 kg • m-2. MTW improved the efficacy of weed control strategies, resulting in an improvement of the total tuber yield and the water use efficiency of potato. The total tuber yield when metribuzin was applied at 420 g a.i. • ha-1 with MTW (3.51 kg • m-2) was more than when metribuzin was applied at 525 g a.i. • ha-1 with non-MTW (2.76 kg • m-2). It can be concluded that the use of MTW can be a safer crop production method by reducing the required dosage of metribuzin to control weeds. Considering the fact that the use of MTW without herbicide application increased the density of weed species, this method should be limited to a scenario where weeds can be effectively controlled.
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