نوع مقاله : مقالات پژوهشی
نویسنده
دانشگاه بوعلی سینا همدان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
Introduction: Although “the pesticides are a global human rights concern” (24), they can secure global food security provided that the rational herbicide application technique is taken into consideration (7). The principal elements of rational herbicide application technique include the selectivity of herbicide, the application of appropriately timed herbicide and the accuracy of application equipment (4). The hydraulic spray nozzle atomizes the spray solution into droplets (9). Thus, it is a key component to influence on the accuracy of spraying (17). The nozzle technology is always improving, resulting in the introduction of more than 60 nozzle types that all are available to apply in different situations. High nozzle diversity can cause some difficult to select a proper nozzle, particularly when wind speed at time of application is authorized or unauthorized for spraying. The present study aims to compare 14 nozzle types in relation to the efficacy of sethoxydim to control winter wild oat at two wind speeds.
Materials and Methods: The seeds of winter wild oat (Avena sterilis ssp. ludoviciana) were treated to germinate (2). Then, the 9 seedlings were planted within each pot and grown in the Research Greenhouse of Bu-Ali Sina University, Hamedan, Iran and thinned to 6 plant pot-1 at the one-leaf stage. At the five-leaf stage, they were treated with 0, 23.5, 47, 94, 187.5, and 375 g sethoxydim ha-1 using 14 nozzle types at two wind speeds of 0.5 and 9.5 m s-1 in outdoor conditions. A standard 210 L ha-1 carrier volume was sprayed at a pressure of 3 bar with the 11002 yellow nozzles of Twin Fan Standard (TFS), Fan Low Drift (FLD), Standard Flat Fan (SFF), Turbo Wide Angle Flat (TWAF), Low Pressure Air Induction Twin Flat (LPAITF), Low Pressure Air Induction Flat (LPAIF), Compact Fan Air (CFA), Compact Fan Air-Tilt (CFA-T), Turbo Twin Flat (TTF), Air Induction Twin Fan 3070 (AITF3070), Twin Fan Low Drift (TFLD), Air Induction Turbo Twin Flat (AITTF), Twin Fan Air (TFA), Turbo Air Induction Flat (TAIF). Four weeks after spraying, the dry weight of plants were obtained and the date were fitted to analyze using a four-parameter log-logistic model to estimate the Effective Doses (ED) (19).
Results and Discussion: The ED10, 50 and 90 values of sethoxydim on the control of winter wild oat were affected significantly by nozzle type or wind speed. When spraying was done at 0.5 m s-1 wind speed, the lowest and the highest ED50 values were obtained with the TFS and TAIF nozzles, requiring 12.81 and 62.72 g sethoxydim ha-1 to give a 50% reduction in dry weight of winter wild oat, respectively. In such a situation of wind speed, the ranking of the nozzle types based on the sethoxydim dose required to give a 50% reduction in dry weight of winter wild oat was TAIF > TFA > LPAIF > TFLD > LPAITF > AITTF > CFA > CFA-T > FLD > TTF > TWAF > AITF3070 > SFF > TFS (Table 1). It can be concluded that the endo-drift by TFS nozzle at low wind speed is lower than other nozzles. When spraying was done at 9.5 m s-1 wind speed, the lowest and the highest ED50 values were obtained with the AITF3070 and TFS nozzles, requiring 45.13 and 87.35 g sethoxydim ha-1 to give a 50% reduction in dry weight of winter wild oat, respectively. In such a situation of wind speed, the ranking of the nozzle types based on the sethoxydim dose required to give a 50% reduction in dry weight of winter wild oat was TFS > FLD > TAIF > TFA > SFF > CFA-T > TWAF > LPAIF > TFLD > AITTF > CFA > TTF > LPAITF > AITF3070. It can be concluded that the exo-drift by TFS nozzle at high wind speed is higher than other nozzles. It seems that a limiting factor for the performance of nozzles categorized as VC to UC at high wind speed can be the spray carrier volume.
Conclusions: As a proper nozzle to spray sethoxydim with 210 L carrier volume ha-1 at a pressure of 3 bar to control winter wild oat at low and high wind speed, the TFS and AITF3070 nozzles can be applied to obtain an optimal herbicide efficacy, respectively.
کلیدواژهها [English]
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