تاثیر نوع و شماره نازل های یک، دو و سه بادبزنه بر عملکرد سیکلوکسیدیم علیه جودره (hordeum spontaneum koch.)

در آزمایشی که به صورت دُزپاسخ اجرا شد، شش مقدار از سیکلوکسیدیم (0، 25/6، 5/12، 25، 50 و 100 گرم ماده موثره در هکتار) با استفاده از 3 نوع نازل (استاندارد، ضد بادبردگی و القاء کننده هوا) در 3 تعداد بادبزن (یک، دو و سه بادبزنه) در 3 شماره نازل (11002، 11003 و 11004 که به ترتیب حجم پاشش های 160، 240 و 320 لیتر آب در هکتار را فراهم کردند) بر روی جودره در مرحله چهار برگی در سرعت وزش باد کمتر از 4/0 متر بر ثانیه پاشیده شدند. مقدار سیکلوکسیدیم لازم برای کاهش 50 درصدی وزن خشک جودره (ed50) به طور معنی داری تحت تاثیر نوع، تعداد بادبزن و شماره نازل قرار گرفت. افزایش تعداد بادبزن سبب کاهش ed50 شد. در بین نازل ها با شماره 11002 در هر تعداد از بادبزن، عملکرد انواع نازل ها به صورت استاندارد gt; ضدبادبردگی gt; القاء کننده هوا بود. با این حال، در بین نازل ها با شماره های 11003 یا 11004 در هر تعداد از بادبزن، عملکرد انواع نازل ها به صورت استاندارد = ضدبادبردگی gt; القاء کننده هوا بود. در بین تمام انواع نازل ها در هر تعداد از بادبزن، افزایش حجم پاشش از 160 به 240 لیتر آب در هکتار سبب کاهش ed50 شد. با این وجود، تنها در نازل القاءکننده هوا در هر تعداد از بادبزن، افزایش حجم پاشش از 240 به 320 لیتر آب در هکتار سبب کاهش مجدد ed50 شد. بنابراین، می توان چنین توصیه کرد که مناسب ترین نازل برای کاربرد سیکلوکسیدیم علیه جودره با هدف بهینه سازی همزمان مصرف علف کش و آب نازل استاندارد سه بادبزنه 11003 می باشد.

The Effect of Type and Size of Single, Twin, and Triplet Flat Fan Nozzles on the Activity of Cycloxydim against Wild Barley (Hordeum spontaneum Koch.)

;Introduction: The herbicide application has caused some environmental problems. Therefore, optimal application of herbicides was followed in recent years. For this purpose, it is essential to minimize the exodrift and/or endodrift of spray droplets. The amount of exodrift and/or endodrift is directly related to the size of spray droplets. By decreasing the size of spray droplets, the exodrift increases and the endodrift decreases (34). This intricate issue is a stimulus to develop the types of nozzles in different sizes (color) producing different sizes of spray droplets at different spraying pressures. Such a development in the production of nozzles has caused difficulty and confusion in selecting a suitable type of nozzle (2). On the other hand, the agriculture sector is faced with water crisis in recent years. Considering that water is the most important carrier of herbicides, selecting a suitable spray volume is thus necessary. According to previous studies (26), the efficacy of different herbicides can influence spray volume negatively (30), neutrally (29), or positively (12). So far, the effect of spray volume on the efficacy of cycloxydim against any weed has not been investigated. Also, since the types of triplet flat fan nozzles have been recently developed, no investigation has been done on their performance compared to the types of single and twin flat fan nozzles. The current study aimed to fill this knowledge gap. ;Materials and Methods: The seeds of wild barely (Hordeum spontaneum Koch.) were treated to germinate. Then, 8 seedlings were planted within each 3L pot and grown in the Research Greenhouse of BuAli Sina University, Hamedan, Iran. At the fourleaf stage, they were treated with 0, 6.25, 12.5, 25, 50, and 100 g cycloxydim ha1 using 3 nozzle types (i.e. Standard, AntiDrift, and Air Induction), at 3 orifice numbers (i.e. single, twin, and Triplet) and 3 nozzle sizes (i.e. 11002, 11003, and 11004). The treatments were sprayed at a pressure of 300 kPa when the wind speed was less than 0.4 m s1. The volume of spray created by 11002, 11003, and 11004 nozzle sizes was 160, 240 and 320 L ha1, respectively. Three weeks after spraying, the dry weight of plants was determined. The date were fitted using a fourparameter loglogistic model to estimate the dose required to achieve 50% wild barley control (ED50).; Results and Discussion: The ED50 was significantly affected by the type, size, and orifice number of nozzle. In all types of nozzles (Standard, antiDrift and Air Induction) and sizes (11002, 11003 and 11004), an increase in orifice number significantly reduced the values of ED50 for cycloxydim against wild barely, indicating increased efficiency of herbicide. This can be explained by two reasons. Firstly, with an increase in orifice number in each type of nozzles, the size of spray droplets decreases. Previous studies have proven that there is a negative relationship between the amount of spray droplets deposited on the target surface and the size of spray droplets. Therefore, by decreasing the size of spray droplets, they can be deposited more on the target surface, resulting in an improvement in the foliageherbicides efficiency. Secondly, increasing the orifice number of nozzle can lead to the penetration of spray droplets into the canopy. Among the nozzles of 11002 in any orifice number, the performance of nozzles was ranked as Standard gt; AntiDrift gt; Air Induction. However, among the nozzles of 11003 or 11004 in any orifice number, the performance of nozzles was as Standard = AntiDrift gt; Air Induction. Among all types of nozzles in any orifice number, increasing spray volume from 160 to 240 L ha1 reduced the ED50. However, only in the types of nozzles of Air Induction in any orifice number, increasing spray volume from 240 to 320 L ha1 reduced the ED50. ;Conclusion: It can be recommended that the most suitable nozzle for the application of cycloxydim against wild barely at a wind speed of less than 0.4 m s1 with the aim of optimizing simultaneously both the dose of herbicide and the consumption of water is Triplet Standard Flat Fan Nozzle 11003 (spray volume= 240 L ha1).