بررسي كارايي علف كش ريم سولفورون در كنترل علف هاي هرز مزارع سيب زميني در مراحل مختلف رشدي

Evaluating Rimsulforon Efficiency on Controlling Weeds in Potato at Different Growth Stages

به منظور بررسی تأثیر علف كش ریم سولفورون (Titus 25% DF) به صورت پس رویشی در كنترل علف های هرز مزارع سیب زمینی، آزمایشی مزرعه ای در روستای شیخ كلخوران اردبیل در سال 1393 انجام شد. آزمایش به صورت فاكتوریل با تیمار شاهد در قالب طرح بلوك های كامل تصادفی با سه تكرار و دو فاكتور و با استفاده از رقم سیب زمینی مرسوم منطقه (آگریا) انجام شد. فاكتور اول، دزهای علف كش ریم سولفورون در شش سطح 5، 10، 20، 30، 40 و 50 گرم ماده مؤثره در هكتار و فاكتور دوم، زمان های كاربرد علف كش در مراحل مختلف رشدی سیب زمینی شامل مرحله سبزشدن سیب زمینی، استولون زایی و حجیم شدن غده بودند؛ همچنین دو تیمار بدون وجین (با علف هرز) و وجین كامل (بدون علف هرز)، به عنوان شاهد در نظر گرفته شد. تجزیه های آماری نشان داد كه دزهای ریم سولفورون و زمان كاربرد آن تأثیر معنی داری بر زیست توده تاج خروس ریشه قرمز (L. Amaranthus retroflexus)، سلمه تره (Chenopodium album L.)، پیچك صحرایی (Convolvulus arvensis L.)، كل علف های هرز، تراكم كل علف های هرز و عملكرد كل غده داشت ولی اثرات متقابل آن معنی دار نشد. نتایج نشان داد كه كاربرد دز 50 گرم ماده مؤثره در هكتار توانست زیست توده و تراكم كل علف های هرز را به ترتیب 63/94 و 38/55 درصد و زیست توده تاج خروس ریشه قرمز، سلمه تره و پیچك صحرایی را به ترتیب 50/95، 87/96 و 79/94 درصد نسبت به شاهد با علف هرز كاهش دهد. در بین زمان های كاربرد ریم سولفورون در مراحل مختلف رشدی سیب زمینی، مرحله سبز شدن سیب زمینی، زیست توده و تراكم كل علف های هرز را به ترتیب 39/79 و 52/42 درصد و زیست توده تاج خروس ریشه قرمز و سلمه تره را به ترتیب 93/72 و 92/82 درصد كاهش داد ولی زمان كاربرد ریم سولفورون تأثیر معنی داری برای زیست توده پیچك صحرایی نداشت. كاربرد ریم سولفورون به میزان 50 گرم ماده مؤثره در هكتار در مرحله سبز شدن سیب زمینی، بالاترین عملكرد غده در هكتار را ایجاد كرد.

Introduction Potato is globally the fourth important food crop after rice, wheat, and maize and is cultivated in several countries worldwide like Iran. Weeds are the most important restriction factor for crop development in agricultural systems and the absence of weed control lead to crop yield reduction between 10 to 100 percent and this reduction could be a serious threat for a growing world population to be considered. Rimsulfuron is a sulfonylurea herbicide for control of weeds in potato, corn, wheat, barley and canola. It can be used as pre or post emergence in potato. These herbicide act through inhibition of enzyme acetolactate synthase (ALS), which catalyzes key reactions in the biosynthesis of basic branched-chain amino acids that are essential components of the growth process in plant cell division such as valine, leucine, and isoleucine Materials and methods In order to study rimsulfuron (Titus 25% DF) effect on weed biomass as a postemergence herbicide, a field experiment was carried out in the farm located 3 km out the city of Ardabil during 2014. The factorial experiment was performed based on randomized complete block design with three replications. Potato cultivar was Agria (common cultivar in Ardabil). The first factor was rimsulfuron doses with six levels (5, 10, 20, 30, 40 and 50 gr a.i. / ha), and the second factor was time of application based on different potato growth stages, (Potato emergence, stoloning and tuber bulking). Also two treatment (with and without weeding) were considered as control. Tubers were hand sown on 22th May in rows 75 cm apart and 20 cm in the rows at 10 cm depth. Rimsulfuron was applied by backpack sprayer fitted with 8001 flat fan nozzles. Three weeks after treatment, weed sampling was carried out by a quadrate sized 0.375 m2. Tubers were harvested from two center rows to determine total tuber yield per hectare. Two models fitted to the data were three parameter logistic and three parameter sigmoid. Data were analyzed using SAS 9.1 and MSTAT-C. Analysis of variance was used to test the significance of variance sources, and Duncan’s Multiple range test (P ≤ 0.05) was used to compare the differences among treatments. Results and Discussion Results showed that the maximum reduction percent of redroot pigweed (Amaranthus retroflexus L.), field bind weed (Convolvulus arvensis L.), lambsquarter (Chenopodium album L.), total weed biomass and density achieved by 40 and 50 gr a.i. / ha application. So that 40 and 50 gr a.i. /ha of rimsulfuron compared to control reduced weed density up to 49.47and 55.38 % and biomass up to 89.97 and 94.63 %, respectively. Also results showed that 40 and 50 gr a.i. /ha of rimsulfuron compared to control reduced biomass of redroot pigweed 89.91 and 95.50 %, Field bind weed 84.28 and 94.79 % and lambsquarter 92.75 and 96.87 percent respectively. That there was not statistically significant difference between 40 and 50 gr a.i. /ha of rimsulfuron. Among rimsulfuron application times, potato emergence stage reduced total weed density and biomass 36.45 and 68.04 %, respectively which is compared to control (weedy). Rimsulfuron application at potato emergence stage reduced biomass of redroot pigweed and lambsquarter 62.51 and 71.08 percent respectively. However it had no significant effect on biomass of Field bind weed. The results showed that potato tuber yield was 46.31 and 45.96 ton/ ha while rimsulfuron applied 40 and 50 gr a.i. / ha. Among rimsulfuron application times, potato emergence stage had total tuber yield 47.58 ton/ha. Conclusion Results showed that the maximum reduction percentage in weed density and biomass was observed for treatments in which were used 40 and 50 gr a.i. / ha application. Application of rimsulfuron at potato emergence reduced weed density and biomass and increased total tuber yield. Itproves the effectiveness of the rimsulfuron for potato emergence without damage. Furthermore the effective dose of rimsulfuron for 50 percent reduction in biomass of redroot pigweed, field bind weed and lambsquarter were 14.36, 12.26 and 10.17 g a.i. /ha, respectively. The results also showed that rimsulfuron application 40 and 50 gr a.i. /ha increased total tuber yield by 19.90 and 20.51% respectively. Application of 40 and 50 gr a.i. / ha at potato emergence stage produced maximum total tuber yield per hectare. The result of this study showed that 40 and 50 gr a.i. /ha rimsulfuron application at potato emergence assessed as the best treatment to control weed and increase total yield.