این مطالعه با هدف ارزیابی امکان استفاده از گیاهان پوششی به عنوان یک روش جایگزین کنترل شیمیایی در مدیریتهای علفهای هرز آفتابگردان به اجرا درآمد. آزمایش بصورت فاکتوریل در قالب طرح بلوکهای کامل تصادفی با سه تکرار انجام شد. فاکتور اول، سه نوع گیاه پوششی شامل ماشک گلخوشهای، گندمسیاه و ارزن مرواریدی و فاکتور دوم تراکم گیاه پوششی شامل صفر، 33 درصد، 66 درصد و 100 درصد تراکم توصیه شده در تککشتی بود.متوسط تعداد بوته مستقر شده در تراکمهای 33، 66 و 100 درصد در گندم سیاه بهترتیب 36، 78 و 100 بوته در متر مربع، در ماشک گل خوشهای بهترتیب 50، 98 و 134 و در ارزن مرواریدی به ترتیب 19، 46 و 64 بوته در مترمربع بود. نتایج نشان داد که استفاده از گیاهان پوششی اثر معنیداری در کنترل علفهایهرز داشت. همچنین یک رابطه عکس بین تراکم گیاه پوششی و زیست توده علفهایهرز نیز مشاهده شد. زیست توده علفهایهرز در تراکم حداکثر گندمسیاه، ماشک گل خوشه ای و ارزن مرواریدی بهترتیب 91، 80 و 86 درصد نسبت به تیمار تداخل تمام فصل کاهش یافت. با این حال عملکرد آفتابگردان نیز با افزایش تراکم گیاهان پوششی از 33 به 100 درصد، کاهش یافت. در میان گیاهان مورد بررسی، گندمسیاه در تراکم 36 بوته در مترمربع بدون اثر منفی بر عملکرد دانه، کاهش معنیداری در زیست توده علفهای هرز ایجاد نمود. بنابراین استفاده از این گیاه به عنوان گیاه پوششی در تراکم 36 بوته از لحاظ صرفه اقتصادی و کاهش آسیبهای زیست محیطی نسبت به کنترل شیمیایی علفهایهرز در آفتابگردان قابل توصیه میباشد.
1Faculty Member of Zanjan University, respectively.
2Graduated M.Sc. Student of Zanjan University, respectively.
چکیده [English]
In order to evaluate alternative strategies for weed management in sunflower using cover crops, an experiment was carried out as a factorial based on a randomized completely block design with three replications. Factors were cover crop type at three levels (hairy vetch, pearl millet and buckwheat) and cover crop density at four levels (0, 33, 66 and 100% of recommended density for each crop in monoculture). Hand weeding was also considered as control. Results showed that all three cover crops had significant effect on the weeds and the weed biomass severely decreased due to suppression by cover crops. There was also a negative correlation between cover crop density and weed biomass. Planting buckwheat, hairy vetch and pearl millet resulted in up to 80, 86 and 91% decreases in weed biomass in comparison to no cover crop plots. However sunflower grain yield were reduce with increasing cover crop densities from 33 to 100% of recommended density of each cover crop in monoculture. Buckwheat at the density of 36 plant.m-2 significantly decreased the weed biomass and saved sunflower grain yield. In conclusion, planting buckwheat at the density of 36 plant.m-2 as a cover crop was recommended as a part of integrated weed management in sunflower farming because it was cost-effective and environment friendly than chemical weed control.
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