تأثیر کدوی تخمه‌کاغذی در کنترل علف‌های هرز در مخلوط سه‌گانه ذرت (Zea mays L.)، لوبیای چیتی (Phaseolus vulgaris L.) و کدوی تخمه کاغذی(Cucurbita pepo L.)

In order to study the effects of intercropping systems on weeds suppression, a field experiment was carried out with using randomized complete block design with three replications at Roudsar (Guilan province) in 2013. Treatments consisted of: The first factor: naked pumpkin sole crops (60 and 90 cm on row), maize – naked pumpkin double crops (30-60 cm and 40-90 cm on row) and maize-pinto bean-naked pumpkin triple crops (30-20-60 cm and 60-30-90 cm on row) and the second factor: hand-weeding (H.W) and no-weeding (N.W). The distance between of rows was 60 cm in all treatment. There were six weeds species in experimental field and dominant weeds were Amaranthus retroflexus L. and Digitaria sanguinalis L.. The results showed that cropping systems and competitive treatments (H.W and N.W) had influenced on pumpkin grain yield and percent weed control. Weed control in H.W (21.53%) was better than N.W (16.03%) in all cropping systems (sole, double and triple cropping). The highest pumpkin yield was observed in sole crops and H.W that had significant differences with N.W treatment. The double and triple cropping pumpkin yield was lower than sole cropping. But H.W treatments in comparison with N.W treatments, reduction in yield of intercropping systems was lower than sole cropping. This showed that sustainability performance and positive role intercropping systems in weeds control in N.W treatments.