Effect of mixed cropping of alfalfa and sanfoin on forage yield and alfalfa weevil (Hypera postica L.) control

Alfalfa and sainfon mixed cropping has a prolonged history in Zanjan province of Iran. In order to evaluate the effect of this approach on forage yield and alfalfa weevil (Hypera postica) population, this research was carried out as split plot based on a randomized complete block design with four replications at Kheir-Abad Research Station of Zanjan Agricultural Research Center in 2003-2005. Spraying and non spraying were considered as levels of the main factor and five ratios of mixed crops (25%, 50%, 75%, and individual crop) were allocated to sub-plots. Combined analysis of variance were made for wet and dry yield and number of weevil larvae population. Results showed that mixed cropping at a ratio of 50% of each crop was the best ratio for mixed cropping, because of its high yield (30.62 t/ha) from sprayed plots, and non-significant yield decrease in unsprayed plots (29.42 t/ha).