Assessment of Dry Forage and Crude Protein Yeilds, Competition and Advantage Indices in Mixed Cropping of Annual Forage Legume Crops with Barley in Rainfed Comditions of Zanjan Province in Iran

To evaluate advantages of mixed cropping of annual forage legume crops grass pea (Lathyrus sativus L.), field pea (Pisum avestum L.), hairy vetch (Vicia villosa L.) and Hungarian vetch (Vicia panonica L.) with barley (Hordeum vulgare L.) in two seeding ratios 3:1 and 1:1, a field experiment was conducted at Khodabandeh dryland agriculture research station in 2009-2011 growing seasons. The field experiment was arranged in randomized complete block design with 13 treatments and four replications. Combined analysis of variance revealed that effect of treatments were significant (P < 0.01) on dry matter yield (DMY), crude protein yield (CPY) and land equivalent ratio (LER). The highest DMY (6.46 t ha-1) and CPY (0.54 t ha-1) were obtained from the sole barley and mixed cropping ratio of 75% field pea + 25% barely. Higher relative crowding coefficient (KBarley = 2.96-4.85) index for barley compenent in mixed cropping treatments indicated that barley was dominant species. Among the mixed cropping treatments the mixture ratio of 75% field pea + 25% barely with CPY of 0.54 t ha-1, LER of 1.11, system productivity index of 2.92, relative crowding coefficient indexof 1.55 and monetary advantage index of +72.7 was determined as the most suitable mixed cropping ratio for rainfed conditions of Zanjan Province in Iran.