Effects of seeding rates on competition indices of barley and vetchintercropping systems in the Eastern Mediterranean

Forage mixtures are common agricultural practices for the energy and protein needs of animals. In this study, common vetch (Vicia sativa L.), Hungarian vetch (Vicia pannonica L.), and barley (Hordeum vulgare L.) mixtures in different seeding rates were investigated in terms of forage yield and quality. In order to evaluate the effect of vetch, cereal intercropping and the competition/economic indices of 8 different legume-barley mixtures, along with their pure stands, were assessed during the 2008-2009 and 2009-2010 growth seasons in the Eastern Mediterranean region of Turkey. The field experiment was arranged as a randomized complete block design with 3 replications for each year. Intercropping indices were calculated by means of land equivalent ratio (LER), aggressivity (A), crowding ratio (CR), and actual yield loss (AYL). Competition indices revealed that both the common vetch-barley and the Hungarian vetch-barley intercroppings at a seeding ratio of 80%:20%, respectively, were advantageous due to their high yield, land use efficiency, and economic value compared to other mixtures or pure stands. All samples were analyzed for quality parameters such as dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) content. While digestible dry matter (DDM) content did not differ among treatments, CP, NDF, ADF, TDN (total digestible nutrients), DDM, RFV (relative feed value), and NE1 (net energy for lactation) content significantly differed among the different vetches-barley mixtures (P < 0.01). The results emphasize that both vetch species combined with barley and using the seeding ratio of 80% vetch:20% barley should be profitable for farmers in terms of implementation and maximum yield per unit area under Eastern Mediterranean conditions.