Plant density and mixture ratio effects on the competition between common vetch and wheat

Abstract

Mixtures of annual forage legumes with winter small grains for forage are practiced traditionally in the Mediterranean countries. The aim of the present study was to investigate the effects of variable seed mixture rates and different plant densities on the forage yield. The study also investigated the competition effects among mixture partners in the mixture of common vetch (Vicia sativa L.) and wheat (Triticum aestivium L.). Field trials were conducted at two locations (L1, Hatay and L2, Adana) during the 2008-09 and 2009-10 growing seasons. Three plant densities (200, 400, 600 plants m-2) and five seed mixture ratios (100 % V, 75% V + 25% W, 50% V + 50% W, 25% V + 75% W, 100 % W) of common vetch (V) and wheat (W) were used. The results of the study showed that increased plant density in the mixture resulted in increased dry matter yield per unit area. In addition, increased seed ratio of wheat in the mixture caused increased dry matter yield per unit area. Also, elevated dry matter yield resulted in increased crude protein yield. Land equivalent ratio (LER), aggressivity (A) and competitive ratio (CR) indexes showed that common vetch was the dominant species in all common vetch-wheat mixtures.