Forage Production in Different Intercropping Patterns of Sorghum (Sorghum Bicolor L.) With Hairy Vetch (Vicia Villosa) in Nitrogen Fertilizer Levels

In order to evaluate the intercropping of forage sorghum (Sorghum bicolor) andhairy vetch (Vicia villosa) at different nitrogen fertilizer levels and planting patterns, a field experiment was conducted at the Agricultural Research Station, University of Tabriz in 2014. The experimental design was factorial based on randomized complete block design (RCBD) with three replications. The treatments were nitrogen fertilizer levels (0, 30 and 60 kg N.ha-1) and three planting patterns [(planting sorghum on the furrow bank and planting vetch in the both side of furrow bank (P1), planting sorghum in one side of furrow bank and planting vetch in other side (P2) and planting sorghum on the furrow bank and planting vetch on the furrow bank and both side of furrow bank (P3)]. Results indicated that nitrogen fertilizer application increased sorghum forage yield. The highest sorghum forage yield was achieved in first and second planting patterns by application of 60 kg.ha-1 nitrogen fertilizer. Also, the highest forage yield (371.7 kg. ha-1) of vetch produced in the third nitrogen fertilizer level (N60) and third planting pattern (P3). In all intercropping treatments, land equivalent ratios (LER) were well above 1 indicating yield advantages for intercropping. The greater LER of the intercrops was mainly due to a greater resource use and resource complementarities that when the species were grown alone. The highest LER (1.94) and RVT (1.14) were obtained in first planting pattern with no nitrogen application. Also the greatest LERs (1.92) were obtained under interaction of second planting pattern and third nitrogen fertilizer level (N60). In general, it can be stated that for the production of forage, the combination of first and second planting patterns with no nitrogen application is superior on other planting patterns.