Increasing the Productivity of Intercropping Corn and Peanuts by Inoculation with Azotobacter Chroococcum

Intercropping and bio-fertilizer application play important roles in sustainable agro-ecosystems. A two-year field experiment was conducted at Astaneh-ye Ashrafiyeh, Northern Iran, to evaluate the effect of Azotobacter (Azotobacter chroococcum) inoculation on the growth and yield of a peanut/maize intercropping system. The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were Azotobacter application [control (non-inoculated) and inoculation (with Azotobacter chroococcum) and different maize (Zea mays L.)/peanut (Arachis hypogaea L.) intercropping pattern (100% peanut + 100% maize, 100% peanut + 50% maize, 50% peanut + 100% maize, 50% peanut + 50% maize, 67% peanut + 33% maize, and 33% peanut + 67% maize). Sole cropping of peanut and maize were also used. Results showed that averaged across years and intercropping patterns, grain yields of peanut and maize were significantly increased by 10% and 16%, respectively, in inoculated plots compared to non-inoculated ones. Azotobacter also had a positive significant effect on nitrogen concentration of grain, while it had no significant effect on oil concentration of peanut grain and significantly decreased the oil concentration of maize grain. Land equivalent ratio (LER) ranged from 1.05 to 1.70, indicating more efficient and productive use of environmental resources by intercrops. Results also showed that inoculated intercropped plots had 12-16% grater LER that non-inoculated ones. The highest LER was observed for inoculated plot with 100% peanut + 50% maize intercropping pattern (1.70), while the lowest one was recorded for non-inoculated plot with 50% peanut + 50% maize intercropping pattern (1.05). Based on the result of this experiment, intercropping pattern of 100% peanut + 50% maize along with Azotobacter application is recommended to obtain the highest productivity in maize/peanut intercropping system.