Effect of organic and biofertilizers on growth, yield and yield components of soybean grown under water deficit stress

In order to study the effects of organic (cattle manure) and biofertilizer (mycorrhiza) on growth, yield and yield components of soybean grown under conditions of water stress, an experiment was conducted at research field of Islamic Azad University, Varamin. Branch during 2011 growing season. The experimental design was laid out in a randomized complete block with a split factorial arrangement of treatments in three replications. Main factor was water stress (normal irrigation and irrigation withholding after 50% flowering) and sub-factors included cattle manure (0, 15 and 30 t/ha) and mycorrhiza application (with and without). The results showed that water stress significantly decreased plant growth and production. Conversely, cattle manure and mycorrhiza application led to increase in growth and improved yield and yield components. Mycorrhiza application dramatically increased pod number in main branches. The highest pod number in sub-branches was obtained from those plots which were treated with 30 t/ha cattle manure and mycorrhiza grown under normal irrigation conditions. These results indicated that mycorrhiza and cattle manure application (30 t/ha) increased seed yield when plants were irrigated completely. It is interesting to remark that mycorrhiza application was more effective under stress conditions than normal irrigation condition. Biological yield increased on account of cattle manure and mycorrhiza application. In addition, the highest oil yield was achieved when soybean plants were treated with 30 t/ha cattle manure and mycorrhiza under normal irrigation conditions. In sum cattle manure and mycorrhiza application could improve soybean growth and seed production even under drought stress conditions.