Evaluating the growth parameters of soybean in response to plant growth promoting fungi under Mazandaran climate conditions

In low-input cropping systems، the natural roles of microorganisms in maintaining soil fertility may be more important than conventional system. In order to investigate the effects of plant growth promoting fungi on improvement of growth and development in soybean (cv: JK) an experiment was conducted at the research farm of Sari Agricultural Sciences and Natural Resources University during the 2011-2012 growing seasons. Treatments were arranged in a factorial experiment based a completely randomized block design with three replications. The first factor was six levels of fungi: inoculation T. harzianum and AMF genus Glumus: G. mosseae، G. intraradices، and co-inoculation of T. harzianum + G. mosseae، T. harzianum + G. intraradices and non-inoculation (control). The second factor was three levels of phosphorus (0، 70 and 140 kg. ha-1) from superphosphate trip. Results showed that inoculation of T. harzianum and G. mosseae significantly had maximum chlorophyll content up to 17% and 16% at reduced phosphorus dosage (70 kg. ha-1) and conventional phosphorus dosage as compared to the control respectively. The greatest effect was recorded at reduced phosphorus dosage (70 kg. ha-1) and conventional phosphorus dosage significant increase in terms of chlorophyll content. In addition، the dry weights and chlorophyll content of soybean plants in reduced phosphorous dosage (70 kg. ha-1) and co-inoculated with T. harzianum + G. mosseae as well as conventional phosphorous dosage were significantly higher than the non-inoculated plants. In this experiment، at reduce phosphate fertilizer (P0%: 0) treatment، not affected of plant growth promoting fungi compared to control. But، reduced phosphorous dosage (70 kg. ha-1) was more affected.