Effect of chemical and biological fertilizers on phytohormone changes and absorption of nutrients in different irrigation periods in sorghum

In order to evaluation combined application of biological and chemical fertilizers with different irrigation periods on qualitative characteristics of sorghum (cv. Speed feed) an experiment was conducted as split plot based on randomized complete block design with three replications and 15 treatments at agriculture research station of Naghade. The main plot was irrigation round (with an interval of 7, 14 and 21 days) and the subplot was 5 levels of fertilizer included 100% of biological fertilizer, 100% chemical fertilizer, 100% biological fertilizer+75% chemical fertilizer, 100% biological fertilizer+50% chemical fertilizer, 100% biological fertilizer+25% chemical fertilizer. The results showed that the highest yield was observed in integrated chemical and bio-fertilizer. The results of analysis of variance exhibited that effect of treatments on macro and micro nutrient uptake and Phytohormones amounts was significant in 1% level. Among the elements, the highest amount of nitrogen was observed in normal irrigation and biological fertilizer + 75% chemical fertilizer. The highest amount of Indole-3-acetic acid hormone was observed in normal level irrigation treatments for all fertilizer levels except 100% chemical fertilizer treatment and the lowest levels of this hormone were recorded in severe stress treatments for all fertilizer levels. Given that, Indole acetic acid hormone plays a key role in the cell division of plants. Therefore, it is expected that all physiological and morphological characteristics change with the changes in the hormone. In terms of gibberellin hormone, superiority was observed in fertilizer and irrigation treatments. During the first irrigation interval, the highest amount of gibberellin was associated with 100% biological fertilizer treatment + 25% chemical fertilizer and the lowest amount was for the treatment of 100% chemical fertilizer. In the following, 100% biofertilizer treatment,100% biofertilizer + 75% chemical treatment and 100% biological fertilizer + 50% chemical was ranked in one group. The highest amount of Abscisic acid hormones was related to 100% fertilizer application and the lowest amount of this hormone was related to normal irrigation conditions in all treatments. The inoculation of seed with growth stimulating bacteria (Azotobacter, Phosphate barvar 2 and Bio-super) had a positive effect on the absorption of nutrients and hormones. As the final result, it can be stated that Due to the dry climate of Iran and positive effects of growth stimulating bacteria and the importance of sorghum forage production, the integrated chemical and bio-fertilizer can be used as an alternative method to reducing the use of chemical fertilizers and reduce environmental pollution caused by them.