Effect of combined application of pgpr and different biochar doses on yield, nutrient uptake and drought tolerance of maize

This thesis was conducted to determine 4 PGPR from a large number of bacteria isolated from different ecosystems, to reveal the interaction of these 4 PGPRs with biochar and to determine the effects of 2 of the best interacting agents on drought stress. In the research, the experiments were carried out as a pot experiment under greenhouse conditions. The soils were taken from six different cities of Turkey; fast growing 24 bacteria were isolated, purified and stored in slant culture in the first phase of the study. In the experiment that carried out with those bacteria revealed that 10 out of 24 bacteria were provided the highest result on the one determined parameters at least. In the next step, 4 bacteria which were found to be better than the others in the first experiment were tested together with 0%, 1% and 2% biochar. In this experiment, all of the selected bacteria had a significant positive effect on all of the determined parameters. The effects of biochar doses on the determined parameters were different; biochar had a neutral or negative effect on plant growth parameters whereas it had positive effects on nutrient contents. Moreover, biochar and bacterial interaction were statistically significant (P<0.05). Based on the results of this experiment, two selected bacteria were examined at this time with 0%, 0.5% and 1.0% biochar doses and 100%, 75%, 50% and 25% irrigation levels. The results obtained from the last experiment showed that limited irrigation had significant negative effects on plant growth parameters; biochar and bacterial inoculations did not completely eliminate the decline in plant growth but partially alleviated. In general, it was concluded that different regions and different ecosystems for PGPR isolation site is a useful approach due to the increasing probability of finding PGPR. The biochar raw material and application dose were important in the direction and severity of the effect, and the positive effects of the selected PGPRs against the water constraint in the trial were limited.