The Interaction Effect between Inoculation with local Azotobacter Isolates and Ristrat application on the Numbers of bacteria in soil and growth of Barley


The study was conducted to isolate Azotobacter chroococcum from ten rhizospher soil from different crops from Dhi Qar and was it province, five samples were collected from soil which were treated previously with pesticides and other five samples were collected from soil not treated with pesticides in order to use these Azotobacter isolates as biofertilizer and study it is effect on the growth of barley. The results showed that the plant hight and shoot & Root dry weight were increused due to inoculation with Azotobacter and the highest value were re corded with isolates B3 and B4 in compare with B9 and B10 isolates which gave the lowest value. The increasf of Ristart concentration from zero to 1500,3000 and 6000 cm3.ha-1 were caused significently elecreasing in shoot dry weight to (61.65,54.88 and 36.84)% respectively while the root dry weight were decreased to (52.00,41.33 and 26.66)% for three above concentrations. The Ristart pesticide caued significantly decrease the Azotobacter numbers after 60 days of planting and the height olensity were re corded with the isolates B3 and B4 isolates compare with B19 &B10 isolates which gave the lowest numbers.