Enhancing Yield and Quality of Sugar Beet through Combining of N and P Fertilizers with Application of Biofertilizer

A field experiment was carried out at Mallawi Agriculture Research Station, Minia Governorate, Egypt, during the two successive seasons (2018/2019 and 2019/2020). The experiments were allocated in a spilt plot design with three replicates. The main plots assigned to four biofertilization treatments i.e. control, Azospirllium ssp, Pseudomonas ssp and mixture of Azospirllium ssp and Pseudomonas ssp). The sub plots were devoted for three levels of nitrogen and phosphorus fertilizers (50, 75, and 100% of RD "(90 kg N) and 31 kg P2O5 (15.5%)". Sugar beet plant growth, microbial densities in the rhizosphere, root yield, Physical and chemical properties of sugar beet roots and recoverable sugar yield (tonfed) were studied. Generally application of the above mentioned fertilizers individually or interaction resulted in a significant effect on all the studied traits in both seasons as compared with the control. On one hand the biofertilizer consisted of a mixture of Azospirllium ssp and Pseudomonas ssp recorded the highest values of microbial densities in the rhizosphere, plant growth parameters root yield, recoverable sugar yield (ton/fed), physical and chemical properties of roots and obtained sugar compare with other treatments?. On the other hand, treatment of 100% of nitrogen and phosphorus fertilizers gave the highest values of all the studied characters. The interactions between biofertilizers, nitrogen and phosphorus fertilizers significantly affected the studied traits in both seasons. Under the conditions of present work, the results suggest that sugar beet inoculated with a mixture of Azospirllium ssp, Pseudomonas ssp combined with 75 % RD of nitrogen and phosphorus fertilizers (204.5 &150 kg/fed) is highly recommended to obtain the highest yield of sugar beet.