Plant growth promotion effects of rhizopheric and endophytic bacteria on sugarcane cultivated on Acrisols of Tay Ninh province, Vietnam

Plant growth promotion of the best two strains: Serratia oryzae CT4b and Bacillus subtilis TPD3b together with chemical nitrogen and phosphorus fertilizers were continuously evaluated on sugarcane cultivated on Acrisols of Tay Ninh province, Vietnam in pots and field experiments. The experiments were arranged into a Split-Plot Design with four replications. The main plot factor was N-P fertilizer at five levels: without N-P, 25% N-P, 50% N-P, 75% N-P and 100% N-P for the pot experiment and at four levels: without N-P; 50% N-P; 75% N-P; and 100% N-P for the field experiment. The sub-plot factor was bacterial inoculation with 4 treatments: no bacteria; CT4bd; TPD3b; and mixture of both. Recommended amount of nitrogen and phosphorus fertilizers for sugarcane planted on Acrisols of Tay Ninh province were 200 kg N, 160 kg P₂O₅ in a hectare. The results showed that a combination of two bacteria had the highest plant growth stimulation potential. The mixture at rate of 75% N- P fertilizers produced sugarcane yield equal to that at level of 100% N-P fertilizer without bacteria in the pot experiment; increased sugar yield by 14.4%, equivalent to 1.02 ton / ha in the field trial and saved 25% of N-P fertilizer application. These two potential strains were proposed to be tested their ability to promote plant growth on many different sugarcane varieties in both plant-cane and ratoon crops in different material sugarcane areas of Tay Ninh province.