Response of Sugarcane Varieties to Nitrogen and Phosphorus as Inoculated by Gluconacetobacter diazotrophicus and PSB

Aims: To study the growth, yield and quality in two sugarcane varieties inoculated with Gluconacetobacter diazotrophicus and phosphate solubilizing bacteria in normal, sodic and saline-sodic soils.
Study Design: 6 x 2 x 2 factorial completely randomized design (FCRD).
Place and Duration of Study: Central Sugarcane Research Station, Padegaon - 415 521, Tal.- Phaltan, Dist.- Satara, Maharashtra State, India between 2012 and 2013.
Methodology: A pot experiment was conducted in different problematic soils. Two sugarcane varieties viz., Co 86032 and Phule 265 were used. Six soil samples (1 normal, 3 sodic and 2 saline-sodic soils) were selected for the study. The single eye bud sets were inoculated with G. diazotrophicus 10 kg + PSB 1.25 kg in 100 lit water/ha for 30 min before planting and the pots planted with such treated sets received 50% recommended N (125 kg/ha) and 75% recommended P2O5 (86.25 kg/ha). The corresponding control pots planted with the untreated bud sets received 100% recommended N (250 kg/ha) and P2O5 (115 kg/ha). The initial and final soil properties and the effect on growth, yield and quality of sugarcane were studied. The population of G. diazotrophicus in cane juice and that of PSB in rhizosphere soil was determined at 9 months and maturity.
Results: The results indicated that the treatment of sugarcane bud sets with G. diazotrophicus 10 kg + PSB 1.25 kg in 100 lit water/ha for 30 min. coupled with 50% recommended N and 75% recommended P significantly improved the growth, yield and quality. The overall performance of the varieties was best in the normal soil (S-6) followed by S-4 (Sodic) and S-1 (Sodic). The inoculation of sugarcane sets showed the best results in normal soil (S-6) closely followed by S-4 (Sodic) and S-1 (Sodic) indicating better performance of inoculation in these problematic soils. The higher population and activity of G. diazotrophicus and PSB was observed at 50% recommended N and 75% recommended P in both the varieties.
Conclusion: The pre-planting bud set treatment in sugarcane with G. diazotrophicus + PSB coupled with 50% recommended N and 75% recommended P significantly improved the growth, yield and quality of cane juice. Bud set treatment showed the best results in normal soil closely followed by sodic soils indicating better performance of inoculants in these problematic soils.