Plant growth promoting rhizobacteria enhance the ratoon productivity of sugarcane

Less than half of the applied chemical fertiliser in intensive cropping systems is utilised by the target crops, with the remaining nutrients contributing to environmental pollution. Reducing the pollution derived from inefficient use of chemical fertilisers has enormous importance for agriculture. Recently, studies have shown that plant growth promoting rhizobacteria (PGPR) Paraburkholderia sp. SOS3 along with a combination of organic and chemical fertilisers, can offer a viable avenue to enhance sugarcane growth while reducing the concentration of chemical fertilisers. Here, we further investigated the effects of adding PGPR with combined organic and chemical fertilisers on sugarcane ratoon productivity (i.e. the second-year ratoon crop). The ratoon crop regenerated from sugarcane fertilised with the chemical-organic fertilisation in the first year, with or without PGPR (4 replicates), was grown in industry-standard practice in the second year. The results show that PGPR inoculation during the initial planting strongly promotes the growth of the ratoon sugarcane in the second year without reapplication of the PGPR. These findings show the high potential of using PGPR along with a combination of organic and chemical fertilisers for improving ratoon crop productivity in sugarcane.