Response of endophytic bacteria in sugarcane roots to different slow-release fertilizers with dicyandiamide (DCD) and humic acid (HA) applications

Abstract

The overuse of chemical fertilizers has severe consequences on environmental ecosystems. However, slow-release fertilizers (SRFs) can reduce the total amount and number of fertilizer applications and improve efficiency. Field experiments were conducted in early March 2016 to investigate the proper usage of SRFs such as dicyandiamide (DCD) and humic acid (HA). Seven treatments were set up as follows: SRF with 120 g t−1 DCD (A); SRF with 150 g t−1 DCD (B); SRF with 235 g t−1 DCD (C); SRF with 3 kg t−1 HA (D); SRF with 8 kg t−1 HA (E); SRF with 18 kg t−1 HA (F); and traditional fertilization (CK). The abundance of endophytic bacteria in sugarcane roots under the B treatment was significantly higher than that under traditional fertilization. At the genus level, Massilia, Granulicella, and Herbaspirillum were unique and dominant in the sugarcane roots under the CK treatment. Compared with CK, Streptomyces was the unique dominant endophytic bacteria in sugarcane roots under different SRFs applications. These results suggest that cane health and tolerance to environmental stresses were not significantly altered after applying SRFs in sugarcane fields.