Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 192 This study evaluates the impact of Biological Nitrogen Fixation (BNF) on reducing fertilizer use in sugarcane cultivation; assesses current practices and challenges related to nitrogen use in sugarcane cultivation, with a particular focus on understanding the limitations and inefficiencies in existing approaches. Additionally, this study examines the role of BNF in enhancing soil nitrogen levels, thereby reducing the dependency on synthetic fertilizers; involves evaluating the environmental benefits of integrating BNF into sugarcane cultivation, particularly concerning the reduction of greenhouse gas emissions. Based on these findings, this study provides recommendations for best management practices that promote sustainable sugarcane production through the utilization of BNF. 2 Biological Nitrogen Fixation in Sugarcane 2.1 Mechanisms of nitrogen fixation Biological nitrogen fixation (BNF) is a microbial-mediated process where atmospheric nitrogen (N₂) is converted into ammonium (NH₄⁺), which plants can readily absorb. This conversion is facilitated by the enzyme nitrogenase, which is present in diazotrophic bacteria. These bacteria can either live freely in the soil or form symbiotic relationships with plant roots, often resulting in the formation of specialized structures called nodules (Soumare et al., 2020; Aasfar et al., 2021). In sugarcane, diazotrophic bacteria have been found to colonize plant tissues without causing any visible anatomical changes or disease symptoms, promoting root growth and increasing plant yield (Carvalho et al., 2022). 2.2 Key microbial players in BNF Several diazotrophic bacteria are known to play crucial roles in BNF within sugarcane. Notable among these are species of Azotobacter, which are free-living nitrogen fixers and have been highlighted for their potential as biofertilizers due to their ability to enhance plant nutrition and soil fertility (Figure 1) (Aasfar et al., 2021). Additionally, endophytic diazotrophic bacteria, which live inside plant tissues, have shown significant potential in improving sugarcane yield and nitrogen content (Antunes et al., 2019; Pereira et al., 2020). Inoculation with a mixture of diazotrophic bacteria strains has been demonstrated to increase nitrogen accumulation and plant growth in sugarcane (Martins et al., 2020). Figure 1 Mechanism of non-symbiotic fixation of atmospheric nitrogen byAzotobacter sp. (Adopted from Aasfar et al., 2021)
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