Field Crop 2024, Vol.7, No.3, 171-181 http://cropscipublisher.com/index.php/fc 176 5.3 Economic benefits The economic benefits of using diazotrophic bacteria in sugarcane cultivation are multifaceted. The increase in yield directly translates to higher revenue for farmers. For example, the yield increases observed in various studies suggest a substantial boost in productivity, which can significantly enhance profitability (Renan et al., 2016; Schultz et al., 2017). The improved quality of sugarcane juice can lead to better market prices for both sugar and bioethanol. The use of diazotrophic bacteria can reduce the dependency on chemical fertilizers, thereby lowering input costs and promoting sustainable agricultural practices (Kruasuwan and Thamchaipenet, 2016; Matoso et al., 2021). This reduction in chemical usage not only cuts costs but also benefits the environment, aligning with the goals of sustainable agriculture. 6 Agronomic Practices Influencing Diazotrophic Activity 6.1 Soil management and fertility Soil management and fertility play a crucial role in the effectiveness of diazotrophic bacteria in promoting sugarcane growth. Studies have shown that the interaction between sugarcane varieties and diazotrophic bacteria is highly influenced by soil type and fertility levels. For instance, sugarcane grown in Alfisol (low fertility soil) showed significant increases in stem yield and biological nitrogen fixation (BNF) when inoculated with diazotrophic bacteria, compared to Oxisol (medium fertility) and Ultisol (high fertility) soils (Oliveira et al., 2006). Additionally, the use of biofertilizers produced from rocks and organic matter enriched with diazotrophic bacteria has been found to improve nutrient absorption and plant growth, leading to increased sugarcane yield (Oliveira et al., 2015). 6.2 Irrigation practices Irrigation practices can significantly impact the activity and effectiveness of diazotrophic bacteria in sugarcane cultivation. Proper irrigation ensures that the soil remains conducive for bacterial activity, promoting better colonization and interaction with the plant roots. Although specific studies on irrigation practices were not detailed in the provided content, it is generally understood that maintaining optimal soil moisture levels is essential for the survival and activity of diazotrophic bacteria. 6.3 Crop rotation and intercropping Crop rotation and intercropping can influence the microbial diversity and activity in the soil, including diazotrophic bacteria. While it did not specifically address crop rotation and intercropping, it is known that these practices can enhance soil health and microbial diversity, potentially benefiting diazotrophic bacteria. For example, the diversity of culturable plant growth-promoting bacterial endophytes, including diazotrophs, was found to be beneficial for sugarcane growth when co-inoculated with actinomycetes (Kruasuwan and Thamchaipenet, 2016). 6.4 Use of biofertilizers The use of biofertilizers containing diazotrophic bacteria has been extensively studied and shown to promote sugarcane growth and yield. Inoculation with diazotrophic bacteria such as GluconAcetobacter diazotrophicus, Herbaspirillum seropedicae, and Azospirillum amazonense has been demonstrated to enhance biomass accumulation, nutrient uptake, and crop growth rates (Schultz et al., 2014; Renan et al., 2016). Additionally, biofertilizers produced from rocks and organic matter enriched with diazotrophic bacteria have been found to be effective in increasing sugarcane productivity and improving plant characteristics (Oliveira et al., 2015). In summary, agronomic practices such as soil management and fertility, irrigation, crop rotation, and the use of biofertilizers significantly influence the activity and effectiveness of diazotrophic bacteria in promoting sugarcane growth and yield. These practices help create a favorable environment for bacterial colonization and interaction with the plant, leading to enhanced growth and productivity. 7 Advances in Research and Technology 7.1 Genetic engineering of diazotrophic bacteria Genetic engineering of diazotrophic bacteria has emerged as a promising approach to enhance their plant growth-promoting capabilities. By manipulating the genetic makeup of these bacteria, researchers aim to improve
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