Molecular Soil Biology 2025, Vol.16, No.4, 162-174 http://bioscipublisher.com/index.php/msb 168 to a shift in the microbial community towards a dominance of beneficial diazotrophic bacteria, which further supports nitrogen cycling and plant growth (Ke et al., 2019). This approach offers a promising strategy for reducing dependency on chemical fertilizers and promoting sustainable agricultural practices. 5.3 Microbial inoculants and biofertilizers The application of biofertilizers, which contain living microorganisms, can significantly boost microbial activity and optimize nitrogen cycling in rice paddies. Biofertilizers such as those containing Azospirillum, Rhizobium, and Bacillus species have been shown to enhance plant growth by improving nitrogen availability and uptake. For instance, the co-inoculation of rice seedlings with Azospirillum brasilense and Pseudomonas fluorescens has been found to significantly enhance ammonification and nitrogenase activities in the rhizosphere, leading to improved nitrogen supply and rice grain yields (Junhua et al., 2021). Additionally, biofertilizers can increase microbial biomass and soil enzyme activities, which are critical for efficient nitrogen cycling and plant nutrition (Yu et al., 2018). Moreover, biofertilizers can help mitigate the negative environmental impacts associated with excessive chemical nitrogen fertilization. By promoting the growth of beneficial microorganisms that enhance nitrogen fixation and reduce nitrogen losses through denitrification, biofertilizers contribute to a more sustainable and eco-friendly agricultural system. For example, the combined application of biochar and nitrogen fertilizer has been shown to increase microbial biomass and nitrogen retention in the rhizosphere, thereby improving soil fertility and reducing nitrogen leaching (Yu et al., 2018). These findings underscore the potential of microbial inoculants and biofertilizers in enhancing NUE and supporting sustainable rice production. 6 Technological Innovations for Monitoring and Managing NUE 6.1 Precision agriculture tools Precision agriculture tools, such as remote sensing, drones, and soil sensors, have revolutionized the monitoring and management of nitrogen use efficiency (NUE) in rice cultivation (Figure 4). Remote sensing technologies, including unmanned aerial vehicles (UAVs), provide a non-destructive means to assess crop nitrogen status in real-time. UAV-based remote sensing can collect spectral reflectance imagery, which is crucial for precision nitrogen management. Machine learning methods, such as random forest algorithms, have been shown to significantly improve the estimation of rice nitrogen nutrition indices, thereby enhancing the accuracy of nitrogen management recommendations (Zha et al., 2020; Liang et al., 2021) (Figure 5). Figure 4 A drone (UAV) conducting remote sensing over a rice field to monitor crop nitrogen status in real time (Photo from Zhigang Fu)
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