FC_2024v7n4

Field Crop 2024, Vol.7 http://cropscipublisher.com/index.php/fc © 2024 CropSci Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved.

Field Crop 2024, Vol.7 http://cropscipublisher.com/index.php/fc © 2024 CropSci Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Publisher CropSci Publisher Editedby Editorial Team of Field Crop Email: edit@fc.cropscipublisher.com Website: http://cropscipublisher.com/index.php/fc Address: 11388 Stevenston Hwy, PO Box 96016, Richmond, V7A 5J5, British Columbia Canada FieldCrop is an International Journal, is an open access, peer reviewed journal published online by CropSci Publisher. This journal publishes research articles of field crops, as well as innovative research conducted in the field, farm or on the land related to edible agricultural food crops. The research must be based on cropping system, crop physiology, crop genetics and breeding. Topics include (but are not limited to) different aspects like crop management, agronomy, plant pathology, entomology, soil science, vegetable and horticultural science related phenomena. All the articles published in Field Crop are Open Access, and are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. CropSci Publisher uses CrossCheck service to identify academic plagiarism through the world’s leading plagiarism prevention tool, iParadigms, and to protect the original authors’ copyrights. CropSci Publisher is an international Open Access publisher specializing in crop science, and crops-related research registered at the publishing platform that is operated by Sophia Publishing Group (SPG), founded in British Columbia of Canada.

Field Crop (online), 2024, Vol.7, No.4 http://cropscipublisher.com/index.php/fc © 2024 CropSci Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Latest Content Sustainable Sugarcane Cultivation: The Impact of Biological Nitrogen Fixation on Reducing Fertilizer Use Kaiwen Liang Field Crop, 2024, Vol. 7, No. 4, 191-200 Comparative Analysis of Triticale and Wheat: Yield, Adaptability, and Nutritional Content Rugang Xu, Qiuxia Sun Field Crop, 2024, Vol. 7, No. 4, 201-211 Assessing the Impact of Various Cotton Diseases on Fiber Quality and Production Jiamin Wang, Jin Zhang Field Crop, 2024, Vol. 7, No. 4, 212-221 The Role of Mineral Fertilizers in Enhancing Maize Nutritional Value Wei Wang, Shanjun Zhu, Jinhua Cheng Field Crop, 2024, Vol. 7, No. 4, 222-231 Innovations in Water Management for Rice Cultivation: Benefits of Alternating Wetting and Drying Yumin Huang Field Crop, 2024, Vol. 7, No. 4, 232-242

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 191 Review Article Open Access Sustainable Sugarcane Cultivation: The Impact of Biological Nitrogen Fixation on Reducing Fertilizer Use Kaiwen Liang Agri-Products Application Center, Hainan Institute of Tropical Agricultural Resources, Sanya, 572000, Hainan, China Corresponding email: kaiwen.liang@hitar.org Field Crop, 2024, Vol.7, No.4 doi: 10.5376/fc.2024.07.0019 Received: 03 May, 2024 Accepted: 14 Jun., 2024 Published: 05 Jul., 2024 Copyright © 2024 Liang, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Liang K.W., 2024, Sustainable sugarcane cultivation: the impact of biological nitrogen fixation on reducing fertilizer use, Field Crop, 7(4): 191-200 (doi: 10.5376/fc.2024.07.0019) Abstract Sustainable sugarcane cultivation is critical for reducing environmental impacts and enhancing agricultural productivity. This study examines the role of biological nitrogen fixation (BNF) in reducing the reliance on synthetic nitrogen fertilizers in sugarcane farming; synthesizes findings from multiple studies to evaluate the effectiveness of BNF in improving nitrogen use efficiency (NUE), soil health, and crop yields. Key insights include the potential of legume cover crops to enhance soil nitrogen storage and microbial biomass, the genetic variability in BNF among sugarcane progenitors, and the influence of endophytic nitrogen-fixing bacteria on nitrogen metabolism in sugarcane. Additionally, this study highlights the environmental benefits of optimized water-fertilizer management and the synergistic effects of intercropping with legumes. The findings underscore the importance of integrating BNF strategies into sugarcane cultivation to achieve sustainable agricultural practices and reduce greenhouse gas emissions. Keywords Biological nitrogen fixation; Sugarcane; Nitrogen use efficiency; Sustainable agriculture; Soil health 1 Introduction Sugarcane is a critical agricultural commodity with a significant role in the global economy, providing raw material for sugar production and biofuels, among other products (Li, 2024). It accounts for 80% of global sugar production and is the second-largest bioenergy crop worldwide (Yang et al., 2020). Major producers like Brazil have seen their sugarcane production more than double in recent decades to meet the increasing global demand for bioenergy, which helps reduce crude oil dependency and mitigate climate change (Bordonal et al., 2018). However, the intensive cultivation practices, including high nitrogen (N) fertilizer inputs, have significant environmental impacts, such as increased nitrous oxide (N2O) emissions, which contribute to greenhouse gas effects (Bordonal et al., 2018; Yang et al., 2020). The rapid expansion of sugarcane cultivation has raised concerns about its sustainability, particularly regarding its environmental footprint. Therefore, optimizing the production performance and adaptability of sugarcane will not only enhance its economic value, but is also an important factor in the continued improvement of the global environment (Liang, 2024). Sustainable agriculture aims to balance the need for food and bioenergy production with the preservation of environmental quality and natural resources. In the context of sugarcane, this involves optimizing agricultural practices to reduce negative impacts such as soil degradation, water consumption, and greenhouse gas emissions (Bordonal et al., 2018). The adoption of best management practices, including the use of organic amendments and precision agriculture, is crucial for enhancing the sustainability of sugarcane production (Bordonal et al., 2018; Yang et al., 2020). Biological Nitrogen Fixation (BNF) is a natural process where atmospheric nitrogen (N2) is converted into a form usable by plants through the action of symbiotic bacteria. This process can significantly reduce the need for synthetic N fertilizers, which are a major source of N2O emissions when used in sugarcane cultivation (Medorio-García et al., 2020; Yang et al., 2020). The integration of legume cover crops, which facilitate BNF, has shown promise in increasing soil nitrogen storage and reducing the dependency on synthetic fertilizers, thereby enhancing the sustainability of sugarcane production (Tenelli et al., 2021).

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)

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 193 Aasfar et al. (2021) illustrates the non-symbiotic nitrogen fixation process carried out by free-living nitrogen-fixing bacteria, specifically Azotobacter species, in soil. The process begins with the conversion of atmospheric nitrogen (N₂) into ammonium (NH₄⁺) via the nitrogenase enzyme complex. The key components of this enzyme, including the Fe-protein (4Fe–4S cluster) and MoFe-protein (P-cluster and FeMo-co), are essential for electron transfer and ATP hydrolysis, which drive the reduction of nitrogen. The NH₄⁺ produced is subsequently taken up by plants and converted into nitrates (NO₃⁻) and amino acids, supporting plant growth. This mechanism underscores the critical role of non-symbiotic nitrogen fixation in enhancing soil nitrogen availability and reducing dependency on synthetic fertilizers. 2.3 Benefits of BNF in agriculture The benefits of BNF in agriculture are manifold. Primarily, BNF reduces the dependency on synthetic nitrogen fertilizers, which are associated with environmental issues such as nitrate pollution and greenhouse gas emissions (Mahmud et al., 2020; Soumare et al., 2020). In sugarcane, BNF has been shown to contribute significantly to the plant's nitrogen needs, with some studies reporting that over 60% of the nitrogen in sugarcane can be derived from BNF (Martins et al., 2020). This not only enhances the sustainability of sugarcane cultivation but also improves soil health by maintaining a natural nitrogen cycle (Mahmud et al., 2020). Furthermore, BNF-associated bacteria can promote plant growth through other mechanisms, such as phytohormone production and protection against phytopathogens (Aasfar et al., 2021). 2.4 Factors influencing BNF efficiency in sugarcane Several factors influence the efficiency of BNF in sugarcane. Nutrient availability, particularly nitrogen and phosphorus, plays a critical role. Excessive nitrogen fertilization can inhibit BNF, while phosphorus addition can have variable effects depending on the type of nitrogen fixation (symbiotic or free-living) (Santachiara et al., 2019; Zheng et al., 2019). Environmental conditions such as water stress, temperature, and flooding also significantly impact BNF efficiency. For instance, water stress and flooding have been shown to reduce BNF activity, especially during the vegetative stage of plant growth (Santachiara et al., 2019). Additionally, genetic factors, such as the specific sugarcane genotype, can influence BNF efficiency. Different sugarcane genotypes exhibit varying levels of BNF, which can be attributed to differences in nitrogen metabolism, hormone regulation, and microbial recognition pathways (Carvalho et al., 2022; Luo et al., 2023). In conclusion, optimizing BNF in sugarcane involves understanding the complex interactions between microbial players, plant genetics, and environmental factors. This optimization is crucial for enhancing the sustainability of sugarcane cultivation and reducing the reliance on synthetic fertilizers. 3 Impact on Reducing Fertilizer Use 3.1 Current fertilizer practices in sugarcane cultivation Sugarcane cultivation traditionally relies heavily on synthetic nitrogen (N) fertilizers to achieve high yields. However, the efficiency of nitrogen use in sugarcane is relatively low, leading to significant environmental concerns such as nitrate leaching and ammonia volatilization (Castro et al., 2019; Junior et al., 2023). Current practices often involve the application of high rates of N fertilizer, sometimes exceeding 150 kg N ha⁻¹, which can result in diminishing returns and increased production costs (Castro et al., 2019). Additionally, the timing of fertilizer application plays a crucial role in optimizing yields, with studies showing that earlier applications can significantly enhance both stalk and sugar yields (Castro et al., 2019). 3.2 Role of BNF in reducing chemical fertilizer dependency Biological nitrogen fixation (BNF) offers a promising alternative to reduce dependency on synthetic N fertilizers in sugarcane cultivation. BNF involves the conversion of atmospheric nitrogen into a form that plants can use, facilitated by nitrogen-fixing bacteria. Research has shown that endophytic diazotrophs, such as those found in various Saccharum species, can significantly contribute to the nitrogen needs of sugarcane (Figure 2) (Singh et al., 2022; Soumare et al., 2022). For instance, the use of legume cover crops has been demonstrated to increase soil nitrogen storage and microbial biomass carbon, thereby reducing the need for additional inorganic fertilizers (Tenelli et al., 2021). Moreover, certain sugarcane varieties and their wild progenitors exhibit high BNF capacity, which remains resilient even under varying nitrogen conditions (Luo et al., 2023).

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 194 Figure 2 Beta-diversity analysis. (A) Matrix heat map of UniFrac; Beta-diversity matrix heatmap visualizes the Beta-diversity data and graphically clusters the samples and samples with similar beta diversity are clustered together to reflect similarities between samples. (B) UniFrac multi-sample similarity tree assessment; the distance matrix derived from Unifrac analysis is used in a wide range of analysis methods. The non-weighted group averaging method unweighted pair group method with arithmetic mean (UPGMA) in hierarchical clustering is used to construct graphical visualization processing such as a phylogenetic tree, that can visually show the similarity and differences in microbial evolution in different environmental samples (Adopted from Singh et al., 2022) Singh et al. (2022) analyzes the beta-diversity of endophytic bacterial communities across different tissues (roots, stems, leaves) of various sugarcane species. The results, visualized through a heat map and hierarchical clustering dendrogram, reveal distinct microbial community structures associated with specific tissue types. Roots from different sugarcane species tend to cluster together, indicating similar microbial compositions, while leaves and stems form separate clusters. This suggests that endophytic bacterial communities are tissue-specific and may be influenced by the unique environmental conditions and physiological functions of each tissue. The clear separation between the microbial communities in roots compared to other tissues highlights the complexity and diversity of endophytic bacteria in sugarcane, with potential implications for crop health and productivity. 3.3 Economic and environmental benefits The integration of BNF into sugarcane cultivation can lead to substantial economic and environmental benefits. Economically, reducing the reliance on synthetic N fertilizers can lower production costs and increase profitability for farmers. For example, the use of cover crops has been shown to provide an annual N fertilizer replacement of 9 to 15 kg ha⁻¹, translating to significant cost savings (Tenelli et al., 2021). Environmentally, BNF can mitigate the adverse effects of excessive fertilizer use, such as greenhouse gas emissions and soil degradation. Studies have highlighted that optimizing BNF can reduce nitrous oxide emissions, a potent greenhouse gas, thereby contributing to climate change mitigation (Yang et al., 2020). Additionally, the use of organic amendments and biofertilizers can enhance soil health and biodiversity, promoting sustainable agricultural practices (Soumare et al., 2022; Junior et al., 2023).

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 195 3.4 Challenges and limitations Despite the potential benefits, there are several challenges and limitations associated with the widespread adoption of BNF in sugarcane cultivation. One major challenge is the variability in BNF efficiency among different sugarcane varieties and environmental conditions. Genetic and environmental factors can influence the effectiveness of nitrogen-fixing bacteria, necessitating further research to identify and develop high-BNF sugarcane varieties (Singh et al., 2022; Luo et al., 2023). Additionally, the establishment and maintenance of beneficial microbial communities in the rhizosphere can be complex and may require specific management practices (Guo et al., 2023). There are also practical considerations, such as the initial costs and labor associated with implementing cover crops or biofertilizers, which may deter some farmers from adopting these practices (Tenelli et al., 2021; Junior et al., 2023). Finally, there is a need for more comprehensive studies to fully understand the long-term impacts of BNF on soil health and crop productivity. In conclusion, while BNF presents a viable strategy to reduce chemical fertilizer dependency in sugarcane cultivation, addressing the associated challenges and limitations is crucial for its successful implementation. Continued research and development, along with farmer education and support, will be essential to harness the full potential of BNF for sustainable sugarcane production. 4 Case Study 4.1 Description of the study area The study area for this case study is located in a region known for its extensive sugarcane cultivation. The soil types in this area include both sandy and clayey soils, which are representative of the diverse agricultural conditions under which sugarcane is grown. The climate is tropical, with distinct wet and dry seasons, providing a suitable environment for sugarcane growth and the implementation of Biological Nitrogen Fixation (BNF) techniques. 4.2 Implementation of BNF techniques In this study, various BNF techniques were implemented to assess their impact on reducing the need for synthetic nitrogen fertilizers in sugarcane cultivation. One approach involved the use of legume cover crops, such as Crotalaria spectabilis, during the renovation period of sugarcane fields. This method aimed to enhance soil nitrogen content through the natural nitrogen-fixing abilities of the legume plants (Tenelli et al., 2021). Another technique included the inoculation of sugarcane with diazotrophic bacteria, which are known to fix atmospheric nitrogen and make it available to the plants. Different strains of these bacteria were tested to evaluate their effectiveness in promoting sugarcane growth and nitrogen uptake (Martins et al., 2020; Pereira et al., 2020). 4.3 Outcomes and observations The implementation of BNF techniques yielded several notable outcomes. The use of legume cover crops resulted in increased soil nitrogen storage and microbial biomass carbon, which contributed to higher sugarcane yields. Specifically, cover crops increased sugarcane yield by 9% in sandy soils and 15% in clayey soils compared to bare fallow fields (Tenelli et al., 2021). Inoculation with diazotrophic bacteria also showed promising results, with some treatments leading to a 15% increase in sugarcane yield and an 18% increase in nitrogen content in the shoots (Pereira et al., 2020). Additionally, the contribution of BNF to the total nitrogen uptake by sugarcane was significant, with some studies reporting that BNF accounted for up to 47% of the nitrogen supply in sugarcane (Monteiro et al., 2021). 4.4 Lessons learned and future directions The case study highlights the potential of BNF techniques to reduce the reliance on synthetic nitrogen fertilizers in sugarcane cultivation, thereby promoting more sustainable agricultural practices. Key lessons learned include the importance of selecting appropriate legume cover crops and diazotrophic bacterial strains to maximize nitrogen fixation and crop yield. Future research should focus on optimizing these techniques for different soil types and environmental conditions to enhance their effectiveness. Additionally, exploring the genetic diversity of sugarcane and its wild relatives, such as Saccharum spontaneum, may provide insights into developing high-BNF sugarcane varieties with improved nitrogen use efficiency (Carvalho et al., 2022; Luo et al., 2023). Further studies should

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 196 also investigate the long-term impacts of BNF techniques on soil health and greenhouse gas emissions to fully understand their environmental benefits (Santos et al., 2019; Soumare et al., 2022). 5 Comparative Analysis with Other Sustainable Practices 5.1 Comparison with organic fertilizers Biological nitrogen fixation (BNF) and organic fertilizers both aim to reduce the reliance on synthetic nitrogen (N) fertilizers, but they operate through different mechanisms. BNF involves the conversion of atmospheric nitrogen into a form usable by plants through symbiotic relationships with nitrogen-fixing bacteria, while organic fertilizers, such as chicken litter, provide nitrogen through the decomposition of organic matter. Studies have shown that the use of organic fertilizers like chicken litter can be as effective as mineral nitrogen (MN) fertilizers in promoting sugarcane growth and yield. For instance, the application of chicken litter increased sugarcane yield and improved plant growth metrics such as height and tiller number, comparable to the effects of ammonium nitrate (Junior et al., 2023). Additionally, organic fertilizers contribute to soil health by enhancing soil organic carbon (SOC) and microbial biomass, which are crucial for long-term soil fertility (Tenelli et al., 2021). 5.2 Comparison with integrated nutrient management Integrated Nutrient Management (INM) combines the use of organic and inorganic fertilizers to optimize nutrient availability and improve crop yields sustainably. INM practices often include the use of cover crops, crop rotations, and the strategic application of fertilizers to enhance nutrient use efficiency (NUE). Research indicates that INM can significantly improve sugarcane yields and reduce environmental impacts. For example, the use of legume cover crops in sugarcane fields has been shown to increase soil nitrogen storage and microbial biomass, leading to higher yields without the need for additional synthetic N fertilizers (Tenelli et al., 2021). Similarly, adjusting the timing and rate of N fertilizer application can enhance NUE and reduce nitrogen losses, as demonstrated by increased sugarcane yields when N was applied at optimal times (Castro et al., 2019). 5.3 Long-term sustainability and yield impacts The long-term sustainability of sugarcane cultivation practices is a critical consideration. BNF offers a sustainable alternative by reducing the need for synthetic N fertilizers, which are associated with greenhouse gas emissions and environmental pollution. Studies have shown that BNF can maintain or even increase sugarcane yields over multiple harvests, contributing to long-term soil fertility and sustainability (Figure 3) (Tenelli et al., 2021; Luo et al., 2023). Luo et al. (2023) illustrates the substantial genetic variation observed in Saccharum spontaneumaccessions for traits such as shoot length, stalk number, and brix percentage. The analysis reveals significant variability among the different genotypes, with some accessions demonstrating superior performance in one or more traits. For instance, accession G152 showed the highest BNF activity, while others like G103 performed poorly. Similarly, shoot length, stalk number, and brix content also exhibited considerable variation, although the range was less pronounced compared to BNF activity. The results underscore the genetic diversity within S. spontaneum and highlight the potential for selecting and breeding specific clones with desirable traits for improving sugarcane cultivation and productivity. This genetic variability is crucial for enhancing crop resilience and yield. In comparison, organic fertilizers also support long-term sustainability by improving soil health and reducing dependency on synthetic inputs. However, the effectiveness of organic fertilizers can vary based on the type and rate of application. For instance, the application of mill mud, an organic fertilizer, has been shown to reduce dissolved inorganic nitrogen (DIN) losses in runoff, thereby protecting aquatic ecosystems (Vilas et al., 2021). INM practices, which integrate both organic and inorganic fertilizers, offer a balanced approach to sustainable sugarcane cultivation. By optimizing nutrient inputs and enhancing soil health, INM can improve crop yields and reduce environmental impacts over the long term. For example, the strategic use of organic and inorganic fertilizers in combination with cover crops has been shown to enhance sugarcane yields and soil fertility (Tenelli et al., 2021; Vilas et al., 2021).

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 197 In conclusion, while BNF, organic fertilizers, and INM each have their unique advantages, integrating these practices can provide a comprehensive approach to sustainable sugarcane cultivation. By leveraging the strengths of each method, it is possible to achieve high yields, improve soil health, and reduce environmental impacts. Figure 3 Variation in shoot length, stalk number per stool and brix (%) of S. spontaneum accessions Values are mean of 6 independent measurements; shoot length l.s.d. 15.4, p < 0.001; shoot number l.s.d. 1.2, p < 0.001; brix l.s.d. 1.09, p < 0.001 (Adopted from Luo et al., 2023) 6 Policy and Management Implications 6.1 Encouraging BNF adoption in sugarcane cultivation The adoption of Biological Nitrogen Fixation (BNF) in sugarcane cultivation can significantly reduce the dependency on synthetic nitrogen fertilizers, thereby promoting sustainable agricultural practices. Research has shown that inoculating sugarcane with diazotrophic bacteria can enhance nitrogen acquisition and improve crop yields (Martins et al., 2020; Pereira et al., 2020). Additionally, the use of legume cover crops has been demonstrated to increase soil nitrogen storage and microbial biomass, which in turn boosts sugarcane yields without the need for additional synthetic fertilizers (Tenelli et al., 2021). To encourage the adoption of BNF, it is essential to educate farmers about the benefits of using nitrogen-fixing microorganisms and provide them with access to high-quality biofertilizers. 6.2 Government policies and subsidies Government policies and subsidies play a crucial role in promoting sustainable agricultural practices. To support the adoption of BNF in sugarcane cultivation, governments can offer financial incentives for farmers who use biofertilizers and adopt nitrogen-fixing cover crops. Subsidies for research and development of efficient nitrogen-fixing microorganisms can also accelerate the commercialization of these biofertilizers (Soumare et al., 2020). Additionally, policies that promote the use of environmentally friendly agricultural practices, such as reducing synthetic fertilizer use, can further encourage the adoption of BNF (Luo et al., 2023).

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 198 6.3 Training and extension services for farmers Training and extension services are vital for the successful implementation of BNF in sugarcane cultivation. Farmers need to be educated on the benefits of BNF, the proper use of biofertilizers, and the management practices required to optimize nitrogen fixation. Extension services can provide hands-on training, demonstrations, and technical support to farmers, helping them to adopt and integrate BNF into their farming systems (Santachiara et al., 2019). Collaborations between research institutions, agricultural extension agencies, and farmer organizations can facilitate the dissemination of knowledge and best practices related to BNF (Singh et al., 2022). 6.4 Future research directions Future research should focus on identifying and developing more efficient nitrogen-fixing microorganisms that can be used as biofertilizers in sugarcane cultivation. Studies should explore the genetic and molecular mechanisms underlying BNF to enhance the nitrogen-fixing capacity of these microorganisms (Monteiro et al., 2021; Luo et al., 2023). Additionally, research should investigate the long-term effects of BNF on soil health, crop yields, and environmental sustainability. Understanding the interactions between nitrogen-fixing microorganisms and sugarcane plants at the physiological and molecular levels can provide insights into optimizing BNF for improved crop performance (Pereira et al., 2020; Singh et al., 2022). Finally, research should also address the challenges and limitations of transferring nitrogen fixation capacity to non-leguminous plants, which can further expand the application of BNF in agriculture (Soumare et al., 2020). 7 Concluding Remarks The research on sustainable sugarcane cultivation has highlighted the significant potential of biological nitrogen fixation (BNF) in reducing the reliance on synthetic nitrogen (N) fertilizers. Several studies have demonstrated that integrating legume cover crops and intercropping with nitrogen-fixing plants can enhance soil nitrogen content and improve sugarcane yields. For instance, the use of legume cover crops like Crotalaria spectabilis has been shown to increase soil nitrogen storage and microbial biomass carbon, leading to a 9%-15% increase in sugarcane yield compared to bare fallow. Similarly, intercropping sugarcane with soybean under reduced nitrogen input has been found to enhance phosphorus acquisition and overall system P-use efficiency, contributing to sustainable sugarcane production. Moreover, optimizing nitrogen fertilization practices, such as the timing and amount of application, can significantly improve nitrogen use efficiency (NUE) and reduce environmental impacts. Studies have shown that applying nitrogen fertilizer at specific times (e.g., 45 days after harvest) can increase sugarcane yield and sugar content. Additionally, the genetic base-broadening of sugarcane using high-BNF Saccharum spontaneum accessions has shown promise in developing nitrogen-efficient varieties. The future of sustainable sugarcane cultivation lies in the continued exploration and integration of biological nitrogen fixation strategies. Research should focus on identifying and utilizing high-BNF sugarcane varieties and optimizing intercropping systems with legumes to maximize nitrogen fixation and improve soil health. Additionally, advancements in molecular and physiological understanding of BNF mechanisms in sugarcane and its wild relatives can pave the way for breeding programs aimed at enhancing nitrogen efficiency. Furthermore, sustainable water-fertilizer management practices, such as drip irrigation combined with optimal fertilization levels, should be promoted to reduce greenhouse gas emissions and maintain soil health. The development of eco-friendly nitrogen application strategies that minimize the use of chemical fertilizers while maintaining high yields is crucial for the long-term sustainability of sugarcane cultivation. In conclusion, the integration of biological nitrogen fixation into sugarcane cultivation presents a viable pathway to reduce the dependency on synthetic nitrogen fertilizers, thereby enhancing the sustainability of sugarcane production. The findings from various studies underscore the importance of adopting legume cover crops, intercropping systems, and optimized fertilization practices to improve nitrogen use efficiency and soil health. Future research should continue to explore innovative approaches to harness the potential of BNF and develop sustainable agricultural practices that can mitigate environmental impacts and ensure the long-term viability of sugarcane cultivation.

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 199 By leveraging the benefits of biological nitrogen fixation and sustainable management practices, the sugarcane industry can move towards a more environmentally friendly and economically viable future, contributing to global efforts in sustainable agriculture and climate change mitigation. Acknowledgments Author thanks to the reviewers for their constructive feedback, which has contributed to the improvement of this study. Conflict of Interest Disclosure Author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest. References Aasfar A., Bargaz A., Yaakoubi K., Hilali A., Bennis I., Zeroual Y., and Kadmiri I., 2021, Nitrogen fixing Azotobacter species as potential soil biological enhancers for crop nutrition and yield stability, Frontiers in Microbiology, 12: 628379. https://doi.org/10.3389/fmicb.2021.628379 PMid:33717018 PMCid:PMC7947814 Antunes J., Freitas A., Oliveira L., Lyra M., Fonseca M., Santos C., Oliveira J., Araújo A., and Figueiredo M., 2019, Sugarcane inoculated with endophytic diazotrophic bacteria: effects on yield, biological nitrogen fixation and industrial characteristics, Anais da Academia Brasileira de Ciencias, 91(4): e20180990. https://doi.org/10.1590/0001-3765201920180990 PMid:31778453 Bordonal R., Carvalho J., Lal R., Figueiredo E., Oliveira B., and Scala N., 2018, Sustainability of sugarcane production in Brazil. A review, Agronomy for Sustainable Development, 38: 1-23. https://doi.org/10.1007/s13593-018-0490-x Carvalho T., Rosman A., Grativol C., Nogueira E., Baldani J., and Hemerly A., 2022, Sugarcane genotypes with contrasting biological nitrogen fixation efficiencies differentially modulate nitrogen metabolism, auxin signaling, and microorganism perception pathways, Plants, 11(15): 1971. https://doi.org/10.3390/plants11151971 PMid:35956449 PMCid:PMC9370643 Castro S., Neto J., Kölln O., Borges B., and Franco H., 2019, Decision-making on the optimum timing for nitrogen fertilization on sugarcane ratoon, Scientia Agricola, 76: 237-242. https://doi.org/10.1590/1678-992x-2017-0365 Guo D., Li D., Yang B., Verma K., Singh R., Singh P., Khan Q., Sharma A., Qin Y., Zhang B., Song X., and Li Y., 2023, Effect of endophytic diazotroph Enterobacter roggenkampii ED5 on nitrogen-metabolism-related microecology in the sugarcane rhizosphere at different nitrogen levels, Frontiers in Microbiology, 14: 1132016. https://doi.org/10.3389/fmicb.2023.1132016 PMid:37649627 PMCid:PMC10464614 Junior A., Santos L., Reis M., Vitorino L., Bessa L., Teixeira M., and Soares F., 2023, Effect of mineral and organic nitrogen sources on vegetative development, nutrition, and yield of sugarcane, Agronomy, 13(6): 1627. https://doi.org/10.3390/agronomy13061627 Li A.M., 2024, Technological innovation in disease detection and management in sugarcane planting, Bioscience Method, 15(2): 58-65. https://doi.org/10.5376/bm.2024.15.0007 Liang K.W., 2024, Implementing genomic selection in sugarcane breeding programs: challenges and opportunities, Plant Gene and Trait, 15(1): 23-32. https://doi.org/10.5376/pgt.2024.15.0004 Luo T., Li C., Yan R., Huang K., Li Y., Liu X., and Lakshmanan P., 2023, Physiological and molecular insights into the resilience of biological nitrogen fixation to applied nitrogen in Saccharum spontaneum, wild progenitor of sugarcane, Frontiers in Plant Science, 13: 1099701. https://doi.org/10.3389/fpls.2022.1099701 PMid:36714748 PMCid:PMC9881415 Mahmud K., Makaju S., Ibrahim R., and Missaoui A., 2020, Current progress in nitrogen fixing plants and microbiome research, Plants, 9(1): 97. https://doi.org/10.3390/plants9010097 PMid:31940996 PMCid:PMC7020401 Martins D., Reis V., Schultz N., Alves B., Urquiaga S., Pereira W., Sousa J., and Boddey R., 2020, Both the contribution of soil nitrogen and of biological N2 fixation to sugarcane can increase with the inoculation of diazotrophic bacteria, Plant and Soil, 454: 155-169. https://doi.org/10.1007/s11104-020-04621-1 Medorio-García H., Alarcón E., Flores-Esteves N., Montaño N., and Perroni Y., 2020, Soil carbon, nitrogen and phosphorus dynamics in sugarcane plantations converted from tropical dry forest, Applied Soil Ecology, 154: 103600. https://doi.org/10.1016/j.apsoil.2020.103600 Monteiro E., Silva C., Martins M., Reis V., Boddey R., Alves B., and Urquiaga S., 2021, Strategy for the sampling of sugarcane plants for the reliable quantification of N2 fixation using 15N natural abundance, Journal of Soil Science and Plant Nutrition, 21(4): 2741-2752. https://doi.org/10.1007/s42729-021-00561-6

Field Crop 2024, Vol.7, No.4, 191-200 http://cropscipublisher.com/index.php/fc 200 Pereira W., Oliveira R., Pereira A., Sousa J., Schultz N., Urquiaga S., and Reis V., 2020, Nitrogen acquisition and 15N-fertiliser recovery efficiency of sugarcane cultivar RB92579 inoculated with five diazotrophs, Nutrient Cycling in Agroecosystems, 119(1): 37-50. https://doi.org/10.1007/s10705-020-10100-x Santachiara G., Salvagiotti F., and Rotundo J., 2019, Nutritional and environmental effects on biological nitrogen fixation in soybean: a meta-analysis, Field Crops Research, 240: 106-115. https://doi.org/10.1016/j.fcr.2019.05.006 Santos R., Freire F., Oliveira E., Trivelin P., Freire M., Bezerra P., Oliveira R., and Santos M., 2019, Changes in biological nitrogen fixation and natural-abundance N isotopes of sugarcane under molybdenum fertilization, Sugar Tech, 21: 925-935. https://doi.org/10.1007/s12355-019-00717-w Singh R., Singh P., Sharma A., Guo D., Upadhyay S., Song Q., Verma K., Li D., Malviya M., Song X., Yang L., and Li Y., 2022, Unraveling nitrogen fixing potential of endophytic diazotrophs of different Saccharumspecies for sustainable sugarcane growth, International Journal of Molecular Sciences, 23(11): 6242. https://doi.org/10.3390/ijms23116242 PMid:35682919 PMCid:PMC9181200 Soumare A., Diedhiou A., Thuita M., Hafidi M., Ouhdouch Y., Gopalakrishnan S., and Kouisni L., 2020, Exploiting biological nitrogen fixation: a route towards a sustainable agriculture, Plants, 9(8): 1011. https://doi.org/10.3390/plants9081011 PMid:32796519 PMCid:PMC7464700 Tenelli S., Otto R., Bordonal R., and Carvalho J., 2021, How do nitrogen fertilization and cover crop influence soil CN stocks and subsequent yields of sugarcane? Soil and Tillage Research, 211: 104999. https://doi.org/10.1016/j.still.2021.104999 Vilas M., Shaw M., Rohde K., Power B., Donaldson S., Foley J., and Silburn M., 2021, Ten years of monitoring dissolved inorganic nitrogen in runoff from sugarcane informs development of a modelling algorithm to prioritise organic and inorganic nutrient management, The Science of the Total Environment, 803: 150019. https://doi.org/10.1016/j.scitotenv.2021.150019 PMid:34500267 Yang L., Deng Y., Wang X., Zhang W., Shi X., Chen X., Lakshmanan P., and Zhang F., 2020, Global direct nitrous oxide emissions from the bioenergy crop sugarcane (Saccharumspp. inter-specific hybrids), The Science of the total environment, 752: 141795. https://doi.org/10.1016/j.scitotenv.2020.141795 PMid:32892043 Zheng M., Zhou Z., Luo Y., Zhao P., and Mo J., 2019, Global pattern and controls of biological nitrogen fixation under nutrient enrichment: a meta‐analysis, Global Change Biology, 25(9): 3018-3030. https://doi.org/10.1111/gcb.14705 PMid:31120621

Field Crop 2024, Vol.7, No.4, 201-211 http://cropscipublisher.com/index.php/fc 201 Research Report Open Access Comparative Analysis of Triticale and Wheat: Yield, Adaptability, and Nutritional Content Rugang Xu, Qiuxia Sun Modern Agricultural Research Center, Cuixi Academy of Biotechnology, Zhuji, 311800, China Corresponding author: qiuxia.sun@cuixi.org Field Crop, 2024, Vol.7, No.4 doi: 10.5376/fc.2024.07.0020 Received: 11 May, 2024 Accepted: 23 Jun., 2024 Published: 14 Jul., 2024 Copyright © 2024 Xu and Sun, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Xu R.G., and Sun Q.X., 2024, Comparative analysis of triticale and wheat: yield, adaptability, and nutritional content, Field Crop, 7(4): 201-211 (doi: 10.5376/fc.2024.07.0020) Abstract This study aims to provide a comprehensive comparison between triticale and wheat in terms of their yield performance, adaptability to various environmental conditions, and nutritional content. Triticale, a hybrid of wheat and rye, has shown promising results in several studies, often outperforming wheat in terms of biomass yield and forage quality, particularly in less favorable environments. This study highlights that triticale generally exhibits higher grain yield stability and better adaptability to water-limited and nitrogen-limited conditions compared to wheat. Additionally, triticale's nutritional profile, including crude protein content and total digestible nutrients, is comparable to that of wheat, making it a viable alternative for both grain and forage production. This study also discusses the potential of triticale in improving soil health and reducing nutrient leaching when used as a cover crop. Overall, this study underscores the potential benefits of incorporating triticale into agricultural systems, particularly in regions facing abiotic stressors such as drought and poor soil fertility. Keywords Triticale; Wheat, Yield stability; Nutritional content; Abiotic stress adaptability 1 Introduction Wheat (Triticumspp.) is one of the most significant cereal crops globally, playing a crucial role in human nutrition and food security. Its success is largely attributed to its versatile grain proteins, particularly gluten, which allows for the production of a wide variety of foods (Sousa et al., 2021). Wheat is cultivated in diverse climatic zones and has been a staple food for thousands of years, evolving from ancient varieties like einkorn, emmer, and spelt to the modern hexaploid and tetraploid varieties that dominate global production today (Sousa et al., 2021). On the other hand, triticale (×Triticosecale Wittmack) is a relatively recent man-made hybrid developed by crossing wheat and rye (Secale cereale L.). This hybridization aims to combine the favorable traits of both progenitor species, resulting in a crop that is more adaptable to less favorable environments and capable of producing higher biomass yield and forage quality (Ayalew et al., 2018). Comparative studies between triticale and wheat are essential for several reasons. Firstly, they provide insights into the adaptability of these crops to various environmental conditions, which is crucial for improving food security in the face of climate change (Wan et al., 2022; Filip et al., 2023). Secondly, understanding the differences in yield and nutritional content between triticale and wheat can guide breeding programs aimed at enhancing crop quality and resilience (Ayalew et al., 2018). Such studies also help in identifying the specific conditions under which each crop performs best, thereby optimizing agricultural practices and resource use (Wan et al., 2022). Moreover, triticale's potential as a cover crop to improve soil health and reduce nutrient leaching further underscores the need for comprehensive comparative analyses (Ayalew et al., 2018). This study conducts a comparative analysis of triticale and wheat in terms of yield, adaptability, and nutritional content. By synthesizing existing research, this study highlights the strengths and weaknesses of each crop, providing a holistic understanding that can inform future agricultural practices and breeding programs; examines how environmental factors affect the yield and quality of these crops, assess their nutritional profiles, and explores their potential uses in various agricultural systems. Through this comparative analysis, this study seeks to contribute to the development of more resilient and productive cereal crops, ultimately enhancing global food security.

Field Crop 2024, Vol.7, No.4, 201-211 http://cropscipublisher.com/index.php/fc 202 2 Agronomic Characteristics 2.1 Yield potential 2.1.1 Comparative yield performance Triticale generally exhibits a higher grain yield (GY) compared to bread wheat (Triticum aestivumL.), particularly in Mediterranean environments where water deficits are common during spring and summer. Studies have shown that triticale has a higher number of kernels per spike and greater 1000 kernel weight, despite having fewer spikes per square meter compared to wheat. This results in a higher overall yield for triticale (Méndez-Espinoza et al., 2019). Additionally, triticale's yield stability across various environments has been demonstrated to be superior to that of wheat, with triticale lines showing good adaptability and stable yields in diverse conditions (Farokhzadeh et al., 2022). Figure 1 Relationships between the environmental index and grain yield of spring wheat (cv. Pandora-INIA) and triticale (cv. Aguacero-INIA) (Adopted from Méndez-Espinoza et al., 2019) Image caption: Data are from 10 localities in 2004 and 2005 (eight Mediterranean and two temperate areas), and two localities (Cauquenes and Santa Rosa), under well-watered and water-deficit conditions, in 2014, 2015, and 2016. Also, data comparing triticale cv. Aguacero-INIA and the spring wheat cv. Domo at nine localities in 2001 and 2002 were included in the analysis. The comparison of the regression lines indicated significant difference among the slopes (P< 0.01) and intercepts (P< 0.0001) (Adopted from Méndez-Espinoza et al., 2019) Méndez-Espinoza et al. (2019) illustrates the relationship between grain yield and environmental index for triticale (cv. Aguacero-INIA) and spring wheat (cv. Pandora-INIA and Domo) across various locations and conditions. The regression analysis shows that triticale has a higher regression coefficient (Finlay and Wilkinson slope), indicating a more stable yield across diverse environmental conditions compared to wheat. This stability is coupled with generally higher yields, even in extreme environments. The significant differences in slopes (P < 0.01) and intercepts (P < 0.0001) between the crops underscore triticale's superior adaptability and yield stability. Triticale also outperforms wheat in grain yield due to its larger grain size, which is consistent across varying grain numbers per square meter. This highlights triticale's potential as a robust crop in diverse and challenging environments.

Field Crop 2024, Vol.7, No.4, 201-211 http://cropscipublisher.com/index.php/fc 203 2.1.2 Factors affecting yield Several factors influence the yield of both triticale and wheat. Drought significantly reduces the yield of wheat, with continuous drought stress causing a more substantial yield reduction compared to terminal drought stress (Wan et al., 2022). Soil organic matter (SOM) also plays a crucial role in yield potential, with higher concentrations of soil organic carbon (SOC) being associated with increased yields, although the benefits level off at around 2% SOC (Oldfield et al., 2018). Furthermore, the initial soil nutrient status, particularly phosphorus (P) and potassium (K), significantly affects wheat yield, with better soil health leading to higher productivity (Li et al., 2022). 2.2 Adaptability to different environments 2.2.1 Climate resilience Triticale has shown a more stable response to varying environmental conditions compared to wheat, making it more resilient to climate fluctuations. This stability is attributed to triticale's higher photosynthetic rates and better water-use efficiency, which contribute to its higher yield under different environmental conditions (Méndez-Espinoza et al., 2019). In contrast, wheat's yield and protein content are more adversely affected by drought, with significant reductions in grain yield and protein yield under drought conditions (Wan et al., 2022). 2.2.2 Soil requirements Both triticale and wheat benefit from soils with high organic matter content. Higher SOC levels are associated with increased yields for both crops, although the relationship is more pronounced in wheat. Maintaining and building SOM is essential for sustainable intensification and improving yield potential (Oldfield et al., 2018). Additionally, soil nutrient status, particularly the availability of P and K, is critical for optimizing yield. Integrated nutrient management approaches, including the use of phosphate-solubilizing bacteria (PSB), have been shown to enhance P uptake and yield effectiveness in wheat under various agro-climatic conditions (Yahya et al., 2023). 2.2.3 Water use efficiency Triticale exhibits higher water-use efficiency compared to wheat, which is a significant advantage in water-limited environments. This efficiency is linked to triticale's higher chlorophyll content, leaf net photosynthesis, and maximum rate of electron transport, which collectively contribute to its superior yield performance under both well-watered and water-limited conditions (Méndez-Espinoza et al., 2019). In wheat, optimizing water and nitrogen management practices can significantly improve water productivity and nitrogen use efficiency, thereby enhancing yield and sustainability (Li et al., 2022). In summary, triticale generally outperforms wheat in terms of yield potential and adaptability to different environments, particularly under water-limited conditions. Factors such as soil organic matter, nutrient status, and water-use efficiency play crucial roles in determining the yield and resilience of both crops. 3 Nutritional Content 3.1 Protein composition Triticale and wheat both serve as significant sources of protein, but they differ in their specific protein compositions. Wheat is rich in gluten proteins, which are crucial for bread-making quality. These proteins are divided into gliadins and glutenins, which have been extensively studied for their roles in determining the elasticity and extensibility of dough (Khalid et al., 2023). Triticale, on the other hand, has a varied amino acid profile, which makes it a valuable feed grain. Studies have shown that sprouted triticale grains contain a high percentage of crude protein, with some varieties reaching up to 15.83% (Kassymbek, 2023). This makes triticale a good alternative for animal feed, providing essential amino acids and enhancing the digestibility of the feed (Kassymbek, 2023). 3.2 Carbohydrates and fiber Both triticale and wheat are rich in carbohydrates, which are the primary source of energy in human and animal diets. Wheat grains contain approximately 72.29% carbohydrates, making them a significant energy source (Mustapha et al, 2019). Triticale also has a high carbohydrate content, with a notable presence of starch and

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