Molecular Microbiology Research 2024, Vol.14, No.6, 290-297 http://microbescipublisher.com/index.php/mmr 292 nutrient-poor soils (Wang et al., 2021). The combined use of organic and inorganic fertilizers can enhance microbial diversity and promote beneficial microbial interactions (Guo et al., 2022). Fertilization practices also impact microbial processes critical for nutrient cycling. Nitrogen fertilization can enhance nitrification and denitrification activities, which are essential for nitrogen availability and loss in the soil3. Phosphorus solubilization, facilitated by specific microbial taxa, is crucial for making phosphorus available to plants. The application of organic fertilizers can promote these microbial processes by providing a steady supply of organic matter and nutrients (Chen et al., 2021; Yang et al., 2022). 3.3 Soil acidification and nutrient imbalances Excessive use of inorganic fertilizers can lead to soil acidification, which negatively affects soil pH and microbial diversity. For instance, long-term application of high nitrogen rates has been shown to decrease soil pH, thereby altering the microbial community structure and reducing microbial diversity(Liu et al., 2021; Mei et al., 2021). This acidification can inhibit the growth of beneficial microbes and promote the proliferation of acid-tolerant species, potentially leading to nutrient imbalances and reduced soil fertility. 4 Co-regulation of Soil Microbial Communities by Straw Incorporation and Fertilizer 4.1 Interactions between straw incorporation and fertilizer application Straw incorporation and fertilizer application interact in complex ways to influence soil microbial communities. Synergistically, straw incorporation enhances soil organic carbon (SOC) and total nitrogen (TN), which in turn supports a diverse microbial community. For instance, straw returning significantly increased soil fertility, enzymatic activities, and the diversity and composition of bacterial and fungal communities compared to traditional planting methods (Yang et al., 2022; Zhou and Xu., 2024). However, nitrogen (N) fertilization alone can decrease the richness of bacterial and fungal communities, indicating a potential antagonistic effect when not combined with organic inputs. The combination of straw incorporation and N fertilization also affects the carbon-to-nitrogen (C/N) ratio and nutrient availability in the soil. Straw incorporation tends to increase the relative abundance of cellulolytic bacteria, which are crucial for breaking down organic matter and releasing nutrients. This practice also enhances the activities of enzymes involved in carbon and nitrogen cycling, such as urease and sucrase, thereby improving nutrient availability (Sui et al., 2022). On the other hand, excessive N fertilization can alter the C/N ratio unfavorably, potentially leading to nutrient imbalances and reduced microbial diversity (Muhammad et al., 2022). 4.2 Effects on key microbial groups Both straw incorporation and fertilizer application significantly impact key functional microbial groups, including nitrogen-fixing bacteria and decomposers. For example, straw mulch has been shown to boost the relative abundances of bacteria involved in chemoheterotrophy, ureolysis, and nitrogen fixation (Chen et al., 2021). Similarly, N fertilization enhances the abundance of copiotrophic bacterial taxa like Alphaproteobacteria, which are involved in nutrient cycling (Sui et al., 2022). Specific microbial taxa respond differently to straw and fertilizer inputs. For instance, the incorporation of straw increased the fungal biomass, particularly of saprotrophic fungi such as Chaetomiaceae and Chaetosphaeriaceae, which play a crucial role in decomposing organic matter. In contrast, N fertilization alone tends to favor bacterial taxa like Proteobacteria and Acidobacteria, which are essential for nutrient cycling but may not be as effective in organic matter decomposition (Sui et al., 2022; Muhammad et al., 2022). 4.3 Temporal dynamics The temporal dynamics of microbial community responses to straw incorporation and fertilizer application can vary significantly. Short-term effects often include immediate increases in microbial activity and enzyme functions, as seen with straw mulch improving soil carbon and nitrogen cycles (Chen et al., 2021). Long-term
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