Molecular Microbiology Research 2024, Vol.14, No.6, 290-297 http://microbescipublisher.com/index.php/mmr 291 2 Effects on Soil Microbial Communities 2.1 Overview of straw incorporation Straw incorporation refers to the agricultural practice of returning crop residues, such as corn stover, wheat straw, and rice straw, back into the soil after harvest. This practice is significant in agriculture as it enhances soil fertility, improves soil structure, and promotes sustainable farming by recycling nutrients and organic matter back into the soil (Chen et al., 2017; Yang et al., 2022; Song et al., 2023). The types of straw commonly used include corn stover, wheat straw, and rice straw, each contributing differently to soil properties and microbial communities due to their unique compositions (Di et al., 2023). 2.2 Microbial responses to straw incorporation Straw incorporation significantly affects soil microbial diversity, composition, and activity. The addition of straw increases microbial diversity and alters the composition of bacterial and fungal communities. For instance, straw returning has been shown to increase the relative abundance of beneficial microbial taxa such as Proteobacteria, Acidobacteria, and Actinobacteria, while also promoting the growth of fungi like Ascomycota and Mortierellomycota (Liu et al., 2021; Zhang et al., 2023). The breakdown of straw components such as cellulose, hemicellulose, and lignin involves complex interactions with soil microorganisms. Specific bacterial groups, including Arthrobacter, Sphingomonas, and Streptomyces, play crucial roles in decomposing these components, thereby enhancing soil nutrient availability and microbial activity (Zhang et al., 2022). 2.3 Nutrient cycling and soil health The decomposition of straw contributes significantly to nutrient cycling, particularly the carbon and nitrogen cycles. Straw incorporation increases soil organic carbon (SOC) and total nitrogen (TN) levels, which are essential for maintaining soil fertility and promoting plant growth (Li et al., 2018). The process of straw decomposition also enhances soil organic matter and microbial biomass, leading to improved soil structure and health. Enzyme activities such as urease, sucrase, and cellulase are elevated in soils with straw incorporation, further facilitating nutrient cycling and microbial processes (Liu et al., 2021). Additionally, straw return has been shown to mitigate the negative effects of inorganic fertilizers on soil microbial communities, promoting a more stable and diverse microbial ecosystem (Zhang et al., 2022). 3 Impact on Microbial Communities 3.1 Overview of fertilizer types Organic fertilizers, such as manure and compost, are derived from natural sources and decompose slowly, releasing nutrients over time. In contrast, inorganic fertilizers are synthetically produced and provide immediate nutrient availability. The choice between organic and inorganic fertilizers can significantly influence soil microbial communities. For instance, long-term application of organic fertilizers has been shown to sustain soil microbial communities and improve soil fertility (Wang et al., 2021). Inorganic fertilizers, while effective in providing immediate nutrient boosts, can lead to soil acidification and alter microbial diversity (Mei et al., 2021). In maize production, the most commonly used fertilizers include nitrogen (N), phosphorus (P), and potassium (K). These nutrients are essential for plant growth and development. Nitrogen fertilizers, such as urea, are crucial for vegetative growth, while phosphorus fertilizers, like superphosphate, support root development and energy transfer. Potassium fertilizers, such as potassium chloride, enhance water uptake and disease resistance. The balanced application of NPK fertilizers has been shown to significantly improve maize yield and soil nutrient status (Muhammad et al., 2022). 3.2 Microbial response to fertilization Fertilizer application can lead to significant shifts in soil microbial community composition. For example, nitrogen fertilization has been found to increase the abundance of certain bacterial phyla such as Proteobacteria and Acidobacteria, while decreasing others like Actinobacteria (Mei et al., 2021). Similarly, phosphorus availability has been identified as a key factor influencing microbial community structure, particularly in
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