5. Conclusion
The results of the 5-year continuous straw return experiment revealed
that the straw return significantly increased the content of soil carbon
and nitrogen pools, particularly active carbon pools, by enhancing the
structural diversity of bacterial communities. Straw return also
enhanced the ability of microorganisms to utilise carbohydrates, amino
acids, and carboxylic acid carbon sources, with amino acid carbon
sources more influential in explaining the changes in soil carbon and
nitrogen pool contents. Additionally, we observed differences in the
fungal community structure and microbial metabolic activity between low
(S1/2) and high (S1, S2) amounts of straw returned to the field,
indicating that the application of an optimal amount of straw to the
field can regulate the soil microbiological environment, affecting the
microbial diversity and consequently the content of soil carbon and
nitrogen pools, improving the soil quality through biological
regulation. Our study provides a theoretical basis for the sustainable
development of high-efficiency and high-quality wheat production in
drylands.