Effect of Low-Temperature-Fermented Straw Compost on Alfalfa (Medicago sativa L.) Growth and Stress Tolerance

The physicochemical properties of soil have a significant impact on plant growth, and fertilizers that improve soil quality play a crucial role in promoting crop development. Abandoned crop straw, once composted and converted into organic fertilizer, is an important resource for agricultural production. However, the mechanisms by which straw compost regulates plant growth remain incompletely understood. In previous work, we demonstrated that low-temperature-fermented straw compost significantly promoted the growth and yield of rice. To further investigate the effects of low-temperature-fermented straw compost on alfalfa growth, this study incorporated 10% and 30% straw compost into soil for alfalfa cultivation and systematically compared plant growth and soil quality indicators. Results showed that compost application increased alfalfa leaf length by 30.55%, with significant improvements observed in multiple physiological parameters. Furthermore, straw compost amendment raised soil pH to 6.88, substantially enhanced soil organic matter content, and increased the activities of sucrase and urease by approximately 181.77% and 223.81%. The abundance of soil microorganisms, including fungi and actinomycetes, increased by approximately 129.59% and 444.44%, respectively, indicating that straw compost effectively improves soil conditions and promotes alfalfa growth. Overall, the study demonstrates that low-temperature-fermented straw compost exerts a promoting effect on crop growth and provides an important theoretical basis for promoting low-temperature straw fermentation technology and the application of straw composting in agricultural and animal husbandry production.