<b>Low-temperature</b><b>-f</b><b>ermented straw compost promotes alfalfa growth and </b><b>imparts stress tolerance</b>

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. Building on this, the present study again focused on the effect of low-temperature-fermented straw compost on alfalfa growth. We found that applying straw compost significantly accelerated alfalfa growth and improved multiple physiological indicators. At the same time, it regulated the expression of key genes in metabolic pathways, secondary-metabolite synthesis pathways, and plant hormone signal transduction. In addition, straw compost improved soil pH, significantly increased soil organic matter content, and enhanced both the activities of certain soil enzymes and the abundance of soil microorganisms, achieving the dual goals of optimizing soil and promoting alfalfa growth. Overall, the study demonstrates that low-temperature-fermented straw compost exerts a broad-spectrum 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.土壤理化性质对植物生长具有显著影响，而改良土壤品质的肥料在促进作物发育方面发挥着关键作用。废弃作物秸秆经堆肥转化为有机肥后，是农业生产的重要资源。然而，秸秆堆肥调控植物生长的具体机制仍未完全阐明。在前期研究中，我们已证实低温发酵秸秆堆肥可显著促进水稻的生长与产量。在此基础上，本研究进一步聚焦低温发酵秸秆堆肥对紫花苜蓿生长的影响。研究发现，施加秸秆堆肥可显著加快紫花苜蓿的生长速度，并改善多项生理指标；同时，其可调控代谢通路、次生代谢产物合成通路以及植物激素信号转导通路中的关键基因表达。此外，秸秆堆肥可改善土壤pH值，显著提升土壤有机质含量，增强部分土壤酶活性与土壤微生物丰度，实现了优化土壤与促进苜蓿生长的双重目标。综上，本研究证实低温发酵秸秆堆肥对作物生长具有广谱促进作用，可为低温秸秆发酵技术的推广以及秸秆堆肥在农牧业生产中的应用提供重要的理论依据。