Jin Xin, Liu Xinyue, Wang Jie, Chang Jianping, Li Caixia, Lu Guangxin
College of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, China.
Plants (Basel). 2025 Jun 23;14(13):1926. doi: 10.3390/plants14131926.
The Qinghai-Tibet Plateau, a critical ecological barrier and major livestock region, faces deteriorating grasslands and rising forage demand under its harsh alpine climate. Oat ( L.), valued for its cold tolerance, rapid biomass accumulation, and ability to thrive in nutrient-poor soils, can expand winter feed reserves and partly alleviate grazing pressure on native rangelands. However, genetic improvement alone has not been sufficient to address the environmental challenges. This issue is particularly severe in the Qaidam Basin, where soil salinization, characterized by high pH, poor soil structure, and low nutrient availability, significantly limits crop performance. Rhizosphere growth-promoting bacteria (PGPR) are environmentally friendly biofertilizers known to enhance crop growth, yield, and soil quality, but their application in the saline soil of the Qaidam Basin remains limited. We evaluated two PGPR application rates (B1 = 75 kg hm and B2 = 150 kg hm) on 'Qingtian No. 1' oat, assessing plant growth, soil physicochemical properties, and rhizosphere microbial communities. The results indicated that both treatments significantly increased oat productivity, raised the comprehensive growth index, augmented soil organic matter, and lowered soil pH; B1 chiefly enhanced above-ground biomass and fungal community stability, whereas B2 more strongly promoted root development and bacterial community stability. Structural equation modeling showed that PGPR exerted direct effects on the comprehensive growth index and indirect effects through soil and microbial pathways, with soil properties contributing slightly more than microbial factors. Notably, rhizosphere organic matter, fungal β-diversity, and overall microbial community stability emerged as positive key drivers of the comprehensive growth index. These findings provide a theoretical basis for optimizing PGPR dosage in alpine forage systems and support the sustainable deployment of microbial fertilizers under saline soil conditions in the Qaidam Basin.
青藏高原是重要的生态屏障和主要牧区，在高寒气候的恶劣条件下，面临着草原退化和饲料需求不断增加的问题。燕麦（L.）因其耐寒性、生物量积累快以及能在贫瘠土壤中生长的能力而受到重视，它可以增加冬季饲料储备，并部分缓解对天然牧场的放牧压力。然而，仅靠遗传改良不足以应对环境挑战。这个问题在柴达木盆地尤为严重，那里的土壤盐碱化特征为高pH值、土壤结构差和养分有效性低，严重限制了作物生长。根际促生细菌（PGPR）是已知的可促进作物生长、提高产量和改善土壤质量的环保型生物肥料，但它们在柴达木盆地盐碱土壤中的应用仍然有限。我们评估了两种PGPR施用量（B1 = 75 kg·hm²和B2 = 150 kg·hm²）对‘青甜1号’燕麦的影响，评估了植物生长、土壤理化性质和根际微生物群落。结果表明，两种处理均显著提高了燕麦产量，提高了综合生长指数，增加了土壤有机质，并降低了土壤pH值；B1主要增强地上生物量和真菌群落稳定性，而B2更强烈地促进根系发育和细菌群落稳定性。结构方程模型表明，PGPR对综合生长指数有直接影响，并通过土壤和微生物途径产生间接影响，土壤性质的贡献略大于微生物因素。值得注意的是，根际有机质、真菌β多样性和整体微生物群落稳定性是综合生长指数的积极关键驱动因素。这些发现为优化高寒饲料系统中PGPR用量提供了理论依据，并支持在柴达木盆地盐碱土壤条件下可持续施用微生物肥料。
