Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin
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 (<i>Avena sativa</i> L.), valued for its cold tolerance, rapid biomass accumulation, and ability to thrive in n...
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2025-06-01
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| author | Xin Jin Xinyue Liu Jie Wang Jianping Chang Caixia Li Guangxin Lu |
| author_facet | Xin Jin Xinyue Liu Jie Wang Jianping Chang Caixia Li Guangxin Lu |
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| description | 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 (<i>Avena sativa</i> 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<sup>−2</sup> and B2 = 150 kg hm<sup>−2</sup>) 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. |
| format | Article |
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| language | English |
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| spelling | doaj-art-cbb007bdf7cc48a49b7bfd42276b6f232025-07-11T14:41:42ZengMDPI AGPlants2223-77472025-06-011413192610.3390/plants14131926Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam BasinXin Jin0Xinyue Liu1Jie Wang2Jianping Chang3Caixia Li4Guangxin Lu5College of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, ChinaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, ChinaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, ChinaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, ChinaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, ChinaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, ChinaThe Qinghai–Tibet Plateau, a critical ecological barrier and major livestock region, faces deteriorating grasslands and rising forage demand under its harsh alpine climate. Oat (<i>Avena sativa</i> 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<sup>−2</sup> and B2 = 150 kg hm<sup>−2</sup>) 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.https://www.mdpi.com/2223-7747/14/13/1926alpine foragePGPRcomprehensive growth indexmicrobial community stability |
| spellingShingle | Xin Jin Xinyue Liu Jie Wang Jianping Chang Caixia Li Guangxin Lu Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin Plants alpine forage PGPR comprehensive growth index microbial community stability |
| title | Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin |
| title_full | Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin |
| title_fullStr | Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin |
| title_full_unstemmed | Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin |
| title_short | Rhizosphere Growth-Promoting Bacteria Enhance Oat Growth by Improving Microbial Stability and Soil Organic Matter in the Saline Soil of the Qaidam Basin |
| title_sort | rhizosphere growth promoting bacteria enhance oat growth by improving microbial stability and soil organic matter in the saline soil of the qaidam basin |
| topic | alpine forage PGPR comprehensive growth index microbial community stability |
| url | https://www.mdpi.com/2223-7747/14/13/1926 |
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