Agronomy

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19 pages, 3189 KB

Open AccessArticle

Microbial Drivers of Seed Vigor in Salvia miltiorrhiza: Bacterial Network Stability, Pseudomonas Enrichment, and Identification of Growth-Promoting Strains

by Yate Zhang, Rui Zou, Meng Yu, Jiayi Fu, Hanxin Ye, Xin Chen, Ruiqi Liu, Pengfeng Zhu, Qingdian Han, Ning Sui, Leran Wang and Guoyin Kai

Agronomy 2026, 16(9), 874; https://doi.org/10.3390/agronomy16090874 - 25 Apr 2026

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Abstract

The global demand for Salvia miltiorrhiza Bunge in the botanical medicine market is steadily increasing. However, its production has long relied on asexual root propagation, making it highly susceptible to germplasm degradation. Transitioning to seed reproduction offers the advantage of genetic renewal, yet [...] Read more.

The global demand for Salvia miltiorrhiza Bunge in the botanical medicine market is steadily increasing. However, its production has long relied on asexual root propagation, making it highly susceptible to germplasm degradation. Transitioning to seed reproduction offers the advantage of genetic renewal, yet it is constrained by unstable seed vigor and slow seedling growth. In the present study, comprehensive physiological and microbiome analyses of S. miltiorrhiza seeds from 14 regions across 7 provinces in China were conducted to elucidate the association between the seed microbiome and vigor, and to identify plant growth-promoting (PGP) strains. The results demonstrated: (1) Seed physical traits and germination characteristics varied significantly across geographic origins. Seed vigor, exhibiting the highest coefficient of variation, served as a key parameter reflecting germination quality. (2) High-vigor seeds harbored distinct microbial communities characterized by higher diversity indices, greater network complexity, and the significant enrichment of potentially beneficial bacteria (e.g., Pseudomonas). (3) Through correlation-directed screening of isolated pure cultures, Pseudomonas mendocina P-6 and Enterobacter ludwigii BM-12 were identified as exhibiting robust, multi-trait PGP capacity. In planta validation showed that these two strains significantly promoted the growth of 1-month-old S. miltiorrhiza seedlings, increasing total fresh weight by 33.9–71.3%. This study reveals the microecological drivers of seed vigor and provides candidate strains for inoculant development, thereby supporting the sustainable, seed-based propagation of S. miltiorrhiza. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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19 pages, 2468 KB

Open AccessArticle

Effects of Microbial Inoculants Combined with Maize Straw on Physicochemical Properties and Microbial Community Structure in Black Soil During Soybean Growth

by Tingting Hou, Chao Jiang, Xiangxiang Wang, Enyue Fan, Tingyu Zhang, Jiabao Zhang and Liqiang Meng

Agronomy 2026, 16(9), 856; https://doi.org/10.3390/agronomy16090856 - 23 Apr 2026

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Abstract

Purpose: Black soils in Northeast China are declining in fertility under intensive fertilization, motivating strategies that integrate crop residue return with microbial inoculation. We conducted a field experiment to test whether maize straw return combined with compound microbial inoculants improves soil properties, [...] Read more.

Purpose: Black soils in Northeast China are declining in fertility under intensive fertilization, motivating strategies that integrate crop residue return with microbial inoculation. We conducted a field experiment to test whether maize straw return combined with compound microbial inoculants improves soil properties, bacterial communities, and soybean performance. Methods: A field experiment compared four treatments: fertilization alone (F), fertilization + inoculants (CF), fertilization and straw (SF), and fertilization and straw with inoculants (CSF). Soil physicochemical properties, enzyme activities, 16S rDNA-based bacterial communities, and soybean agronomic yield were measured across growth stages. Results: CSF produced the highest soybean performance, and increased yield by 3.91–5.46% compared with F. CSF increased soil pH, moisture, and nutrient availability (notably available P and K) and enhanced sucrase, urease, catalase, and acid phosphatase activities compared with other treatments. Bacterial communities were dominated by Acidobacteriota and Proteobacteria. CSF increased bacterial abundance and shifted community composition, and pH and available P were key factors associated with community variation. Conclusions: Co-applying maize straw and compound microbial inoculants enhances soybean yield while improving soil biochemical functioning and reshaping bacterial communities in black soil. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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24 pages, 6475 KB

Open AccessArticle

Nitrogen-Fixing Bacterial Inoculation Can Enhance Maize Yield and Alter Soil Microbial Community Structure Under Fertilizer Reduction

by Yan Zou, Xiping Wei, Zuoheng Yu, Yening Jin, Eunice Jingmei Tan and Fajun Chen

Agronomy 2026, 16(6), 634; https://doi.org/10.3390/agronomy16060634 - 17 Mar 2026

Cited by 1 | Viewed by 1304

Abstract

Excessive fertilizer application is a common practice in agricultural production in the North China Plain. To determine an optimal fertilization strategy for summer maize with nitrogen-fixing bacterial inoculation, we conducted a two-year field experiment (2022–2023) using the conventional fertilization rate (600 kg ha [...] Read more.

Excessive fertilizer application is a common practice in agricultural production in the North China Plain. To determine an optimal fertilization strategy for summer maize with nitrogen-fixing bacterial inoculation, we conducted a two-year field experiment (2022–2023) using the conventional fertilization rate (600 kg ha⁻¹ NPK; N:P₂O₅:K₂O = 28:8:10; 100F by default) as a control and examined the effects of fertilizer reduction (at 90%, 80%, 62.5%, and 50% of 100F) combined with Azotobacter chroococcum inoculation on maize plants and soil. Although fertilizer reduction increased free amino acid content, soluble sugars, proteins, and fatty acids contents were reduced. However, bacterial inoculation significantly enhanced all the above nutritional indices in maize leaves. Bacterial inoculation under fertilizer reduction conditions can enhance the activity of key nitrogen metabolism enzymes (i.e., GS and GOGAT), which further supports nitrogen, sugar, and lipid metabolism in maize plants. Additionally, bacterial inoculation promoted root development, biomass accumulation, and grain nutritional value while significantly increasing yield under reduced fertilizer conditions. The highest yield (11,454 kg ha⁻¹) was achieved with bacterial inoculation at approximately 87F (≈522 kg ha⁻¹ NPK), while the non-inoculated control reached a peak yield (11,032 kg ha⁻¹) only at around 90.5F (≈543 kg ha⁻¹). The complementary effects of bacterial inoculation with fertilizer reduction resulted in improved nutrient supply and modulation of soil microbial diversity. Inoculation of A. chroococcum increased soil ammonium and nitrate levels and decreased soil pH, though it was associated with a decline in overall bacterial richness, which may have persistent and adverse effects on the soil. Both fertilizer reduction and bacterial inoculation significantly altered microbial community structure, with notable interannual variation. Collectively, our findings suggest that moderate fertilizer reduction (9.5–13%) combined with nitrogen-fixing bacteria inoculation can support sustainable maize production by maintaining higher yield, enhancing nutrient use efficiency, and improving soil health. However, due to pH-lowering effects, long-term monitoring is necessary to assess the ecological impact of nitrogen-fixing bacteria inoculation on soil microbial balance. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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15 pages, 2280 KB

Open AccessArticle

Bradyrhizobium elkanii Y63-1 Strain Enhances the Nodulation Capability and Yield of Soybean Variety Zhongdou 41

by Songli Yuan, Lu Lu, Jiayu Lu, Qianqian Hu, Fuxiao Jin, Wanwan Liang, Yi Huang, Chanjuan Zhang, Zhonglu Yang, Shuilian Chen and Haifeng Chen

Agronomy 2026, 16(5), 492; https://doi.org/10.3390/agronomy16050492 - 24 Feb 2026

Cited by 1 | Viewed by 630

Abstract

To assess the application potential of the Y63-1 strain in soybean varieties other than its capture host, Zhongdou 63 (ZD63), we investigated the response of Zhongdou 41 (ZD41) to Y63-1 inoculation under four levels of NH₄NO₃ in greenhouse and five [...] Read more.

To assess the application potential of the Y63-1 strain in soybean varieties other than its capture host, Zhongdou 63 (ZD63), we investigated the response of Zhongdou 41 (ZD41) to Y63-1 inoculation under four levels of NH₄NO₃ in greenhouse and five field trials. Compared to the control group, the increased percentages in nodule number for ZD41 in the greenhouse and field were 8.6% to 145.7% and 18.3% to 323.4%, respectively. The increased percentages of nodule dry weight were 10.5% to 46.7% and 7.9% to 890.3%, respectively. The growth, development, and chlorophyll content of ZD41 were promoted by inoculation with Y63-1 under greenhouse and field conditions. The grain weight per plant of ZD41 was increased by 7.90% to 17.10% in HC-2024, 14.50% in ZMD-2024, and 13.40% in YL-2025-1 compared to the control group. The increased plot yield of ZD41 after inoculation with the Y63-1 strain reached 7.9% in HC-2024 and 10.6% in ZMD-2024. It was concluded that ZD41-Y63-1 symbiosis is suitable for different nitrogen levels and multiple field environments. Our findings provide technical support for the application of Y63-1 in other soybean cultivars and a reference for the identification of symbiotic nitrogen-fixation characteristics of soybean varieties. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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19 pages, 2991 KB

Open AccessArticle

Effects of Co-Application of Diammonium Phosphate Fertilizer with Microbial Inoculant on Soil Nitrogen Levels and Alfalfa Growth Performance in Saline-Alkali Soil

by Shuai Wang, Changning Li, Xiaohu Wang, Chen Zhang, Yi Feng, Yang Lei and Jiahao Xu

Agronomy 2026, 16(3), 305; https://doi.org/10.3390/agronomy16030305 - 25 Jan 2026

Cited by 1 | Viewed by 933

Abstract

Soil salinization leads to soil nutrient loss and decreased crop yield. This research aims to determine the optimal reduction rate of diammonium phosphate (DAP) and suitable microbial inoculant for alfalfa cultivation and nitrogen-level improvement in saline-alkali land. The experiment consisted of a factorial [...] Read more.

Soil salinization leads to soil nutrient loss and decreased crop yield. This research aims to determine the optimal reduction rate of diammonium phosphate (DAP) and suitable microbial inoculant for alfalfa cultivation and nitrogen-level improvement in saline-alkali land. The experiment consisted of a factorial arrangement of three DAP fertilizer levels (X1, 60%; X2, 70%; and X3, 80%) and four microbial inoculants (Y1, rhizobial inoculant; Y2, phosphate-solubilizing microbial inoculant; Y3, composite microbial inoculant; and Y4, control) in a split-plot design. The results indicated that DAP fertilizer, microbial inoculant, and their interaction significantly affected (p < 0.05) forage yield, crude protein, available nitrogen (N), and enzyme activities. Under 80% DAP fertilizer combined with the composite microbial inoculant, forage yield, plant height, soil urease (S-UE), and ammonium nitrogen (NH₄⁺-N) reached maximum values of 17.1 t ha⁻¹, 65.7 cm, 292.3 μg d⁻¹ g⁻¹, and 3.1 mg kg⁻¹, respectively. However, the soil total nitrogen (TN) significantly increased at the 60% DAP fertilizer application rate (p < 0.05). Overall, this study demonstrates that co-application of DAP fertilizer with compound microbial inoculant delivers a green, science-based fertilization approach for improving nitrogen levels and alfalfa cultivation in saline-alkali soils. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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17 pages, 1843 KB

Open AccessArticle

Characterization of a Salt-Tolerant Plant Growth-Promoting Bacterial Isolate and Its Effects on Oat Seedlings Under Salt Stress

by Yincui Zhang, Changning Li and Yue Wang

Agronomy 2026, 16(1), 135; https://doi.org/10.3390/agronomy16010135 - 5 Jan 2026

Cited by 1 | Viewed by 1220

Abstract

Oats (Avena sativa L.) are a staple grain and forage crop with substantial market demand. In China, they are the second most-imported forage grass, only after alfalfa (Medicago sativa L.). Enhancing the salt tolerance of oats to facilitate their cultivation in [...] Read more.

Oats (Avena sativa L.) are a staple grain and forage crop with substantial market demand. In China, they are the second most-imported forage grass, only after alfalfa (Medicago sativa L.). Enhancing the salt tolerance of oats to facilitate their cultivation in saline areas can thereby increase forage yield and promote the utilization of saline land, which constitutes an important reserve land resource in China. This study aimed to identify the bacterial strain Bacillus sp. LrM2 (hereafter referred to as strain LrM2) to determine its precise species-level classification and evaluate its effects on oat photosynthesis and growth under salt stress through indoor pot experiments. The results indicated that strain LrM2, capable of urease production and citrate utilization, was identified as Bacillus mojavensis. The strain LrM2 had a positive effect on shoot and root growth of oats under 100 mM NaCl stress conditions. Strain LrM2 inoculation modulated osmotic stress in oats under 100 mM NaCl stress by significantly increasing soluble sugar and decreasing proline content in leaves. It inhibited Na⁺ uptake and promoted K⁺ absorption in the roots, thereby reducing Na⁺ translocation to the leaves and mitigating ionic toxicity. Inoculation with strain LrM2 significantly increased photosynthetic pigment content (chlorophyll a, carotenoids), improved gas exchange parameters (stomatal conductance, transpiration rate, net rate of photosynthesis), enhanced PSII photochemical efficiency (maximum quantum yield, coefficient of photochemical quenching, actual photosynthetic efficiency of PSII, electron transfer rate), and reduced the quantum yield of non-regulated energy dissipation. These improvements, coupled with increased relative water content and instantaneous water use efficiency, thereby collectively enhanced the overall photosynthetic performance. In conclusion, strain LrM2 represents a promising bio-resource for mitigating salt stress and promoting growth in oats, with direct applications for developing novel biofertilizers and sustainable agricultural strategies. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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16 pages, 2145 KB

Open AccessArticle

Cellulolytic Microbial Inoculation Enhances Sheep Manure Composting by Improving Nutrient Retention and Reshaping Microbial Community Structure

by Ze Zhou, Yincui Zhang, Changning Li, Xiaohong Chai, Shanmu He, Yang Lei and Weigang Fu

Agronomy 2026, 16(1), 79; https://doi.org/10.3390/agronomy16010079 - 26 Dec 2025

Cited by 2 | Viewed by 1213

Abstract

Livestock manure is a major source of environmental pollution and greenhouse gas emissions if improperly managed. Aerobic composting represents a sustainable approach to manure recycling that can stabilize organic matter, mitigate carbon loss, and recover nutrients for agricultural use. In this study, sheep [...] Read more.

Livestock manure is a major source of environmental pollution and greenhouse gas emissions if improperly managed. Aerobic composting represents a sustainable approach to manure recycling that can stabilize organic matter, mitigate carbon loss, and recover nutrients for agricultural use. In this study, sheep manure was mixed with sawdust to optimize the carbon-to-nitrogen (C/N) ratio and enhance aeration, and the mixture was subjected to aerobic composting with a cellulose-degrading microbial inoculant. To rigorously evaluate the biological effects, a control treated with sterilized inoculant was included to eliminate nutrient inputs from the carrier matrix. The inoculant significantly improved composting performance by extending the thermophilic phase by five days and reducing the C/N ratio to 19.8 on day 32, thereby shortening the composting cycle. Moreover, microbial inoculation enhanced nutrient retention, resulting in a 20.14% increase in total nutrient content, while the germination index (GI) reached 89.75%, indicating high compost maturity and reduced phytotoxicity. Microbial community analysis revealed that cellulose-degrading inoculants significantly altered microbial richness and diversity and accelerated community succession. Redundancy analysis (RDA) and hierarchical partitioning analysis showed that total organic carbon (TOC) and GI were the main environmental drivers of bacterial community dynamics, whereas pH and GI primarily regulated fungal community succession. These findings suggest a strong link between compost maturity and microbial community restructuring. This study demonstrates that cellulose-degrading microbial inoculation accelerates the composting of sheep manure, enhances organic matter degradation, and improves fertilizer efficiency while reducing the phytotoxicity of the final product. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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20 pages, 7984 KB

Open AccessArticle

Research on Fermentation Characteristics and Microbial Community of Mixed Sorghum-Sudangrass and Sesbania Silage

by Qianqian Huo, Yangyang Song, Yulin Zhang and Linqiao Xi

Agronomy 2026, 16(1), 44; https://doi.org/10.3390/agronomy16010044 - 23 Dec 2025

Cited by 1 | Viewed by 974

Abstract

To explore the optimal mixing ratio and fermentation mechanism of sorghum-sudangrass and sesbania mixed silage, this study prepared silages at ratios of 10:0, 9:1, 8:2, 7:3, and 6:4 and analyzed their chemical composition, fermentation quality, and microbial characteristics on days 3, 30, and [...] Read more.

To explore the optimal mixing ratio and fermentation mechanism of sorghum-sudangrass and sesbania mixed silage, this study prepared silages at ratios of 10:0, 9:1, 8:2, 7:3, and 6:4 and analyzed their chemical composition, fermentation quality, and microbial characteristics on days 3, 30, and 60 of fermentation. The results showed that dry matter (DM) content gradually decreased with prolonged fermentation, with the 7:3 and 6:4 groups maintaining relatively higher mean DM content. The 6:4 and 7:3 groups have more crude protein (CP) content at D60. Water-soluble carbohydrates (WSC) decreased gradually during fermentation. In terms of fermentation quality, pH values decreased progressively and eventually stabilized. Lactic acid (LA) content accumulated over time, with the 10:0 group displaying higher NH₃-N/TN content. Butyric acid was not detected in any treatment. Microbiologically, the counts of lactic acid bacteria (LAB) and yeasts gradually decreased with fermentation time, while Escherichia coli and mold were effectively suppressed. Bacterial diversity declined during fermentation, with Firmicutes being the dominant phylum. Weissella predominated in the early stage, while Pediococcus became dominant later. In conclusion, sorghum-sudangrass and sesbania mixed silage promote nutrient preservation and fermentation stability. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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18 pages, 2549 KB

Open AccessArticle

Biochar and Arbuscular Mycorrhizal Fungi Promote Rice Paddy Phosphorus Cycle by Altering Soil Phosphorus Turnover and Leaf Phosphorus Distribution

by Zhonghua Wen, Xu Yang, Xuanwei Zhou, Yongjia Shi, Haoyue Zheng and Jun Meng

Agronomy 2025, 15(11), 2562; https://doi.org/10.3390/agronomy15112562 - 6 Nov 2025

Cited by 4 | Viewed by 1405

Abstract

Biochar and arbuscular mycorrhizal fungi (AMF) make significant contributions to improving soil and plant mineral nutrition, primarily phosphorus (P). However, the response of soil and leaf P fractions dynamics to biochar and AMF amendment in paddy ecosystems remains unclear. A pot experiment in [...] Read more.

Biochar and arbuscular mycorrhizal fungi (AMF) make significant contributions to improving soil and plant mineral nutrition, primarily phosphorus (P). However, the response of soil and leaf P fractions dynamics to biochar and AMF amendment in paddy ecosystems remains unclear. A pot experiment in greenhouse was conducted to study the effects of three biochars produced from rice husk (HBC), maize straw (MBC), and wood chips (WBC) and Rhizophagus irregularis on soil and leaf P fractions, soil chemical properties, and rice growth. The combination of biochar and AMF increased soil content of labile inorganic P (38.25%, 50.87% and 23.65%, respectively) and decreased that of labile organic P (52.31%, 61.12% and 44.60%, respectively) compared to the control. Similarly, HBC and MBC with AMF combination increased leaf contents of inorganic (7.29% and 8.81%, respectively) and nucleic acid (18.75% and 14.73%, respectively) P, which were strongly correlated with soil labile P fractions. Biochar and AMF amendment governed the transformation of soil P by altering total P, organic matter, and pH. Meanwhile, the distribution of leaf P was influenced by leaf total P content, soil organic matter, and electrical conductivity (EC). In addition, MBC and HBC increased the rice mycorrhizal colonization rate by 6.78% and 18.19%, respectively. The application of HBC and AMF increased leaves’ and stems’ biomass (28.57% and 26.67%, respectively), and three biochars and AMF also facilitated P accumulation in rice. Therefore, these results provide the first evidence for the interaction between biochar and AMF to alter P distribution among leaf fractions in paddy fields. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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24 pages, 6051 KB

Open AccessArticle

Trichoderma harzianum DQ002 Enhances Oriental Melon Resistance Against Fusarium oxysporum f.sp. melonis by Regulating Soil Microbial Communities in the Rhizosphere

by Yihan Xie, Chunxia Li, Yuting Zhang, Xiaoqian Yue, Yuanyi Zhong, Ting Yang, Yazhong Jin and Xueqing Geng

Agronomy 2025, 15(8), 1931; https://doi.org/10.3390/agronomy15081931 - 10 Aug 2025

Cited by 1 | Viewed by 2593

Abstract

Continuous planting results in a higher occurrence rate of oriental melon Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (FOM), and treatment with Trichoderma can considerably alleviate the incidence of disease. However, the tripartite interaction mechanisms among T. harzianum–melon–rhizosphere [...] Read more.

Continuous planting results in a higher occurrence rate of oriental melon Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (FOM), and treatment with Trichoderma can considerably alleviate the incidence of disease. However, the tripartite interaction mechanisms among T. harzianum–melon–rhizosphere microorganisms remain poorly understood in current research. Pot experiments elucidate the growth-promoting, antagonistic, and rhizosphere-regulating effects of T. harzianum on oriental melon. The experiment consisted of two treatments: (1) water control (CK), and (2) T. harzianum inoculation (MM) with three repetitions per treatment. Illumina high-throughput sequencing was employed to analyze the microbial community and associated metabolic pathways. Additionally, a comprehensive correlation analysis clarified how T. harzianum-modulated physiological factors regulate soil microbial communities to enhance melon resistance to FOM. T. harzianum inoculation significantly promoted plant growth, decreased the incidence rate of Fusarium wilt by 41.85%, and increased rhizosphere nitrate-N, pH, EC, and soil enzyme activity (e.g., sucrose and alkaline phosphatase). Notably, T. harzianum inoculation altered the rhizosphere microbial community’s relative abundance and structure, with the most striking changes in the fungal community. Principal coordinate analysis showed this fungal restructuring accounted for 44.9% of total community variation (37% from PCo1, 7.9% from PCo2). Soil-borne pathogens (e.g., Fusarium, Verticillium, Phytophthora) decreased in relative abundance with the inoculation of T. harzianum. Meanwhile, the microbial community shifted from a “fungal-dominated” to “bacterial-dominated” state: fungal proportion decreased by 9.47% (from 23.95% in CK to 14.48% in MM), while bacterial proportion increased by 9.47% (from 76.05% in CK to 85.52% in MM). Microbial abundance shifts primarily impacted amino acid and cofactor biosynthesis metabolic pathways. The application of T. harzianum modified the soil environment, restructuring microbial communities through these changes, which in turn regulated microbial metabolic pathways, creating a soil environment conducive to melon growth and thereby enhancing oriental melon resistance to FOM, while mitigating the obstacles of continuous cropping. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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20 pages, 4774 KB

Open AccessArticle

Study on Pathogen Identification and Biocontrol Fungi Screening of Oat Sheath Rot

by Yichao Shi, Guiqin Zhao, Liang Zeng and Jikuan Chai

Agronomy 2025, 15(8), 1776; https://doi.org/10.3390/agronomy15081776 - 24 Jul 2025

Viewed by 1432

Abstract

Oat sheath rot disease significantly reduces commercial oat yields, yet research on its incidence, causative pathogens, and control strategies remains limited, particularly in China. This study investigated the occurrence of oat sheath rot in major oat-producing regions of Northern China. Here, we isolated [...] Read more.

Oat sheath rot disease significantly reduces commercial oat yields, yet research on its incidence, causative pathogens, and control strategies remains limited, particularly in China. This study investigated the occurrence of oat sheath rot in major oat-producing regions of Northern China. Here, we isolated and identified two species of primary pathogenic fungi, Scopulariopsis brevicaulis and Alternaria alternata. Next, we conducted pathogenicity tests to confirm their role in the progression of oat sheath rot disease. Subsequently, we screened putative biocontrol fungi and identified Trichoderma harzianum and Trichoderma koningii as effective antagonistic biocontrol fungi. Both species demonstrated strong inhibitory effects against two primary pathogens through competitive interactions, with T. koningii achieving 100% inhibition in one test. Overall, T. harzianum and T. koningii both exerted strong inhibitory effects against pathogenic fungi via different forms of competition. Most importantly, infection experiments showed that T. harzianum and T. koningii both exerted strong antifungal effects against the pathogenic fungi that cause oat sheath rot. Taken together, our findings provide a foundation for developing biological control strategies to mitigate oat sheath rot in oat cultivation in China. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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20 pages, 5984 KB

Open AccessArticle

Potassium Fulvate Alleviates Salinity and Boosts Oat Productivity by Modifying Soil Properties and Rhizosphere Microbial Communities in the Saline–Alkali Soils of the Qaidam Basin

by Jie Wang, Xin Jin, Xinyue Liu, Yunjie Fu, Kui Bao, Zhixiu Quan, Chengti Xu, Wei Wang, Guangxin Lu and Haijuan Zhang

Agronomy 2025, 15(7), 1673; https://doi.org/10.3390/agronomy15071673 - 10 Jul 2025

Cited by 2 | Viewed by 1518

Abstract

Soil salinization severely limits global agricultural sustainability, particularly across the saline–alkaline landscapes of the Qinghai–Tibet Plateau. We examined how potassium fulvate (PF) modulates oat (Avena sativa L.) performance, soil chemistry, and rhizospheric microbiota in the saline–alkaline soils of the Qaidam Basin. PF [...] Read more.

Soil salinization severely limits global agricultural sustainability, particularly across the saline–alkaline landscapes of the Qinghai–Tibet Plateau. We examined how potassium fulvate (PF) modulates oat (Avena sativa L.) performance, soil chemistry, and rhizospheric microbiota in the saline–alkaline soils of the Qaidam Basin. PF markedly boosted shoot and root biomass, with the greatest response observed at 150 kg hm⁻². At the same time, it enhanced soil fertility by increasing organic matter, nitrate-N, ammonium-N, and available potassium, and improved ionic balance by lowering Na⁺ concentrations and the sodium adsorption ratio (SAR), while increasing Ca²⁺ levels and soil moisture content. Under the high-dose treatment (F2), endogenous fungal contributions declined sharply, exogenous replacements increased, and fungal α-diversity fell; multivariate ordinations confirmed that PF reshaped both bacterial and fungal communities, with fungi exhibiting the stronger response. We integrated three machine learning algorithms—least absolute shrinkage and selection operator (LASSO), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost)—to minimize the bias inherent in any single method. We identified microbial β-diversity, organic matter, and Na⁺ and Ca²⁺ concentrations as the most robust predictors of the Soil Salinization and Alkalization Index (SSAI). Structural equation modeling further showed that PF mitigates salinity chiefly by improving soil physicochemical properties (path coefficient = −0.77; p < 0.001), with microbial assemblages acting as key intermediaries. These findings provide compelling theoretical and empirical support for deploying PF to rehabilitate saline–alkaline soils in alpine environments and offer practical guidance for sustainable land management in the Qaidam Basin. Full article

(This article belongs to the Special Issue Utilization of Microorganisms for Sustainable Agricultural Development)

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