Light intensity significantly influences plant growth in hydroponic green fodder systems, yet research exploring the growth dynamics and nutrient accumulation in hydroponically grown barley under various light conditions has been limited. This study investigated the impact of different light intensities—0, 100, 200, and 300 μmol/m²/s—on the nutritional composition and quality of hydroponic barley fodder. Assessments were made on biomass production, physiological responses including photosynthetic parameters, and nutritional components such as essential amino acids five days post-treatment. The findings indicated that increasing light intensity boosted photosynthetic activity, expanded leaf area, enhanced root length, and promoted biomass accumulation. However, the highest intensity tested, 300 μmol/m²/s, led to significant chlorophyll degradation, increased water loss, and induced oxidative stress, adversely affecting fodder quality and reducing essential amino acids. In contrast, an intensity of 200 μmol/m²/s was identified as optimal for promoting robust barley growth through principal component analysis. This optimal setting supported vigorous growth and ensured the production of nutrient-rich, high-quality fodder, providing a basis for scaling up production efficiently. This research offers crucial insights into optimizing light conditions to maximize both the yield and nutritional quality of hydroponically grown barley fodder, presenting a significant step forward in enhancing hydroponic farming practices.

Ecological stoichiometry offers critical insights into nutrient dynamics and soil–plant interactions in agroecosystems. To explore the effects of long-term fertilization on soil–cotton C, N, P stoichiometry and stoichiometric homeostasis in arid gray desert soils, this study was conducted at a national gray desert soil monitoring station in Xinjiang (87°28′27″ E, 43°56′32″ N, elevation: 595 m a.s.l.)—an arid and semi-arid region with an annual mean temperature of 5–8 °C and annual precipitation of 100–200 mm. Established in 1989, the 31-year experiment adopted a wheat–maize–cotton annual rotation system with six treatments: CK (control, no fertilizer), N (nitrogen fertilizer alone), NK (nitrogen + potassium fertilizer), NP (nitrogen + phosphorus fertilizer), PK (phosphorus + potassium fertilizer), and NPK (nitrogen + phosphorus + potassium fertilizer). Key results showed that balanced NPK fertilization significantly increased soil organic carbon (SOC) by 22.7% and soil total phosphorus (STP) by 48.6% compared to CK, while the N-only treatment elevated soil N:P to 3.2 (a 68.4% increase vs. CK), indicating severe phosphorus limitation. For cotton, NPK increased seed phosphorus content by 68.2% (vs. N treatment) but reduced straw carbon content by 10.2% (vs. PK treatment), reflecting a carbon allocation trade-off from vegetative to reproductive organs under nutrient sufficiency. Stoichiometric homeostasis differed between organs: seeds maintained stricter carbon regulation (1/H = −0.40) than straw (1/H = −0.64), while straw exhibited more plastic N:P ratios (1/H = 1.95), highlighting organ-specific adaptive strategies to nutrient supply. Redundancy analysis confirmed that soil available phosphorus (AP) was the primary driver of cotton P uptake and yield formation. The seed cotton yield of NPK (5796.9 kg ha⁻¹) was 111.7% higher than CK, with NP (N-P co-application) achieving a 94.7% yield increase vs. CK—only 7.9% lower than NPK, whereas single N application showed the lowest straw yield (5995.0 kg ha⁻¹) and limited yield improvement. These findings demonstrate that long-term balanced NPK fertilization optimizes soil C-N-P stoichiometric balance by enhancing SOC sequestration and phosphorus retention, regulating cotton organ-specific stoichiometric homeostasis, and promoting efficient nutrient uptake and assimilate translocation. The study confirms that phosphorus is the key limiting factor in arid gray desert soil cotton systems, and balanced NPK supply is essential to mitigate stoichiometric imbalances and sustain soil fertility and productivity. This provides targeted practical guidance for rational fertilization management in arid agroecosystems, emphasizing the need to prioritize phosphorus supply and avoid single-nutrient application to maximize resource use efficiency.

Determining regional and global carbon cycles hinges on investigating the dynamic characteristics and influencing factors of soil respiration in various types of natural grasslands located in arid regions, and these characteristics are important indicators for assessing the structural and functional health of grassland ecosystems. Such investigations also provide theoretical support for carbon sink monitoring, energy conservation, emission reduction and low-carbon development in the western arid zone and are important for obtaining an in-depth understanding of the carbon cycle, as well as for ecosystem management, restoration and the reconstruction of arid areas. In this study, during the growing season (from May to October) of 2022, the LI-8100A automated soil CO₂ flux system was used to measure the soil respiration rate (Rs), temperature from 1.5 m above the surface to depths of 5–25 cm (T, T₅, T₁₀, T₁₅, T₂₀ and T₂₅) and the soil moisture content (SM) at a depth of 20 cm in four types of grasslands: lowland meadow, alpine meadow, temperate desert steppe and temperate steppe desert. Five replicates were established for each plot, and the responses of Rs to T and SM were fitted to construct the optimal regression model. The results revealed that (1) the daily average soil respiration was highest in the lowland meadow (0.07 to 5.76 μmol·m⁻²·s⁻¹), followed by the alpine meadow (−0.57 to 0.95 μmol·m⁻²·s⁻¹), the temperate desert steppe (−0.45 to 3.0 μmol·m⁻²·s⁻¹) and the temperate steppe desert (−1.29 to 1.61 μmol·m⁻²·s⁻¹); (2) the soil respiration rates of the four grassland types were significantly correlated with the temperature in the 5–15 cm soil layer, and the best model was an exponential function; the peak values generally appeared between 13:00 and 17:00 (h), with the minimum values at 2:00 or 8:00 (h); the maximum value was observed in July–August, and the minimum value was observed in October; and the soil respiration in the lowland meadow was higher than that in the other three types of grassland during the same period. The average variation intensities of the soil respiration from May to October were as follows: temperate steppe desert (91.78%) > temperate desert steppe (76%) > alpine meadow (58.77%) > lowland meadow (43.93%). (3) The partial correlation analysis revealed that when soil temperature was used as a control, the correlation between SM and soil respiration in the four types of grasslands changed, and the coefficient of determination (R²) increased to varying degrees, explaining up to 80% of the variation in the soil respiration in the lowland meadows. The correlation between soil respiration and the SM normalized to 10 °C explained up to 93.8% of the variation in soil respiration; the two-factor fitting equations revealed that the model with soil temperature and SM was superior to the single-factor model with either soil temperature or SM.

Rhizosphere microorganisms effectively exploit nutrient resources within the rhizosphere, while growth-promoting bacteria in this environment play a vital role in regulating soil fertility and enhancing plant health. In this study, we utilized a comprehensive approach that included the isolation, purification, and identification of dominant microorganisms, alongside high-throughput sequencing technology. This methodology was employed to analyze the primary microbial groups and their diversity within the rhizosphere soil of Helichrysum arenarium (L.) Moench in Altay, Xinjiang, China. By isolating bacterial strains from the rhizosphere soil using a dilution coating method, we successfully obtained 43 distinct strains. Subsequently, selective media were employed to screen for growth-promoting characteristics among these isolated strains derived from the rhizosphere soil of H. arenarium (L.) Moench. The results, obtained through high-throughput amplification sequencing, revealed diverse bacterial communities belonging to 35 phyla, 93 orders, 215 families, 324 genera, and 231 species associated with H. arenarium (L.) Moench, as well as fungal communities comprising 14 phyla, 47 orders, 96 families, 204 genera, and 571 species present in the rhizosphere soil. Among these identified communities, Actinobacteriota emerged as the predominant bacterial phylum while Ascomycetes and Mortieromycetes were recognized as the principal fungal phyla found in the rhizospheric soil of H. arenarium (L.) Moench. Analysis of culturable bacteria’s promotion activity within this rhizospheric environment indicated that three strains—S16, S31, and S29—exhibited the highest solubility index for inorganic phosphorus; additionally, the screened strains S7 and S10 demonstrated nitrogen-fixing capabilities. Furthermore, ten strains exhibiting excellent iron-bearing capacities were identified; notably, strain S16 displayed the highest D/d value indicating, its superior iron-bearing capacity. The growth-promoting bacteria were identified as Kocuria rosea, Priestia megaterium, Bacillus mobilis, Bacillus bataviensis, three variants of Bacillus mycoides, Bacillus paramobilis, Bacillus sonorensis, and Alcaligenes faecalis. This study provides a foundational understanding of how microorganisms in the rhizosphere of H. arenarium (L.) Moench influence soil nutrient release and offers valuable insights into enhancing yield and quality cultivation by isolating, screening, and identifying growth-promoting bacteria from rhizosphere soil.

Rhizosphere microorganisms can utilize nutrient resources in the rhizosphere efficiently, while rhizosphere growth-promoting bacteria play a crucial role in regulating soil fertility and promoting plant health. In this study, we employed a combination of isolation, purification, identification of dominant microorganisms, and high-throughput sequencing technology to analyze the main microbial groups and diversity in the rhizosphere soil of Helichrysum arenarium（L.）Moench. in Altay, Xinjiang，China. By isolating bacterial strains from the rhizosphere soil using a dilution coating method, we successfully obtained 43 strains. Subsequently, selective medium was utilized to screen for growth-promoting characteristics among these isolated strains from the rhizosphere soil of H. arenarium（L.）Moench.. The results obtained through high-throughput amplification sequencing revealed that the rhizosphere soil harbored diverse bacterial communities belonging to 35 phyla, 93 orders, 215 families, 324 genera and 231 species associated with H. arenarium（L.）Moench., as well as fungal communities consisting of 14 phyla ,47 orders ,96 families ,204 genera and 571 species. Among these bacterial communities identified, eight phyla exhibited relative abundances exceeding 1%, with Actinobacteriota being most predominant at an abundance rate of 41.30%. Additionally,five bacterial genera were found to have relative abundances exceeding 1% ,with Arenimicrobium_luteum being most abundant at 6.11% . Furthermore,four fungal phyla displayed relative abundances surpassing1 % ,with Ascomycota accounting for 67.21% of total fungal community composition.Finally,four fungal genera demonstrated relative abundances higher than 1% ,with Knufia representing 3.80% of total fungal community composition.The analysis on culturable bacteria's promotion activity within the rhizospheric soil indicated that two strains,S16and S29, exhibited the highest solubility index for inorganic phosphorus. However, it lacked the ability to dissolve organophosphorus and potassium. On the other hand, strains S7 and S10, which were screened, demonstrated nitrogen-fixing capabilities. Nine strains with excellent iron-bearing capacity were identified, with strain S16 exhibiting the highest D/d value and strongest iron-bearing capacity among them. Our findings revealed that 43 rhizosphere soil bacteria belonged to three genera. The ten growth-promoting bacteria were identified as Kocuria rosea, Priestia megaterium, Bacillus mobilis, B. bataviensis, B. mycoides (two strains), B. paramobilis, and Alcaligenes faecalis. This study provides a particular research basis for the influence of H. arenarium（L.）Moench. rhizosphere microorganisms on soil nutrient release and depicts a solution for improving the yield and quality cultivation of H. arenarium（L.）Moench. by isolating, screening, and identifying rhizosphere soil growth-promoting bacteria, including screening strains with growth-promoting functions and analyzing the population structure of rhizosphere and habitat soil in combination with high-throughput sequencing technology.