This study aimed to clarify the effects of jujube–cotton intercropping on cotton yield and photosynthetic characteristics, providing a theoretical basis for its application in the oasis irrigation areas of southern Xinjiang and offering practical recommendations to local farmers for increasing economic benefits. The effects were investigated from 2020 to 2023 using Zhongmian 619 cotton and juvenile jujube trees. Changes in leaf area index (LAI), transpiration rate (Tr), stomatal conductance (Gs), net photosynthetic rate (Pn), intercellular CO₂ concentration (Ci), yield, and economic benefits were evaluated over the years. The results showed that (1) a positive correlation was observed between LAI and the photosynthetic characteristics of cotton. Compared to monoculture cotton, intercropped cotton exhibited lower Pn, Gs, and Tr, and at the peak boll stage, monoculture cotton had significantly higher photosynthetic characteristics, indicating that intercropping affected cotton photosynthesis. (2) From 2020 to 2023, the land equivalent ratio (LER) of jujube–cotton intercropping remained above 1, with overall yield and economic benefit surpassing those of monoculture cotton and jujube, particularly in 2023 when the yield increased by 55.35%. (3) A significant positive correlation was found between cotton yield and LAI. In conclusion, jujube–cotton intercropping enhances photosynthesis, improving yield, economic benefits, and land use efficiency.

To explore the improvement effect of diversified crop rotation on soil quality in long-term continuous cotton fields (15 years), a field experiment was conducted in southern Xinjiang in 2024. With continuous cotton (C-C) as the control, four crop rotations, namely, cotton–maize (C-M), cotton–wheat (C-W), cotton–soybean (C-S), and cotton–peanut (C-P), were set up. The results showed that compared with C-C, the soil organic carbon (SOC) treated by C-P and C-S increased significantly by 11.76% and 3.38%, respectively, and the easily oxidized organic carbon (EOC) increased by 45.18% and 37.15%, respectively. The dissolved organic carbon (DOC) treated with C-S increased by 14.36%, while C-M decreased by 10.98%. The carbon pool index (CPI) of C-P was the highest in the 0–20 cm soil layer, which was 13.00% higher than that of C-C. The β-1, 4-glucosidase (BGL) activity of C-C at 0–20 cm and 20–40 cm was 144.70–387.26% and 48.01–71.32% higher than that of other treatments, respectively. The RuBisCo activity of C-P was 80.96% higher than that of C-C. The soil quality index was the highest for C-S, followed by C-P, which was 74.56% higher than that of C-C. In conclusion, the cotton–peanut rotation can effectively improve the soil quality of continuous cotton fields by increasing the organic carbon composition, enhancing the activity of carbon-fixing enzymes and bacterial diversity.

Asia minor bluegrass (Polypogon fugax), a widespread Poaceae weed, exhibits broad tolerance to abiotic stresses. Validated reference genes (RGs) for reliable RT-qPCR normalization in this ecologically and agriculturally significant species remain unidentified. This study identified eight candidate RGs using transcriptome data from seedling tissues. We assessed the expression stability of these eight RGs across various abiotic stresses and developmental stages using Delta Ct, BestKeeper, geNorm, and NormFinder algorithms. A comprehensive stability ranking was generated using RefFinder, with validation performed using the target genes COR413 and P5CS. Results identified EIF4A and TUB as the optimal RG combination for normalizing gene expression during heat stress, cold stress, and growth stages. EIF4A and ACT were most stable under drought stress, EIF4A and 28S under salt stress, and EIF4A and EF-1 under cadmium (Cd) stress. Furthermore, EIF4A and UBQ demonstrated optimal stability under herbicide stress. Additionally, application of validated RGs revealed higher acetyl-CoA carboxylase gene (ACCase) expression in one herbicide-resistant population, suggesting target-site gene overexpression contributes to resistance. This work presents the first systematic evaluation of RGs in P. fugax. The identified stable RGs provide essential tools for future gene expression studies on growth and abiotic stress responses in this species, facilitating deeper insights into the molecular basis of its weediness and adaptability.

Cotton root systems sustain photosynthesis by nutrient uptake and coordinate with above-ground growth to influence yield. This study explored the effects of fulvic acid (FA) and phosphorus (P) fertilizers on the relationships between cotton photosynthetic capacity (CAP) and root carbohydrate metabolism. A field experiment was conducted including five treatments: no P fertilizer (CK), 105 kg P₂O₅ ha⁻¹ (P1), 150 kg P₂O₅ ha⁻¹ (P2), 105 kg P₂O₅ ha⁻¹ + FA (FP1), and 150 kg P₂O₅ ha⁻¹ + FA (FP2). Results found that FP2 showed the most significant advantage, ensuring a suitable leaf area index (LAI) and cotton fractional interception of photosynthetically active radiation (IPAR) and consequently maintaining a high CAP. Compared with FP2, FP1 resulted in an increase in the boll loading of the root system (BLR) by 8.1% and the boll capacity of the root system (BCR) by 9.3%. From the peak flowering stage to the peak boll setting stage, sucrose and starch contents in FP1 were 6.2–19.2% and 26.5–27.9% lower than those in FP2, respectively. Conversely, fructose and glucose contents in FP1 were 6.4–10.8% and 7.2–8.8% higher than in FP2. The cotton reproductive organ biomass was increased by 11.1% and 14.7% relative to FP2. Moreover, FP1 achieved the highest yield, with an increase of 8.5% and 11.0% compared with P2 and FP2, respectively. Taken together, our study suggests that application of FP1 (105 kg P₂O₅ ha⁻¹ + FA) could be a proper P fertilization method in cotton production of saline-alkali and arid regions.

Salt stress is one of the environmental factors that limit the growth and development of cotton. Screening salt-tolerant varieties is of great significance for the utilization of salt-tolerant cotton germplasm resources and efficient production in saline land. This study used seven varieties, TH2 (Tahe 2), TH2311, XTM3 (Xintamian 3), XHM1 (Xinhuimian 1), QH18 (Qianhai 18), XLZ61 (Xinluzhong 61), and ZM63 (Zhongmian 63), to investigate the growth and physiological responses of different varieties to salt stress and to comprehensively evaluate their salt tolerance by setting three salt concentrations (0, 0.3, and 0.6%). The results showed that the K⁺ content of many varieties was significantly reduced under salt stress, such as ZM63, XHM1, XTM3, and TH2311. However, the K⁺ content in TH2 was significantly increased under salt stress; at 0.6% salinity, the K⁺ content in QH18 and XLZ61 did not change significantly compared with the control, which may mean that TH2 has a unique ability to regulate potassium homeostasis under salt stress, while QH18 and XLZ61 can maintain relatively normal potassium levels even in a high salt environment. Furthermore, this study found that salt stress significantly reduced the activity of some antioxidant enzymes in most varieties, but some varieties maintained high enzyme activity levels even at a salinity of 0.3%. Compared to the control, QH18 and TH2311 showed no significant change in SOD activity at 0.3% salinity; ZM63 showed no significant difference in POD activity; and XHM1 showed no significant difference in CAT activity. In addition, this study found that QH18, TH2311, and XHM1 exhibited relatively strong salt tolerance among the seven varieties. The research results provide a basis for the screening and utilization of salt-tolerant cotton varieties. Due to the fact that the research results were obtained based on seedling stage data, further research should be conducted in conjunction with multiple growth stages and field experiments to confirm.

The objective of this study is to clarify the effects of jujube-cotton intercropping on cotton yield and photosynthetic characteristics, to provide a theoretical basis for jujube-cotton intercropping in the oasis irrigation area of southern Xinjiang, and to provide new ideas for local farmers to improve their economic benefits. In this study, the effects of jujube-cotton intercropping on the photosynthetic characteristics and yield of cotton were studied from 2020 to 2023 using Zhongmian 619 cotton and juvenile jujube trees as experimental materials. The changes of lower leaf area index (LAI), transpiration rate (Tr), stomatal conductance (Gs), net photosynthetic rate (Pn), intercellular CO2 concentration (Ci), yield and economic benefits were evaluated in different years. The results showed that: (1) There was a positive correlation between leaf area index (LAI) and photosynthetic characteristics of cotton under different planting patterns; Compared with monoculture cotton, the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of jujube-cotton intercropping were lower than those of monoculture cotton in the intercropping mode. At the peak boll stage, the photosynthetic characteristics of monoculture cotton were significantly higher than those of intercropping cotton, indicating that the intercropping pattern of jujube cotton affected the photosynthesis of cotton to a certain extent. (2) From 2020 to 2023, the land equivalent ratio (LER) of jujube-cotton intercropping was greater than 1, and the overall yield and economic benefit of jujube-cotton intercropping system were higher than those of cotton monoculture and jujube monoculture, especially in 2023, the yield of IC treatment was as high as 55.35%. (3) From 2020 to 2023, there was a significant positive correlation between cotton yield and leaf area index (LAI). In conclusion, intercropping cotton can improve the land equivalent ratio and land utilization rate by improving the photosynthetic characteristics, and increase the economic benefits and total yield of juvenile jujube orchards.