[Objective] This study aims to systematically identify the chemical constituents of cotton stalk, laying the basis for in-depth exploitation and utilization of cotton stalk. [Methods] The ultra-high-performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry (UHPLC-Q-Exactive orbitrap MS) was performed with a Thermo Scientific Hypersil GOLD^TM aQ (100 mm × 2.1 mm, 1.9 μm) chromatographic column using gradient elution consist of 0.1% formic acid (A)-acetonitrile (B) as the mobile phase at a flow rate of 0.3 mL·min^-1, while the column temperature was set at 40 ℃, and the injection volume was 2 μL. The MS used electrospray ionization(ESI) source to gain the high-resolution mass data in positive or negative models by full MS scan with data dependence MS²(full MS/dd-MS²) involved in parallel reaction monitoring (PRM). [Results] A total of 102 components from cotton stalk were identified, including 13 flavonoids, 48 organic acids, 8 nucleotides, 10 terpenoids, 8 amino acids, 3 coumarins, 2 alkaloids, and 10 other compounds. Among them, 92 were found in cotton stalk for the first time. [Conclusion] The method based on UHPLC-Q-Exactive orbitrap MS combined with PRM was established, which is easy to operation, with high sensitivity, good specificity and rapid analysis. By this method, 102 compounds were identified in cotton stalks, and 92 compounds were identified for the first time, laying the foundation for the further development and utilization of cotton stalk. It provides reference for the in-depth exploitation and utilization of cotton stalk.

[Objective] This study aims to investigate the development characteristics of cotton carpel, the differentially expressed genes and plant hormone content among different carpel numbers, and the relationship between carpel number and cotton boll development. [Methods] Cotton plants with three carpels (C3), four carpels (C4), and five carpels (C5) were used as the research subjects. The development process of cotton carpel was observed, and the number of carpel in the offspring of different combinations was counted. Transcriptome sequencing and plant hormone content measurement of the carpels were performed at 5 days and 10 days after flower bud development, and on the day of flowering. Phenotype of cotton boll was measured at different developmental stages. [Results] When the flower bud length was 2-3 mm, the development of carpel primordia started; and when the flower bud developed to 4-5 mm, the carpel fused to form fully fused carpel. The development of carpel primordia preceded of pistil organ. The average number of carpel in F₁ from different crosses between C3, C4, and C5 parents was between the two parents. The differentially expressed genes of C3, C4, and C5 are mainly enriched in biological processes. During floral bud development at 5 days and 10 days, and on the day of flowering, the expression levels of key genes related to carpel development in the enrichment pathway, including AP1, AGL6, WUS, MYB21, and ARF6, in C5 were higher than that in C4, and significantly higher than that in C3. At 5 days and 10 days of floral bud development, jasmonic acid (JA) content in C5 was significantly higher than that in C3 and C4, while indole acetic acid (IAA) content was significantly lower than that in C3 and C4; abscisic acid content in C4 was significantly lower than that in C3 and C5. At 20 days, 35 days, and 60 days after flowering, the cotton boll diameter, fresh weight of cotton boll, thickness of cotton boll petals, and fresh weight of fiber and ovule in C5 were significantly higher than that in C3 and C4. [Conclusion] The average number of carpel in the offspring from different crosses between the parents with 3, 4, and 5 carpels was between the two parents. Several carpel development-related genes showed higher expression level in C5. Before flowering, C5 has the highest content of JA and the lowest content of IAA. Increasing carpel number is conducive to increase the boll diameter, boll fresh weight, and fresh weight of fiber and ovule.

[Objective] This study aims to explore the impact of diverse mulching techniques and irrigation quota on each application on cotton production. [Methods] Field experiments were conducted in Aral City, Xinjiang from 2017 to 2019. For the experiments under drip irrigation with plastic-film mulching in 2017 and 2018, Xinluzhong 46 was used as the test material, and three irrigation quotas on each application of 24 mm (M1), 30 mm (M2), and 36 mm (M3) were set. For the experiments under drip irrigation without plastic-film mulching in 2018 and 2019, Zhongmian 619 was used as the test material, and three irrigation quotas on each application of 36 mm (W1), 45 mm (W2), and 54 mm (W3) were set. The effects of different treatments on the soil temperature and water content in 10 cm, 20 cm and 40 cm soil layers, seed cotton yield, and irrigation water use efficiency were analyzed. [Results] The soil water content in 10 cm, 20 cm, and 40 cm soil layers of cotton fields, and seed cotton yield under the two mulching modes showed an increasing trend with the increase of irrigation quota on each application. Notably, the seed cotton yield of M2 and M3 treatments were significantly increased by 8.82%-11.47% and 14.24%-18.96% compared with M1 treatment, respectively. The seed cotton yield of W2 and W3 treatments were increased significantly by 15.18%-22.61% and 32.53%-46.29%, respectively, in comparison to W1 treatment. Both soil temperature and irrigation water use efficiency showed a declining trend with the increasing of irrigation quota on each application. The irrigation water use efficiency of M2 and M3 treatments were significantly declined by 10.82%-12.94% and 20.70%-23.84%, respectively, in comparison to M1 treatment. The irrigation water utilization efficiency of W2 and W3 treatments also showed a reduction, ranging from 1.91%-7.85% and 2.47%-11.65%, respectively, in comparison to W1 treatment. When the irrigation quota on each application were the same in 2018, the soil water content, soil temperature in 0-40 cm soil layer, seed cotton yield, and irrigation water use efficiency of M3 treatment were higher than that of W1 treatment. The comprehensive evaluation based on the technique for order preference by similarity to ideal solution (TOPSIS) indicated that superior outcomes could be obtained by aligning 30 mm irrigation quota on each application with the drip irrigation with plastic-film mulching treatment, and 54 mm irrigation quota on each application with the drip irrigation without plastic-film mulching treatment. [Conclusion] An increase in irrigation quota on each application can serve to offset the reduction in seed cotton yield resulting from the filmless planting mode to a certain extent, albeit at the cost of reduced irrigation water use efficiency. The findings of this study may provide reference for the promotion of drip irrigation without plastic-film mulching cotton planting technology in the local area.

[Objective] Low temperature is one of the main agrometeorological disasters during the cotton seedling period in Aksu Prefecture of Xinjiang, which seriously limits the stability and safety of cotton production. Clarifying the risk areas of cotton low temperature disaster during cotton seedling period in Aksu Prefecture can effectively improve the defense ability of this region to cope with low temperature. [Methods] Based on the meteorological data of Aksu Prefecture from 1961 to 2020, the changing trends of daily maximum temperature, daily minimum temperature, daily average temperature, and the changing frequency of low temperature disasters (cold wave and late frost injury) during the seedling period of cotton were analyzed by using the climatic tendency rate. The time distribution characteristics of cold wave and late frost injury in April to May were also analyzed. A comprehensive risk assessment model for low temperature disaster was established, and the risk regionalization of low temperature disaster during cotton seedling stage was carried out by analyzing the hazard index of low temperature disaster-inducing factors, and combining the exposure index of the hazard-bearing body, and local the disaster prevention and mitigation capacity. [Results] From 1961 to 2020, the daily minimum temperature, daily maximum temperature, and daily average temperature during the cotton seedling period in Aksu Prefecture showed a significant increasing trend, and the frequency of cold wave and late frost injury showed a decreasing trend. The incidence of cold wave and late frost injury in Aksu Prefecture is below 20% after 10 April and 12 April, respectively. The risk level of spring low temperature disaster-causing factors in Aksu Prefecture showed the spatial distribution characteristics of “high in the north and low in the south, high in the west and low in the east”. The results of comprehensive risk regionalization indicated that the central and east-central areas of Aksu Prefecture, which including Aral City, the central part of Aksu City, the north-eastern part of Awati County, the eastern edge of Kalpin County, the eastern part of Xinhe County, the south-western and central part of Kuqa City, the northern part of Xayar County, and the south-eastern part of Wensu County are the highest or higher level risk zones of low temperature disaster. [Conclusion] Although the spring temperature increased, and the frequency of cold wave and late frost injury decreased in Aksu Prefecture, the risk of low temperature disaster is still high in the central and east-central cotton growing areas in Aksu Prefecture, and targeted measures are needed to be taken to mitigate the impact of low temperature disasters on cotton production.

[Objective] This research aims to analyze the resilience level and its influencing factors of China's cotton industrial chain, and to provide reference for the development of cotton industry. [Methods] Based on the resilience theory, a evaluation index system for resilience of cotton industrial chain was constructed from four dimensions of resistance capability, recovery capability, update capability, and government power. And a dynamic evaluation model based on entropy weight-virtual optimal solution technique for order preference by similarity to an ideal solution (TOPSIS) and grey relational analysis was used to measure the resilience level of cotton industrial chain in China from 2007 to 2022. The spatial evolution characteristics of resilience level of cotton industrial chain in China were studied by using the geographic information system (GIS) spatial analysis techniques. Tobit regression model was used to explore the influencing factors of cotton industrial chain resilience. [Results] From 2007 to 2022, the resilience level of China's cotton industrial chain showed a trend of increasing first and then decreasing. In 2007-2016, it was a stable growth period; 2017-2021 was an accelerated growth period; and in 2022, the resilience level decreased, which is a challenging recovery period. From 2007 to 2022, the number of high and higher resilience value area of cotton industrial chain increased, while the number of lower value area decreased. The resilience levels of cotton industrial chain in Xinjiang, Gansu, Shandong, and Hubei were increasing. The levels of opening to the outside world as well as government support showed significant positive impact on the resilience of cotton industrial chain. The impact of scientific and technological innovation level and transportation infrastructure level on the resilience of cotton industrial chain were positive; while the impact of cotton price level was negative. [Conclusion] The resilience level of China's cotton industrial chain is on the rise in general, and the spatial pattern has changed greatly. It is necessary to continue to implement the cotton target price policy, strengthen scientific and technological innovation, and promote infrastructure construction to continuously enhance the resilience of China's cotton industrial chain.

[Objective] This research aims to measure the digital development level of cotton field in Xinjiang, analyze the obstacle factors and the main issues of the digital transformation, and propose corresponding countermeasures, so as to provide reference for promoting the modernization development of cotton industry in Xinjiang. [Methods] The evaluation index system was constructed from four dimensions: digital foundation, digital support, digital application, and digital efficiency. Analytic hierarchy process-entropy combination assigning method and the obstacle factor analysis method were used to analyze the digital development level and main obstacles of cotton field in Xinjiang from 2012 to 2021. [Results] The digital development level of cotton field in Xinjiang is increasing year by year. The composite score was raised from 1.68 in 2012 to 28.42 in 2021. The main obstacles to the digital development of Xinjiang cotton field have changed from the digital foundation, digital support, and digital applications in 2012 to digital applications and digital efficiency in 2021. Xinjiang cotton field has shortcomings in digital technology application, capital investment, large-scale development, technical personnel and so on. [Conclusion] The digital development of cotton field in Xinjiang has achieved some results, but there are still some problems. By strengthening the research and promotion of digital technology, promoting the scale and organization of cotton field, increasing policy support, and cultivating composite technical talents, it is expected to promote the digital transformation and upgrading of cotton field in Xinjiang.

[Objective] This study aims to analysis the effects of partial organic substitution for chemical fertilizer on soil and cotton root growth in different continuous cotton fields in Xinjiang, and to reveal the optimal proportion of organic fertilizer dosage, so as to provide reference for the rational application of fertilizers in continuous cotton fields in Xinjiang. [Methods] The cotton were planted in the grey desert soil and aeolian sandy soil, two common soil types of cotton fields in Xinjiang, and decomposed farm chicken manure was used as organic fertilizer, and setting up three fertilizer treatments: T1 treatment, 100% chemical fertilizer; T2, 80% chemical fertilizer + 20% organic fertilizer (2 250 kg·hm^-2 organic fertilizer); T3, 60% chemical fertilizer + 40% organic fertilizer (4 500 kg·hm^-2 organic fertilizer). The experiments were conducted using polyvinyl chloride pipes to study the effects of partial organic substitution for chemical fertilizer on the physical and chemical properties of cotton soil at the cotton budding stage and boll-opening stages, the morphological and physiological characteristics of cotton roots, as well as the biomass and yield of cotton. Principal component analysis and regression analysis were conducted on all indicators by using the comprehensive membership function method, to comprehensively evaluate the overall impact of different proportions of organic fertilizer and chemical fertilizer combinations on the soil-cotton system. [Results] Both T2 and T3 treatments significantly increased the total nitrogen content and available phosphorus content in grey desert soil and aeolian sandy soil. For grey desert soil, compared with T1, T2 treatment increased the total phosphorus content of the soil by 14.7% and 30.3%, and increased the available phosphorus content by 138.7% and 202.6% during the budding stage and boll-opening stage, respectively. For grey desert soil, compared with T1, T3 treatment increased the soil total nitrogen content by 39.2% during the budding stage and increased the soil total phosphorus content by 46.2% during the boll-opening stage. In T2 and T3 treatments, the total root length, specific root length, specific surface area, soluble sugar content, and nitrate reductase activity of cotton root were significantly increased, while the root tissue density and aboveground biomass were significantly decreased in gray desert soil. During the cotton budding stage in aeolian sandy soil, the specific root length of cotton were significantly increased by 11.9% and 9.6% under T2 and T3 treatments, respectively. Under T2 and T3 treatments during the cotton boll-opening stage in aeolian sandy soil, the alkaline nitrogen contents in the soil significantly were increased by 51.3% and 97.9%, respectively, while the total root length of cotton were significantly decreased by 26.9% and 21.0%; the specific root length of cotton were significantly decreased by 33.4% and 36.5%. T2 treatment significantly reduced the specific root surface areas by 18.8% and 19.3% during two stages, respectively. T3 treatment significantly increased the average root diameter (65.3%) and aboveground biomass (27.6%) of cotton during the boll-opening stage in aeolian sandy soil. [Conclusion] Partial substitution of chemical fertilizers with organic fertilizers can improve the physical and chemical characteristics of grey desert soil and aeolian sandy soil, increase soil nutrient contents, promote the physiological activity of cotton root, optimize root configuration, and enable cotton root to invest less biomass to obtain higher nutrient absorption benefits, optimize the allocation of biomass, and ultimately alleviate continuous cropping obstacles. In grey desert soil, organic fertilizer replacing 40% chemical fertilizer treatment has the best effect. The effect of partially substituting chemical fertilizers with organic fertilizers in sandy soil varies depending on the proportion of organic fertilizer added and the growth period.