This study addresses the low yield and fertilizer utilization efficiency of potatoes in the arid region of Xinjiang, Northwest China. The effect of a novel, fulvic acid-based specialized fertilizer for drip application on potato growth, development, yield, and fertilizer efficiency is investigated. The aim is to identify a suitable fertilizer formula for potato cultivation in Xinjiang and promote its demonstration and application, providing a theoretical basis for improving fertilizer efficiency and achieving stable, high yields in the region. The experiment was conducted with potato variety ‘Xisen 6’ using a field trial design, which included five treatments: no fertilizer (CK), conventional fertilizer (CF: N-P-K = 258-245-338 kg·ha⁻¹), formulated fertilizer 1 (F1: 120 g·L⁻¹ fulvic acid, N-P-K = 110-100-120 g·L⁻¹), formulated fertilizer 2 (F2: 60 g·L⁻¹ fulvic acid, N-P-K = 130-120-150 g·L⁻¹), and formulated fertilizer 3 (F3: 30 g·L⁻¹ fulvic acid, N-P-K = 170-150-130 g·L⁻¹). Agronomic traits, gas exchange parameters of leaves during the tuber expansion stage, and yield components at harvest were measured, along with the fertilizer use efficiency for each treatment. Results show that F1, F2, and F3 improved the potato plant height, stem diameter, aboveground dry weight, SPAD value, stomatal conductance (Gs), and yield. Among these, F2 significantly enhanced plant height, stem diameter, aboveground dry weight, and the accumulation of relative chlorophyll content (SPAD value) during the tuber expansion stage, increased photosynthesis, and further improved yield and fertilizer efficiency, resulting in a yield increase of 121.29% and 34.6% compared to CK and CF, respectively. Therefore, formula fertilizer F2 is identified as the optimal fertilization strategy for potato cultivation in Xinjiang. Its application has been further extended in demonstration trials. Field demonstration results show that F2 significantly increased potato yield, with a 14.79% yield increase compared to CK, proving its effectiveness in replacing conventional fertilizers and enhancing production.

Soil salinization is a major limiting factor for cotton growth in Southern Xinjiang. Studying technologies and mechanisms to improve cotton salt tolerance is of significant importance for the development and utilization of saline–alkaline land. In this study, ‘Xinluzhong 40’ cotton was used as the material, and 150 mmol·L⁻¹ sodium chloride (NaCl) and 1.2% natural saline–alkaline soil extract were employed to simulate single-salt (SS) and mixed-salt (MS) stresses, respectively. The effects of different exogenous substances (sodium nitrophenolate, 24-epibrassinolide, and γ-aminobutyric acid) on the growth characteristics of cotton under salt stress were investigated. The results show that: (1) Under salt stress, the height and biomass of cotton (50 d old) were reduced. Both SS and MS stresses led to increased superoxide dismutase (SOD) activity, elevated proline (PRO) content (with an increase of 50.01% and no significant difference), and increased malondialdehyde (MDA) content (with increases of 63.14% and 32.42%, respectively). At the same time, catalase (CAT) activity decreased, Na⁺ and Cl⁻ contents increased, K⁺ content decreased, and the K⁺/Na⁺ ratio was reduced. (2) Application of sodium nitrophenolate (S), 24-epibrassinolide (E), and γ-aminobutyric acid (G) significantly improved SOD activity and PRO content while reducing MDA content (decreased by 29.33%, 25.48%, and 30.47% compared to SS treatment; and 1.68%, 5.21%, and 5.49% compared to MS treatment, respectively). They also increased CAT activity (increased by 75.97%, 103.24%, and 80.79% compared to SS treatment; and 91.06%, 82.43%, and 119.68% compared to MS treatment, respectively) and K⁺/Na⁺ ratio (increased by 57.59%, 66.35%, and 70.50% compared to SS treatment; and 38.31%, 42.97%, and 66.66% compared to MS treatment, respectively), reduced Cl⁻ content, and promoted increases in plant height and biomass. The effects of exogenous substances on antioxidant capacity and ion balance under salt stress were significant, particularly under SS stress. (3) Principal component analysis revealed that under SS and MS stresses, principal component 1 mainly reflects cotton’s antioxidant capacity, with SOD, CAT, and PRO having high weights; principal component 2 mainly reflects cotton’s ion balance and nutrient absorption, with root Na⁺, stem Na⁺, leaf Na⁺, root K⁺, and root Cl⁻ having high weights. These findings highlight the potential of exogenous substances to improve cotton salt tolerance and provide scientific evidence for cotton cultivation on saline–alkaline land, offering new insights into cultivation techniques from an applied research perspective.

Northern China is a major potato-producing region, where water scarcity and low fertilizer use efficiency significantly constrain potato production. A field experiment was conducted in Xinjiang, China, in 2023 using the potato cultivar ‘Xisen 6’ to investigate the effects of a novel fulvic acid (FA)-enriched specialized fertilizer on potato growth, photosynthetic characteristics, yield, and water-fertilizer use efficiency under different drip irrigation levels. Three irrigation regimes were applied: conventional irrigation (W1: 4582.5 m³·ha^-1), 15% deficit irrigation (W2: 3865.5 m³·ha^-1), and 30% deficit irrigation (W3: 3165 m³·ha^-1). Five fertilization treatments were implemented: no fertilizer (CK), conventional fertilizer (CF), and three FA-enriched formula fertilizers—F1 (FA: 120 g·L^-1, N-P-K = 110-100-120), F2 (FA: 60 g·L^-1, N-P-K = 130-120-150), and F3 (FA: 30 g·L^-1, N-P-K = 170-150-130). The results indicated that both irrigation (W) and fertilization (F) significantly influenced potato growth, yield, and the efficiency of water and fertilizer use. Under W2 irrigation, the W2F2 treatment achieved optimal performance, with plant height, aboveground dry weight, SPAD, and tuber yield increasing by 56.67%, 71.24%, 21.69%, and 121.29%, respectively, compared to CK. WUE and PFP reached 13.84 kg·m^-3 and 100.1 kg·kg^-1, respectively, while maintaining a yield of 59.49 t·ha^-1 under 15% water-saving conditions. Tuber yield exhibited highly significant positive correlations with plant height, aboveground dry weight, SPAD, net photosynthetic rate, WUE, and PFP. Principal component analysis based on growth, yield, and resource use efficiency identified W2F2 as the highest-ranked treatment. In conclusion, for ‘Xisen 6’ cultivation in Northwest China, applying formula fertilizer F2 (FA: 60 g·L^-1, N-P-K = 130-120-150) under a drip irrigation rate of 3865.5 m³·ha^-1 significantly enhances plant growth, yield, and water use efficiency, providing a sustainable strategy for optimizing potato production.