Soil salinization is a critical issue impacting agriculture, particularly in arid and semi-arid regions. The objective of this study was to evaluate the effects of different drip irrigation and fertilization treatments on soil water and salt dynamics, maize water use efficiency, and crop yield in the saline–alkali soils of northern Ningxia, China. Over three years, four irrigation treatments were tested: CK (flood irrigation, 810 mm), W1 (low-volume drip irrigation, 360 mm), W2 (medium-volume drip irrigation, 450 mm), and W3 (high-volume drip irrigation, 540 mm). The results demonstrate that treatments W2 and W3 significantly increased soil moisture content at depths of 0–20 cm and 60–100 cm compared to CK, facilitating uniform salt leaching in the 0–40 cm soil layer. However, in the 40–100 cm layer, decreased porosity and upward moisture movement hindered salt migration, resulting in subsurface salt accumulation. Furthermore, drip irrigation combined with fertilization significantly reduced phosphorus fixation and nitrogen leaching, enhancing nutrient availability. This led to a reduction in underground leakage and surface evaporation by up to 39.63%, while water use efficiency improved by 18.97% to 55.13%. By the third year, grain yields under drip irrigation treatments increased significantly compared to CK, with W3 showing the highest gains (up to 21.90%). This study highlights the potential of integrating drip irrigation and fertilization as an effective strategy for managing saline–alkali soils, improving water use, and increasing crop productivity, providing valuable insights for sustainable agricultural practices.

As a beneficial nutrient and essential trace element, selenium plays a significant role in plant growth functions and human protein biosynthesis. Plant selenium enrichment is mainly obtained from both natural soil and exogenous selenium supplementation, while human beings consume selenium-enriched foods for the purposes of selenium supplementation. In this study, different types of selenium fertilizers were sprayed onto Lycium barbarum in Ningxia, and transcriptomics and metabolomics techniques were used to explore the effects of selenium on the fruit differentials and differential genes in Lycium barbarum. Taking the “Ning Qiyi No.1” wolfberry as the research object, sodium selenite, nano-selenium, and organic selenium were sprayed at a concentration of 100 mg·L⁻¹ three times from the first fruiting period to the harvesting period, with a control treatment comprising the spraying of clear water. We determined the major metabolites and differential genes of the amino acids and derivatives, flavonoids, and alkaloids in ripe wolfberries. We found that spraying selenium significantly enhanced the Lycium barbarum metabolic differentiators; the most effective spray was the organic selenium, with 129 major metabolic differentiators and 10 common metabolic pathways screened after spraying. Nano-selenium was the next best fertilizer we screened, with 111 major metabolic differentiators, the same number as organic selenium in terms of differential genes and common metabolite pathways. Sodium selenite was the least effective of the three, with only 59 of its major metabolic differentials screened, but its differential genes and metabolites were enriched for five common pathways.

The co-application of N and Fe can improve wine grape composition and promote the formation of flavor compounds. To understand the effects of foliar co-application of N and Fe on wine grape quality and flavonoid content, urea and EDTA-FE were sprayed at three different developmental stages. Urea and EDTA-Fe were sprayed during the early stage of the expansion period, at the end of the early stage of the expansion period to the late stage of the veraison period, and during the late stage of the veraison period. The results demonstrated that the co-application of urea and EDTA-Fe, particularly N application during the late stage of the veraison period and Fe application during the early stage of the berry expansion period (N3Fe1), significantly improved grape quality. Specifically, the soluble solid content of berries increased by 2.78–19.13%, titratable acidity decreased by 6.67–18.84%, the sugar-acid ratio became more balanced, and yield increased by 13.08–40.71%. Further, there was a significant increase in the relative content of amino acids and flavonoids. In conclusion, the application of Fe and N fertilizers at the pre-expansion and late veraison stages of grapes can significantly improve the quality and yield of berries; ultimately, this establishes a foundation for future improvement in the nutritional value of grapes and wine.