In this study, eight‐year‐old wine grape plants (Cabernet Sauvignon) were subjected to five different iron treatments: ferrous sulfate, ferric ethylenediaminetetraacetic acid (EDTA‐Fe), ferric citrate, ferric gluconate, and ferric sugar alcohol, and conventional fertilization. Foliar spraying with clear water was used as the control treatment. The effects of different iron treatments on berry quality and flavonoid accumulation in grape peels were explored. All five iron treatments affected the sugar, acid, and peel flavonoid contents of grape berries, but the contents varied greatly among the different iron treatments. Foliar spraying with iron increased berry sugar content and reduced acid content. In addition, foliar spraying with ferrous sulfate, EDTA‐Fe, ferric gluconate, and ferric sugar alcohol reduced the total anthocyanin, flavanol, and flavonol contents in the peel. The unique flavonoid monomer content of the peel was significantly higher under ferric citrate treatment than under the control and other iron treatments. Moreover, the results showed that foliar spraying with ferric citrate balanced the berry sugar–acid ratio and also increased the anthocyanin, flavanol, and flavonol contents of the grape peel, thereby improving the overall nutritional status of the berries and the final wine quality. The results obtained in this study demonstrate that different iron treatments could improve grape berry quality and clarify the effects of different exogenous iron treatments.

Soil secondary salinization in the Yellow River Diversion Irrigation Area of Northwest China seriously threatens local agricultural production. Drip irrigation technology is one of the largest contributors to low-yielding saline-alkali land; however, research on the high spatio-temporal scale variability of soil moisture and salinity in drip irrigation is still lacking. Herein, four treatments, CK (flood irrigation, 900 mm), W1 (small volume drip irrigation, 360 mm), W2 (medium volume drip irrigation, 450 mm), and W3 (large volume drip irrigation, 540 mm), were set up to investigate the characteristics and laws of soil moisture and salinity under different irrigation methods. The results showed that the soil moisture of drip irrigation was 5.02%–17.88% (W1), 7.36%–21.06% (W2), and 13.79%–27.88% (W3) higher than that of flood irrigation, resulting in a vertical distribution of soil moisture being low at the top and high at the bottom. Under drip irrigation, the soil salinity formed a desalination zone centered on the drip emitter and this zone gradually expanded to deeper soil with continuous drip irrigation, gradually transforming the soil from surface aggregation type to the bottom accumulation type. The desalination rates of W1, W2, and W3 were 18.46%, 20.84%, and 22.94%, respectively, whereas the salt leaching rate of CK was slower and the salt distribution was not uniform; therefore, the desalination rate was only 5.32%. By precisely controlling the irrigation water volume and flow, drip irrigation significantly reduced surface evaporation and subsurface leakage of water and improved water use efficiency, thus increasing grain yield. Compared with flood irrigation, the yield increase rates of W1, W2, and W3 were 6.6%, 16.18%, and 18.32%, respectively. Therefore, drip irrigation with an appropriate irrigation volume in the saline land in northern Ningxia can improve water saving, salt suppression, and maize yield.

Conventional organic soil amendments and drip irrigation are insufficient for mitigating soil salinization. The development of a more potent soil amendment with higher water retention capability is critical. Carboxymethyl cellulose (CMC) has excellent water retention and adsorption properties and is suitable for soil water retention and amendment; however, its effects on water and salt distribution, soil nutrients, and maize yield have not been clearly investigated. We set up five treatments with flood irrigation (CK), drip irrigation (W), drip irrigation combined with 100 kg CMC ha−1 (WC1), drip irrigation combined with 200 kg CMC ha−1 (WC2), and drip irrigation combined with 300 kg CMC ha−1 (WC3). Our findings demonstrate that the application of CMC in conjunction with drip irrigation led to a significant surge in soil water content within the 0–40 cm layer, ranging from 3.73% to 16.46%, while simultaneously inducing a reduction in salt content of 4.08% to 16.61%. Consequently, this resulted in a desalination rate spanning from 10.32% to 12.93%. The salt was gradually washed down and formed a desalination area with the drip emitter as the center, and the salt distribution characteristics shifted from a surface accumulation type to a bottom deposition type. The drip irrigation and CMC application also increased the content of available nutrients, reduced surface evaporation, underground water loss, and maize evapotranspiration, and improved water-use efficiency, thus increasing the aboveground biomass and grain yield. In summary, CMC had a significant effect on water retention, desalination, and yield increases. It can serve as a novel soil amendment for salt-affected soil.