Functionally Responsive Hydrogels with Salt-Alkali Sensitivity Effectively Target Soil Amelioration.

The long-standing crisis of soil salinization and alkalization poses a significant challenge to global agricultural development. High soil salinity -alkalinity, water dispersion, and nutrient loss present major hurdles to soil improvement. Novel environmentally friendly gels have demonstrated excellent water retention and slow -release capabilities in agricultural enhancement. However, their application for improving saline -alkali soil is both scarce and competitive. This study proposes a new strategy for regulating saline -alkali soil using gel -coated controlled -release soil modifiers (CWR-SRMs), where radical -polymerized gels are embedded on the surface of composite gel beads through spray coating. Characterization and performance analysis reveal that the threedimensional spatial network structure rich in hydrophilic groups exhibits good thermal stability (first -stage weight loss temperature of 257.7 degrees C in thermogravimetric analysis) and encapsulation efficiency for fulvic acid-potassium (FA -K), which can enhance soil quality in saline -alkali environments. The molecular chain relaxation under saline -alkali conditions promotes a synergistic effect of swelling and slow release, endowing it with qualifications as a water reservoir, Ca2+ source unit, and slow -release body. The results of a 6 weeks incubation experiment on 0-20 cm saline -alkaline soil with different application gradients showed that the gradient content had a significant effect on the soil improvement effect. Specifically, the T2 (the dosage accounted for 1 % of soil mass) treatment significantly increases water retention (30 % - 90 %), and nutrient levels (30 % - 50 %), while significantly decreasing soil sodium colloid content (30 % - 60 %) and soil pH (10 % - 15 %). Furthermore, PCA analysis indicates that the addition of 1 % CWR-SRMs as amendments can significantly adjust the negative aspects of soil salinity and alkalinity. This highlights the excellent applicability of CWR-SRMs in improving saline -alkali agricultural ecosystems, demonstrating the potential value of novel environmentally friendly gels as an alternative solution for soil challenges persistently affected by adverse salinity and alkalinity.