Abstract:

To investigate the synergistic effects of combined application of flue gas desulfurization gypsum (FGD gypsum) and biochar on soil improvement and rice growth in coastal saline-alkali land, this study was conducted on typical coastal saline-alkali soils with different ratios of FGD gypsum to biochar. The effects of the treatments on soil salinity, physicochemical properties, aggregate stability, enzyme activities, and rice yield were systematically analyzed. The results showed that the combined application significantly reduced soil salinization: soil pH decreased by 0.46-0.76 units, and the sodium adsorption ratio (SAR) dropped significantly by 35.27%-60.48%. Meanwhile, the treatment markedly improved soil nutrient status, with available phosphorus, alkali-hydrolyzable nitrogen, and organic matter contents increasing by 10.57%-65.43%, 16.68%-35.38%, and 11.54%-32.55%, respectively; soil bulk density also exhibited a decreasing trend. In terms of soil structure, the combined treatment optimized aggregate composition: large aggregate content, mean weight diameter (MWD), and geometric mean diameter (GMD) increased significantly by 3.43%-10.74%, 9.83%-26.30%, and 11.04%-36.76%, respectively. Additionally, soil enzyme activities were significantly activated: sucrase, phosphatase, catalase, nitrate reductase, and polyphenol oxidase activities increased by 12.39%-55.71%, 17.67%-56.74%, 8.40%-28.54%, 28.57%-73.33%, and 17.99%-65.40%, respectively. Based on the soil quality evaluation using the full dataset, the B1F3 treatment (application of 6 000 kg/hm² FGD gypsum + 3 750 kg/hm² biochar) demonstrated the best comprehensive amelioration effect and the highest rice yield, making it a preferred mode for soil improvement and fertility enhancement in coastal saline-alkali land that can be promoted as a demonstration model.

Key words: rice, coastal saline alkali land, sodium adsorption ratio, aggregate stability, soil physical and chemical properties, soil enzyme activity, yield

摘要：

为探究脱硫石膏与生物炭配施对滨海盐碱地土壤改良及水稻生长的协同效应，本研究以典型滨海盐碱地为对象，设置脱硫石膏与生物炭不同配比处理，系统分析其对土壤盐碱度、理化性质、团聚体稳定性、酶活性及水稻产量的影响。结果表明，脱硫石膏与生物炭配施可显著降低土壤盐碱化程度，降低土壤pH值0.46~0.76个单位，显著降低钠吸附比（SAR）35.27%~60.48%。同时，该措施显著提升了土壤养分状况，有效磷、碱解氮及有机质含量分别增加10.57%~65.43%、16.68%~35.38%和11.54%~32.55%，且土壤容重呈下降趋势。在土壤结构方面，配施处理优化了团聚体组成，大团聚体含量、平均重量直径（MWD）及几何平均直径（GMD）分别显著提高3.43%~10.74%、9.83%~26.30%和11.04%~36.76%。此外，土壤酶活性亦得到显著激活，蔗糖酶、磷酸酶、过氧化氢酶、硝酸还原酶及多酚氧化酶活性分别提升12.39%~55.71%、17.67%~56.74%、8.40%~28.54%、28.57%~73.33%和17.99%~65.40%。基于全数据集的土壤质量评价结果显示，B1F3处理（施用脱硫石膏6 000 kg/hm²+生物炭3 750 kg/hm²）综合改良效果最优，对应水稻产量最高，可作为滨海盐碱地土壤改良与地力提升的优选模式示范推广。

关键词: 水稻, 滨海盐碱地, 钠吸附比, 团聚体稳定性, 土壤理化性质, 土壤酶活性, 产量