Abstract The aim of this study was to develop alginate-based hydrogels for application in horticultural field as bio-based substrate additives to control moisture. For this purpose, a 2-level factorial design was performed to select the appropriate levels of significant variables, i.e. polymer concentration (2–3% w/v), CaCl2 concentration (0.2–0.4% w/v), and cross-linking time (10–30 min). Statistical analysis showed that CaCl2 concentration and cross-linking time were the most significant variables affecting the swelling properties of the alginate-based hydrogels. Hence, two formulations (2 or 3% w/v of alginate, cross-linked with 0.2% w/v of CaCl2 for 10 min) were chosen for further analysis. A complete characterization of each material was performed in terms of swelling degree (SD) and kinetics in distilled and tap water, gel fraction, thermal properties, morphology, and Fourier transformed infrared spectroscopy. SD after 24 h in distilled water was above 55 g/g dry hydrogel in both formulations. Bioassays performed in lettuce plants as well as substrate microbiota provided evidence for the putative application of alginate-based hydrogels in horticultural systems, with an 80% increase in fresh weight of the plants grown in substrate supplemented with 5% hydrogels compared to control substrate after 7 days under drought conditions.

中文翻译：

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大孔海藻酸盐水凝胶控制土壤基质水分：对干旱胁迫下生菜植物的影响

摘要 本研究的目的是开发用于园艺领域的藻酸盐基水凝胶作为生物基基质添加剂来控制水分。为此，进行了 2 水平因子设计以选择适当水平的重要变量，即聚合物浓度 (2–3% w/v)、CaCl2 浓度 (0.2–0.4% w/v) 和交联时间（10-30 分钟）。统计分析表明，CaCl2 浓度和交联时间是影响藻酸盐基水凝胶溶胀性能的最重要变量。因此，选择了两种配方（2% 或 3% w/v 的藻酸盐，用 0.2% w/v 的 CaCl2 交联 10 分钟）进行进一步分析。在蒸馏水和自来水中的溶胀度 (SD) 和动力学、凝胶分数、热性质、形貌和傅里叶变换红外光谱。在蒸馏水中 24 小时后，两种制剂的 SD 均高于 55 g/g 干水凝胶。在生菜植物和底物微生物群中进行的生物测定为基于藻酸盐的水凝胶在园艺系统中的假定应用提供了证据，与对照底物相比，在添加 5% 水凝胶的底物中生长的植物的鲜重增加了 80%。干旱条件下的天数。