Comparative Effects of Synthetic Zeolite and Chabazite on Soil Hydrological Properties and Lettuce Growth

The careful selection of soil amendments is critical for agricultural purposes. Zeolites stand out as an abundant, affordable solution whose unique porous structure improves soil quality and crop growth. However, their properties and agronomic performance vary depending on their origin and composition. This study aimed to compare the effects of natural chabazite and synthetic zeolite (derived from coal fly ash) on soil hydrophysical characteristics and the growth of lettuce (Lactuca sativa L.) under greenhouse conditions. A greenhouse experiment was conducted using a randomized block design with four replicates. Lettuce plants were grown in sandy-loam soil under three treatments: (i) 2% chabazite, (ii) 2% synthetic zeolite, and (iii) a control without amendment. Soil water retention curves (SWRCs) were used to assess hydrophysical properties. Growth parameters, including gas exchange, leaf water potential, fresh and dry biomass, leaf area, plant height, plant diameter, and water use efficiency, were measured. The chabazite-amended soil showed the highest available water (46.6%) and improved water retention, with reduced drainage water (36.8%) compared to the control (42.4%) and synthetic zeolite (42.6%). Lettuce plants grown in chabazite-treated soil exhibited superior growth performance, with higher fresh and dry weights, larger leaf area, and greater plant height. Natural chabazite significantly enhanced soil water availability and lettuce growth compared to synthetic zeolite and control treatments, demonstrating its potential as an effective, low-cost amendment for improving soil quality and crop productivity.