Cellulose-Based and Commercial Polyacrylate Hydrogels as Soil Amendments and Soilless Substrates for Microgreens...

Water scarcity restricts agricultural productivity and crop yield in many regions. Hydrogels have emerged as promising materials for soil amendment and soilless cultivation. Herein, cellulose hydrogels prepared from waste paper via a DMAc/LiCl solvent system (HG-WP) and from cotton microcrystalline cellulose via NaOH/aq. dissolution (HG-MCC) were investigated. HG-WP formed semi-solid, mechanically stable materials with high porosity, capable of retaining their shape during handling and plant cultivation, whereas HG-MCC appeared denser and less elastic. Their properties and agricultural performance were compared with those of a commercial polyacrylate hydrogel (HG-PA). The three hydrogels differed substantially in water capacity: HG-PA demonstrated the highest (50.13 g/g), whereas HG-WP and HG-MCC showed 30.57 and 3.66 g/g, respectively. Soil amended with 20 wt.% cellulose hydrogel exhibited improved water retention compared with untreated soil during the first 7 days of drying. Under laboratory conditions, hydrogels increased mustard biomass in soil under regular watering and plant survival under drought conditions. In soilless systems, cellulose hydrogels accelerated germination and improved plant development compared with control substrates. In soilless pea cultivation, HG-WP increased total biomass and survival from 56.7% to 79.3%. During basil cultivation in soil, cellulose hydrogel increased plant survival by 13.3% and mean biomass by 10.5% compared with the control. The results demonstrate the potential of cellulose hydrogels as biodegradable soil amendments and soilless substrates for short-cycle crop cultivation, outperforming the commercial polyacrylate hydrogel as an independent soilless substrate.