Cellulose nanofibers boost soil water availability, plant growth, and irrigation water use efficiency under deficit irrigation

Under climate change, even previously rainfall-prone areas may experience droughts, and effective strategies are vital for soil conservation. Owing to their cutting-edge water absorption and storage properties, cellulose nanofibers (CNF) are expected to increase soil water availability and help plants resist water stress. However, the role of CNF in improving plant growth and soil water retention under various irrigation regimes is not yet known. We evaluated the effects of CNFs on plant available water (PAW), germination, plant growth, and irrigation water use efficiency (IWUE) under both adequate and deficit irrigation conditions. Plant cultivation experiments were conducted using different CNF dosages (0%, 0.1%, 0.5%, and 1.0%), irrigation levels (I100, I50, and I25), and soil types (sandy and silty loam). The results indicated that CNF significantly increased field capacity (FC) and PAW in both soil types, with PAW in CNF-amended soils increasing by up to 110% and 88% in sandy and silty loam soil, respectively, at 1% CNF dosage. In germination tests, CNF showed no phytotoxicity and supported the germination process during water stress, with enhancements of up to 64% and 163% at I50 and up to 125% and 214% at I25 in germination percentage and germination index, respectively. Plant growth experiments revealed that CNF addition helped plants resist water stress, maintaining plant height and weight close to those under full irrigation, while using 50% less water. IWUE analyses demonstrated that CNF enhanced IWUE, with increases of up to 56% under sufficient watering (I100), 169% under moderate water stress (I50), and 120% under severe water stress (I25), at 1% CNF dosage. These findings highlight the potential of CNF as a multifaceted amendment, offering practical solutions for addressing water scarcity challenges and contributing to more resilient and sustainable agricultural practices.