Cellulose-based phosphorylated bamboo with slow urea release and lower carbon footprints improves rainfed rice crop productivity in field trials.

With unprecedented global climate changes, rice crop cultivation under rainfed conditions encounters alternate wetting and drying cycles with water and nutrient stress, which leads to poor yield, quality, and productivity. A modified cellulose-based, slow urea-releasing and water-retaining system from bamboo is developed for rainfed rice crops, to overcome such challenges to emerging rice crops and improve soil health for subsequent crop cycles. Bamboo was delignified to expose the cellulose and subsequent phosphorylation (DPB), followed by strategic urea infiltration and melting to deposit it into the microporous matrix. The melted DPB urea (MDU) presents a zone of influence of 52.5 cm/cm MDU, with water retention of 72 h for supporting plant growth during water stress upto ~6 days. MDU also displays a sustained release of 45-55 % urea for ~11 days in black, red, and alluvial soils. The application of MDU in the field study of rainfed rice crops showed improved plant height (16.66 %), chlorophyll content (32 %), grain yield (230 kg/ha), nitrogen (1.60 %), and phosphate content (0.089 %) of rice grains with the presence of ureolytic microbes (Sporosarcina) for improved soil quality. Cellulose-based MDU is biodegradable (98.1 %) in soil and generates relatively lower carbon footprints during production (~70.7 % lower GWP) than non-degradable acrylamide. Cellulose from renewable forest resources like bamboo, has been modified strategically using an eco-friendly approach to enhance the rainfed rice crop yield and soil conditions creating a closed-loop circular bioeconomy with low-carbon footprints for sustainable agriculture.