Lignin-polybutylene adipate-co-terephthalate(PBAT)-starch@urea bilayer nanohybrid biocomposite enable superior controlled slow-released fertilizer with good water-retention.

Slow-release fertilizers (SRFs) have revolutionized agricultural practices by enhancing nutrient utilization efficiency and minimizing environmental contamination. However, conventional SRFs face significant limitations, including unpredictable release patterns, dependence on non-biodegradable synthetic coatings, and inadequate performance in arid soil conditions. To address these challenges, we have developed an innovative approach to transform agricultural waste biomass into a multifunctional lignin-based SRF with superior water retention properties. Our bilayer lignin-based slow-release urea fertilizer (PSLB-SRF) was engineered using cost-effective, biodegradable materials: starch, poly(butylene adipate-co-terephthalate) (PBAT), and lignin derived from corn stover, a major agricultural byproduct. The resulting nanohybrid biocomposite exhibits exceptional controlled-release properties, demonstrating only 55 % cumulative urea release over 28 days - well within the Chinese National Standard GB requirement of <60 %. Furthermore, the material shows remarkable water retention capabilities, as evidenced by its ability to maintain 100 % chickweed survival under simulated drought conditions in field experiments. This breakthrough highlights the composite's potential for arid region applications. This cost-effective, biodegradable, and multifunctional lignin-based nanohybrid biocomposite represents a significant advancement in sustainable agriculture, offering a dual solution for agricultural waste valorization and developing high-performance fertilizers for sustainable farming practices.