Abstract:
The increasing demand for sustainable agricultural practices necessitates the
development of advanced fertilizers that can efficiently deliver nutrients while
minimizing environmental impact. In this study, a dual-coated fertilizer was developed
to enhance the efficiency of urea by coating bio-based polymer derived from cotton
stalk and subsequently zinc-doped carbon quantum dot (Zn-CQDs) integrated in a
hydrogel. This innovative approach addresses the need for controlled N release and
tailored Zn supplementation, essential for optimal plant growth, human health, and
environmental sustainability. Characterization of Zn-CQDs confirmed successful Zn
doping, with XRD peaks between 30° to 35° indicative of crystalline graphitic layers
and ZnO, while FTIR spectra revealed the presence of key functional groups.
Furthermore, SEM images displayed well-attached zinc oxide particles on spherical
carbon dots, further corroborated by EDX analysis showing the presence of C, N, O,
and Zn elements. At the next step, the prepared dual-coated fertilizer was evaluated
following ISO-standards for slow N release characteristics over 28 d in both water and
sand columns. Aliquots were collected and quantified for N contents using Total
Kjeldahl N (TKN) and Zn via Atomic Absorption Spectrophotometer. Cumulative N
release was almost 75% in 28 days, while cumulative Zn release was up to 1ppm in
both water and sand. They are following the ISO standards and fertilizer Zn demand.
Future studies should focus on performing controlled lab tests on selected major crops
followed by field experiments aiming to enhance crop yields and meet food security
targets.
