Characterization and functional evaluation of urea-mesoporous nano-silica and urea-reduced graphene oxide nanocomposites on rice–wheat and soil health

Nanocomposites, a novel class of eco-friendly delivery materials, have emerged as promising candidates for improving nutrient retention and delivery efficiency in agricultural systems. This research covers synthesis of mesoporous nano silica (mNs) and reduced graphene oxide (rGO) based urea nanocomposites to assess their impact on crop response and soil health under greenhouse rice–wheat pot sequence. The characterization of developed nanocomposites was performed using FTIR, EDX, SEM, TEM, XRD and SAED technology. FTIR spectroscopy revealed molecular signatures viz N–H and C=O stretching patterns, confirming the incorporation of urea into nanomaterial framework. SEM and TEM further showed the formation of interface structures on silica and graphene surfaces due to urea engraftment. Functional evaluation revealed that urea-mNS nanocomposite at N120 (Urea-mNS)-P60-K40 consistently showed highest grain and straw yield, nitrogen content and nitrogen uptake in rice–wheat sequence. Further, N90 (Urea-mNS)-P60-K40 led to higher available N, P, K, microbial population and dehydrogenase activity (DHA). Contrarily, rGO-based nanocomposites reduced crop performance, nutrient availability and microbial activity at higher nitrogen levels. These findings suggest that mNS-based nanocomposites may serve as promising nutrient carrier systems in agriculture, while emphasizing the need for tailored strategies for rGO-based formulations. Nevertheless, dedicated release studies are required to confirm their potential controlled nutrient-release behavior.