Improving soil enzyme activity and nutrient use efficiency in rice-wheat cropping systems through integrated use of neem coated urea

Purpose Chemical fertilizers have supported global food production for over six decades, contributing nearly 50% of agricultural nitrogen (N) inputs; however, crop nitrogen use efficiency (NUE) remains low (10–50%) due to losses through nitrate leaching, ammonia volatilization, and nitrous oxide emissions. This study evaluated nitrogen inhibitors and slow-release fertilizers to enhance nutrient uptake, nutrient use efficiency (NuUE), and soil enzymatic activity in rice. Materials A field experiment was conducted at the Research Farm of Lovely Professional University, Phagwara, Punjab, using a randomized block design with nine treatments and three replications. Treatments included conventional recommended fertilizer dose (RDF), neem-coated urea (NCU), anhydrous ammonia, and their combinations with PK, sulfur, and zinc sources. Result Enzyme activities increased during heading and declined after harvest, with maximum activity in the surface layer. The treatment NCU + PK + S + Zn-EDTA showed the highest enzymatic activity, resulting in up to 36% NUE improvement compared to control. Conclusion The study demonstrated that integrating slow-release nitrogen fertilizers with balanced nutrient management enhances NUE, soil enzyme activity, and overall fertilizer efficiency, supporting sustainable crop production.