2025-05-162025-05-162025https://hdl.handle.net/10883/35643CIMMYT manages Intellectual Assets as International Public Goods. The user is free to download, print, store and share this work. In case you want to translate or create any other derivative work and share or distribute such translation/derivative work, please contact CIMMYT-Knowledge-Center@cgiar.org indicating the work you want to use and the kind of use you intend; CIMMYT will contact you with the suitable license for that purposeAGRICULTURAL SCIENCES AND BIOTECHNOLOGYArticle10.3390/nitrogen6010007Best Management PracticesNitrogen ManagementMaize ProductivityThe imbalanced use of fertilizers, particularly the inefficient application of nitrogen (N), has led to reduced nitrogen use efficiency (NUE), lowered crop yields and increased N losses in Nepal. This study aimed to enhance yields, NUE and farm profitability by optimizing N fertilizer rates, application timing and methods through multilocation trials and demonstrations. In 2017, 57 field trials were conducted in two mid-hill districts using a completely randomized block design. The treatments included control (CK), NPK omission (N0, P0 and K0), variable N rates (60, 120, 180 and 210 kg N ha-1) and top-dressing timings (120 kg N ha-1 applied at knee height and shoulder height, V6, V10 and V8 stages). A full dose of recommended P (60 kg ha-1) and K (40 kg ha-1) were applied at planting, while N was top-dressed in two equal splits at knee-height and shoulder-height growth stages for P and K omission treatments, as well as for treatment with variable N rates. Grain yields responded quadratically, with optimum N rates ranging from 120 to 180 kg ha-1 across the districts. N applied at 120 kg ha-1 and top-dressed at V6 and V10 increased maize yield by 20-25%, partial factor productivity of nitrogen (PFPN) by 12%, agronomic efficiency of nitrogen (AEN) by 21% and gross margin by 10% compared to conventional knee and shoulder height application. In 2018 and 2019, fertilizer BMPs, including V6 and V10 top-dressing and the urea briquette deep placement (UDP) were demonstrated on 102 farmers' fields across five mid-hill districts to compare their agronomic and economic significance over traditional farmers' practice (FP). UDP, validated in 2018 field trials, increased yields by 34% (8.8 t ha-1) and urea top-dressing at V6 and V10 increased yield by 33% (8.7 t ha-1) compared to FP (5.8 t ha-1), reducing the average yield gap by 3.0 t ha-1. Moreover, the gross margin was increased by 39% (V6 and V10) and 40% (UDP) over FP. The findings highlight the need for widespread adoption of fertilizer BMPs to close the yield gap and maximize profitability with minimal nitrogen footprint.NITROGENMAIZEPRODUCTIVITYNITROGEN-USE EFFICIENCYFARM INCOMEOpen AccessSustainable Agrifood Systems