Peer review

Enhanced-efficiency nitrogen (N) fertilizers (EENFs) such as slow-release polymer-coated urea (PCU) and deep placement of urea briquettes (UBs) improve nitrogen use efficiency (NUE) by reducing N losses and increasing nitrogen uptake by plants. Multilocation field trials (81) with cauliflower were conducted across two agroecological regions covering seven districts during two crop-growing seasons between 2018 and 2020 to assess the potential of three EENFs, i.e., PCU, sulphur-coated urea (SCU) and UB for increasing curd yields, agronomic NUE (AEN) and economic benefits over conventional urea (CU). Results were compared with farmers’ current nutrient management practice (FP): applying CU at 58.5 kg N ha−1 (ranging from 33 to 88 kg N ha−1). The N rates in three EENF treatments were 33% lower (100 kg N ha−1), considering their higher N use efficiency, than for CU (150 kg N ha−1). We hypothesize that EENFs produce similar or even higher yields compared with CU. For both years, all three EENFs resulted in significantly (p < 0.05) higher curd yields than CU (36.7 ± 1.1 t ha−1). PCU, SCU and UB increased yields by 21, 21 and 24% over those for CU. The yield increment was much higher (PCU, 44%; SCU, 43%; UB, 46%) than for FP. Similarly, PCU, SCU and UB increased the partial factor productivity of N (PFPN) by 91, 90 and 94% and the AEN by 133, 129 and 138%, respectively, compared with CU. The gross margins of all three EENFs were similar: an average 25% more than with CU and 51% more than with FP. These results suggest that EENFs could help increase productivity and farmer income while considerably reducing N input, compared to use of CU. The government of Nepal should promote these EENFs by removing barriers to access for the associated fertilizers and foster their use through extension.

Text in English

Pandit, N.R. : Not in IRS staff list but CIMMYT Affiliation

Gaihre, Y.K. : Not in IRS staff list but CIMMYT Affiliation

Maharjan, S. : Not in IRS staff list but CIMMYT Affiliation