Effects of nitrogen fertilizer types and alternate wetting and drying irrigation on rice yield and nitrous oxide emission in rice cultivation

• Published in: Can Tho University Journal of Science no. 6
• Main Authors: Thanh Phong Vo, Thi Anh Dao Nguyen, My Hoa Nguyen
• Format: Journal Article
• Language: English
• Published: CAN THO UNIVERSITY PUBLISHING HOUSE 01.07.2017
• Subjects: alternate wetting and drying irrigation; fertilizer deep placement; isobutylidene diurea; nitrous oxide emission; NPK briquette; rice yield
• ISSN: 2615-9422; 2815-5602
• DOI: 10.22144/ctu.jen.2017.025

Improvements on nitrogen (N) efficiency in rice cultivation have been increasingly concerned till now with using new types of N fertilizer. Aims of the study were to investigate the effect of N fertilizer types and alternate wetting and drying irrigation on rice yield and N2O emission in rice cultivation in the Mekong Delta of Vietnam. The design of experiment was split plot with two water management regimes in main plots which were (1) alternate wetting and drying (AWD) and (2) farmer practice (FP); and four N fertilizer types in sub-plots were (1) urea (2) N-(n-Butyl) Thiophosphoric Triamide (nBTPT) urease inhibitor, (3) NPK briquette deep placement technique and (4) Isobutylidene Diurea (IBDU) slow N-release. N2O emission was investigated every three days from 10 to 60 days after sowing (DAS). The results showed that AWD treatment had higher rice yields (5.14 t.ha-1) than FP treatment (4.68 t.ha-1), but rice yields of the new fertilizer type treatments were not significantly different compared with that of urea treatment. Concentrations of N2O increased after broadcasting fertilizer in treatments of urea and urea-nBTPT and then decreased thereafter in both FP and AWD irrigations. In treatments of NPK briquette and NPK IBDU, N2O fluxes remained low throughout crop although the fluxes increased in times  of soil drainage under AWD regime. Cumulative N2O emissions of urea-nBTPT, NPK briquette or NPK IBDU treatments (1.67, 1.47 or 1.29 kgN2O.ha-1, respectively) were significantly lower than that of urea treatment (2.47 kgN2O.ha-1). The results suggested that application of urea-nBTPT, NPK briquette and NPK IBDU were effective in mitigating N2O emission in rice fields which contributes to attenuate the greenhouse effect.