Effect of rates and sources of nitrogen on rice yield, nitrogen efficiency, and methane emission from irrigated rice cultivation uri icon

abstract

  • The agronomic benefits of manure application to increase rice production have been recognized, but the impact on global change has always been a controversial topic. This study was designed to determine the separate and combined effects of cattle manure (CM) and nitrogen (N) fertilizer on rice yield, N efficiency, and methane (CH4) emissions from rice cultivation. A pot-scale experiment was conducted with four levels (0, 60, 120, and 180kgha(-1)) of N from urea and two levels (120 and 180kgha(-1)) of N from combination of urea and CM (Urea:CM=60:60 and 60:120). Rice yield and physiological N efficiency were obtained using agronomic measurements. To determine the global warming potential (GWP) of each treatment, CH4 emissions were measured throughout the rice-growing period. Grain yield (GY) was not significantly different between the treatments of 120 and 180kgha(-1) regardless of N source. However, both rates of CM treatments enhanced CH4 emission and differences in GWP were significant. In conclusion, urea applied at 120kg N ha(-1) was optimal for rice productivity and environmental impact (EI) despite CM played a crucial role in improving the N efficiency and total N in the soil after harvest.

publication date

  • 2017
  • 2017
  • 2017