US EPA

4312041 

Journal Article 

Determining optimum nitrogen input rate and optimum yield-scaled nitrous oxide emissions: Theory, field observations, usage, and limitations 

Kim, DG; Giltrap, D 

2017 

1 

Agriculture, Ecosystems & Environment
ISSN: 0167-8809 

247 

371-378 

10.1016/j.agee.2017.07.003 

WOS:000408597800041 

Nitrous oxide (N2O) is one of the major greenhouse gases causing global warming and climate change. Recently, studies showed that the nitrogen (N) input producing optimum amount of crop yields may minimise yield-scaled N2O emissions in agricultural production. Objectives of the study were to 1) investigate theoretical backgrounds of yield, N2O emission, and yield-scaled N2O emission responses to N input, 2) suggest concepts of optimum N input rate and optimum yield-scaled N2O emission and derive equations for them and 3) test with field observations, and 4) assess usage and limitations and suggest future studies. We have proposed a concept and equations for optimum N input rate and optimum yield-scaled N2O emission, and applied them to field-measured data from 10 independent experimental studies worldwide. Field-measured data showed that the suggested equations could be used to determine optimum N input rate and optimum yield-scaled N2O emissions. However, in some cases, any N input resulted in increased yield-scaled N2O emission and minimum yield-scaled N2O emissions occurred when N input was zero. The suggested optimum N input rate and optimum yield-scaled N2O emission can be useful indicators for best management practices to mitigate greenhouse gas emissions and secure food supply. However, in some cases, taking into account yields and N2O emissions separately is required to identify best management practices. Further studies are needed to better understand the characteristics of yield scaled N2O emissions response to N input and its use for management purposes. 

Nitrogen input; Yields; Nitrous oxide; Yield-scaled N2O emissions; Optimum nitrogen input rate; Optimum yield-scaled N2O emissions