『Abstract
　There is a high spatial variation in N2O emission from agricultural fields and N2O emissions from fields cultivated with stalk-crops was generally measured in the interrow area. The aim of this study was to evaluate the difference in seasonal N2O emissions between interrow soil and interrow + row soil, and to understand the effect of different fertilizers on N2O emissions in a maize-cultivated sandy loam soil in the North China Plain. The experiment included five treatments: organic manure (OM), half-organic manure N plus half fertilizer N (HOM), fertilizer NPK (NPK), fertilizer NK (NK) and control (CK). Cumulative N2O emission from interrow + row soil during the maize growth season was 0.84-1.22 kg N ha^-1 with an average of 0.98 kg N ha^-1 in the N-fertilized treatments, significantly higher than the 0.30-0.49 kg N ha^-1 from interrow soil. however, no significant difference was observed in the CK treatment. The measurement in interrow soil underestimated N2O emissions by 44-67%. This difference mainly occurred at the two peak emission periods following fertilizer application probably due to discrepancy in soil denitrification potential. Manure application more efficiently increased difference in N2O emission between interrow soil and interrow + row soil than inorganic N fertilizer application. The higher NO3^- concentration did not induce larger N2O emission from interrow soil in the NK treatment than in the NPK treatment, but did from interrow + row soil, resulting in greater difference in N2O emission between interrow soil and interrow + row soil. It is suggested that measuring N2O emission solely from interrow soil could underestimate seasonal N2O emissions, and partly mask the effect of N fertilizer application rates on N2O emission in a maize-cultivated soil in the North China Plain.

Keywords: Nitrous oxide; Inorganic N fertilizer; Organic manure; Spatial variation; Peak emission』

1. Introduction
2. Materials and methods
　2.1. Study site and experimental design
　2.2. Nitrous oxide emission measurement
　2.3. Auxiliary measurements
　2.4. Soil sampling and analysis
　2.5. Maize biomass and yield measurement
　2.6. Statistical analysis
3. Results
　3.1. Maize biomass and the amount of N uptake
　3.2. Temperatures, precipitation and soil moisture
　3.3. N2O emission rates
　3.4. Cumulative N2O emissions and emission factors
4. Discussion
　4.1. Effect of crop growth on spatial variation of N2O emission
　4.2. Effect of fertilizer type on spatial variation of N2O emission
5. Conclusions
Acknowledgments
References