Soil nitrous oxide emissions from global specialty crop systems

The data were extracted from published studies. All references and data sources are listed.  

We conducted an exhaustive literature search using Google Scholar and Web of Science databases. The searched keywords were ‘soil nitrous oxide emission’, ‘soil greenhouse gas emission’, and ‘soil trace gas emission’ respectively combined with each specialty crop. We searched for the common specialty crops listed by USDA, including fruits, tree nuts, and vegetables (https://www.ams.usda.gov/services/grants/scbgp/specialty-crop). The most recent search was in November 2023. For each article returned by the search, we evaluated whether it reported field observations of annual cumulative N2O emissions. Laboratory and greenhouse studies were excluded. This process identified 1137 observations from 114 studies. These studies covered six continents and four main climate types (Köppen climate classification). Area-scaled N2O emissions were reported as annual cumulative emissions (kg N2O-N ha−1 year−1).  Yield-scaled N2O emissions were calculated by dividing area-scaled N2O emissions by fresh weight yield (kg N2O-N Mg fresh yield−1). The emission factor (EF) for annual cumulative N2O emission was calculated by EF (%) = (EN − E0)/Nrate. The EN and E0 are the N2O emissions (kg N2O-N ha−1 year−1) with and without N fertilizer, respectively. The Nrate is the N fertilizer application rate (kg N ha−1 year−1). Soil properties and environmental factors were also listed if they were avalable. Empty cells in the datasheet indicate no data avalable for that category or variable.