DOI: 10.5061/dryad.cz8w9gj9v
title: A global meta-analysis of yield-scaled N2O emissions and its mitigation efforts for maize, wheat, and rice

description: Maintaining or even increasing crop yields while reducing nitrous oxide
 (N2O) emissions is necessary to reconcile food security and climate
 change, while the metric of yield-scaled N2O emission (i.e., N2O emissions
 per unit of crop yield) is at present poorly understood. Here we conducted
 a global meta-analysis with more than 6000 observations to explore the
 variation patterns and controlling factors of yield-scaled N2O emissions
 for maize, wheat, and rice and associated potential mitigation options.
 Our results showed that the average yield-scaled N2O emissions across all
 available data followed the order wheat (322 g N Mg-1, with the 95%
 confidence interval (CI): 301-346) &gt; maize (211 g N Mg-1, CI:
 198-225) &gt; rice (153 g N Mg-1, CI: 144-163). Yield-scaled N2O
 emissions for individual crops were generally higher in tropical or
 subtropical zones than in temperate zones, and also showed a trend towards
 lower intensities from low to high latitudes. This global variation was
 better explained by climatic and edaphic factors than by N fertilizer
 management, while their combined effect predicted more than 70% of the
 variance. Furthermore, our analysis showed a significant decrease in
 yield-scaled N2O emissions with increasing N use efficiency or in N2O
 emissions for production systems with cereal yields &gt; 10 Mg ha-1
 (maize), 6.6 Mg ha-1 (wheat) or 6.8 Mg ha-1 (rice), respectively. This
 highlights that N use efficiency indicators can be used as valuable
 proxies for reconciling trade-offs between crop production and N2O
 mitigation. For all three major staple crops, reducing N fertilization by
 up to 30%, optimizing the timing and placement of fertilizer application
 or using enhanced-efficiency N fertilizers significantly reduced
 yield-scaled N2O emissions at similar or even higher cereal yields. Our
 data-driven assessment provides some key guidance for developing effective
 and targeted mitigation and adaptation strategies for the sustainable
 intensification of cereal production.
description: # A global meta-analysis of yield-scaled N2O emissions and its mitigation
 efforts for maize, wheat and rice Author: Zhisheng Yao, Haojie Guo, Yan
 Wang, Yang Zhan, Tianli Zhang, Rui Wang, Xunhua Zheng, Klaus
 Butterbach-Bahl Any correspondence has to be send to
 ## Description of the Data and file
 structure Note: There are six sheets in the dataset. The variable name,
 unit, and description for each column of each sheet are shown below. The
 empty cells in this Excel file mean that data are not available. Variable
 List: #### Sheet1: Overview | Column | Name | Unit | Description | |
 :----- | :----------- | :--- | :----------------------------------- | | A
 | Full Name | None | Full name of collected parameters. | | B |
 Abbreviation | None | Abbreviation of collected parameter. | #### Sheet2:
 Maize | Column | Name | Unit | Description | | :----- |
 :----------------------------- | :--------- |
 :------------------------------------------------ | | A. | Number |  None
 |  Number of References used in the meta-analysis. | | B. | Reference |
  None |  References used in the meta-analysis. | | C. | Location |  None |
  Location of the experimental site. | | D. | Country |  None |  Country of
 the experimental site. | | E. | Continent |  None |  Continent of the
 experimental site. | | F. | Longitude |  None |  Longitude of the
 experimental site. | | G. | Latitude |  None |  Latitude of the
 experimental site. | | H. | Category |  None |  Category of the
 experimental site. | | I. | Observation period |  None |  Observation
 period. | | J. | Climate |  None |  Climate of the experimental site. | |
 K. | MAT |  °C |  Mean annual temperature. | | L. | Category  |  None |
  Category of Mean annual temperature . | | M. | MAP |  mm |  Mean annual
 precipitation. | | N. | Category  |  None |  Category of Mean annual
 precipitation. | | O. | Sand |  % |  Sand content of soil. | | P. | Silt |
  % |  Silt content of soil. | | Q. | Clay |  % |  Clay content of soil. |
 | R. | Soil texture |  None |  Soil texture of soil. | | S. | SOC |  g C
 kg-1 |  Description:Soil organic C of soil. | | T. | Category  |  None |
  Category of Soil organic C. | | U. | TN |  g N kg-1 |  Total N of soil. |
 | V. | Category  |  None |  Category of Total N . | | W. | C/N ratio |
  None |  C/N ratio of soil. | | X. | Category |  None |  Category of C/N
 ratio. | | Y. | Soil pH |  None |  pH of soil. | | Z. | Category |  None |
  Category of Soil pH. | | AA. | BD |  g cm-3 |  Bulk density of soil. | |
 AB. | Category |  None |  Category of BD. | | AC. | Crop type |  None |
  Crop type of experiment. | | AD. | Replicates |  None |  Replicates of
 experiment. | | AE. | N type |  None |  N type of experiment. | | AF. |
 Category |  None |  Category of N type. | | AG. | N rate |  kg N ha-1 |  N
 rate of experiment. | | AH. | Category |  None |  Category of N rate. | |
 AI. | N fertilizer management |  None |  N fertilizer management of
 experiment. | | AJ. | Optimized timing and placement |  None |  Optimized
 timing and placement. | | AK. | Straw return |  Unit:None |  Straw return.
 | | AL. | Water regime |  None |  Water regime. | | AM. | Tillage type |
  None |  Tillage type. | | AN. | Plastic-film mulching |  None |
  Plastic-film mulching | | AO. | Cumulative N2O fluxes  |  kg N ha-1 |
  Cumulative nitrous oxide fluxes of experiment. | | AP. | SE |  kg N ha-1
 |  Standard error of Cumulative N2O fluxes. | | AQ. | SD |  kg N ha-1 |
  Standard deviation of Cumulative N2O fluxes. | | AR. | Grain yield |  Mg
 ha-1 |  Grain yield of experiment. | | AS. | SE |  Mg ha-1 |  Standard
 error of Grain yield. | | AT. | SD |  Mg ha-1 |  Standard deviation of
 Grain yield. | | AU. | Yield-scaled N2O emission |  g N Mg-1 |
  Yield-scaled N2O emission of experiment. | | AV. | SE |  g N Mg-1 |
  Standard error of Yield-scaled N2O emission. | | AW. | SD |  g N Mg-1 |
  Standard deviation of Yield-scaled N2O emission. | | AX. | PFPN |  kg kg
 -1 |  partial factor productivity of N. | | AY. | ANE |  kg kg -1 |
  agronomic N efficiency. | | AZ. | EFd |  % |  Direct N2O emission factor.
 | #### Sheet3: Wheat | **Column** | **Name** | **Unit** | **Description**
 | | :--------- | :----------------------------- | :--------- |
 :------------------------------------------------ | | A. | Number |  None
 |  Number of References used in the meta-analysis. | | B. | Reference |
  None |  References used in the meta-analysis. | | C. | Location |  None |
  Location of the experimental site. | | D. | Country |  None |  Country of
 the experimental site. | | E. | Continent |  None |  Continent of the
 experimental site. | | F. | Longitude |  None |  Longitude of the
 experimental site. | | G. | Latitude |  None |  Latitude of the
 experimental site. | | H. | Category |  None |  Category of the
 experimental site. | | I. | Observation period |  None |  Observation
 period. | | J. | Climate |  None |  Climate of the experimental site. | |
 K. | MAT |  °C |  Mean annual temperature. | | L. | Category  |  None |
  Category of Mean annual temperature . | | M. | MAP |  mm |  Mean annual
 precipitation. | | N. | Category  |  None |  Category of Mean annual
 precipitation. | | O. | Sand |  % |  Sand content of soil. | | P. | Silt |
  % |  Silt content of soil. | | Q. | Clay |  % |  Clay content of soil. |
 | R. | Soil texture |  None |  Soil texture of soil. | | S. | SOC |  g C
 kg-1 |  Soil organic C of soil. | | T. | Category  |  None |  Category of
 Soil organic C. | | U. | TN |  g N kg-1 |  Total N of soil. | | V. |
 Category  |  None |  Category of Total N . | | W. | C/N ratio |  None |
  C/N ratio of soil. | | X. | Category |  None |  Category of C/N ratio. |
 | Y. | Soil pH |  None |  pH of soil. | | Z. | Category |  None |
  Category of Soil pH. | | AA. | BD |  g cm-3 |  Bulk density of soil. | |
 AB. | Category |  None |  Category of BD. | | AC. | Crop type |  None |
  Crop type of experiment. | | AD. | Replicates |  None |  Replicates of
 experiment. | | AE. | N type |  None |  N type of experiment. | | AF. |
 Category |  None |  Category of N type. | | AG. | N rate |  kg N ha-1 |  N
 rate of experiment. | | AH. | Category |  None |  Category of N rate. | |
 AI. | N fertilizer management |  None |  N fertilizer management of
 experiment. | | AJ. | Optimized timing and placement |  None |  Optimized
 timing and placement. | | AK. | Straw return |  None |  Straw return. | |
 AL. | Water regime |  None |  Water regime. | | AM. | Tillage type |  None
 |  Tillage type. | | AN. | Plastic-film mulching |  None |  Plastic-film
 mulching | | AO. | Cumulative N2O fluxes  |  kg N ha-1 |  Cumulative
 nitrous oxide fluxes of experiment. | | AP. | SE |  kg N ha-1 |  Standard
 error of Cumulative N2O fluxes. | | AQ. | SD |  kg N ha-1 |  Standard
 deviation of Cumulative N2O fluxes. | | AR. | Grain yield |  Mg ha-1 |
  Grain yield of experiment. | | AS. | SE |  Mg ha-1 |  Standard error of
 Grain yield. | | AT. | SD |  Mg ha-1 |  Standard deviation of Grain yield.
 | | AU. | Yield-scaled N2O emission |  g N Mg-1 |  Yield-scaled N2O
 emission of experiment. | | AV. | SE |  g N Mg-1 |  Standard error of
 Yield-scaled N2O emission. | | AW. | SD |  g N Mg-1 |  Standard deviation
 of Yield-scaled N2O emission. | | AX. | PFPN |  kg kg -1 |  partial factor
 productivity of N. | | AY. | ANE |  kg kg -1 |  agronomic N efficiency. |
 | AZ. | EFd |  % |  Direct N2O emission factor. | #### Sheet4: Rice |
 **Column** | **Name** | **Unit** | **Description** | | :--------- |
 :----------------------------- | :--------- |
 :------------------------------------------------ | | A. | Number |  None
 |  Number of References used in the meta-analysis. | | B. | Reference |
  None |  References used in the meta-analysis. | | C. | Location |  None |
  Location of the experimental site. | | D. | Country |  None |  Country of
 the experimental site. | | E. | Continent |  None |  Continent of the
 experimental site. | | F. | Longitude |  None |  Longitude of the
 experimental site. | | G. | Latitude |  None |  Latitude of the
 experimental site. | | H. | Category |  None |  Category of the
 experimental site. | | I. | Observation period |  None |  Observation
 period. | | J. | Climate |  None |  Climate of the experimental site. | |
 K. | MAT |  °C |  Mean annual temperature. | | L. | Category  |  None |
  Category of Mean annual temperature . | | M. | MAP |  mm |  Mean annual
 precipitation. | | N. | Category  |  None |  Category of Mean annual
 precipitation. | | O. | Sand |  % |  Sand content of soil. | | P. | Silt |
  % |  Silt content of soil. | | Q. | Clay |  % |  Clay content of soil. |
 | R. | Soil texture |  None |  Soil texture of soil. | | S. | SOC |  g C
 kg-1 |  Soil organic C of soil. | | T. | Category  |  None |  Category of
 Soil organic C. | | U. | TN |  g N kg-1 |  Total N of soil. | | V. |
 Category  |  None |  Category of Total N . | | W. | C/N ratio |  None |
  C/N ratio of soil. | | X. | Category |  None |  Category of C/N ratio. |
 | Y. | Soil pH |  None |  pH of soil. | | Z. | Category |  None |
  Category of Soil pH. | | AA. | BD |  g cm-3 |  Bulk density of soil. | |
 AB. | Category |  None |  Category of BD. | | AC. | Crop type |  None |
  Crop type of experiment. | | AD. | Replicates |  None |  Replicates of
 experiment. | | AE. | N type |  None |  N type of experiment. | | AF. |
 Category |  None |  Category of N type. | | AG. | N rate |  kg N ha-1 |  N
 rate of experiment. | | AH. | Category |  None |  Category of N rate. | |
 AI. | N fertilizer management |  None |  N fertilizer management of
 experiment. | | AJ. | Optimized timing and placement |  None |  Optimized
 timing and placement. | | AK. | Straw return |  None |  Straw return. | |
 AL. | Water regime |  None |  Water regime. | | AM. | Tillage type |  None
 |  Tillage type. | | AN. | Plastic-film mulching |  None |  Plastic-film
 mulching | | AO. | Cumulative N2O fluxes  |  kg N ha-1 |  Cumulative
 nitrous oxide fluxes of experiment. | | AP. | SE |  kg N ha-1 |  Standard
 error of Cumulative N2O fluxes. | | AQ. | SD |  kg N ha-1 |  Standard
 deviation of Cumulative N2O fluxes. | | AR. | Grain yield |  Mg ha-1 |
  Grain yield of experiment. | | AS. | SE |  Mg ha-1 |  Standard error of
 Grain yield. | | AT. | SD |  Mg ha-1 |  Standard deviation of Grain yield.
 | | AU. | Yield-scaled N2O emission |  g N Mg-1 |  Yield-scaled N2O
 emission of experiment. | | AV. | SE |  g N Mg-1 |  Standard error of
 Yield-scaled N2O emission. | | AW. | SD |  g N Mg-1 |  Standard deviation
 of Yield-scaled N2O emission. | | AX. | PFPN |  kg kg -1 |  partial factor
 productivity of N. | | AY. | ANE |  kg kg -1 |  agronomic N efficiency. |
 | AZ. | EFd |  % |  Direct N2O emission factor. | #### Sheet5: Potential
 mitigation strategies | Column | Name | Unit | Description | | :----- |
 :------------------------------- | :--------- |
 :--------------------------------------------------- | | A. | Number |
  None |  Number of References used in the meta-analysis. | | B. |
 Reference |  None |  References used in the meta-analysis. | | C. | Crop
 type |  None |  Crop type of experiment. | | D. | C\_Cumulative N2O fluxes
 |  kg N ha-1 |  Cumulative N2O fluxes of control soil. | | E. |
 T\_Cumulative N2O fluxes |  kg N ha-1 |  Cumulative N2O fluxes of
 experimental soil. | | F. | ln RR\_Cumulative N2O fluxes |  None |
  Response ratio of Cumulative N2O fluxes. | | G. | C\_Grain yield |  Mg
 ha-1 |  Grain yield of the control soil. | | H. | T\_Grain yield |  Mg
 ha-1 |  Grain yield of the experimental soil. | | I. | ln RR\_Grain yield
 |  None |  Response ratio of Grain yield. | | J. | C\_Yield-scaled N2O
 emission |  g N Mg-1 |  Yield-scaled N2O emission of the control soil. | |
 K. | T\_Yield-scaled N2O emission |  g N Mg-1 |  Yield-scaled N2O emission
 of the experimental soil. | | L. | ln RR\_Yield-scaled N2O emission |
  None |  Response ratio of Yield-scaled N2O emission. | | M. | Potential
 mitagation strategies |  None |  Potential mitagation strategies. | ####
 Sheet6: References | Column | Name | Unit | Description | | :----- |
 :-------- | :--- | :----------------------------------- | | A | Number |
 None | Number of references. | | B | Reference | None | References used in
 the meta-analysis | ## Sharing/Access information Data was derived from
 the following sources: We identified a total of 608 published experimental
 studies covering 30 countries and 724 sites, including 236 experiments for
 maize, 190 for wheat and 298 for rice. Collect the yield-scaled N2O
 emissions, grain yields, total cumulative N2O emissions, and other key
 information, including geographical location (country, longitude and
 latitude), general climate (tropical, subtropical and temperate), mean
 annual air temperature (MAT) and precipitation (MAP), soil properties
 (e.g., soil texture, soil organic C (SOC), total N content (TN), soil C/N
 ratio, soil pH and bulk density (BD)), management practices (e.g., straw
 return, tillage and N fertilizer type and rate). And recorded in our full
 dataset. ## Code/Software None