Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Creation of Nr in mainland China for the period 1910–2010. Upper represents the Nr creation amount by natural sources (lightning, forest, and grassland BNF) and anthropogenic sources (agriculture BNF, INF, and fossil fuel combustion); Lower represents the percentage of each source.
