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Ammonia (NH 3) is an important alkaline reactive nitrogen (Nr) species which is involved in global nitrogen (N) biogeochemical cycling, but which has negative impacts on the environment and human health. In order to better understand and control the NH 3 loss potential in soil-upland crop systems in China, an integrated data analysis including 1302 observations from 236 published articles between 1980 and 2021 was conducted. The typical NH 3 volatilization rate (AVR) and the main factors influencing AVR in the major Chinese upland crops (maize, wheat, openfield vegetables and greenhouse vegetables and others) were estimated and analyzed. The mean AVR for maize, wheat, openfield vegetables and greenhouse vegetables were 7.8%, 5.3%, 8.4% and 1.8%. The most important influencing factors were fertilizer placement, meteorological conditions (especially temperature and rainfall) and soil properties (especially SOM). Subsurface N application produced a significantly lower AVR compared to surface application. High N recovery efficiency and N agronomic efficiency were generally associated with low AVRs. In conclusion, high N application rates, inefficient application methods and the use of loss-prone N fertilizer types are the main factors responsible for high AVRs in major Chinese croplands. [Display omitted] • We analyzed ammonia emission rates from fertilized upland crops in China. • Greenhouse vegetables had the lowest ammonia emission rates. • Placement of nitrogen fertilizer was a major control of ammonia loss. • High N recovery efficiency and agronomic efficiency were generally associated with low ammonia loss. [ABSTRACT FROM AUTHOR]