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Ammonia Emissions from Croplands Decrease with Farm Size in China

Authors :
Wang, Chen
Duan, Jiakun
Ren, Chenchen
Liu, Hongbin
Reis, Stefan
Xu, Jianming
Gu, Baojing
Source :
Environmental Science & Technology; July 2022, Vol. 56 Issue: 14 p9915-9923, 9p
Publication Year :
2022

Abstract

Farm size affects nitrogen fertilizer input and agricultural practices, which are key determinants of ammonia (NH3) emissions from croplands. However, the degree to which NH3emissions are associated with changes in farm size is not well understood yet despite its crucial role in achieving agricultural sustainability in China, where agricultural production is still dominated by smallholder farms. Here we provide a first analysis of the relationship between farm size and NH3emissions based on 863 000 surveys conducted in 2017 across China. Results show that NH3emissions (kg ha–1) on average decrease by 0.07% for each 1% increase in average farm size. This change occurs mainly due to a reduction in nitrogen fertilizer use and the introduction of more efficient fertilization practices. The largest reduction in NH3emissions is found in maize, with less pronounced changes in rice cultivation, and none for wheat production. Overall lower NH3emissions factors can be observed in the north of China with increasing farm size, especially in the northeast, the opposite pattern was found in the south. National total NH3emissions could be approximately halved (1.5 Tg) in a scenario favoring a conversion to large-scale farming systems. This substantial reduction potential highlights the potential of such a transition to reduce NH3emissions, including benefits from a socioeconomic point of view as well as for improving air quality.

Details

Language :
English
ISSN :
0013936X and 15205851
Volume :
56
Issue :
14
Database :
Supplemental Index
Journal :
Environmental Science & Technology
Publication Type :
Periodical
Accession number :
ejs59775806
Full Text :
https://doi.org/10.1021/acs.est.2c01061