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| Estimation of nitrogen loss fluxes from livestock farming into aquatic environments in China during 2006-2016 |
| Received:January 19, 2018 |
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| KeyWord:livestock farming;nitrogen discharges into water;scatter-feed farming;large-scale farming;aquatic environment |
| Author Name | Affiliation | E-mail | | WANG Meng-zhu | School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China | | | ZHAO Yue | Chinese Academy for Environmental Planning, Beijing 100012, China | | | TONG Yin-dong | School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China | | | XU Yan-xue | Chinese Academy for Environmental Planning, Beijing 100012, China | xuyanxue1018@126.com | | LI Jia-qi | School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China | | | Qi Miao | School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China | | | LIN Yan | College of Resources and Environment, Yangtze University, Wuhan 430100, China | |
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| Abstract: |
| In recent decades, the growing demand for animal meat has led to quick development of livestock farming in China, especially large-scale farming. Excreta from the animals that could not be effectively treated were discharged into aquatic systems directly. To assess the impact of changes in nitrogen fluxes owing to livestock farming and farming patterns in approximately the last decade, we estimated the nitrogen discharges into aquatic systems from livestock farming (including both scatter-feed farming and large-scale farming) from 2006 to 2016. The differences in nitrogen discharges of five typical regions of China (north, east, south central, southwest, and northwest China) and from different animal species (sheep, pig, beef cattle, dairy cattle, laying hens, and broilers) were analyzed. The results showed that the total average nitrogen flux discharged into water from 2006 to 2016 was 4384 Gg, and the highest and lowest values were 4832 Gg (in 2006) and 4010 Gg (in 2008), respectively. South central China and north China were the major regions with the largest nitrogen discharges, followed by east China and southwest China, with the northwest region discharging the least. In 2016, the proportions of nitrogen discharges from the livestock farming in north China, south central China, east China, southwest China, and northwest China were 27%, 26%, 20%, 17%, and 10%, respectively. In 2016, the proportion of nitrogen discharges from the large-scale livestock farming was 53% of the total. Differences in nitrogen discharges existed among the different animal species. Pig and beef cattle produced the largest nitrogen discharges, occupying 68% of the total discharges. Regarding the sheep, laying hens, and beef cattle, their nitrogen discharges from the scatter-feed farming were higher than those from the large-scale farming, whereas for the pigs and broilers, the nitrogen discharges from the large-scale farming were larger. |
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