International Livestock Research Institute (ILRI), Mazingira Centre, PO Box 30709, Nairobi, 00100, Kenya.
Karlsruhe Institute of Technology, Institute of Meteorology & Climate Research (IMK-IFU), Kreuzeckbahnstr. 19, 82467, Garmisch-Partenkirchen, Germany.
Nat Commun. 2020 Sep 15;11(1):4644. doi: 10.1038/s41467-020-18359-y.
Sub-Saharan Africa (SSA) is home to approximately ¼ of the global livestock population, which in the last 60 years has increased by factors of 2.5-4 times for cattle, goats and sheep. An important resource for pastoralists, most livestock live in semi-arid and arid environments, where they roam during the day and are kept in enclosures (or bomas) during the night. Manure, although rich in nitrogen, is rarely used, and therefore accumulates in bomas over time. Here we present in-situ measurements of NO fluxes from 46 bomas in Kenya and show that even after 40 years following abandonment, fluxes are still ~one magnitude higher than those from adjacent savanna sites. Using maps of livestock distribution, we scaled our finding to SSA and found that abandoned bomas are significant hotspots for atmospheric NO at the continental scale, contributing ~5% of the current estimate of total anthropogenic NO emissions for all of Africa.
撒哈拉以南非洲(SSA)拥有全球约四分之一的牲畜,在过去 60 年中,牛、山羊和绵羊的数量增加了 2.5-4 倍。牲畜是牧民的重要资源,它们中的大多数生活在半干旱和干旱地区,白天在户外漫游,晚上被关在畜栏(或 bomas)中。粪便虽然富含氮,但很少被利用,因此随着时间的推移会在畜栏中积累。在这里,我们对肯尼亚 46 个畜栏的 NO 通量进行了现场测量,结果表明,即使在废弃 40 年后,通量仍然比相邻的热带稀树草原高出一个数量级。我们利用牲畜分布地图,将我们的发现扩展到整个 SSA,发现废弃的畜栏是大气中 NO 的重要热点,对整个非洲目前估计的人为 NO 排放总量贡献了约 5%。