陇中地区农业源高分辨率氨排放清单及分布特征

High-resolution inventory and distribution characteristics of agricultural source ammonia emissions in Longzhong Region

为掌握陇中地区农业源氨排放的来源贡献及分布特征,通过调查搜集各排放源的区县级活动水平,选取合适的排放系数开展本地化修正,利用排放因子法建立了2019年陇中地区高分辨率农业源氨排放清单.结果表明:2019年陇中地区农业源氨排放量为86.3×10^(3)t,其中,畜禽养殖和氮肥施用为主要排放源,分别占排放总量的61.3%和34.9%.在畜禽养殖中,肉牛(36.1%)和绵羊(29.1%)是最大的排放源;在氮肥施用中,尿素的贡献率最高(95.7%),施肥方式以追施肥为主(87.7%).从空间分布来看,会宁县农业氨排放量最高,占陇中地区排放总量的11.7%;畜禽养殖氨排放强度高值区主要集中在西部和中部,氮肥施用高值区则集中在东南部和中北部,两类排放源共同决定了陇中地区氨排放强度的空间特征.从时间分布来看,畜禽养殖氨排放各月份差异不大,而氮肥施用差异明显,在7月达到峰值,占全年排放总量的17.6%.

To understand the source contribution and distribution characteristics of agricultural ammonia emissions in Longzhong Region,county-level activity levels of various emission sources were collected,and suitable emission factors were selected for local correction.Using the emission factor method,a high-resolution inventory of agricultural ammonia emissions for Longzhong Region in 2019 was established.The results showed that in 2019,the total agricultural ammonia emissions in Longzhong Region amounted to 86.3×10^(3) t,with livestock and poultry farming and nitrogen fertilizer application being the main emission sources,accounting for 61.3%and 34.9%of total emissions,respectively.Among the livestock and poultry farming sector,beef cattle(36.1%)and sheep(29.1%)were found to be the largest emission sources.Regarding nitrogen fertilizer application,urea had the highest contribution rate(95.7%),and the dominant fertilization method was topdressing(87.7%).Spatially,Huining County had the highest agricultural ammonia emissions,contributing 11.7%of the total emissions in Longzhong Region.High-intensity areas of livestock and poultry breeding emissions were mainly concentrated in the western and central parts,while the high-intensity areas of nitrogen fertilizer application were concentrated in the southeast and north-central parts.These two emission sources jointly determined the spatial characteristics of ammonia emission intensity in Longzhong Region.Temporally,there was no significant monthly difference in ammonia emissions from livestock and poultry breeding,while the differences in nitrogen fertilizer application were significant,reaching a peak in July,accounting for 17.6%of the total annual ammonia emissions.