种养一体规模化农场温室气体排放量分析

摘要

The North China Plain is one of the most important crop and livestock production regions, and large-scaled crop and livestock integrated farms are common and typical of the region and thought to be an effective way to solve the environment pollution.Emission of greenhouse gases from the crop and livestock system is already accepted as a main cause of climate change.The objective of this study is to quantify greenhouse gas (GHG) emission from a farm of such a nature in the North China Plain.The life-cycle-based assessment method was used to estimate GHG emission during the operation of the farm by referring to the calculation methodology and emission coefficients specified in the "IPCC 2006 National Guide for and List of GHG".Results show that the annual total GHG emission from the farm was 32 528.02 t (CO2-equivalence, the same below), among which the farming system contributed 28.09%, and the livestock system did 71.91%.During the operation of the farm, the processes of livestock waste handling and storage, animal feed production and processing, intestinal fermentation and nitrogen production and application were the main sources of GHG emission, contributing 34.66%, 21.24%, 15.48% and 20.08% to the total, respectively.The production of 1 kg of wheat and maize grains emitted 1 059.39 and 411.92 kg, respectively;the production of 1 kg of raw milk and 1 kg of fat-protein corrected milk (FPCM) did 1.04 and 1.14 kg, respectively, which was lower than the average of the world;and production of 1 kg of live pig and beef cattle did 2.58 and 10.00 kg, respectively, similar to those from other intensive animal farms in the country.Scenario analysis shows that to reduce N (fertilizer) application rate, improve the capacity of handling and treating livestock waste, intensify N management and modify feed composition may directly or indirectly mitigate GHG emissions from such farms.%为准确评估华北平原种养一体规模化农场温室气体排放量,以河北某种养一体规模化农场为例,应用生命周期评价方法,根据《IPCC 2006国家温室气体清单指南》中的排放系数,计算该农场运行过程中温室气体排放量.结果表明,农场运行过程中年温室气体总排放量(以CO2当量计,下同)为32 528.02 t,其中农田生产系统排放占28.09%,养殖场排放占71.91%,其中粪便贮存管理、饲料生产和加工、肠道发酵及氮素生产和施用等生产环节是温室气体主要排放源,分别占总排放量的34.66%、21.24%、15.48%和20.08%.生产1 t小麦、玉米籽粒的温室气体排放量分别为1 059.39和411.92 kg;生产1 kg原奶和1 kg按蛋白质和脂肪纠正的牛奶(FPCM)的温室气体排放量分别为1.04和1.14 kg,低于全球平均水平;生产1 kg活体猪、肉牛的温室气体排放量分别为2.58和10.00 kg,与国内其他集约化养殖场的排放量相当.通过情景分析发现,种植生产中采取减氮(化肥)以及提高畜禽粪便废弃物处理能力等措施,加强农场氮素管理,改善饲料结构,可直接或间接减少农场水平温室气体排放.