我国典型茶区化学氮肥施用与生产运输过程的温室气体排放量估算

基于相关统计数据和文献调研方法,估算了我国14个典型茶区中化学氮肥施用、生产及运输过程中的温室气体排放量。结果表明,化学氮肥施用导致的土壤N₂O直接排放和生产过程中的温室气体排放是茶园化学氮肥消费带来的温室气体主要排放源;14个典型茶区消费的化学氮肥产生的温室气体排放量(以CO₂排放当量计算)为16.81~344.80万t·a^-1,其中贵州、云南、湖北和四川4省的茶园消费的化学氮肥带来的温室气体排放量较高,均超过200万t·a^-1,占全部区域温室气体排放量的59.98%;单位面积温室气体排放量为3.22~9.76 t·hm^-2·a^-1,单位产量温室气体排放量为2.10~12.96 t·t^-1·a^-1、单位产值温室气体排放量0.39~1.90 t·万元^-1·a^-1;总体而言,贵州、云南、湖北、湖南和四川5省的茶园消费的化学氮肥带来的温室气体排放量、单位面积温室气体排放量、单位产量温室气体排放量和单位产值温室气体排放量较高,福建、河南省及重庆市3个茶区相对较低。在茶园化学氮肥施用量控制为300 kg·hm^-2和450 kg·hm^-2两种情景下,茶园生态系统温室气体减排总量为617.07万t·a^-1和228.94万t·a^-1,减排潜力为34.12%和12.66%,减排潜力较大的区域主要有湖北、四川、贵州、湖南和江西等5省。

Estimation of Greenhouse Gas Emissions from Fertilization,Production and Transportation of Synthetic Nitrogen for Tea Garden in Typical Region of China

In this research, the amount of greenhouse gas emissions from fertilization, production and transportation of synthetic nitrogen for tea garden in typical region of China was assessed based on the analysis of statistical data using a data mining method. The results show that direct N₂O emissions from soil and greenhouse gas emissions (CO₂ emission equivalents) from the production of synthetic N fertilizers were the main sources of greenhouse gas emissions from synthetic N fertilization in tea garden. In 14 typical regions, the total greenhouse gas emissions from synthetic N fertilization were 168.1-3 448.0 kt CO₂ equivalent per year. And Guizhou, Yunan, Hubei and Sichuan were the top four provinces with high greenhouse gas emissions from synthetic N fertilization. Over 2 000 kt CO₂ equivalent per year occurred in each province, which accounted for 59.98% of the total emissions. The greenhouse gas emissions per unit area, per yield and per output value was 3.22-9.76 t CO₂ equivalent per hectare, 2.10-12.96 t CO₂ equivalent per ton of dry semifinished tea and 0.39-1.90 t CO₂ equivalent per 10 000 yuan. In general, the total greenhouse gas emissions, emissions per unit area, per yield and per output value from synthetic N fertilization were mainly concentrated in Guizhou, Yunan, Hubei, Hunan and Sichuan provinces, and the relatively low total emissions and emission intensity were happened in Fujian, Henan provinces and Chongqing city. It was concluded that reducing the synthetic N application rate for tea garden in China to a reasonable level of 300 kg·hm^-2 and 450 kg·hm^-2 could greatly reduce the emission of greenhouse gases. And the estimated mitigation potential of greenhouse gas emissions for these provinces were 6 170.7, 2 289.4 kt CO₂ equivalent per year, and reduce the total greenhouse gas emissions by 34.12% and 12.66%. Notably, Hubei, Sichuan, Guizhou, Hunan and Jiangxi provinces were the leaders of the mitigation potential of greenhouse gas emissions, and these areas should focus on reducing greenhouse gas emissions.