GCB | 中国农田氨排放与作物产量解耦及其驱动机制
The following article is from 土壤氮循环 Author 土壤氮循环
文献信息：
Adalibieke Wulahati1, Zhan Xiaoying1, Cui Xiaoqing, Reis Stefan, Winiwarter Wilfried, Zhou Feng*. Decoupling between ammonia emission and crop production in China due to policy interventions. Global Change Biology, 2021, 27, 5877–5888. DOI: 10.1111/gcb.15847.
摘 要：农田排放的氨是引发大气雾霾的关键原因之一。过去40年，为了提高作物产量与氮肥利用率，政府出台了多项农业政策，然而这些政策在农田氨减排方面的成效并未得到系统评估。基于环境-农艺措施耦合的农田氨排放模型与高分辨率农艺管理措施数据集，本研究估算了1980年至2050年中国农田的氨排放量，并首次量化了政策在其中所发挥的作用。结果表明，1980至1996年，农田氨排放量从1.93 Tg NH3-N增加至4.02 Tg NH3-N，2017年下降至3.50 Tg NH3-N，与作物产量已解耦。如果4项政策（测土配方施肥、发展高浓度氮肥、农业节本增效工程、菜篮子工程）不出台，2017年时农田氨排放会在现在的基础（3.50 Tg NH3-N）上增长约3.0 Tg NH3-N，这些排放主要集中在施肥强度高的种植区。优化肥料管理及农产品消费行为可以使得中国农田氨排放在2050时进一步减少3/4，此时单位产量的氨排放量可以降低至欧洲和美国的水平。研究结果为我国作物产量与氨排放解耦提供了证据，同时为其他发展中经济体制订农田氨减排策略提供了建议。
Abstract: Cropland ammonia (NH3) emission is a critical driver triggering haze pollution. Many agricultural policies were enforced in past four decades to improve nitrogen (N) use efficiency while maintaining crop yield. Inadvertent reductions of NH3 emissions, which may be induced by such policies, are not well evaluated. Here, we quantify the China's cropland-NH3 emission change from 1980 to 2050 and its response to policy interventions, using a data-driven model and a survey-based dataset of the fertilization scheme. Cropland-NH3 emission in China doubled from 1.93 to 4.02 Tg NH3-N in period 1980–1996, and then decreased to 3.50 Tg NH3-N in 2017. The prevalence of four agricultural policies may avoid ~3.0 Tg NH3-N in 2017, mainly located in highly fertilized areas. Optimization of fertilizer management and food consumption could mitigate three-quarters of NH3 emission in 2050 and lower NH3 emission intensity (emission divided by crop production) close to the European Union and the United States. Our findings provide an evidence on the decoupling of cropland-NH3 from crop production in China and suggest the need to achieve cropland-NH3 mitigation while sustaining crop yields in other developing economies.
表1 20世纪90年代中期以来中国政府在肥料管理与作物结构方面出台的相关措施
TABLE 1. Policies on fertilization and crop structure issued by the Chinese Government since mid-1990s
表2 未来农田NH3减排途径
TABLE 2. Cropland-NH3 mitigation pathways in future
图1 中国农田NH3排放量、作物产量和NH3排放强度的时序变化
FIGURE 1 The interannual variabilities of cropland-NH3 emissions, crop production and NH3 emission intensity in China. The national mean emission intensity was defined as the cropland-NH3 emission divided by total crop production (in kilocalories, Table S7) at national scale
图2 中国农田NH3排放趋势的空间格局，以及各省作物产量与NH3排放量的解耦时间
FIGURE 2 Spatial pattern of China's cropland-NH3 emission trends and the breakpoint at province scale. Panels (a) and (b) represent the spatial pattern of cropland-NH3 emission trends in P1 (1980–1996) and P2 (1997–2017), respectively. Panel (c) represents the year began to decouple its NH3 emission from crop production, that is, the year which emission intensity turned to significant decrease (p<0.05) at province scale. Piecewise linear regression was applied to detect the provincial breakpoint following Zhou et al., (2020, see Text S8)
图3 中国农田NH3排放量和NH3挥发速率的贡献因子
FIGURE 3 Contributions of driving factors to China's cropland-NH3 emission and NH3-VRs. Panel (a) represents four main driving factors’ contributions to cropland-NH3 emission. Panel (b) represents five secondary driving factors’ contributions to NH3-VRs
图4 1980-2017年中国农田施氮强度、肥料类型、施肥方式和种植结构的变化及对农田NH3排放量的潜在影响
FIGURE 4 Changes of N application rate, forms, placement, crop structure and their potential effects on cropland-NH3 emission from 1980 to 2017. (a) ACE, VTB, EUP and STNR Program represent Agricultural Cost-saving and Efficiency-increasing Program, Vegetable Basket Program (Phase II), Encouragement of urea production guideline, National Soil Testing and Nutrient Recommendation Program, respectively. Detailed descriptions of above four policies are shown in Table 1. (b) Share of basal fertilizer incorporated by machine for four field crops, that is, wheat, maize, potatoes and legumes. (c) Sowing areas of rice, wheat, and vegetables and fruits in China. (d) Consumption of two forms of alkaline fertilizer, that is, urea and ammonium bicarbonate (ABC). (e) N application rate (line) and implemented area of the STNR program at national scale (column). After 2013, implemented area of the STNR program is not publicly available
图5 政策实施导致的农田NH3减排量（2017年）
FIGURE 5 Cropland-NH3 mitigation induced by policies implement in 2017. ACE, VTB, EUP and STNR Program represent Agricultural Cost-saving and Efficiency-increasing Program, Vegetable Basket Program (Phase II), Encouragement of urea production guideline, National Soil Testing and Nutrient Recommendation Program, respectively. Detail descriptions of four policies are shown in Table 1. Values (SUM) denote the probable NH3 reductions induced by each policy at national scale
图6 中国农田NH3减排潜力（2020-2050年）
FIGURE 6 Mitigation potentials of China's cropland-NH3. (a) Future NH3 emissions under four scenarios; (b) China's cropland-NH3 mitigation potentials by crop under scenario ALL; (c) Spatial pattern of China's cumulative NH3 abatement potentials under scenario ALL
版权声明
文章来源：土壤氮循环公众号，仅用于学术分享，侵权告改或删！