基于生命周期法的中国2004—2015年油菜生产氮足迹分析

Assessment of the nitrogen footprint in oilseed rape production of China during 2004 to 2015 base on life cycle assessment method

农业领域的活性氮排放日趋严重,系统分析农业生产过程中活性氮排放有利于促进我国农业绿色健康发展。本文基于2004-2015年我国油菜产量、农资投入产出等统计资料数据,运用氮足迹理论和生命周期法系统评价我国油菜生产氮足迹时空分布状况及其构成。结果表明,我国油菜生产单位面积氮足迹为7572.0 g N-eq hm^-2,呈现逐年下降的趋势。氮肥投入和NH3挥发是我国油菜生产活性氮排放主要来源,分别占油菜生产氮足迹的20%和54%。内蒙古、上海、江苏3个省、区、市的单位面积氮足迹和单位产量氮足迹显著高于低产省市,其中氮肥、磷肥、复合肥产生的氮足迹值分别高80.6%、76.9%和57.8%(P<0.05)。我国油菜单位面积氮足迹随着油菜产量的增加呈增加的趋势,但不存在显著相关性。研究结论表明,发展油菜生产节肥技术是我国油菜绿色健康发展的重要举措。

The loss of reactive nitrogen in agriculture has increasingly become serious,systematic analysis of reactive nitrogen emissions from agricultural production is conducive to promoting the green and healthy development of agriculture in China.Based on the statistical data of crop yield and farmland investment in the oilseed rape production of China,the spatiotemporal dynamic change of nitrogen footprint(NF)and its composition of oilseed rape during 2004.2015 in China was estimated using the theory of NF and life cycle assessment method in the agricultural sector.The NF of oilseed rape was 7572.0 g N-eq ha^–1 during 2004.2015,and decreasing year by year,with an average annual decline of 1.0%.The main components of the NF were from fertilizer application(20%)and NH3 emission(54%)in the oilseed rape production.Obvious differences also were observed among mainly agricultural provinces in China,that is,the higher nitrogen footprint per area(NFa)and nitrogen footprint per yield(NFy)in Inner Mongolia,Shanghai,and Jiangsu region.The NFa and NFy in high yield region were significantly higher than those in low yield region.Among them,the NF of nitrogenous fertilizer,phosphate fertilizer and compound fertilizer increased by 80.6%,76.9%,and 57.8%,respectively(P<0.05).The NFa of rapeseed in China showed a trend of increase with the increase of rapeseed yield,but there was no significant correlation.The results suggest that improving crop management practices that limit fertilizer consumption is an important measure for the green and healthy development of rapeseed in China.