Life cycle environmental assessment of summer maize in a North China high-yield region
华北高产粮区夏玉米生命周期环境影响评价

Life cycle assessment was used to establish an inventory of resource use and emissions and to assess life cycle environmental impacts of summer maize production system with different nitrogen fertilizer intensity in Huantai County, Shandong province. The assessment was conducted with per product as the functional unit and the life cycle of the summer maize production system was divided into three phases, including raw material mining & transportation, agricultural production & transportation and crop planting. The results revealed that the life cycle environmental impacts of summer maize production system show an exponential upward trend with the increase of nitrogen fertilizer application. The most significant environmental impact was water depletion because agriculture is a water\|intensive industry and water productivity in the study area was low. The most important pollution effect type was global warming at a low nitrogen application rate, but aquatic eutrophication with high nitrogen fertilizer input. As such, to reduce the nitrogen and water consumption as well as to increase their productivities are the key to control the life cycle environmental impacts of summer maize production system, which decrease resource consumption and emissions not only directly in the crop planting stage but also indirectly in the upstream production stage.