1:45 PM - 3:15 PM
[HCG25-P09] Nitrogen flow model of food system in area with population decline
-A Case Study of Yamanashi Prefecture-
Keywords:Food system, Nitrogen flow
Since the Green Revolution, the anthropogenic use of nitrogen has enabled the growth of food production to sustain population. On the other hand, the food system leaks some nitrogen into the environment, causing environmental pollution. Therefore, improvement of the food system has been proposed by a nitrogen flow model focusing on regions (Li et al., 2023). However, the target area is limited to population growth areas. Regions with declining populations are likely to be dependent on imported food and decrease their own food production, resulting in nitrogen accumulation. In this study, therefore, we analyzed nitrogen flow in the food system in Yamanashi Prefecture as a region with declining population, with the aim of identifying hotspots for nitrogen management.
We first analyzed nitrogen flows among industries associated with the food system in Yamanashi Prefecture in 2011 and 2015. Nitrogen flows were analyzed from the Input-Output table and other existing statistics. Literature values were used for the amount and form of nitrogen leaked into the environment.
A brief overview of the nitrogen input and output of the food system in Yamanashi Prefecture is shown in Figure 1. The figure shows that the amount of nitrogen leaked into the environment decreased by 7.0% from 2011 to 2015. A comparison of the formation and runoff environment and sources of nitrogen leaked into the environment is summarized in Figure 2.
At first, for the surface water and groundwater, only nitrate from wastewater increased by 5.5%. This nitrogen can be a source of pollution, but they can also be a source of nutrients. For example, fuel conversion with algae. Secondly, for the atmosphere, total nitrogen emissions had increased by 16.8%. Among these emission sources, livestock-derived emissions were particularly high. This may be due to a decrease in the supply of livestock manure to its domestic cropland due to a decrease in the cropland.
We first analyzed nitrogen flows among industries associated with the food system in Yamanashi Prefecture in 2011 and 2015. Nitrogen flows were analyzed from the Input-Output table and other existing statistics. Literature values were used for the amount and form of nitrogen leaked into the environment.
A brief overview of the nitrogen input and output of the food system in Yamanashi Prefecture is shown in Figure 1. The figure shows that the amount of nitrogen leaked into the environment decreased by 7.0% from 2011 to 2015. A comparison of the formation and runoff environment and sources of nitrogen leaked into the environment is summarized in Figure 2.
At first, for the surface water and groundwater, only nitrate from wastewater increased by 5.5%. This nitrogen can be a source of pollution, but they can also be a source of nutrients. For example, fuel conversion with algae. Secondly, for the atmosphere, total nitrogen emissions had increased by 16.8%. Among these emission sources, livestock-derived emissions were particularly high. This may be due to a decrease in the supply of livestock manure to its domestic cropland due to a decrease in the cropland.