Using land-use management policies to reduce the environmental impacts of livestock farming

The manure produced by livestock animals across all of Japan is approximately 90million tonnes a year, which represents approximately 25% of the overall biomass of Japan's natural resources. In recent decades, the supply of the livestock animal compost has decreased due to various factors—a decrease in fodder, decrease in deserted cultivated land and increase in the importation of fodder—while the domestic animal manure portion of the livestock waste and associated increases have risen dramatically. Most of this manure leads to negative environmental effects by increasing nitrogen (N) loads in rainfall events and causing excess fertilisation, especially in agricultural areas. Animal manure accounts for approximately 23% of all categories of waste in Japan and 89% of all livestock waste in Japan. This 89% of livestock waste is generally utilised as compost or fertiliser. In Japan, the oversupply of fertiliser has already been identified as a problem in the field of agriculture. To address these issues, we assessed the two-dimensional (2D) concentration distribution of N in a water system to specifically analyse the effect of livestock contamination. From the results of this analysis, we observed that industrial factory wastewater creates a narrow localised impact, while the livestock industry creates a medium/broad impact. Therefore, this study provided a simultaneous representation of the total and specific impacts of both human and livestock activities under typical rural catchment conditions. The difference between the environmental impact index value of the current situation and the policy effect was quantitatively assessed. These results will contribute to the construction of a practical decision-making method. Additionally, reduced greenhouse gas emissions, a widely expanded network of protected areas and/or efforts to provide corridors to ease species movement may be necessary to achieve more globally sustainable practices.