Environmental impact caused by agricultural nutrient use in present state, prefectural standard and low-input and extended forage production were compared by life cycle assessment (LCA) method. N and P2O5 surplus was the highest in present state and upland field that occupy 22% of total farmland, accounted for about half of N and P2O5 surplus. Application along with prefectural standard reduced both N and P2O5 surplus and non-utilized livestock excreta. This indicates present livestock excreta application causes lack of organic resources and cannot maintain soil fertility. However, non-utilized livestock excreta still remained. Extended forage production and low input of chemical fertilizer indicated that all livestock excreta would be consumed and chemical fertilizer application reduced. Although surplus on farmland would increase in this scenario, N and P2O5 surplus plus non-utilized livestock excreta was the least. Along with change of fertilization, environmental impacts caused by fertilizer ingredients were reduced in standard and low input, especially regarding aquatic eutrophication potential and global warming, although reduction of terrestrial eutrophication and acidification was relatively low. Abiotic resource consumption for chemical fertilizer production was also reduced. On the other hand, environmental toxity by heavy metals accompanying with chemical fertilizer and livestock excreta use was increased standard and low-input and expanded forege production, because of high Zn and Cu concentrations in livestock excreta. Although we have dilemma, keep standard chemical fertilizer use and extend forege production are attractive. Seeking optimal point of this dilemma would link to sustainable agriculture.