Abstract
A significant amount of livestock waste is generated in Miyazaki Prefecture and a large part of it is applied to agricultural land as manure. It has been reported that the surplus application of livestock waste contaminates groundwater with nitrogen and causes the accumulation of phosphate in soil, which could also lead to eutrophication. To preserve the quality of this water resource, effective measures should control the application of surplus nutrients. The purpose of this study is to estimate the nutrient (nitrogen and phosphate) balance, and provide fundamental data for designing an organic waste recycling system suitable to the conditions of Miyazaki. The estimated amounts of nitrogen and phosphate applied to agricultural land are approximately 2 and 3 times higher than those of standard applications. These results suggest that, to conserve water quality, livestock waste should be used not only for compost but also for other products such as alternatives to chemical fertilizers and industrial materials.
