Changes of Potential NPK Input by Chemical Fertilizers and Livestock Manure from 1990 to 2011 in Korea

The livestock manure is a good source of major plant nutrients such as nitrogen, phosphorus and potassium and micronutrient that plants require. As aspect of establishment of nutrient management policy in nation scale, the use of livestock manure for agricultural purpose is a key factor for improving national nutrient balance. In this study, we evaluated the tendency of livestock manure production and amount of chemical fertilizer used in Korea from 1990 to 2011. The number of pig and chicken has been increased about two times in 2011 compared with 1990 and therefore livestock manure continually increased with the lapse of year, but cattle and dairy was not changed significantly. The chemical fertilizer consumption of nitrogen, phosphorus and potassium per hectare arable land was decreased by 54.6, 66.0 and 63.2% in 2011 compared with 1990, respectively. In contrast, the potential input of nitrogen, phosphorus and potassium to arable land through livestock manure was increased by 220, 210 and 210% during this period, respectively. Therefore we need a reasonable strategy for nutrient management such as combination of both manure and chemical fertilizers in near future.