Nutrient Use and Efficiency in East Asian Agriculture

摘要

To determine the available nitrogen (N), phosphorus (P) and potassium (K) resource budgets (application minus plant uptake), we obtained data on inorganic fertilizers and livestock manure from statistical yearbooks for Japan, the Republic of Korea and China. Uptake of N, P and K via crop production was also calculated using national nutrient content factors. From the budget and crop production data, we calculated the N, P and K surpluses and use efficiencies. Japan used too much P, Korea balanced its use of inorganic fertilizer but needed to improve manure use, and China had high nutrient inputs and outputs in crop yield. To improve nutrient use efficiency and decrease the surplus, we set some guidelines, such as N, P and K output by crop yield should be more than 60 percent, 40 percent and 75 percent of applied inorganic fertilizer plus manure, respectively, or the inorganic N fertilizer application level should be around half of the crop yield, with the effectiveness of organic P and K as 100 percent of inorganic P and K fertilizers. Based on this analysis, we found that Japan should apply inorganic P fertilizer primarily to compensate for soil P deficiency, Korea should develop forage crop production and build recycling pathways within the country, and China should reduce its excessive use of N to reduce the N content of crops.