2024 Volume 35 Issue 2 Pages 121-128
Increased importation of nitrogen (N) through food, feed, and fertilizer, as well as the effect of N release into the environment, has become a hot topic of discussion in Japan. To enhance N use, N cycling, and reduction of the negative impact of N, it is important to obtain an accurate estimation of the amount of organic waste that originates from livestock production, the food industry, composted material, and daily human activities. The amount of compost generated in Japan has been estimated at 3.3-6.5 Tg N per year. This amount approaches or exceeds the national demand for chemical N fertilizer. To utilize this compost, it is necessary to consider balancing the other nutrient ingredients within Japan and to address the uneven distribution and variety of the compositions of organic wastes. The methods for evaluating N, and other nutrient ingredients, include nutrient balance, use efficiency, and a numerical model for predicting N infiltration. Although organic agriculture is thought to be one method for enhancing the use of composts, we should guard against its unrealistic expectations as crop productivity and the demand for nutrients by food and feed crops are not dissimilar to those of conventional agriculture. Effective actions for utilization of compost must include estimation of local fertilizer resources and ensuring the optimal use of organic waste.
