We have composed a numerical model, which can calculate nitrogen concentration in the Asian major rivers. We adopt cell model, and the resolution is fixed to be 0.5 x 0.5 degree. The model incorporates water balance and nitrogen balance that generated from food supply and consumption process. Nitrogen load from atmosphere is also included in the balance. The total nitrogen load generated in the major river basins is 21.8 [million t/y], currently. Water pollution by nitrogen is serious in the Yellow river even today. The nitrogen load generated from food system must be increased in the 21st century, and water pollution by nitrogen will spread all over Asia.
Asian major river basin, Food supply and demand, Nitrogen balance, Numerical model.