The study aimed to assess the effect of corn straw as dairy manure on productivity and profitability of wheat and then set up fertilization scheme of wheat-corn cropping system. Fourteen treatments of N, P O and K O fertilizer was carried out in the field, where corn was 2 5 2 used as silage corn, and dairy manure was returned to customary field. Yield, wheat price, fertilizer cost and incidental expense were investigated. The relationship between the amount of fertilizer and wheat yield was studied. The most economical fertilizer plan was made according to marginal effect.

recycling systems covering the Asian area from the point of view of both economic and environmental standpoint. The maintenance of lawful domestic recycling systems is certainly essential. And so, we have to recognize there 2. Domestic-recycling systems within Japan are many products leaking out of lawfiul systems. and international cooperative systems [11 1-4244-0081-3/05/$20.OO ©)2005 IEEE.