Abstract: More than 80 field experiments on fertilizer effect on wheat were conducted from 1986 to 1990 to investigate the curves equation of fertilizer effects and indices of economic application of fertilizers in soil with different fertilities after the wheat production,came to the high-output-stage in Shijiazhuang area. The results indicated that the economical fertilizer application indices for a high output of wheat in the fields with different fertilities were as follows. In the field with high fertility, N-11.1 to 13.8kg/mw, P₂O₅ -10.7 to 13.9 kg/mu; in the field with medium fertility, N-12.6 to 15.2 kg/mu, P₂O₅9.8 to 12.1 kg/ma, in the field with low feretility, N-13.3 to 15.5 kg/mu, P₂O₅-9.1 to 11.7 kg/ma. In addition, three parameters of fertilizer application for a target-output were also studied. (1) The amounts of nutrients absorbed for obtaining 100 kg of wheat grain were as follows. For control (non fertilized treatment), N-2.32kg,P₂O₅-1.05kg, K₂O2.72kg; for fertilized treatment, N-2.82kg, P1O5-1.03kg,K₂O₃.15kg. ( 2 ) Correction coefficients were C_P=0.41 + 4.01/Pand C_N- 0.28 + 0.035P for soil available phosghorous (C_P) and alkali hydrolytic nitrogen (C_N) respectively. (3) The utilization rates for nitrogen and phosphorus (Z_N and Z_P) were as follows. Z_N (%) = 42.1 - 0.35P, Z_P (%) =27.6-1.20P (where P is the content of soil available phosphorus) .

Key words: Wheat, Fertilizer application indices, Fertilizer application parameters, Soil fertility, Yield