Abstract: By means of simulation models, the dynamic change of dry matter production by winter wheat and summer maize at production level 1 is obtained. The results show that the simulated values match well with the measured ones in 1990/1991 and 1991/1992. The grain yield 1000 kg·mu^-1 ·yr^-1 can be considered as a target yield for winter wheat followed by summer maize in the Huanghuaihai Plain without intercropping at the production level 1. If winter wheat followed by intercropped medium maturity summer maize is adapted, instead of the winter wheat followed by early maturity summer maize without intercropping, the total grain yield of the both crops is increased by more than 10%. The simulations for various LAIs show that the dry matter production and the grain yield of the two crops within a year without intercropping can reach up to 46 and 19.1 t·hm^-2, respectively.

Key words: Winter wheat, Summer maize, Simulation, target enzyme, pesticide, multi-pesticide resistance, ecological equilibrium