Growth trajectories and interspecific competitive dynamics in wheat/maize and barley/maize intercropping

Competition between intercropped species is important for yield advantage, but little attention has been given to interspecific competitive dynamics in intercropping. A field experiment with five cropping systems (wheat/maize, barley/maize intercropping, wheat, maize and barley sole cropping), two N levels (0 and 225 kg N ha(-1)) and two maize mulching treatments (with and without) were performed. Sequential harvest of subplots was performed between 7 and 10 times, and the data were fitted to a logistic growth model. Intercropping significantly increased the maximum biomass and maximum growth rates of wheat and barley, but suppressed the early and maximum growth rate of intercropped maize. Maize growth recovered after the wheat or barley was harvested. In the presence of film mulch and/or fertilization, maximum biomass of intercropped maize was close to or significantly higher than that of maize alone. Fertilization and film mulching had much stronger effects on growth of maize than on wheat and barley. Interspecific competitive dynamics regulated by fertilization and film mulching can be quantified by the logistic model, which is helpful to understand the yield advantage of intercropping. This has important implications for managing interspecific competition through agronomic practices at field.