Weed competition in maize as a base for weed management.
Total shoot yield of maize was reduced significantly when weeds were present after the crop had developed the 7th to 8th leaf in the case of Chenopodium album and the 10th to 11th leaf in that of Echinochloa crus-galli. If weeds were present only from the 7- to 8-leaf stage onwards no significant interference with crop growth was observed although growth was slightly greater if the weed-free period was extended. From about the 10- to 11-leaf stage weed growth is severely restricted by crop shade, making weed control measures unnecessary. Weed germination is discussed in relation to the time of year as well as to crop development.