Weeds and Their Ecological Indicator Values in a Long-Term Experiment

The floristic composition and weed infestation in wheat and maize crops were studied in a long-term field experiment in Serbia.A total of 35 weed species were identified, out of which 12 were common for both crops.The greatest floristic diversity (20 species) was found under wheat crops in unfertilized two-year rotation, while the lowest diversity (5 species) was determined in maize crops in monoculture and fertilized four-year rotation.The highest weed infestation was observed in wheat monoculture (490.47 ind/m 2 ) and maize monoculture (111.98 ind/m 2 ), while the lowest level of weed infestation (17.31 ind/m 2 ) was observed in maize crops under intensive two-year rotation.Significant differences were found in the number of weed species and in the level of weed infestation between wheat and maize, as well as in the level of weed infestation in monoculture compared to other treatments of crop rotation for both crops.Ecological analysis indicated that the type of crop rotation and the species of crops have impact on the ecological characteristics of the studied area, which is reflected in different floristic composition and differences in the abundance of certain weeds.