Long-term dynamics of weeds in grassland-crop rotations. 1. Effect of the duration of the grassland phase used in mowing

摘要

The objective of the study was to evaluate the effect of the duration of phases of mowed grass and the effect of their fertilization on weed dynamics during several successive rotations. The study was conducted during the period 2005-22. The experimental treatments included 3-year old and 6-year old grasslands subjected to two levels of N fertilization, in rotation with a succession of 3-year crop (corn, winter wheat, winter barley). These treatments were compared to the "controls" crop succession without grassland and sown permanent grassland. Results showed that the presence of a grassland phase altered the dynamics, diversity and composition of weed communities. The presence of 3 or 6-year old grassland reduced the abundanceof weed during the cropping phase if the grassland was fertilized. It had no effect if the 6-year-old grassland was not fertilized. The results show that the aftereffect of temporary grasslands on weeds during the cropping phase is highly dependent on the management of these grasslands.