Abstract: Ambrosia artemisiifolia L. is a major invasive weed in many regions of the world, and has significant impact on agricultural ecosystems. This paper studied the allelopathic effects of the burned and unburned A. artemisiifolia residues and their water extracts on wheat growth, aimed to approach whether burning could eliminate or weaken the allelopathic effects of A. artemisiifolia residue. Both the residue and its water extracts had inhibitory effects on the early growth of wheat, but the impact of the residue was smaller than that of the extracts, suggesting that the allelochemicals in A. artemisiifolia residue were water-soluble, and water extraction could release the allelochemicals into soil to a great extent. The addition of the residue also made the soil physical and chemical properties changed. With the increasing amount of added A. artemisiifolia residue, the soil pH, conductivity, organic carbon content, and the contents of phenolic compounds (main components of allelochemicals) all increased to some extent, which in integration inhibited wheat growth. Both the burned and unburned residues inhibited wheat growth significantly, and no significant difference was observed between the residues. Therefore, it was not the good way to burn the A. artemisiifolia residue to eliminate its allelopathic effects on native plants.

Key words: Soil organic matter, Soil organic carbon