Abstract: Growth degeneration and yield declination are becoming obvious after a long term continuous cropping of crops, vegetables, fruit trees and nursery seedlings.Many studies show that soil ecological environment greatly affect the growth of plant under continuous cropping, and particularly, the decomposition products of plant residues and pathogenic microbes have a toxic effect to plants and affect the normal metabolism of root exudates, producing an auto-toxic effect.In this paper, the rhizospheric effects of soil environmental factors (air, moisture, nutrient and microorganisms), active substances (phytotoxin, residue decomposition substances, microbial toxin), and pathogenic microbes on root exudates under conditions of continuous cropping were systematically introduced, which would afford inspiration for further studying on the interaction mechanism between root exudates and continuous cropping obstacle.

Key words: Roots exudates, Environmental factors, Active substances