[1][2] Negative plant–soil feedback occurs when plants are less able to grow in soil that was previously occupied by a member of the same species, and positive plant–soil feedback occurs when plants are more able to grow in soil that was previously occupied by a member of the same species.
Studies have shown that, on average, plant–soil feedback tends to be negative;[3] however, there have been many notable exceptions, such as many invasive species.
[4] Negative plant–soil feedback is thought to be an important factor in helping plants to coexist.
If a plant is over-abundant, then soil pathogens and other negative factors will become common, hurting its growth.
[2] Similarly, if a plant becomes overly rare, then so too will its soil pathogens and other negative factors, helping its growth.