Allelopathy

The effects of chemical products exuded from the roots of a plant. The products are often beneficial, or have neutral impacts, to plants of the same species, but detrimental to other species by reducing the latter's competitive ability. The exuded chemicals might, for example, restrict overall nutrient availability within the soil producing conditions that are more favourable to the originating species than other species. In addition, the exudates may be taken up by other species effectively poisoning them, reducing their growth and development. Yorkshire fog grass has shown allelopathic characteristics and this may be one of the reasons why it can be very difficult to remove (except for physical cutting out) from some turfgrass surfaces, especially fine turf ones such as golf and bowling greens. (Watt, T.A. (1978) ‘Yorkshire fog (Holcus lanatus L.) ¯ A review and some recent research', The Journal of the Sports Turf Research Journal, No.54, pp15-22)