The Effect of Allelopathic Chemicals in Different Soil Types

Abstract

Allelopathy is the suppression of growth of one plant species by another.1 Many plants release allelochemicals to ensure their survival. The Black Walnut (Juglansnigra)is the most notorious of allelopathic trees.2 Juglone is the allelopathic chemical that inhibits germination or growth in plants. Juglone becomes the most toxic when it is exposed to air.3 As rain washes juglone from leaves and other plant material it builds up in the soil where the neighboring plants then absorb the allelopathic chemical. Because allelopathic chemicals might strongly reduce the germination success rate in some plants, the extraction of julone from the Black Walnut might be useful as a natural herbicide for agricultural plants.1