Allelopathy in forest and agroecosystems in the Himalayan region

Abstract

A great variety of metabolic chemicals potentially involved in plant-plant chemical interactions are released from plants primarily through leaching from aboveground parts, thus, play a significant role in plant interactions on a day-to-day basis (Tukey, 1970). The plant leachates have an effect upon the soil structure, texture, aeration, permeability and exchange. Roots, especially those of large plants, extract substances from deep and distant areas of the soil from where they are translocated into the plant system, later to be returned to the soil by leaching and litter fall. Forest litter has long been recognized as a possible deterrent to tree seedling establishment (Koroleff, 1954), and differences in germination and growth of plant species beneath trees of various species are well known (Telfer 1972). Thus, trees build a characteristic profile of their own by this method; however, the magnitude of materials supplied to the soil layers depends upon the rate of leaching, litter fall and chemical disintegration of the compounds in the environment.