Abstract
Allelopathic characteristics of Lolium perenne L. have been previously reported in sand culture. The objectives of this study were : (i) to confirm if allelopathic interference of Trifolium repens by Lolium perenne might exist under soil culture condition, and (ii) to determine the toxic effects of soil previously planted with Lolium perenne. The result obtained are summarized as follows : 1. In intercropping experiment on soil (red-yellow color clay loam), plant growth of Trifolium repens was apparently inhibited by associating with Lolium perenne, showing the greater inhibition at the higher proportion of Lolium in mixture. Lolium perenne showed the oppositeresponse, growing better in association with Trifolium repens (experiment 1). 2. Growth of Lolium perenne and Trifolium repens was generally found to be reduced in soil in which Lolium plants had been grown previously (Lolium-soil) ; whereas in the soil where Trifolium plants had been planted (Trifolium-soil), there was benefit effect in stimulating the plant growths of both species (experiment 2). 3. Methanol extracts from Lolium soil and Trifolium soil caused a reduction in seedling growth of Trifolium repens in bioassay ; showing the greater inhibition in Lolium soil compared with Trifolium soil (experiment 3). 4. Form these results, it is suggested that allelopathic mechanism may occur in the interference of Trifolium repens by Lolium perenne in soil culture that involves the exudation of allelochemics from root of Lolium plants.
