Abstract
Replanting of asparagus (Asparagus officinalis L.) often results in lower yields and extensive damage of young plants. One of the causes is considered allelopathy. In this study, we examined the participation of allelopathy on injury by continuous cropping of asparagus in alluvial soil. The presence of strong allelochemical substances, which have the growth-inhibitory activity, was detected by bioassay of rhizosphere soil around asparagus. This growth-inhibitory activity was not attributed to salt accumulation, pH fluctuation, or inorganic nutrient imbalance in the rhizosphere soil. Asparagus foliage incorporated into the soil did not demonstrate a close relation to the growth inhibition or decreased yield of asparagus. However, strong growth-inhibitory activity was demonstrated in the storage roots of asparagus. It is assumed that an allelochemical is exuded from the storage roots and is one of the causes of unsuccessful continuous cropping of asparagus.
