Permalink : http://hdl.handle.net/2115/84966

JaLCDOI : 10.14943/EJFR.22.33

KEYWORDS : Black locust;root-barrier panel;root-shoot communication;soil nutrients;sprouting root

Black locust (Robinia pseudoacacia L.) is an alien species that is commonly planted in devastated lands, parks, residential gardens and is used as a nectar source for bees. However, the Japanese government has designated this species as an “Industrial exotic species under watch" because its rapid growth and reproductive capacity allows it to outcompete indigenous vegetation. Field surveys revealed that the back locust spreads through its sprouting roots and the elongation of its horizontal roots at soil depths between 0 and 10 cm. A practical method to regulate the spread of black locust would be to suppress the development of horizontal roots. Based on a nursery experiment, we propose the use of root-barrier panels to block and suppress the growth of horizontal roots. Monitoring the growth of roots in the field is labor-intensive, so we investigated the impact of root-barrier panels on shoot development by measuring the length of sprouting roots, the decrease in secondary flush, the increase in yellowed leaflets, and impact on plant height in a nursery setting. We concluded that root-barrier panels set at a depth of 30 cm effectively inhibited the growth of the horizontal roots of young black locust less than 3years old.