Effect of Submergence Factor on Reed Early Growth for Small Stump Transplantation

We study small stump transplantation for the regeneration of the reed bed in the Kitakami river mouth that was destroyed by the Great East Japan Earthquake, taking workability into consideration. We experimentally examined the optimal suitable submergence factors (water depth, submergence time and salinity) for small reed stumps harvested with and without above-ground organs. Consequently, a suitable water depth and submergence time for transplanting a small reed stump harvested with above-ground organs were concluded to be less than 20 cm and less than 12 h d-1 (2 cycles d-1, 6 h cycle-1) , respectively. Also, even with a submergence time of 12 h d-1 and water depth of 10 cm, a salt concentration of 1.5-2.0% was inferred to be inadequate for transplanting a small stump harvested with above-ground organs. In contrast, when reed harvested without above-ground organs was submerged 24 h d-1 at water depths of 10, 20, 30 and 40 cm, early growth was not inhibited. From the above results, for the transplantation of small reed stump harvested without above-ground organs, continuous submergence at water depths of 10-40 cm was inferred to cause no problems.