水ヨシ生育に及ぼす植栽条件の影響に関する研究

抄録

This study aims to find out influences of planting methods and site conditions on reed growth. Reed growth was observed at an experimental field in Lake Biwa every month from December 1997 to August 1998. Influences of several factors on reed growth, such as planting method, water depth, erosion, were examined from the results of the observations, and the following results were drawn: 1) Out of 1081 pieces of reeds planted on October 1997, 449 pieces failed to grow, which were mainly planted with the Bittmann Method and the Root Method, while the other methods produced 89% in survival ratio, especially, high percentage (98%) in the Mat Method. 2) Average density of reeds in the autumn is 86.6, 67.8, 65.3 and 20.6 stalks/m², respectively for the Mat Method. the Pot Method. the Sandbag Method and the Big Stump Method. 3) The erosion exceeding 12cm depth had adverse effects on reed growth, while the erosion less than 4cm did not show abstraction on reed growth apparently. 4) All of the factors (methods, sites, dates, and any of their combinations) are statistically proved to have some significant influence on the reed growth variation with a risk less than 0.1%. The contribution of planting method on reed growth was 20% of the whole variation