PROBLEM TO BE SOLVED: To create an artificial reed field in a brackish water region through planting reeds so as not to wither up even if affected by the salinity of the brackish water region.SOLUTION: The artificial reed field B is created through the following steps: setting a brackish water zone A as a planned area where an artificial reed field B is to be created by building a water permeable bank 11 such as a stone mound 11a； putting planting soil 12 for reeds into the inside of the bank 11 up to a ground height preset to a level higher than the mean sea level so that the salinity in pore water contained in soil becomes 14 PSU or less in terms of practical salinity； and planting the root of the reeds in the thus prepared planting soil 12.【課題】ヨシを汽水域の塩分でも枯れないように植栽して、汽水域に人工的なヨシ原を創出する。【解決手段】汽水域Ａを人工ヨシ原Ｂの予定区域に、石塁１１ａなどの透水性の堤１１を築く。堤１１の内側に、ヨシの植栽土壌１２を入れ、その地盤高を平均潮位より高めに設定して、土壌間隙水の塩分を実用塩分で１４ＰＳＵ以下になるようにする。かかる植栽土壌１２にヨシを株植えして人工ヨシ原Ｂを構築する。【選択図】図１
