| 摘要 |
An agricultural plastic tunnel cultivation frame which is an arcuate frame comprising a long member containing fiber-reinforced synthetic resin and consisting of a bent portion and a body portion, characterized in that the cross-section of the bent portion is different from that of the body portion and the ratio [Rm/Rf] of the rigidity (Rm) of the body portion and the rigidity (Rf) of the bent portion is 2.0-4.0. A method for producing a frame having a cross-section of three-layer structure forming an arch by a ceiling portion, a bent portion, an erected portion and an underground buried portion, and a plastic tunnel cultivation frame made of fiber-reinforced resin and capable of forming an inverted U-shaped tunnel are also provided. |
