Delta system

The delta system has emerged in recent years as a valid alternative to the zig-zag structure due to its lower installation costs. Unlike the zig-zag structure, the films are not connected to each other but are independently fixed to a longitudinal wire placed below the top wire of the adjacent row. Since the longitudinal wire running through the center of the row is no longer needed, the transverse rope can be directly fixed to the post cap. This reduces the materials needed for the construction and the time required for installing the structure. In case of windy areas, it is recommended to reinforce the structure with a second transverse rope, fixed to the concrete post. The tensioning of the films is ensured by a polyethylene rope which is connected on one side to the lower longitudinal wire and on the other one to the bungee ropes. These bungee ropes are then anchored to the sheet in four equidistant points, form the characteristic delta design. The delta system can be made with tarpaulin or laminated films, depending on the crop requirements. Unlike the zig-zag system, it does not allow for total coverage of the row for early fruit maturity. It is recommended not to exceed 25 square meters of land surface per intermediate post.