Effects of a New-Concept Wrapping System on Alfalfa Round-Bale Silage

Abstract

A field trial has been performed to compare a new-concept selective wrapper (3D) based on biaxial rotation of the film applicators with a conventional rotating-table bale wrapper. The objectives were to evaluate the working rates, total plastic consumption, uniformity of plastic distribution on the bale surface, fermentation characteristics, and mold development in alfalfa round-bale silages. The conventional wrapper was set to wrap four (ST4) or six (ST6) layers of film, while the 3D wrapper was programmed to wrap at least four (MODE5) or six (MODE6) layers over the whole bale surface. The conventional wrapper consumed 0.696 and 1.013 kg of plastic per bale for ST4 and ST6, respectively, and was characterized by the number of layers at the ends of the bale, which was five times larger than that at the side. The 3D wrapper utilized 0.862 and 0.976 kg of plastic per bale for MODE5 and MODE6, respectively, and showed a better uniformity in the number of layers applied at the side and ends of the bale, allowing at least seven layers to be applied over the whole bale surface. The 3D system greatly reduced the damage by alfalfa stems to the plastic on the corners of the bale, and it improved the fermentation quality of the alfalfa bale silage over a 180-day conservation period. The 3D system reduced the amount of plastic used by 4% to 15% in comparison to six layers (ST6), which is the optimum amount for the preservation of alfalfa round-bale silage for storage periods longer than 120 days.