Hay & Forage Grower showcased the results of a research project funded through alfalfa inspections, officially named the American Alfalfa Farmers Research Program, managed by the National Alfalfa and Forage Alliance (NAFA). The reconciliation program promotes farmer-funded research.

Shinners and his colleagues wanted to compare whether wrapping hay bales with breathable film when using a tube wrapping machine helps maintain the quality of the bale. The breathable film allows water vapor to escape from the bale, but releases liquid water on the bale. Its technology is used in a specific commercial hay baler to pack individual bales, but it has not been used after baling using a tube packing machine.

Researchers hope that the combination of tube packaging material and breathable film can reduce packaging costs and reduce the damage caused by the current use of plastic packaging materials. Compared with stretched plastic film, breathable film does reduce condensation on bales, but the breathable film and tube packaging materials need to be modified to make this system a viable option.

"The reason for the difference (forage quality) is the moisture content of the wrapped bales," Shinners explains. "If it is not less than 20%, we will see a lot of condensation and deterioration on the surface of the bale. When our moisture content is 16%, 17% or 18%, we do not see condensation and deterioration. The number of layers of packaging There is no difference, and there is no difference in the color of the packaging in terms of condensation and deterioration."

"Obviously, four layers are cheaper than eight layers, so manufacturers may consider using only four layers," he added. "And the black film does tend to heat the outer layer of the hay and caramelize it, but it is such a thin layer, I am not sure if it matters. Since the results show no difference, the manufacturer can use any color packaging or number of layers As long as the moisture content of the bale is less than about 18%, the hay will be preserved."

Breathable films do not have stretchable properties, so the researchers improved the packaging materials by adding elastic cords to fix the film on the bale and adding tape dispensers to seal the film seams. Researchers including UW agricultural engineers Matthew Digman and Joshua Friede, and then graduate student David Pintens conducted two experiments on the first and second cut of alfalfa. From these two cuttings, samples are collected to determine the moisture content, and then the compositional composition is analyzed. Weigh and measure all packages.

Seven treatments were studied. Shinners’ team compared straw bales wrapped in three layers of breathable film, four and eight layers of white stretch film and black stretch film, as well as bales unfolded and stored on outdoor rock mats, and in open hay sheds. Unfolded and stored bales.

The first cut bales were stored for 148 days; the second cut bales were stored for 97 days. Weigh, measure and sample them, and determine the final moisture and dry matter content of the straw bales. The preliminary cut results show that there is no statistical difference in the dry matter (DM) loss between different treatment methods during storage, although the moisture content of the bales treated with stretched plastic film is significantly higher than that of breathable film bales or unpackaged bales. Almost no damage was found during any treatment of the two-cut cotton bales out of the warehouse.

"If you think that the weather doesn't allow you to press hay into the middle-to-low age period, why not pack it to a moisture content of 35%, 40% or 45% and pack it?" Sinnas asked. "If you want to sell hay and preserve it, you can reduce its moisture content to less than 17%, and then wrap it with a film to preserve it, and it will make it a better-looking bale for sale."

1. The traditional online tube bale packaging machine has been improved, so the breathable film can be applied to dry alfalfa bales.

2. No matter the color or the number of layers of the plastic film, it will not have a significant impact on storage and preservation. Compared with large bags wrapped in plastic film, the surface of the breathable film is less damaged.

3. 16% to 18% of the initial moisture of the cotton bale enters the storage to promote the good preservation of the packaged dry bale without causing surface damage.

This article was published on pages 28 and 29 of the November 2021 issue of Hay & Forage Grower.

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