Sulfur Dioxide Preservation of Forage Crops

Abstract

One of the most difficult problems in grassland farming is that of storing the crop for later feeding. Most forage crops are produced and should be harvested for their maximum feeding value at a time of year when it is very difficult to field-dry and nlake thenl into hay. In efforts to find a better method of pre- serving forage crops, Knodt (4) treated successfully the contents of a silo with SO_~ at the rate of 5 lb. per ton of green material. Alternate loads of tinlothy- red clover were placed in two silos which were filled using 200 lb. of hominy and 5 lb. of SO.,, respectively, per ton of green material. In a feeding trial with lactating Holstein dairy cows fed 60 lb. of silage per day, the two silages were equal in feeding value, on a pound-for-pound basis. Twice as much carotene was found in the SO~_ silage as in the hominy-treated silage when fed. As a result of this previous work, the experiments described in this report were conducted in 1950, to study the use aud value of S02 for preserving various forage crops. This report presents the chemical studies of SO~ silages compared to two control silages made from four different forage crops and corn. EXPERIMENTAL For these chemical studies the silages were made and stored at atmospheric temperature in 50-gal. steel barrels with removable tops. For each combination of treatment and material a set of eight barrels of silage was prepared or a total of 40 barrels for each crop studied. Materials tested included timothy and red clover cut at the pre-bloom stage of the timothy, brome grass cut when in bloom, second cutting orchard grass and ladino clover, second cutting alfalfa just at the beginning of the bloom stage, and corn cut in September. Each of these materials was treated with liquid SO2 at rates of 3, 5 and 7 lb. per ton of green material. Two control silages were made from each material, the first without treatment and the second with the addition of 200 lb. of finely ground corn-and-cob meal per ton of chopped material. The corn-and-cob meal treatment was omitted in the corn silage series. Thus, the S02 silages could be compared, chemically, with the two sets of con- trol silages which depended on fermentation for their preservation.