Sulfur Dioxide Preservation of Forage Crops

Abstract

Summary Data on the chemical analysis of 24 experimental silages, made and stored in 50-gal. steel barrels, are presented for the purpose of comparing the preservative effect of SO 2 with that of corn-and-cob meal. Four different types of haycrop silages and corn silage were tested with three levels of sulfur dioxide treatment, no treatment and with 200lb. of finely ground corn-and-cob meal per ton. Liquid SO 2 , at levels of 5 and 7lb. per ton of green material, proved to be very effective in developing the desired acidity for proper silage preservation in a very short time, as compared to the time required for the development of such acidity by fermentation. Reducing sugar levels in the SO 2 silages increased over the levels found in the original fresh grass materials. These high levels of sugar were maintained throughout the 120 days storage period. Lactic acid values in the SO 2 silages did not increase markedly during the storage period, as did those in the control silages. The high sugar values and the low lactic acid values in the SO 2 silages indicate that bacterial fermentation had been decreased by this treatment. Carotene destruction, which was most evident during the first day of storage, was kept to a minimum by treating the silages with SO 2 . The SO 2 silages maintained much higher levels of carotene than the control silages during the entire storage period. Ammonia nitrogen levels in the SO 2 silages were much lower than in the control silages. Evidently, the use of SO 2 in these silages prevented considerable protein decomposition. Volatile acid values were lower in the SO 2 silages, compared to those in the control silages.