Effect of Salt on Fermentation of Alfalfa. 1. Treatment with Potassium Chloride

¹ USDA, Agricultural Research Service, US Dairy Forage Research Center, Ohio Cluster, Department of Dairy Science
² Department of Agronomy, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691

Potassium chloride was added to alfalfa before ensiling in experimental silos to determine the effects of potassium addition on fermentation. Well-mixed, wilted (50% DM), third-cutting alfalfa was divided, and KCl was added at a rate of 38.1 g KCl/kg wet forage. Forage was packed into experimental plastic cylinders (610 x 102 mm) and allowed to ferment for 1, 4, 7, 28, and 60 d when DM, protein, ammonia, and 2-amino N, pH, lactic and acetic acids, soluble sugar and starch, and total anaerobes were measured. Addition of KCl to alfalfa at the time of ensiling inhibited microbial activity and slowed acid production and the rate of pH decline of the resulting silage. Even though rate of pH decline was faster (.023 vs. .015 units/d) for control than for treated forage, proteolysis, estimated by changes in protein N, ammonia N, and 2-amino N, was not inhibited. Faster rates of pH decline caused by increased microbial activity may not effectively inhibit proteolysis.

Key Words: alfalfa • salt • fermentation

Submitted on February 26, 1990
Accepted on August 6, 1990