Mechanical conditioning of forage can be accomplished by passing the crop through fluted intermeshing rolls or by passing the crop over the tines of an impeller rotor. Three impeller conditioners and one intermeshing roll conditioner were compared in field experiments. The impeller conditioners differed on the type of tine used on the rotor. Hood position and impeller speed were the two adjustments made on all impeller conditioners. The linear load on the rolls was the only adjustment made on the intermeshing roll conditioner. The effect of the conditioning mechanisms and their adjustments on drying rate and leaf loss in alfalfa and grass crops was measured. Comparisons were made exclusively among impeller conditioners using all adjustment combinations and among all machines with specific aggressive and nonaggressive adjustments selected. In alfalfa, among impeller conditioners exclusively, the fast rotor speed caused about 7.3% leaf loss, which was 1.1 percentage point greater than the leaf loss caused by the slow rotor speed. With respect to hood position, the maximum average leaf loss was 6.77% and varied by less than 0.1 percentage point. Incidentally, in the first day of drying, alfalfa conditioned with the fast impeller speed exhibited a 3% greater drying rate constant than the drying rate constant of alfalfa conditioned with the slow impeller speed. In the first day of drying, grass conditioned with the fast impeller speed exhibited a 13% greater drying rate than the drying rate of grass conditioned with the slow impeller speed. In addition, drying rates in alfalfa varied less than 8% and drying rates in grass varied less than 10% in the first day of drying with respect to hood position. When comparisons were made exclusively among impeller conditioners, statistically significant differences in drying rate and leaf loss were only exhibited between the fast and slow impeller speeds. In the first day of drying, forage (both grass and alfalfa) conditioned by aggressively-set impeller machines exhibited drying rates 23 to 63% greater than drying rates of forage conditioned by the aggressively-set intermeshing roll conditioner. Also in the first day of drying, forage (both grass and alfalfa) conditioned by nonaggressively-set impeller machines exhibited drying rates 49 to 60% greater than the drying rates of forage conditioned by the nonaggressively-set intermeshing roll conditioner. Results also suggest that aggressively-set impeller machines, caused 1.7 to 3.4 percentage points more leaf loss than the aggressively-set intermeshing roll machine, and nonaggressively-set impeller machines caused 1.2 to 2.2 percentage points more leaf loss than the nonaggressively-set intermeshing roll machine.
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