Harvesting alfalfa fields during the late fall to remove existing forage can be detrimental to long-term stand persistence. However, producers have noted that the standing over-wintered material (aftermath) lowers quality of first-cut forage. For this reason, producers sometimes remove the standing forage in the fall, thus decreasing stand persistence, or drag the aftermath forage in the early spring to avoid cutting and windrowing the dead material. To study the impact and magnitude of fall aftermath forage on first-cut forage quality, the Fond du Lac County Forage Council initiated a study in 1990. Participating cooperators were Rick Kastning (1990) and Brian Costello (1991-92).

Materials and Methods: Sample fields were chosen in the spring of each year with moderate to large amounts of overwintered alfalfa forage. Two replications of each treatment were imposed during late-March to mid-April depending upon year and field conditions. Treatments were as follows:

Plots were harvested before June 1 in all three study years with a conventional forage chopper. Subsamples of the chopped forage were collected and analized for quality. Results are averages of the two replications by year.

Results: Overall forage quality results are presented in Table 1. Flail chopping effectively removed the dead material and consistently improved the quality of the first-cut harvested forage. Crude protein was improved 0.5 to 1.0 percentage unit and fiber values were lowered 1.4 to 5.6 percentage units when compared to control plots. The magnitude of improvement varied with year and the amount or condition of the dead aftermath forage. The effect of dragging (imposed in 1990 and 1991) on forage quality was always intermediate between the control plots and flail chopping.

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Conclusions: The results of this demonstration study clearly indicate that fall aftermath forage can lower first-cut forage quality. The magnitude of this reduction will depend on many factors including the amount and condition (laying or standing as a result of previous snow cover) of dead plant material, time of harvest, method of harvest, and environmental conditions. To overcome the reduction in forage quality, producers can either harvest a late October cutting or eliminate the dead plant material in the early spring. Harvesting a late fall cutting is not recommended in years when forage is abundant due to the risk of winter stand injury or death. Flail chopping or dragging the dead plant material is effective but not without risk. Fields should be firm and dry or frozen when these operations are performed. At the same time, it has to be done before significant plant regrowth is initiated. In some years, this leaves very few days when these field operations could be performed. A good example of this was 1992 when warm wet conditions prevailed through much of March and April. Flail chopping or dragging alfalfa fields in the spring should be considered for fields where abundant dead plant material remains standing and conditions are suitable for field operations. For producers wishing to maximize forage quality, the practice offers another "fine-tuning" management alternative.