What should you do with fall alfalfa? Leave it? Cut it? Graze it? Each of these options can be correct under appropriate conditions. Making the best decision requires balancing the associated rewards and risks with each option.
Rewards: Fall alfalfa often produces the best quality forage of the year. Leafy plants with fine stems grown with reduced temperature stress can result in award-winning, high value dairy hay or haylage.
Resulting forage provides immediate value compared to the delayed returns the following year by leaving it.
Minimizing the amount of alfalfa stubble entering winter has been shown to often reduce injury from alfalfa weevils the following spring.
Risks: Alfalfa dries very slowly during the cooler temperatures and shorter daylengths of fall, increasing the risk of weather damage. It can be tempting to bale before hay is adequately dry for safe storage, requiring use of costly preservatives or risking storage losses.
Heat damage, mold, or spontaneous combustion fires can occur when rich, fine-stemmed, high quality hay is packaged into tight, heavy bales, especially if it is baled just a little too damp. Plentiful nutrients in a tight, dense package that is a little too wet is an ideal environment for heat producing microbes.
High quality alfalfa that experiences weather or heat damage or mold can quickly turn into low to moderate quality forage, reducing or eliminating the potential economic benefit from taking the late season cutting.
Competition for labor from harvest of annual grain crops can be high.
Winter kill or injury may increase if the winterhardening process is disrupted by harvest. Alfalfa plants are more likely to survive winter when, following final harvest, they either have sufficient regrowth to accumulate adequate nutrient reserves or they experience little depletion of an already adequate accumulation of nutrient reserves.
Rewards: Alfalfa can provide considerable, high quality grazing during fall, avoiding problems of slow curing and the cost of baling.
It can extend the grazing season in areas where pasture typically becomes limited in the fall.
It can be used as a protein supplement when grazed along with low quality forages such as crop residues or dormant pasture.
Risks: Bloat risk must always be understood and managed. Fully bloomed out alfalfa is of low risk but young, vegetative growth can be very dangerous. After a hard freeze, bloat risk increases for several days until plants begin to wilt, after which bloat risk declines considerably.
Fence and water may need to be added.
Stands can be damaged if fields aren’t dry and firm when grazed. Sacrifice areas or penned feeding areas may be needed to minimize damage.
Large cow pies that degrade slowly can plug sickle bar mowers at first harvest next spring.
Rewards: Winterhardiness should be maximized with vigorous early growth next spring. Taller stubble will hold snow for extra moisture and insulation as well as provide more reliable erosion control. Heaving should be minimized. Ice damage may be reduced.
Cost of harvesting the relatively low late season yield is eliminated.
Various wildlife species may use remaining growth for shelter or as a feedstuff. (This may be considered a risk in some instances).
Risks: Use it or lose it.
Value of next year’s forage is less certain than that of the current year.