While the first cut harvest of many alfalfa fields in Manitoba was above average and early in 2006, the second cut harvest did not yield so well. Dry conditions and hot temperatures pushed many alfalfa stands to flower early and provide below average yields.
As a result, many producers are looking to either squeeze more feed out of a minimal third cut or take poor cereal crops for green feed.
Glenn Friesen, a forage business development specialist with Manitoba Agriculture, says when deciding to cut hay stands late in the season, it’s especially important in the case of alfalfa to observe the critical fall harvest period also known as the fall rest period.
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Adequate root reserves are necessary for winter survival and persistence, as well as vigorous spring growth and good first cut yields. All alfalfa stands require enough time to prepare for the overwintering period, especially seedling stands.
Harvesting before the critical fall harvest period for alfalfa allows the plants enough time before the killing frost to regrow and build sufficient root energy reserves for overwintering.
Harvesting during this period will reduce winter hardiness and potentially reduce stand densities the following spring.
If harvesting before this period is not an option, producers may wait until after a killing frost.
The critical fall harvest period for alfalfa is approximately the final 450 growing degree days of the growing season before the first killing frost – approximately six weeks depending on location. Harvesting after this time but before a killing frost increases the likelihood of winterkill.
If the decision is made to harvest during the critical period, the benefits of the additional harvested forage should be weighed against the potential for winterkill and early spring yield losses. Yield sacrificed by not harvesting during the critical fall harvest period is usually easily regained in first cut yield the following year.
