There’s no busier – nor more hectic – time than late May, when many farmers are winding up corn planting while starting to harvest their hay crop. Sometimes both can be done at the same time, but if this isn’t possible, which comes first? Individual situations differ, but in most cases as soon as forage grasses are approaching the late boot stage, or alfalfa is in the mid-bud stage, you should park the corn planter and start mowing.

That’s because you can still get good yield and quality from corn planted a week or so later than ideal by switching to earlier maturing corn hybrids. Some of these short-season hybrids can really yield, especially if planted at a moderately high population.

If you miss the ideal time to harvest the first cut, there’s little you can do to make everything right. However, if you have a field that’s mostly or entirely alfalfa you could set your mower to leave higher stubble; that will increase the quality of what you harvest since the bottom of the stem is much lower in quality. Of course you’ll sacrifice yield and there will be that long stubble to deal with during the second cut. If you have grass, or even an alfalfa-grass stand with a lot of grass, cutting higher won’t much improve the quality since the bottom half of the grass stem is almost as good as the top half.

Besides, you should already be leaving about a 4-inch stubble on straight grass stands because that’s where a lot of the nutrients are to get the second cut off to a fast start. Delaying the first cut of grass often results in much lower second-cut yields since some grass species – particularly timothy – don’t do well at all once the soil warms up. And compared to alfalfa, a higher percentage of annual grass yield is in the first cut so missing first cut timing is particularly bad.

Alfalfa harvest management: An accumulation of insults

How you should manage alfalfa this spring may be influenced by how you managed it last fall. If you took a fall harvest, especially prior to a killing frost, it may be best to wait until the very late bud stage to mow.

Alfalfa harvest management involves managing taproot carbohydrates; the more carbs in the taproot, the faster the alfalfa will recover after harvest. Maximum carbohydrate accumulation is at full bloom. If you mowed alfalfa in late August and didn’t take a fall harvest you can expect root reserves to be fully replenished – this assumes a healthy root system, of course, which, with older stands, often isn’t the case.

That’s why more conservative fall management is often recommended with older stands. Repeated field operations – mowing, chopping or baling, fertilizer and manure application, etc. – damage the crowns of alfalfa plants, exposing them to crown and root diseases. It stands to reason that a diseased plant won’t take up nutrients nearly as efficiently as will a healthy plant. This is also the case with soil insects that attack the taproot of the alfalfa plant.

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The most devastating of these is the alfalfa snout beetle, but fortunately this pest is only found in a few isolated areas in New York. Snout beetles are flightless, which has greatly slowed their spread. Much more common is the clover root curculio, which, contrary to its name, will readily attack alfalfa taproots. The time to notice the damaging effects of this insect is about now, when alfalfa has started to grow. Alfalfa with a damaged root system will often be stunted.

When other plants are a foot high, damaged plants may be only a few inches high, often with chlorotic (yellowish or pale green) foliage. There’s currently no effective chemical control for either snout beetles or clover root curculios. A beneficial nematode is being used against the snout beetle in some affected areas of New York, and shows great promise.

I often see recommendations that if a field of first-cut alfalfa was harvested the previous fall or if it suffered winter damage, it should be allowed to mature to 25 percent bloom to permit the accumulation of additional root carbohydrates. That may be good for the plant, but not for forage quality.

A compromise might be to allow stressed alfalfa to reach the 10 percent bloom stage, but if the forage is going to be fed to lactating cows that’s as long as I think you should normally wait. However, if the alfalfa is shorter than normal (often the case with damaged root systems) you may be able to delay harvest and still get good quality; for instance, an alfalfa field where the tallest stems are 24 inches at 10 percent bloom has about the same milk production potential as early-bud alfalfa with the tallest stems at 30 inches.

This information is based on extensive field research showing the relationship between alfalfa height, stage of maturity and milk production potential. I participated in some of this early research and have confidence in the data.

There may be a difference in how intensively you manage alfalfa (or to some extent grass) depending on whether it will be harvested as dry hay for sale, or harvested as silage and fed to dairy cattle. A fairly low percentage of alfalfa hay harvested in the northeastern United States is sold as “dairy cow quality” hay. The exception would be that small amount of very high quality alfalfa sold – usually at a premium price – for feeding to racehorses.

I’ve commented in the past that some of the best and worst hay sold in the Northeast is sold for horse hay. The best is sold for racehorses, the worst to folks who have a “backyard horse” and who know little about hay quality except that it should be green. Some of these people actually prefer seeing heads on timothy since that’s the only way they know what it is.

I’d still recommend harvesting the crop at the previously recommended stages of growth but some differences are justified based on the health of the plants and the intended final use.

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