Steps to Speed up Field Curing of Hay Crops

tractor pulling mower through field of hay

The rainy weather in many regions of Ohio and surrounding states is making it difficult to harvest hay crops.  We usually wait for a clear forecast before cutting hay, and with good reason because hay does not dry in the rain! Cutting hay is certainly a gamble but waiting for the perfect stretch of weather can end up costing us through large reductions in forage quality as the crop matures.

As we keep waiting for perfect haymaking weather, we will reach the point where the drop in quality becomes so great that the hay has little feeding value left. In such cases, it may be better to gamble more on the weather just to get the old crop off and a new one started. Some rain damage is not going to reduce the value much in that very mature forage.

Before cutting though, keep in mind that the soil should be firm enough to support equipment. Compaction damage has long-lasting effects on hay crops. We’ve seen many fields where stand loss in wheel tracks led to lower forage yields, weed invasion, and frustrating attempts to “fill in” the stand later.

This article summarizes proven techniques that can help speed up the process involved in storing good quality forage. While the weather limits how far we can push the limits, these techniques can help us improve the chances of success in those short windows of opportunity between rains, and hopefully avoid overly mature stored forages.

Haylage vs. Hay
Consider making haylage/silage or baleage instead of dry hay. Haylage is preserved at higher moisture contents, so it is a lot easier and quicker to get it to a proper dry matter content for safe preservation compared with dry hay. Proper dry matter content for chopping haylage or wrapping baleage can often be achieved within 24 hours or less as compared with 3 to 5 days for dry hay.

“Hay in a day” is possible when making hay crop silage. The forage is mowed first thing in the morning and laid in wide swaths to be raked in the late afternoon and chopped as haylage starting in early evening. Proper dry matter content for haylage ranges from 30 to 50% (50 to 70% moisture) depending on the structure used.

Wrapped baleage usually requires 24 hours to cure. Wrapped baleage should be dried to 40 to 55% dry matter (45 to 60% moisture).

Dry hay should be baled at 80 to 85% dry matter (15 to 20% moisture), depending on the size of the bale package. The larger and the denser the dry hay package, the drier it must be to avoid spoilage. For example, safe baling moistures for dry hay without preservatives are 18-20% for small square bales (80 to 82% dry matter), 18% or less for large round bales, and less than 17% for large square bales. See below for more information on baling with preservatives.

Mechanically Condition the Forage
Faster drying of cut forage begins with using a well-adjusted mower-conditioner to cause crimping/cracking of the stem (roller conditioners) or abrasion to the stems (impeller conditioners). Adjust roller conditioners so at least 90% of the stems are either cracked or crimped (roller conditioners) or show some mechanical abrasion (impeller conditioners).

Some excellent guidelines for adjusting these mower conditioners can be found in  an article by Dr. Ronald Schuler of the University of Wisconsin, available online at https://fyi.extension.wisc.edu/forage/adjusting-the-conditioning-system-....

Consider Desiccants
Desiccants are chemicals applied when mowing the crop that increase the drying rate. The most effective desiccants contain potassium carbonate or sodium carbonate. They are more effective on legumes than grasses and most useful for making hay rather than silage or baleage. Desiccants work best under good drying conditions. They do not help increase drying rate when conditions are humid, damp, and cloudy, such as we have often experienced this summer. Consider the weather conditions before applying them.  

Maximize exposure to sunlight
I once heard someone say "You can’t dry your laundry in a pile, so why do you expect to dry hay that way?"

Exposure to the sun is the single most important weather factor to speed drying. The trick is to expose to sunshine as much of the cut forage as possible.

a windrow of hay dryingThe swath width should be about 70% of the actual cut area. The mowers on the market vary in how wide a windrow they can make, but even those that make narrow windrows have been modified to spread the windrow wider. Details can be found in articles at the Univ. of Wisconsin website mentioned above (see especially “Getting the Most from the Mower Conditioner” by Kevin Shinners, https://fyi.extension.wisc.edu/forage/getting-the-most-from-the-mower-conditioner/).

Another way to spread out and aerate the crop for faster drying is with a tedder. Tedders are especially effective with grass crops. They can cause excessive leaf loss in legumes if used when the leaves are dry. Tedders can be a good option when the ground is damp, because the crop can be mowed into narrow windrows to allow more ground exposure to sunlight for a short time, and then once the soil has dried a bit the crop can be spread out with the tedder. Tedding twice may decrease drying time. Tedding shortly after mowing allows 100% ground coverage, then tedding the next day helps keep the crop off the ground. Be cautious to set tedder properly so that dirt is not incorporated into the hay but all hay is lifted off the ground.

Take precautions to follow manufacturer recommendations on ground speed and RPM’s when tedding.  Many of the modern in-line “fluffer” type tedders are ground driven and operators often exceed recommended speeds, which can result in bunching and wrapping of the hay, which will increase drying time and make raking more difficult.

When making haylage, if drying conditions are good, rake multiple wide swaths into a windrow just before chopping. For hay, if drying conditions are good, merge or rake multiple wide swaths into a windrow the next morning when the forage is 40 to 60% moisture to avoid excessive leaf loss.

Research studies and experience have proven that drying forage in wide swaths can significantly speed up drying. Faster drying in wide swaths results in less chance of rain damage and studies by the University of Wisconsin showed that wide swaths (72% of the cut width) result in lower neutral detergent fiber (NDF) and higher energy in the stored forage.

Consider Preservatives
Sometimes the rain just comes quicker than we have time for making dry hay. As mentioned above, making haylage helps us preserve good quality forage in those short rain-free windows. A second option is to use a preservative. The most effective preservatives are based on proprionic acid, which is caustic to equipment, but many buffered proprionic preservatives are available that minimize that problem.

Preservatives inhibit mold growth and allow safe baling at moisture contents a little higher than the normal range for dry hay. Carefully follow the preservative manufacturer’s directions and application rates for the hay moisture content at baling. Be sure the application is uniform to avoid spots that spoil. Most products are effective when hay moisture is less than 25% but become iffy between 25-30% and do not work if moisture is over 30%. When utilizing preservatives, safe baling moisture can go up to 26% on small squares and round bales, but only 23% on large squares, according to label guidelines on most proprionic acid based products.  Baling at these moistures requires properly calibrated equipment to apply the correct amounts of preservative, and it does not guarantee that bales will not generate internal heat. 

While the acid works to limit the production of mold and fungal spores that can lead to additional heating, any type of bale made over 20% moisture always has the potential to heat.  Although mold production may be limited, discoloration and carmelization of the higher moisture stems can still occur.  This heating can also degrade proteins in the hay, reducing overall feed quality despite still helping to preserving the hay from spoilage and hopefully making it safe to store indoors. Keep in mind that preservative treated hay should be fed within a year or less, as the preservative effect will wear off over time.

If baling on the wet side, watch those bales carefully! If hay is baled at higher moisture contents that are pushing the safe limits, keep a close watch on them for two to three weeks. Use a hay temperature probe and monitor the internal temperature of the hay during the first three weeks after baling. See the following article for more information on monitoring wet hay: https://agcrops.osu.edu/newsletter/corn-newsletter/15-2021/hay-barn-fires-are-real-hazard

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.