Given our recent weather pattern, the topic of haymaking is almost certain to come up in any conversation with farmers. Last week while bemoaning the havoc our rainy weather is inflicting upon harvest schedules and hay quality, a member of my program advisory committee brought up the topic of haylage in a day. This is a concept that is being promoted in New York by forage folks at Cornell. Later, that member sent me a copy of a newsletter from Cornell that outlined some of the important principles of the haylage in a day concept. Those principles include maximizing photosynthesis, maximizing cutting widths, and wide swaths. Now let's look at each of these factors in a little more detail.
After forage is cut, quick dry down is driven by photosynthesis. Photosynthesis is the process where the plant uses water and carbon dioxide to produce sugars (carbohydrates) and oxygen. This only happens when the sun is shining. Even though the plant has been cut, photosynthesis will continue until the plant reaches approximately 60% moisture. In a cut plant, the only source of available water is the moisture in the plant tissue, particularly the stem. The more leaf area that is exposed to sunlight after being cut, the more of that moisture is used and the quicker the plant dries down to 60% moisture content. Ideally, forages can be chopped for haylage between 65and 55% moisture content. According to the Cornell newsletter another benefit is that the sugars produced by photosynthesis in this drying down process stay in plant tissues since they can't be moved into the roots as would normally occur with the whole (roots attached) plant.
The other, and obvious, benefit of sunshine is that the more sunshine that hits plant material the higher the temperature of that material and the quicker it dries. So, in order to maximize the plant surface area exposed to sunlight, there must be a wide swath width. Anything that restricts swath width after the forage is cut will increase dry down time. Work at Cornell has shown that any swath width that is less than 80% of the cutterbar width will make it difficult to achieve haylage in a day especially in first cut crops and/or heavy yield forage stands. Farmers in New York who have bought into the haylage in a day are removing center diverters in mowers and in some cases adding spreaders to the back of mowers to increase swath widths to 90% or more of cutterbar width. Other farmers are removing deflector shields to reduce clumping and provide more uniform wide swaths.
The key components of this concept are mowing without conditioning so that stems remain whole, and spreading out the cut plants into a wide swath so that photosynthesis and sunlight hitting plant material is maximized. Of course we have no control over whether the sun shines or not, but when it does, we can be ready to take maximum advantage of even a day of sunshine.