Recently, chemical drying agents have been proposed as an additional means of reducing the duration of field-curing. Preliminary studies conducted in Australia suggested that potassium carbonate solutions were effective in increasing drying rates of alfalfa. Subsequent research has confirmed these results and demonstrated increased effectiveness of using combinations of potassium carbonate and emulsions of fatty acid esters. Work at Colorado State by Iwan et al. They are least effective under cool, humid conditions.
Available evidence suggests that drying agents are of limited effectiveness with grass hay.
Several carbonate-based commercial formulations are available and have generally produced similar results when used on alfalfa. The carbonate-based drying agents function by modifying the waxy cutin layer of the plants so it is more permeable to water. The formulations are most effective when applied to stems at cutting. Commercially available applicator kits include a holding tank and pump, hoses, nozzles and deflector bar mounted in front of the header about 8 to 10 inches above the cutting level. This device pushes plant tops over so the spray can be directed primarily at the stems.