Farmers have a variety of choices for equipment that rakes, spreads and merges hay before baling. They must consider crop yield, harvest losses, contamination of the crop and drying time when deciding which machinery will best suite their needs.
A hay tedder is used to spread out the hay crop as wide as the cut width of the hay conditioner or mower. When fields are damp due to rain or high humidity, the use of a hay tedder helps the crop to dry out before being raked and baled. This procedure not only aerates the swath of hay, but also allows the sunlight to dry the hay on the field. When the hay is in a small windrow, the sunlight will mostly hit bare ground and will not affect the majority of the hay in the windrow. If hay with high moisture content is baled and stored, it will most likely mould and be unsuitable for livestock feed. The moisture content in hay when baled should be 18 per cent to 20 per cent for small bales and 16 per cent or less for large bales.
A hay rake is used to bring hay into windrows and prepare it to be baled. There are three different types of hay rakes: parallel bar, rotary and wheel. Forward motion of the tractor and engaging the wheels of the rake into the crop powers the wheel rakes. Wheel rakes are not PTO driven, which hinders their ability to work well with hay that is heavy and wet.
Losses and Drying Rates
Tedders cause more leaf loss than rakes, especially in alfalfa hay, which is partially dry. However, tedders do allow for a quicker drying rate because of the wide swath in which the hay is placed.
In a study by Savoie et al., they found that "tedding increased the drying rate slightly but the results were not very consistent. During good drying conditions, tedding did not appear to be beneficial but may be beneficial after a heavy rain, which creates a windrow that was dense and matted."
Contamination and Damage of Crop
It is important to good crop harvesting and the maintenance of the equipment to produce windrows that do not contain rocks, soil, excess ash or other debris. Use of tedders that pick up the crop and move it across a conveyor and then place it back on the ground aids in keeping the crop from being contaminated. Additionally, with hay rakes, inadequate tension of the rake springs will cause the teeth to wear faster and allow for greater contamination of the hay.
When to Use
In order to speed the drying time of the hay, tedding is generally done the second day after the hay has been mowed or after a heavy rainfall. Raking, however, is not done until the hay has less than 35 per cent to 45 per cent moisture content. Raking is usually done right before baling.