Tedders: Drying in the field

When it comes to harvesting grassland, the farmer usually has two options: Preserving fodder by silaging or drying. Those who opt for the drying process rely on the power of the sun when the weather is fine. The more evenly the forage is spread out and the more often it is turned, the faster the drying process will be. What used to be done laboriously by hand is now done by a machine: the rotary tedder, also known as tedders, supports the farmer in the hay harvest.

Function of the tedder

The tedder consists of one or more pairs of rotors driven in opposite directions and fitted with tines. The pairs of rotors are driven by the tractor PTO shaft and are set so that the spring steel tines at the front grip the crop just above the ground, but the rotor as a whole has an inclined position. This allows the tines to grip the crop on the ground, lift it and then discharge it in a wide spread. To ensure that the set height of the rotors is maintained even on uneven terrain, each rotor has a feeler wheel that follows the unevenness of the ground. The inclination of the rotors can be individually adjusted by the farmer to suit different conditions.

Tasks of the tedder

The task of the tedder is to promote the drying of the crop in the field. The work with the tedder can be divided into tedding and turning. The main purpose of tedding is to distribute the crop evenly over the sward to enable better drying. This is particularly necessary if the crop has been deposited in pronounced swaths (e.g. with drum mowers). To tedge, the farmer sets a rather low discharge angle.

Another task of the tedder is to turn the crop. This involves setting a larger discharge angle so that the crop is repeatedly turned over. This encourages the plants to release water and thus ensures faster drying progress. Depending on the growth and weather situation, the turning process can be repeated several times.

Frequency of tedding and turning

The optimum number of turns may vary depending on the region, weather conditions and composition of the grassland. As a general rule, the more frequent the turning, the better the drying process is supported. However, frequent turning also leads to increased crumble loss, which can reach up to 40% of the total forage mass. The farmer must therefore weigh up whether a reduced number of turning passes makes sense, even if this means longer drying times are possible.

Alternatives to the rotary tedder

When it comes to turning and tedding, the tedder has almost exclusively established itself as the technical solution. This is suitable for almost all agricultural green areas. Only for very special applications, e.g. in alpine areas, are machines such as the belt or chain tedder still used. These have the great advantage that they can still be used on slopes of up to 80% due to their light weight and the fact that they are mounted close to the vehicle in combination with hand-held motorized equipment. Other alternatives to the tedder such as the fork tedder or drum tedder are hardly used today.