What is a stripper header?
A Stripper header is a type of combine header which removes the grain from the plant, leaving the stem standing in the field. Stripper headers work by using rotating fingers which are able to catch and pull the grain from cereal plants, boasting increased work rates due to less material passing through the combine. They are available for most combines and are attached in a similar manner to a standard header.
Why are the regen group interested in the stripper header?
James at Cloud Farming, Ross at Castleton Farm and Hugh at Backboath have trialled a stripper header this harvest, and they are interested in this machine for a number of reasons. Stripper headers can boost harvest output by approximately 30% due to the reduced amount of material passing through the combine, providing increased work rates which can be useful in intermittent weather.
However, the mains reason for trialling this machine is to look at new ways to deal with the straw residue. Chopping the straw can provide a significant mat on the soil surface which is beneficial for soil protection. Although it can also create ideal conditions for slugs and provide a large quantity of carbon into the soil very quickly, potentially resulting in nitrogen lock up for the following crop.
A stripper header which leaves the straw standing may therefore make it easier to manage subsequent crops due to reduced slug pressure.
Furthermore, stripper headers can also harvest in wetter conditions as the straw is not processed, providing more opportunities to harvest. This machine is particularly effective in barley crops where the ears have bent over. A conventional header would need to harvest low to the ground to catch all the ears however a stripper header can pick up the ears and leave the maximum amount of straw present. Ross also trialled this header in brackled barley, finding it very effective at picking up plants which have lodged.
What are the downsides?
Nevertheless, stripper headers are not suitable for all crops, for example, oilseed rape and beans still require harvesting with a conventional header to avoid high in field losses. A stripper header can also have higher losses in very dry crops, in particular wheat. This is because the forward pressure from the header can cause very dry grains to fall out on to the ground. At Castleton farm, it was estimated that the losses were approximately 50kg/ha, even in a dry wheat crop at 18% moisture content. There is also an additional cost associated with the purchase of one of these headers. This cost would need to be justified above the cost of a conventional header depending on the diversity of a rotation. Although, this type of header may outlast several combines. In brackled barley, the harvesting process is also not as smooth as standing crops. The uneven height causes more tearing of the stems and the straw lies in different directions. From a harvesting point of view, there is still an increase in output, and Ross found that his combine which usually has an output of 22 to 23t/hour in a comparable crop was achieving 30t/hour with the stripper header. However, the challenge may come at sowing time, providing a challenge for trash management on the drills.
Ross, James and Hugh will all try to establish crops into the standing residue, this will be an interesting experiment and will put their drills to the test. However, the group will not only be looking at emergence but also overwinter survival rate and the soil conditions in each field harvested. This will provide a more complete test for this innovative machine.
Zach Reilly, Farm facilitator for the Soil Regenerative Agriculture Group.