File:Working in tandem, once again - geograph.org.uk - 982771.jpg

English: Working in tandem, once again. Having reached the end of the harvested ridges the two machines disengage, if only briefly in order to turn around, before realigning themselves once again to resume their task, this time headed in the opposite direction. – What at first glance looks like stubble are the dried remains of flailed potato vines. On maturity of the tubers the potato vines are killed in order to terminate growth and hence control tuber size, and to set skin, which reduces skinning and bruising during harvest, and shrinkage in storage. The most common method of vine killing is chemical desiccation. Sometimes a flail vine shredder (982636, 982683) is used, an implement consisting of varying knife lengths to accommodate the contours of the hill and furrow, producing a very rapid vine kill by mechanically removing all but about 15 centimetres of the vines which are then removed by chemical desiccation. – The crop is now ready for harvesting and a root crop harvester (red) can be seen working in tandem with a trailer-pulling tractor (green). Most potato harvesters operate by cutting through the ground with a digger blade and forcing the dirt and potatoes over a series of chains that transport the potatoes while removing the dirt and vines. The potatoes are elevated by the chains and other conveyers so that they can reach a sufficient height to be dumped into a truck or trailer and hauled away. This process requires constant cooperation between the harvester and the tractor running side by side.