Separation Settings on a Potato Harvester: How Webs and Agitation Protect the Crop
The digging unit of a potato harvester lifts the crop, but the sieving webs decide how much soil, clods and damage reach the store. The right setup depends on soil type and weather.
A potato harvester digs the crop, but the quality of the harvest is decided later. On the sieving webs, the machine separates tubers from soil, clods and plant material. The setup of this part must match the soil. Otherwise, growers lose tubers or damage them.
How separation works
A common intake design uses a diabolo roller and three shares for each row. The shares dig under the ridge and lift soil and potatoes onto the intake web. According to a technical guide on the information site onions-potatoes.com, the gaps between the rods of the web are 42–44 mm wide. Agitators under the web shake the soil through the gaps. The potatoes stay on the web and move on to the next cleaning stage.
Harvesters come with one, two or three webs. According to the same guide, the more clay the soil contains, the more webs and agitation are used to separate soil from potatoes.
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Width of the first web
The width of the first sieving web has a strong effect on separation capacity. According to an analysis of harvester performance on the Russian trade site potatosystem.ru, widening the first web from 1,500 mm to 1,700 mm increases its area by 13%. A larger web gives more room for the soil to sieve out before the crop moves on.
Dry seasons also cause damage
Wet soil is not the only problem. In dry conditions, tubers hit hard clods. According to the same Russian analysis, in the dry season of 2024 the share of damaged tubers in some cases reached 50% of the harvest.
In the chat discussion, growers compared intakes with rollers and open intakes for wet and heavy soil. They did not give measured data, so this comparison is not quantified here.
Why it matters
Losses and damage on the sieving webs reduce the share of marketable potatoes that reach the store. Growers who buy a new harvester or prepare an old one for the next season should match the number of webs, the web width and the agitation to their soil. Settings should be checked field by field and adjusted to the weather, not left at the factory default.
The topic was raised by practitioners in the MAX messenger chat «КАРТОФЕЛЬ И Т.Д. (Potato etc.)», a community of more than 1,100 potato growers and industry specialists. Participants are not named. Join the discussion.
Photo: Potato harvester on a farm in Herseaux, Belgium (illustrative). Jamain / Wikimedia Commons, CC BY-SA 4.0
