Required result of cultivation
- A loose, friable soil with good vertical fissuring, no large clods or stones and no compacted layers.
- The key is only working the soils at the correct moisture content, i.e. not above the plastic limit where soil can be easily rolled into a ribbon.
- N.B. Cultivations can never be totally prescriptive.
Soil at the plastic stage – not suitable for cultivation.
Detecting and removing compaction
- Soil pits should be dug to detect any compacted layers.
- Penetrometers can be used provided the soil has not dried out – remember to “ground prove” the penetrometer by digging some sample holes to confirm the readings, which will vary with moisture.
- If needed, subsoiling can be performed with low disturbance wings set correctly just below the compacted layer.
- If early ploughing is carried out on heavier soils subsoiler attachments on the plough can be considered, provided that soil at this depth is dry enough to fissure, and enough depth of soil below the plough is available.
Drying of soil
- On most soils spring ploughing at about 28 cm depth is the best method to achieve drying of soil to depth.
- Considerable skill is needed to achieve correct drying of the soil without over drying the surface.
- Once soil is dry enough, cultivations with either or both bed-tillers and stone and clod separators can be performed with the soil below the plastic limit at the required depth.
- The small cost saving using tined cultivations may not be justified.
- Note that careful setting of bed tillers and separators is vital.
- Often, working deeper than necessary can raise damper soil and produce more clods than would be present if working slightly shallower.
- Start shallow and adjust deeper only if absolutely necessary and provided that the clods formed, or discharged, do not increase as a result.
- Note also, the need to set tractor tyre pressures as low as safely possible to minimise compaction effects.
- Where wheeling eradicators are used, ensure these have adequate lift, but low rake angles, to avoid raising clods into the seedbed.
- Here, prevention (low pressures) is far better than cure (eradication), especially if the soil is damp or wet at depth – which can be likely.
Variations in practice
- On some soils there may be an advantage in deep ridging prior to bed tilling and stone separating.
- Other soils may not need bed tilling prior to stone or clod separating.
- Avoid unnecessary additional bed tilling if possible, as this risks over-working the soil and increases the potential to form a tough layer at working depth.
- See Avoiding compaction notes for information on removal of compaction under bed tillers.
- Planting in beds rather than ridges offers advantages in reducing greening and retaining moisture.
- Three row beds offer further advantages.
- Depth of planting is discussed under Planting and harvesting.
- Indentations in the tops of beds, and to a lesser extent ridges, can improve infiltration of water and reduce run-off (see Cultivation for potatoes 2007).
- Run-off from wheelings can be reduced by tools such as the “Wonderwheel” from Bye Engineering (see Reducing run-off 2016 and Baselier tines for restructuring beds 2016).
Notes on cultivation
Soil management strategies for potatoes 2020 (Cultivation in difficult conditions)
Tines vs plough 2018 (Potential advantages of either technique)
Reducing run-off 2016 (Cultivation techniques to reduce run-off in tramlines)
Baselier tines for restructuring beds 2016 (Supporting notes for 2016 presentation, from an external source)
Cover crops 2012 (Information on potential cover crops to use before potatoes)
Use of cover crops before potatoes 2012 (Discussion of potential problems)
Structuring soil for potatoes 2011 (New cultivation tools for specific uses)
Cultivation for potatoes 2007 (Soil structure; crop establishment; infiltration of water)
Notes for 1993 (Chapter 3: Soil structure – measurement of soil characteristics and effects on root growth)