Improving cultivation practices in potatoes to increase window of workability and soil structural stability


Potato seedbeds need to be fine, friable, non-compacted, free-draining and structurally stable. Whilst soil type can vary considerably across fields, even in uniform-textured fields there remains large variability in natural water content and bulk density at planting which will affect the seedbed produced if cultivation takes place at a fixed depth.  Reducing the depth of cultivation slightly can often reduce compaction.  The soil nitrogen supply (SNS) is likely to be modified greatly by timing and depth of cultivations, soil water content and rooting activity.

The objectives of the trials were:

  • To quantify the effects of water content at cultivation and OM content on soil cultivatability, bulk density, structural stability and the consequences for crop performance and quality, energy use and machinery work rates on contrasting soils.
  • To determine the effect of different seedbed cultivation depths on SNS on contrasting mineral soils, including the effect on SNS of incorporation of green manures with variable depth seedbed cultivation.
  • To quantify the effects of consolidation and profile of ridges on soil properties and crop performance and quality.


On average, data from 16 experiments conducted in 2011-2014 with four to six destoner depths as a factor, showed that a significantly lower yield (50.5 ± 0.70 t/ha) was achieved when destoning 3‑5 cm deeper than the commercial depth (53.4 t/ha).  The yields from destoning at 22-28 cm (55.3 t/ha) were numerically greater than at the commercial depth (typically 30-38 cm), although not significantly different but there was no evidence that destoning shallower than commercial depth resulted in lower yield.

Shallow destoning did not affect planting depth or time from planting to emergence, however there was greater variation in planting depth and emergence in soil destoned deeper than commercial practice, particularly on heavy soils. Shallower destoning gives greater opportunity for soils to be cultivated closer to their optimum soil water content as well as reducing the wear on machinery and lowering labour costs.

Where soils have sufficient clay content to have a plastic limit (PL), growers should be aware that the critical cultivation depth in most springs would be shallow enough to cause issues of compaction, even by cultivating at the standard depths used by the industry.

Whilst most sites showed no effect of destoning depth on tuber bruising following commercial harvesting, on very stony soils or stony areas of fields destoning should be carried out 5 cm deeper than the optimum for yield to reduce the risk of stone impact causing bruising and careful attention paid to harvester share depth. The apparent lack of effect of depth of destoning on SMN and crop N uptake is of interest and may be due to most OM being in the top 25 cm of the soil profile.

Project code:
R459, R452
01 April 2012 - 03 January 2016
Project leader:
Mark Stalham


R459 Report (2015-2016) R459 Final Report (2015) R452 Report 2012

About this project

To improve cultivation practices in potatoes to increase soil structural stability, lengthen the window of cultivatability, improve soil N use efficiency, reduce wastage and energy consumption and produce consistently larger marketable yields, thereby improving competitiveness and sustainability.