Soil & Water Management Centre

Developing & improving your soils

Rachel Lockley

Study area:
Minimising post-harvest losses due to cracking in radishes (Raphanus sativus) by manipulation of the pre-harvest soil water availability.

Commercially cracking in European radishes can account for losses up to 30%. This equates to a loss of £800,000 to the largest British radish grower annually.

Previous work on Asian radishes found altering the irrigation frequency or the water content the soil was irrigated to affected the levels of cracking which were observed at harvest. Similar experiments in European radishes showed varying the irrigation frequency and irrigating at the same frequency to different water contents had no significant effect on cracking at harvest.

Aim of your study
To minimise cracking in radishes

Most interesting find so far
Radishes undergo a physiological change around day 17 called secondary thickening where the outer cortex and exodermis split and slough away leaving the periderm exposed. Once this has happened the hypocotyl expands rapidly. The majority of radish growth happens in the final 10 days before harvest. It has been found that the volumetric water content at the point of secondary thickening strongly correlates with the amount of cracking observed at harvest. 

The yield is determined by the water content of the soil in the final 10 days of growth. Therefore, having a dry period prior and up to secondary thickening does not compromise yield in terms of weight harvested but increases yield in terms of commercially viable product which has not split.

How may it help food production in the future?
Radish waste can be minimised.

The cost of post-harvest sorting can be minimised.

Cracking at harvest can be forecasted by monitoring the water content of the soil at the point of secondary thickening. This stage can be easily and non-destructively identified in the field.

This knowledge can be used in irrigation scheduling, irrigation should not be applied until after secondary thickening.


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