July 12, 2013 12:00 am Published by omexadmin
Nutritional Agronomy Note

12 July 2013

As main crop potatoes progress from tuber formation to bulking, now is the time to consider the use of foliar nutrition to help reach those all-important final quality targets that secure the best value for the harvested crop.

General guidance on this approach is available in the Omex Potato Nutrition Application Programme leaflet, but the best choice of product and timing will depend on a range of factors including:

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  • Soil status and the previous application programme
  • The end market requirements, e.g. size and skin finish for pre pack, dry matter for processing
  • Prevailing weather conditions and the availability of irrigation
  • The likelihood of disorders such as internal rust spot or growth cracking
  • The stage of development and the tuber number potential of the crop – if in doubt dig in and take a look!

Seasonal weather variations can have a big influence on the uptake of available nutrition, and resources available to the rapidly growing tubers can quickly become a limiting factor in hot, dry weather. A particular risk in periods of rapid growth during low rainfall is calcium deficiency, which can lead to disorders such as Internal Rust Spot and growth cracking and higher risk of bruising.

In these circumstances it is always advisable to monitor the nutrient status within the plant using Omex AP Testing.

SAP testing gives a very rapid analysis of a full range of nutrients within the plant, allowing timely applications of corrective foliar treatments before the symptoms of deficiency reduce quality or yield.

The table below gives some broad examples of how to use Omex foliar nutrition to address specific concerns. All of these treatments can be included with the regular blight control applications.

For more detailed guidance to suit your own particular circumstances please speak to your Omex District Sales Manager

Required Outcome
Example Foliar Strategy
Higher Dry Matter
Folex K 5 l/ha, 2 to 4 applications during bulking, possible reduction in planned N and Mg applications
Lower Dry Matter
Magnesium Plus 2 l/ha regular applications with blight sprays towards the end of the programme
Delayed Senescence (highly determinate varieties)
Folex N, 50 l/ha, up to 4 applications during bulking
Reduced Internal Rust Spot
CalMax + DP98, 2 applications mid-season
Reduced Growth Cracking, better skin finish
CalMax + DP98, and either Folex Zn 1 – 2 l/ha or use Folex PZ rather than straight foliar phosphate
Improved processing quality
CalMax + DP98 mid-season, K50 with later blight sprays
Improved tuber size
Folex P or Folex PZ programme
General treatment of short term stress
Bio 20 2 – 5 l/ha

David Booty

Technical Development Manager

david.booty@omex.com


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