Broad nutrition resources are outlined in the Agronomists Toolkit. Specific nutrient categories are listed below:



Constraint – Boron

Plant use

  • Boron is a micronutrient 

  • It is mainly involved in the movement of sugars, but also in the metabolism of nitrogen, carbohydrates, and hormones, and in the uptake and efficient use of calcium 

  • Boron may induce both toxicities and deficiencies in Australia


  • Young plants develop shortened stems and deformed leaves that cup outwards and thicken

  • The emerging leaf is red-brown to purple, and may have interveinal blotching

  • The leaf may suffer tip and edge death which slowly kills the whole leaf

  • The growing point may die 

  • Flowers form but abort


  • Deficiencies often disappear after rainfall since plant roots may be unable to access boron in dry soils

  • Yield penalty is rare, but severe deficiency will cause reduction in seed production


A plant tissue test should be used to confirm boron deficiency. Seek expert advice to determine the appropriate boron types and application rates, and apply a boron fertiliser. Retest in 2-3 years. Be careful to avoid higher rates than necessary as this can cause boron toxicity in plants. Liming also increases soil boron availability.


Links and Resources

AOF - Canola nutrition. Boron

Page 6 of 8. Information on both boron deficiency and toxicity, tolerance limits, and fertiliser recommendations.

DAFWA - Diagnosing Boron deficiency in canola

Introduction, what to look for in paddock and plant, what else it could be, where does it occur, management strategies, and monitoring. Page last updated 2014.

DEPI VIC - What nutrients do plants require? Boron

Section 6.4.6. Lists plant uses of boron, deficiency and toxicity symptoms, soils and management practices that increase risk of boron deficiency, and management strategies. Page last updated 2013.

GRDC - Best Practice Management Guide. Boron

92 page PDF. Page 36. Information on role of boron in plant performance, toxicity and deficiency symptoms, and fertiliser requirements. Published 2009.

GRDC - Micronutrients and trace elements. Boron

4 page PDF. Key points, general introduction, crop demand and uptake, tissue testing, soil testing, visual symptoms, soilmapp, effects of soil type, and treatment. Published 2013.

IPNI - Canola 4R Guide. Boron

Pages 17, 18 and 19 of 21. Information on boron deficiency and toxicity, including soil tests, description, impact, contributing factors, and management. Published 2013.