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That is almost the question

In a three part series that I will be writing for the next three months, I will explore the finer parts of plant nutrition and protection. Boron has many functions within the plant. Below are some key points about boron and absorption.

Why plants need boron?

·         Boron absorption is high with high pH and Organic matter

·         Boron becomes less available as pH goes down

·         Boron leaches more as pH goes down

·         There is low B in sandy soils. Higher levels in clay and loam soils

·         B uptake is pH dependant @ pH 6 uptake = 100% @ pH 9 uptake @ 50%

·         Boric acid is the main form of uptake

·         Boron can be actively transported when there are low B levels in the plant

·         Usually passively transported through channels and membrane diffusion

·         The active B transporter is in the Xylem loader


Role of Boron

·         Structural component of cell wall


·         NO growth without Boron

·         Largest Demand during reproduction

Symptoms of Boron Deficient Plants

·         Deformed leaves

·         Dying tissues

·         Brittle young leaves

·         Auxiliary meristems

·         Chlorsis of young leaves

·         Flowers are deformed

·         Cracks in stems

·         Incomplete fertilization

·         B deficient canola all the stomata are closed (problem for exchanges)





15-80 PPM

>200 PPM


3-10 PPM

80 PPM

·         Boron is regarded as immobile

·         No transport in the phloem

·         No transport of a foliar

·         Need a constant supply

·         Will not be moved to the new leaves, only to ones that are contacted during application

·         B deficiency is often induced by drought

·         At low transpiration rates, some foliar was mobile and transported to the roots. Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants (similar to sweating), especially in leaves

With all this information, what does it all really mean? The best and most effective way to supply boron is in the soil, that way the plant will have the constant supply of boron through the growing cycle.  But as stated above the most important time for boron is at fertilization. So if the boron deficiency is high and needs to be addressed a foliar could be applied at early flower in canola to help boost yield. 

Yours in crop protection, 

Eric Brodie