A simple introduction to brix
Brix is a measure of the dissolved solids in a liquid and in agriculture, we use it to measure the sugar content of plant sap. It is measured in degrees via a refractometer with one degree of brix indicating that a hundred grams of sap contain one gram of dissolved sugar.
Nick Thorp
Reading time: 6 minutes
Understanding Brix: A Key Indicator of Plant Health and Productivity
Brix is a measure of the dissolved solids in a liquid and in agriculture, we use it to measure the sugar content of plant sap. It is measured in degrees via a refractometer with one degree of brix indicating that a hundred grams of sap contain one gram of dissolved sugar.
In horticulture this can help to define quality and taste but it’s primary use in regenerative agriculture is to determine nutrient density and assess plant health.
(If the line is clear or blurred is an instant indicator to calcium levels in the plant. A straight clear line shows that there is a deficiency which will need to be addressed).
When it comes to plants, the higher the brix value, the healthier the plant is and so should be more resistant to pest and disease, can tolerate greater abiotic & biotic stress. In simplistic terms, if the brix level of the plant is 12 or higher (yes of course there are some caveats to this as it couldn’t possibly be that simple) then that can be a good indicator of a healthy plant.
In effect, brix can be used as a measure of the plants ability to photosynthesize thus reducing the markers in nature which will be attractive to insects and pathogens.
Image Credit – Joe Gardener
Essential Nutrients and Factors Influencing Plant Health
Temperature, light levels, soil moisture and fertility determine the potential for the plant to create sugar via photosynthesis, however assuming the plant is getting these there are other factors which can affect brix even when conditions are good.
There are 5 primary nutrients that can increase brix, Calcium, Magnesium, Phosphorus, Potassium & Boron. Silicon also plays a major role and probably could and should be added to this list (although it’s still not considered an ‘essential’ nutrient in the UK). However, amino acids and seaweed extracts alongside humic & fulvic acids play their part making nutrition more available or allowing for improved activity in the plant for cycling.
Excessive nitrogen in the form of nitrates increases water uptake, therefore reducing brix levels by diluting the concentration of sugar.
Caveats were mentioned earlier and it is worth understanding some of these to make best use of brix measurements.
The Complex Role of Brix in Plant and Soil Health
Most plants can and will exudate up to a third of their sugar production out from the roots to feed the soil microbiome. This is a major part of the symbiotic process that nature has devised to allow plant and soil to cycle nutrients. It is often soil bacteria & fungi etc that colonise around roots which the plant must ‘feed’ so they can process often unavailable nutrients into plant available forms. So whilst a high brix is notionally always a good thing there are times when it can be the opposite. If you have a high brix at night or in the early morning on a cloudy day (so when photosynthesis isn’t occurring) then this can be an indicator that the plant has not been able to shunt sugar down from the leaves into the roots. This could be a symptom of a boron deficiency as that nutrient is essential for that movement of sugars in the late afternoon.
Brix measurements should be a tool used in a much bigger assessment of soil and plant health, its just another item in the toolbox of inputs and options that can be used to improve growing crops. Random snapshots aren’t determinative and so measuring brix should be undertaken routinely, noting time of day and weather conditions as part of an ongoing systems approach.
What Do you Think?
Could this approach work for you? At AIVA, we may not have all the answers, but we are good at asking the right questions. Your system is unique, and we’re here to help you find the best solutions. Reach out to one of our consultants today to discuss how our products can benefit your farm.
