Managing Micronutrients : Iron, Magnesium, Boron

Iron (Fe)

Plants: Carrier of oxygen for the essential production of chlorophyll.

People: Central elements in haemoglobin and essential in the function of hundres of enzymes and proteins.

Magnesium (Mn)

Soil: More available in low pH soil and can be tied up in soils with high calcium or phosphorous.

Plants: Strongly support seed germination, fruiting and ripening. Important for nitrogen metabolism.

People: found in mitochondria and is a key component in energy metabolism.

Animals: Needed for normal growth and bone formation. Essential is reproductive health.

Boron (B) Boost

Soil: Humus is the boron storehouse, so if you don’t have good levels of organic matter you will probably have boron deficient soils. Calcium is the “trucker of all minerals” and boron is the “steering wheel”, so calcium will not work as well when boron is lacking.

Plants: Calcium can operate to full effect only if boron is present. Boron is also very important during the reproductive stage as it regulates flowering, pollination and the fruit to flower ratio. This is particularly important in fruit trees. A foliar spray just before flowering will supply boron and all other minerals at this critical time.

Deficiency Symptoms: Hollow stems in broccoli, woody texture in strawberries, flower and fruit drop in the orchard and poor seed set are all symptoms of boron deficiency. You may also see die back on passionfruit and grape vines.

People: This mineral also impacts calcium metabolism in humans. Boron influences the release of calcium into the blood and the absorption of calcium into our bones. Boron deficiency has also been strongly linked to arthritis and it is important in red blood cell development.

Animals: Boron has been used for over 30 years for the treatment of osteoporosis and osteoarthritis in farm animals and could also be used to treat these problems in pets.

Mastering Magnesium (Mg)

Soil: Magnesium tends to tighten soils so it can be used to improve the loose structure of sandy soils. However, if there is too much magnesium in a heavy clay it makes the soil sticky and can tighten it up with an associated restriction of oxygen and soil-life. Gypsum is the best tool to reduce a magnesium excess.

Plants: Magnesium is the central molecule in chlorophyll, the green pigment which houses the sugar factories that fuel photosynthesis. If the soil is missing magnesium, the lifeblood of the leaf will be lacking and that loss of chlorophyll will be clearly visible. It is a little like the anaemia associated with iron deficiency in humans as magnesium is to plant sap what iron is to blood, Magnesium is the most important enzyme activator of all minerals so it impacts many different aspects of plant growth and health.

Deficiency Symptoms:  Interveinal mottling (pale blotches between the veins) occurring on the older leaves. There may also be premature leaf drop in some species.

People: Magnesium has been claimed to be the single biggest deficiency in the western world. It is the “master mineral” responsible for 350 different enzymes. This missing mineral is needed for a healthy immune and detoxification system and it is an important mineral for heart health. It is important for bone health as calcium but often ignored.

Animals: Magnesium plays a major role in neuro-muscular health and bone density in animals. Grass tetany in ruminant animals is directly linked to a magnesium deficiency.

Common Forms: Magnesium carbonate (magnesite), dolomite and sulphate (Epsom salts). 

Getting your pH right!

The first step to getting the pH ( figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid, and higher values more alkaline) of your soil right, is to measure the soil’s pH. This is as simple of making a50/50 mixture of soil and deionised water, waiting 5 minutes and then dipping a pH strip into the mixture. These inexpensive strips are available from Plant Health Solutions in a form that measures finer graduations than normal. You are seeking a pH of 6.4 for optimal plant health growth. It is always important to try to understand why your soil is acidic or alkaline.

The best option is a soil test so there is no guess work involved. If you have acreage, a soil test can be worth its weight in gold. It is common to waste huge amounts of precious time, driving blind in an acreage gardening project, when a soil test would immediately clarify options and strategies.

If you can’t justify a soil test then these guidelines may assist you to diagnose the source of your pH imbalance:

If you have a light, sandy soil that is acidic, then you probably need a mixture of calcium and magnesium (dolomite) to correct the imbalance.

If it is heavier soil with more clay component then you probably need limestone to alkalise the soil and you might choose to include some gypsum to help break up the clay. If the soil is heavy and alkaline, then there is probably too much magnesium and sodium, so gypsum is the correction of choice.