AGRICULTURAL CARBON EMISSIONS AND POSSIBLE ANSWERS
MYCORRHIZA FUNGI AND THEIR USE IN AGRICULTURAL SOIL IN NEW ZEALAND
Christopher Roberts Director Clovertone Ltd
The answer to reducing carbon emissions from agricultural production in New Zealand, lies in
the living organisms in the soil. Namely Mycorrhiza fungi. With all the emphasis on carbon
emissions and the future costs to the economy of New Zealand, it is timely to look for answers
that are simple and cost effective.
Mycorrhiza, What are they?
★ Mycorrhiza are fungi that have a mutually beneficial relationship with the roots of many
plants. They are common in most soils.
★ Mycorrhiza play an important role in plant nutrition.
★ Because they do not photosynthesize, mycorrhiza cannot fix their own carbon.
★ Mycorrhiza receive their carbohydrates from the host plant. In return, the mycorrhiza absorb
nutrients from the soil which are passed to the plant.
★ Since the fungi take the carbon from the plants, the storage of carbon in the soil is enhanced
by the fungi. This is very important in reducing the amount of carbon in the atmosphere.
The more mycorrhiza that are attached to the plants, the more carbon is stored in the
soil by these fungi.
How do Mycorrhiza work?
• Because the mycorrhiza fungi are thinner than the plant's roots, they are able to come into
contact with more soil on a per-volume basis.
• The mycorrhizal fungi are made up of a root-like structure and have a network of very fine
hair-like mycelium outside the plant roots that extend into the soil.
• These mycelium absorb nutrients from the surrounding soil and feed them back to the host
plant. As a result, there is an increase in the absorption surface area of the roots.
• Some plant nutrients move slowly in the soil and may appear to be unavailable to the plant.
The result of this slow movement is a sick looking plant. This is particularly important in the
case of phosphorus.
• Most of the phosphorus in the soil is in an insoluble form. Insoluble phosphorus is unavailable
to plants that do not have mycorrhiza on their roots.
• Mycorrhiza can protect the host plants from disease. Mycorrhiza increase a plant's tolerance
to drought, high temperatures, frosts, salinity, and acidity, or a build-up of toxic elements
in the soil like cadmium and fluorine.
• Mycorrhizal deficiency may occur in soils that have been fumigated or areas where large
amounts of topsoil have been removed.
• Additions of nitrogen, phosphorus, or complete fertilisers will reduce the presence and activity