The creature most often missing in agricultural soils is a fungus that burrows into the crop roots. This usually evokes images of an undesirable parasite but this is not a disease organism. Once this creature is locked into a food source from the plant, it gives far more than it receives. In fact, that flow of root sugars is repaid handsomely. The soil, the other root zone microbes, the plant, your livestock, your family and the planet are all beneficiaries of this exchange. This generous life force is called Mycorrhizal fungi.

Ancient Heroes

Endomycorrhizal fungi should be found attached to the roots of over 80% of crops. They were originally called VAM (vesicular arbuscular mycorrhiza) but their classification was recently changed to AM or AMF (arbuscular Mycorrhizal fungi).
Their maze of hyphae filaments effectively increases the original surface area of the roots by up to 1000% with a remarkably productive outcome. Root benefits are magnified tenfold and the plant is perfectly positioned to achieve its true genetic potential. The only plants that do not attract Mycorrhizal colonisation are brassicas and the chenopods. Brassicas release chemical exudates that repel nematodes and these same chemicals also discourage AM Fungi.
AMF create structures within root cells called arbuscules that facilitate the transfer of nutrients between the plant and the fungus. Fossil studies reveal the presence of these creatures 500 million years ago but they were first recognized last century and serious study has only begun during the past three decades. In 1996, a researcher called Sara F. Wright, discovered glomalin, a sticky substance produced by mycorrhizal fungi that generates stable humus in the soil. It is apparent that the decline in humus mirrors the decline in AMF in our soil.

The Humus Imperative

The principal producers of stable carbon are Mycorrhizal fungi and glomalin is a huge player. This substance is produced by Glomales, the taxonomic order of which AMF are a part. These fungi use sugar exudates (carbon) from the plant to make glomalin. This remarkable material permeates organic matter, binding it to silt, sand and clay particles in the soil. The substance itself contains 40% carbon but it also creates aggregates that stabilize carbon in the soil and prevent its return to the atmosphere as part of the carbon cycle.

Reducing the Fertiliser Bill

While humus building is obviously important, there are many other benefits associated with increasing the number of AM fungi in your soils. One of these relates to the potential to reduce the fertiliser bill.
AM fungi can provide the key as they effectively enable the recovery of past investments. The ten-fold increase in root surface area provided by AMF allows exploitation of a much larger root volume and the uptake of all minerals is enhanced. However, it is phosphorous that receives the most profound kick along. It is suggested that over 70% of all applied soluble phosphate becomes locked up in an insoluble form within weeks.
The key to accessing this treasure is AM fungi. Many studies have reported increased P uptake and associated improvements in early growth and reproduction following inoculation with Mycorrhizal fungi. The maze of pipe-like filaments seeks out this immobile mineral and the acidic exudates of the fungi solubilise locked up P and absorb the mineral for transportation back to the plant. However, with all good things there are always a couple of cautions. If you over-apply soluble phosphorous, the plant reduces root exudates that feed AMF. The host has less need to feed this fungal P supplier when it already has all of the phosphate it requires. The acidity of unbuffered DAP can also reduce AM colonization. When these acid granules hit the soil, the loosely held ammonium ion breaks free. The harsh phosphoric acid that remains sizzles the fragile hyphae of AMF like a blowtorch on human hair.

AMF and Free Nitrogen

The atmosphere contains the equivalent of 5000 truckloads of urea per hectare. This nitrogen gas, in the atmosphere, is where plants are supposed to access the majority of their nitrogen requirements. However, access to this free gift has been seriously compromised by our mismanagement of soils and our misunderstanding of the benefits of soil biology. Nitrogen-fixing organisms are the key to this access. Several recent studies have shown that both major forms of nitrogen-fixing organisms in the soil improve their performance in the presence of Mycorrhizal fungi. These two groups include Rhizobium bacteria that are housed in the nodules attached to the roots of all legumes, and free-living bacteria that surround plant roots to access sugar exudates. These creatures convert nitrogen gas in the atmosphere into ammonium nitrogen in the soil and their importance cannot be overemphasized. Mycorrhizal fungi are the perfect partners for nitrogen fixing organisms.

Benefits with AMF

Ten times more root area confers many benefits and one of these gains is increased plant resilience. Colonised crops are more resistant to a variety of stresses ranging from drought to heavy metal contamination and reduced plant immunity. Several studies have shown that AMF treated plants fare better in drought conditions. There are several theories about the mechanism involved but it is thought that it may be a combination of additional moisture storage in the massive network of fine pipes (hyphae) attached to the roots, combined with the moisture holding capacity of the extra humus that comes with the AMF package.
The benefits we have highlighted are substantial and should be of appeal to all primary producers, however, there are still more gains to increasing AMF colonisation in your crop. In 1992, Azcon and Barea showed that AMF inoculated plants absorb and utilize potassium more efficiently. AMF can reduce potassium leaching and help gain access to potassium trapped between clay platelets in some soils.
In 1994, Maksoud et al repeated these findings in relation to AMF and potassium. In 1994, Marschner and Dell found that AMF inoculated plants contained significantly higher levels of calcium, magnesium, copper, zinc and iron. In 1999, Alkarati and Clarke repeated those findings

Accessing AMF Action

At this point you may be wondering how to increase the AMF action on your farm. There are two ways to achieve this and they include the creation of conditions favorable to AMF, to build numbers and diversity, and secondly, the inoculation of AMF blends to introduce a new workforce in biologically compromised soils.

Abron’s Solution: Platform – Mycorrhizal Fungi & Trichoderma

Platform is one of the great Nutri-Tech (NTS) products Abron supplies. Huge numbers of Arbuscular Mycorrhizal Fungi (AMF) and Trichoderma together in one breakthrough blend work to optimise root health; root health is plant health and these two species are the essence of healthy roots.

7 benefits of using Platform:

• Builds humus – Glomalin produced by AMF generates 1/3 of the world’s soil carbon.
• Increases root zone with all of the associated benefits.
• Can reduce fertiliser requirements through improved nutrient uptake.
• Boosts phosphate and zinc availability.
• Lifts calcium levels in plants.
• Improves bio-balance and associated plant resilience in the root zone.
• Serves as a synergist to improve nitrogen fixation.

 Need more help with this?

At Abron, our Farm Performance Consultants are trained to focus on the health of your soil. As a result of that knowledge they can grow your pasture production, reduce your reliance on nitrogen fertiliser and help you to understand how to maximise the return you make per cow on your farm. Call us today on 0800 722 766 if you have any questions or would like to know more.