Thanks you David H for the link.

With all the bad news in the world, I want to do something positive. As a local small business, we are feeling the strain as well. If you have received the government stimulus or have a few extra dollars, we hope to entice you to make a purchase.

For the next week, we will include a 20 gram sample of MycoGold https://biostim.com.au/shop/myco-gold/ with every order. We hope you will give it to someone who might benefit (drop in their letter box and message them) or pass it onto a family member to use.

This is just our little goodwill effort to help get our thoughts off the virus. Get into the garden/land and grow a plant. The vitamin D and fresh air can only be beneficial 🙂

p.s If you have a business and would like some free promotion, send me a reply email with your details to feature in our next newsletter.  

Kind regards
Tim Lester

Saprophytic plants, literally, are plants that live of rotting material (sapros = rotting, and phyton = plant in Greek), but in fact, no plant have been found yet which can use dead organic material for food directly.
Anyway, these plants have no chlorophyll in their cells, which means they are unable to assimilate carbon by themselves. They have no green leaves, often they even have no leaves at all. Saprophytes are mostly whitish, but can have brightly coloured flowers. They grow in places with lots of rotting dead leaves, often in deep shade in tropical forests.

In their underground parts (rhizomes or roots) are certain cells that are filled with structures (hyphae) of soil fungi. Often, but not always, these fungi are capable of ‘digesting’ the rotting material and converting it by enzymes into molecules (sugar) which they can feed on. So, the fungi are the real saprophytes, living of rotting material. Now, the plants without chlorophyll digest the fungus that live inside their roots or rhizomes, thus they are not autotrophic/self supporting, but heterotrophic plants (hetero = another, trophein = feed). And because they are living on fungi they are called myco-heterotrophic plants / MHP’s (mycos = fungus). This mycorrhiza (mycos = fungus, rhizon = root) of MHP’s makes it possible for them to grow in places with not enough light for ordinary autotrophic plants to survive. The same might be the case for places without enough nutrients in the soil.

To complicate matters there is evidence that some fungi neither are saprophytes but have underground connections with big forest trees or other autotrophic plants. So the trees, the fungi, and the myco-heterotrophic plants all three together form a kind of plant community, a symbiosis (living together), to make it possible for the MHP to live. In the special case of MHP’s, the linking fungus delivers the assimilated carbon from the autotrophic plant to the myco-heterotrophic plant.

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

We are still very much interested in new collections of saps, and we are always willing to identify them.
Our knowledge about saprophytes from Africa and Asia is less extensive, but we are interested to study them as well (especially in the genus Thismia).

Here some hints, how to collect saprophytes:

• If you find one it is likely that there are more, since circumstances seem to be favorable for this mode of life.
• Most important is to preserve specimens in spirit (roots, buds, flowers, fruits).
• Do not forget to collect the root system if possible.
• Look for pollinators, smell, and something about the flower biology
• Make drawings or take colour slides.

In general: take some time to have a good look at the plants when you find them: they deserve it!

Achlorophyllous plants are puzzling! They are always characterized by remarkable reductions concerning root, shoot and leaf structure and sometimes even hardly resemble a flowering plant. It is no wonder that they are often collected by mycologists! Here some basic information:

Since assimilation of carbohydrates through photosynthesis without chlorophyll is impossible (as far as we know) and the direct metabolization of dead organic material has never been detected in flowering plants, achlorophyllous plants must have another source of carbon. They split up in two distinct groups:

Parasites

These plants develop special organs (haustoria) penetrating foreign plant tissue in order to participate at least to some extend from their host’s assimilates (carbon compounds), water or nutrient uptake (e.g. Dodder, Broomrapes).

Mycoheterotrophic Plants (‘Saprophytes’)

In these plants a fungus (or several?) lives inside their roots (‘mycorrhiza’) providing all requirements for plants growth. This is the plant group that I investigate.

More than 400 species, in 87 genera and 11 families, of mycoheterotrophic plants have been described. Of those, only orchids and members of the Monotropaceae (Indian-Pipe Family) are fairly well investigated. Information about the other families are scarce. The most recent work on the neglected genera has been done by Hiltje and Paul Maas and co-workers in Utrecht/Netherlands. Nevertheless, root structures (morphology, anatomy, mycorrhiza) are often entirely unknown. Most probably this is due to the remote and hardly accessible habitat of these plants, the deep shaded tropical rainforest, and the fact that they are easily overlooked in the field (see the picture to your left!). Hence, they get found by mycologists!

Lately, I focused on the genus Voyria of the Gentianaceae (Gentian Family) where 19 species have been distinguished so far, all except one living in tropical America. Then I looked after Triuridaceae and Burmanniaceae (Triuris, Sciaphila, Burmannia, Dictyostega). Momentarily, I’m working on Burmanniaceae and Polygalaceae (Afrothismia, Epirixanthes). All of these plants share some morphological characters with Voyria but are not at all related to them. I could show that their mycorrhiza is an arbuscular mycorrhiza (AM), a form of fugus-plant-symbiosis which is very well known for more than hundred years. However, the achlorophyllous species so far investigated revealed some very unique features, yet unknown despite the long and intensive research on AM.

My approach was led by the following questions. Answers I found so far are indicated shortly:

What kind of morphological/anatomical adaptations have evolved in connection to its special life form?

At least one of those adaptations is a ‘condensation’ of the root system (becoming short and thick).

Are mycorrhizas in myco-heterotrophic species different from mycorrhizas in autotrophic species?

Yes, definitely in Voyria tenella, V. obconica, V. aphylla, Triuris hyalina, and Afrothismia winkleri, less pronounced but still different in Voyira truncata, Burmannia tenella, and Dictyostega orobanchoides. More strange mycorrhizal patterns may be anticipated.

Do the mycorrhizas between various myco-heterotrophic species differ?

Yes they do, only in Voyria tenella and V. obconica I found the same ‘intraradical fungus garden’.

What do mycorrhizal structures tell us about taxonomy and systematics?

The closely related Voyria tenella and V. obconica do have the same mycorrhiza whereas V. aphylla shows an intermediate pattern, linking to the mycorrhiza of V. truncata and the autotrophic gentians. The two Burmanniaceae Burmannia tenella and Dictyostega orobanchoides show at least in the root cortices the same intracellular hyphal pattern. Afrothismia winkleri, a Burmanniaceae from Africa, however, has an entirely deviating mycorrhizal pattern (although it is an AM!).

How do these plants use their root fungus?

Very sophisticated!! Please read the abstracts e.g. on Afrothismia winkleri and Voyria tenella .

What is the actual carbon source?

From the observed direct hyphal bridges between roots of neighboring plants and the achlorophyllous plants we must infer the carbon (and most probably everything else too) must come from the neighboring plant.

by Ian St George

Sentences like “In vesicular-orbuscular mycorrhizas, the mycobiont undergoes pronounced alterations in morphogenesis involving appressoriuin formation, (and) arbuscule development…” leave the amateur gasping for breath. This is a complex subject with its own expert language: fortunately writers like Warcup and Perkins from Australia demonstrate the ability to convey complex information simply.

Fungi

What is a fungus? We think of toadstools, bracket fungi, ringworm, athlete’s foot – they are all fungi. The fungi are called Mycota, about 50,000 species described, including mushrooms, yeasts, rusts, smuts, mildews and molds. The mushroom we eat is the fruit (also known as the “perfect state”) of a larger organism, which has hollow branched filaments called hyphae that form networks in the soil; the bracket fungus we see is the fruit of a larger organism whose hyphae thread the dead bark and wood of the tree. Ringworm is the infection of the human skin by similar organisms; if you scrape the skin cells and look at them under the microscope you can see fungal hyphae.

The study of fungi is mycology, and many words referring to fungi have “myc-” in them. Mycoses are fungal diseases. ascomycetes are a genus of fungi, Mycetophilidae are the fungus – loving gnats. Medical mycologists identify pathogenic fungi by their asexual spores; plant mycologists may deal with fungi that develop perfect states – the fruit that contain sexual spores – and use these for identification. Where perfect states cannot be achieved in cultivation, the structure of the hyphae, the pattern of branching and rejoining of hyphae (anastomosis), or the number of nuclei in cells may give a clue as to identity.

Mycorrhizas

If you read about orchids you can’t escape phrases like “fungal associations”, and “pine needle layer rich in fungal hyphae”. In fact the roots of most vascular plants have evolved in association with soil fungi. The resulting combined structures are called mycorrhizas (“fungus-roots”). There are seven main kinds of mycorrhizas, the four most carefully studied involving crop plants, forest trees, heaths and orchids [1].

Many orchid mycorrhizal fungi belong to the form genera Rhizoctonia, Epulorrhiza, or Ceratorhiza. These same genera may contain species that are orchid pathogens, form associations with other plants, or have no plant associations.

The habitat of the fungus may determine the habitat of the orchid – thus the fungus Rhizoctonia borealis requires acid soils under conifers, so that is where its associated European orchids Spiranthes gracilis and Goodyera repens are found.

Strictly, the term mycorrhiza should apply only to the fungus/root association, but it is loosely association between the fungus and the developing orchid protocorm (the stage between seed and embryo).

Orchid mycorrhizas

Orchids require the relationship with a fungus for their existence. The importance differs among species, the “infection” by the fungus being heaviest in temperate terrestrials, but light in tropical epiphytes. The relationship is essential for the germination of the seed of all orchids in the wild, and remains essential for a few species throughout life.

Seeds, protocorms and fungi

Orchid seeds are tiny and lack the built-in nutrition of bigger seeds; orchids then pass through a nongreen (“achlorophyllous”) developmental stage when they cannot use fats, break down starch, obtain phosphates or photosynthesise, and therefore rely on an external source. This is provided either by man in the form of simple carbon-containing foods in sterile seed germination, or by a fungus which breaks down complex compounds into simpler ones in symbiotic germination. The fungal hyphae penetrate via the base end of the seed. The hyphae enter the cells and coil into structures called pelotons Germination of the seed into a protocorm follows. The cells eventually digest the pelotons, but occasionally the fungi become parasitic and destroy the protocorm.

Roots and fungi

In some species (Gastrodia, Danhatchia and Corybas cryptanthus in New Zealand) chlorophyll never does develop, so the orchids rely for all their lives on associations with fungi. In others, the leaf-size is too small to support the rest of the orchid, and the orchid continues to rely partly on the fungus for its nutrition (Corybas cheesemanii for instance); such plants have been called saprophytic, but that is an incorrect application of the term. Some plants of the European Spiranthes spiralis pass alternate seasons underground, apparently fully nourished by their fungus during that time; some NZ orchids do not appear above ground every year and may do the same.

Most terrestrials seem to thrive better in the wild than in pots (some cannot be cultivated “artificially” at all), probably because they must have access to at least some of their nutrition via their ~ association.

In different terrestrial orchids the fungi penetrate the stems, tubers or root hairs, via epidermal (“skin”) cells after hyphae have spread over the root surface [2]. Pelotons are formed, and eventually digested.

“Symbiosis” suggests mutual benefit and indeed Cymbidium and its fungus each require the vitamin thiamine, made up of thiazole and pyridine; the fungus supplies the thiazole and the orchid supplies the pyridine [3]. Most orchid-associated fungi can, however, live without the orchid, and it seems that whereas the fungus supplies the orchid with a range of nutrients and stimuli, the orchid usually provides little in return.

Many orchids have “host” cells that store fungus, and adjacent digestion cells that break the fungus down by means of substances known as phytoalexins. The partnership between orchid and fungus has been called symbiosis (a ‘Swan situation’ as the politicians say in Wellington these days), or a “delicately balanced mutual antagonism’ [4], or plain parasitism (of the orchid on the fungus, that is.

Fungi that are apparently symbiotic can turn nasty and attack the orchid; furthermore the fungi of epiphytes may invade the orchid’s host tree to the tree’s (and ultimately the orchid’s) detriment.

Specificity

Some studies in the laboratory suggest that specific orchids require specific fungi, but few associations have been studied in the wild. Fungi are difficult to isolate and difficult to grow (especially to the usually readily identifiable perfect state), and even in one orchid species, the fungus required by the protocorm may be different from that required by the adult. Certainly some orchids can establish successful relations with several different fungi.

Perkins has looked at the Australian orchids Pterostylis acuminata and Microtis parviflora in the wild and in the laboratory [19, 20]. Whereas only a few species of fungi were associated in the wild, several more would form associations in the laboratory – thus, ecological specificity” (what happens in the wild) is different from “potential specificity” (what could happen if laboratory experiments were to reflect the wild state) [18].

New Zealand Studies

In 1911 Lancaster showed that fungal hyphae do penetrate the root hairs of NZ epiphytes and form pelotons which are digested by the orchid cells [5].

Ella Campbell began a series of papers on the fungal associations of NZ’s nongreen orchids in 1962 [6-10]; she showed: –

• Gastrodia cunninghamii is associated with the fungus Armililaria mellea which is itself a parasite on the roots of forest trees [6].
• G. minor is associated with and derives nutrients from an unidentified fungus which also penetrates the roots of adjacent manuka [7].
• What is probably the bracket fungus Fomes mastopourus inhabits the roots of Acacia melanoxylon and is an endophyte of Gastrodia aff. sesamoides, which digests it [8];

All around the roots of taraire trees grow the hyphae of the puftball fungus Lycoperdon perelatum, and these form a network around and attach to the rhizomes of Danhatchia australis, invade the tips of root hairs, and are digested by the cells of the orchid. The orchid is parasitic on the fungus, which in turn derives nutrients from, and may damage, the roots of the taraire [9].

Corybas cryptanthus has an associated unidentified fungus that invades the roots through root hairs attached at tiny conical projections; the fungus spreads among the beech leaf litter, and is a weak parasite on the Nothofagus[10].

Australian work

J.H. Warcup, M. Clements, K. Dixon and A. Perkins and their co-workers have been the major contributors to the study of Australian orchid/fungus relationships [2, 11-21]. Readers interested in delving deeper are referred to these authors (for instance Warcup [16] gives an excellent general overview of the fungal relationships of South Australian orchids). Here are a few snippets.

• Warcup and Talbot seem to have had a genius for inducing orchid fungi to fruit in culture. They grew fungi from pelotons teased from the cells of Australian native orchids – of 102 isolates from 25 orchid species 66 fungi were induced to fruit. Fungal species of the following genera formed mycorrhizal associations with orchid:: species (of the genera in brackets): Thanatophorous(Acianthus, Thelymitra), Ceratobasidium (Pterostyis, Prasophyllum, Acianthus), Tulasnella (Diuris, Acianthus, Thelymitra, Caladenia, Cymbidium, Dendrobium) and Sebacina (Acianthus, Caladenia, Glossodia, Microtis); the same fungal species often formed mycorrhizal associations with European orchid species. These truly intracellular fungi were often different from those found on the surface of orchid roots [12].
• Fire affected the abundance, behaviour and composition of fungus infecting West Australian orchids; there were six categories of fungus, and each was specific and consistent within species and within most genera; the rare and related Drakaea, Paracaleana and Spiculaea had a unique and culturally distinct fungus noted for its intense violet-pink colour [2].
• Initial contact between fungus and seed is haphazard – there is no evidence that an attractant is used by the orchid seed. Seeds appeared to resist entry by incompatible fungi, while allowing the entry of compatible fungi. There was a strong specificity of fungus for each orchid studied. Pelotons appeared about a week after initial infection in some cells and signified a compatible orchid/fungus match that would lead to germination. The protocorm seemed to have entry, holding and digestion zones for the fungus, though the way the fungus is controlled in these zones is unknown. Failure of germination was caused by fungal hyphae failing to penetrate the seed, or by penetrating all the embryo’s cells resulting in death of the embryo [21].
• In Pterostylis the fungi can be grouped, and where the groups are found is determined by the environment. One fungus, for instance, was found only under Pinus radiata. Geographic distribution (and perhaps some aspects of habitus?) of orchid species may thus be determined by fungal ecology [17].
• Perkins and co-workers found only two fungi associated with Microtis parviflora in the wild, and the same two in protocorms: they concluded that the adult roots associate with a narrow range of fungi in the field (have a narrow ecological specificity) and these assmiations are established in the protocom. On the other hand, many fungi were able to form associations with M. parviflora in the laboratory, indicating a broad potential specificity [19].
• It would seem logical that the germination of orchid seed in the wild should depend on the amount of fungus in the soil, but this may not be so. Perkins and co-workers studied Pterostylis acuminata and its fungal associations: this orchid appears to associate with only one specific fungus, a subspecies of Rhizoctonia solani. Furthermore this orchid reproduces asexually (i.e. essentially by cloning). The orchid and the fungus may therefore be co-distributed, and if an orchid is able to establish at a new site, the resultant increase in the associated fungus may favour further spread of the orchid. There are implications here for the resiting of rare orchids – if there is a single fungus associated with the orchid, a new site will need to be apt for the fungus as well as for the orchid: if the fungus does not survive, neither will the orchid [20].

Orchids that form ecologically specific relationships with single pollinating insects can only survive in the presence of that specific insect. We now see that there are orchids which form ecologically specific relationships with single mycorrhizal fungi: they can only survive in the presence of that specific fungus. How these observations apply to the New Zealand species is open to speculation.

Acknowledgements

I am grateful to Dr A.J. Perkins for supplying a list of Australasian papers.

References

1. Peterson RL, Farquhar ML. Mycorrhizas – integrated development between roots and fungi. Mycologia 1994; 86 (3): 311-326.
2. Ramsay RR, Dixon KW, Sivasithamparam K. Patterns of infection and endophyte associations with Western Australian orchids. Lindleyana 1986; 1: 203-214.
3. Hijner JA, Arditti J. Orchid mycorrhiza; vitamin requirements and production by the symbionts. Amer.J.Bot. 1973; 60: 829-835.
4. Arditti J, Fundamentals of orchid biology. Wiley, New York, 1992. p445.
5. Lancaster T.L. Preliminary note on the fungi of the New Zealand epiphytic orchids. Trans.N.Z.L 1911; 43: 186-191.
6. Campbell E.O. The mycorrhiza of Gastrodia cunninghamii HookF. Trans.Roy.Soc.N.Z 1962; Bot 1: 289.
7. Campbell E.O. Gastrodia minor Petrie, an epiparasite of Manuka. Trans.Roy.Soc.N.Z 1963; Bat 2: 73.
8. Campbell E.O. The fungal association of a colony of Gastrodia sesamoides R.Br. Trans.Roy.Soc.N.Z. 1964; Bot 2: 237.
9. Campbell E.O. The Fungal Association of Yoania australis. Trans.Roy.Soc.N.Z. 1970; Biol.Sci. 12: 5-12.
10. Campbell E.O. The Morphology of the Fungal Association of Corybas cryptanthus. J.Roy.Soc.N.Z 1972; 2: 43-47.
11. Dixon K. Seeder/clonal concepts in Western Australian orchids. In Population ecology of terrestrial orchids. Eds T.C.E. Wells and J.H. Willems. J.H. SPB Academic Publishing: The Hague, 1991, ppl11-124.
12. Warcup J.H. and Talbot P.H.B. Perfect states of Rhizoctonias associated with orchids I-III. New Phytologist 1967; 66: 631-641; 1971; 70: pp35-40; 1980; 86: pp267-272.
13. Warcup J. H. Specificity of mycorrhiza association in some Australian orchids. New Phytologist 1971; 70: pp41-46.
14. Warcup J. H. Symbiotic germination of some Australian orchids. New Phytologist 1973; 72: pp387-392.
15. Warcup J.H. ne mycorrhizal relationship of Australian orchids. New Phytologist 1981; 87: pp371-387.
16. Warcup J. H. Mycorrhiza. In Orchids of South Australia. Eds R.J. Bates and J.Z. Weber. Flora and Fauna of South Australia Handbook Committee, Adelaide, 1990. pp21-26.
17. Ramsay R.R. Sivasithamparam K. and Dixon K.W. Anastomosis groups among Rhizoctonia-like endophytic fungi in south western Australian Pterostyis species. Lindleana 1987; 2: pp161-167.
18. Matsuhara G. and Katsuya K. In situ and in vitro specificity between Rhizoctonia spp. And Spiranthes sinensis. New Phytol. 1994; 127: 711-718.
19. Perkins A.J. Masuhara G. McGee P.A. Specificity of the associations between Microtis parviflora and its mycorrhizal fungi Australian J. Bot. 1995; 43: pp85-91.
20. Perkins A.J. and McGee P.A Distribution of the orchid mycorhiza1 fungus, Rhizoctonia solani, in relation to its host Pterostyis acuminata, in the field. Australian Journal of Botany 1995; 3(6): pp565-575.
21. Clements M. Orchid mycorrhizal associations. Lindleyana 1988; 3: pp73-86.

This article is designed to be a primer centered around the topic of Mycorrhizae and their interactions with plants.

The question and answer format will help you learn how life in the soil benefits your plants health and how to increase the presence of mycorrhizae and other beneficial life in your soil. This will allow you to harvest the best possible crops whether it be in your home garden or on a larger scale such as an orchard or field.

 

 

Intro

In modern society we are generally taught to stay away from bacteria, fungi and other microbes and tend towards sterile environments or ones with little diversity. In reality these little creatures are an essential part of any natural ecosystem and are necessary to grow the best plants. The most abundant and resilient farming systems have soil health at their core, a large component of which is soil life. The important types of soil life are almost too numerous to count but a certain group of fungi, the Mycorrhizae, have been well studied and linked to increased plan growth, vigour and health.

What are Mycorrhizae?

Mycorrhizae are types of soil fungi that live in a mutually beneficial symbiosis with plants. They grow in, on and around the roots of plants helping the plant to get more out of the soil. They help make the root zone of the plant as beneficial as possible.

How does it Help?

Mycorrhizae essentially increase the surface area available to the plants roots, acting as little networks of root extensions. This allows for the plant to be able to reach more nutrients and minerals more efficiently than it could on its own. The plant feeds the mycorrhizae extra sugars it produces and in turn the mycorrhizae brings in water, nutrients and minerals the plant needs. It’s a mutually beneficial arrangement that has had hundreds of millions of years in the making. Many plants still grow without mycorrhizae but not as well or as quickly as they would with it.

On top of being able to grow faster and larger with an extended and enhanced root system, there are many other benefits to mycorrhizae in the soil. Having a healthy population of good microfauna can help ward off certain diseases like ones caused by unwanted fungi or bacteria. The enhanced root system can also grow deeper and hold more water within itself, making any crop more drought tolerant. There is also a measurable benefit to larger root systems aerating and putting more carbon into the soil, help to build it up and make it more suitable for life of all sorts. Unfortunately many soils are depleted of mycorrhizae and other life for various reasons.

What can cause a loss of Mycorrhizae?

The leading causes of loss of mycorrhizae are harsh agricultural practices. Certain crop sprays like pesticides and fungicides can kill mycorrhizae or prevent them from growing back properly. Other disruptive practices like deep tilling, burning, and leaving soil bare can also greatly affect the life in soil, including the mycorrhizal fungi. These fungi normally exist in undisturbed and naturally mulched soils so when they are churned or baked in the sun, they do not fair well. Mimicking the best conditions is the easiest way to promote healthy mycorrhizal fungi populations.

Building Mycorrhizal populations

While properly managed soils should in theory recolonize with microfauna over time, the turn-around time is on the scale of years if not decades. One of the best, and quickest, ways to jump start your soils health and biodiversity, especially if it is degraded or damaged, is to add an inoculant like MycoGold by Biostim ( https://biostim.com.au/shop/myco-gold/) . Inoculants contain beneficial types of Mycorrhizal fungi and some of the best, like MycoGold, contain other beneficial microorganisms too. Inoculants are an easy and cost effective way to make sure your plants or crop are starting out with the microbiome they need to flourish.

Other Factors affecting Soil Health

Soils of all types can support healthy life of some sort but certain factors affect how well microbes and mycorrhizal fungi can grow and support your plants. Below are some other factors to consider in building and maintaining healthy soil microfauna.

Moisture/Sun Exposure- While dry soils can have lots of dormant microbes in them that will spring to life when water comes, a steady source moisture is required to keep them active and thriving. Making sure your soil doesn’t bake in the sun or dry out for prolonged periods of time can help keep it healthy. A great way to do this is to never leave the soil bare, whether it is seeded with a cover crop or mulched heavily, shading the soil and preventing it from drying is essential to healthy soil life.

Drainage/Aeration-While moisture is important it is also important that the soil does not become waterlogged or compacted. The best way to ensure this is to have an inorganic component like sand in your soil.

Organic Matter- Organic matter acts like a sponge, helping hold moisture in the soil near to the surface where the soil life can get it. As discussed above, having moisture readily available has a large impact on soil life.

Mineral Content-While organic matter is great, soils that are completely organic matter, such as pure black top soil, can sometimes be mineral deficient. This can not only affect the health of your plants directly but also through the soil life. Little microbes and fungi need minerals too! They can be the first one to feel deficiencies as they are competing with the plants for them in a way. This is why adding things like rock dust, crushed shale, or even sand can help boost the life in your soil. These soil additives will give back two-fold. Indirectly though better capacity for soil life and directly through uptake into the plants.

A Cyclical System

Having healthy soil life, like a strong mycorrhizae population, not only helps with your current growing but for several crops or plantings to come. When the soil is alive and healthy, it is essentially growing, getting better and more plant friendly as time goes on. The actual lifetime of the full effect of an application of a soil inoculant may vary based on several of the factors discussed above. However, meeting the guidelines for health soil and promoting healthy soil life can help the effect last for years, theoretically forever in a cyclical process of regenerating the soil.