HelpfulGardener.com

Ok we know of Mycorrhizal fungi (helps with phosphorus), Rhizobia bacteria (nitrogen), and there are bacteria that help release sulphur too? What are those called and is there anything else? Does the Mycorrhizal fungi also relay other micro-nutrients? Is there anything that relays potassium in a symbiotic way?

Hi Caverdude, I'm taking a Master Gardener's course and we just learned about symbiotic organisms. The teacher has a PHD in Botany and told us when we're master gardeners, to not recommend symbiotic organisms. There have been plenty of studies on whether they work, but results have shown they do little to none for your garden. What's recommended is getting a good fertilizer that will take care of the nutrients your plants need. Hopes this helps!

Whoa! That is why I never took the Master Gardener class - because I totally disagree with the approach they take.

There is only one sense in which what you say is true:

Mycorrhizas are fungal associations between plant roots and beneficial fungi. The fungi effectively extend the root area of plants and are extremely important to most wild plants, but less significant for garden plants where the use of fertilisers and cultivation disrupts and replaces these associations https://www.rhs.org.uk/advice/profile?pid=633

(RHS is the Royal Horticultural Society)

Pesticides and herbicides and perhaps to a somewhat lesser extent synthetic fertilizers are toxic to the soil life community. Therefore if you are already gardening with a lot of chemicals, you have disrupted all that soil life and therefore you must rely on synthetic fertilizers to provide what the soil naturally would. IN THOSE CIRCUMSTANCES, mycorrhizal fungi are not effective. In the wild OR in naturally/organically grown gardens, mycorrhizal fungi and other symbiotic organisms have been shown to make a big difference.

These unique members of the soil community are key players in numerous biological processes: helping plants take up more phosphorus, accumulating carbon in the soil, and improving its clumping ability. Mycorrhizal fungi don't accomplish these processes on their own; they work in concert with plant roots through the power of symbiosis.
Many species of mycorrhizal fungus spores exist naturally in most soils. If plant roots are present when soil conditions prompt the fungal spore to germinate, the newly developing fungal "roots" (or hyphae) link with the cell walls of the plant roots and grow into them, creating structures that allow for the transfer of nutrients between the two organisms. In this symbiosis, the plant provides the mycorrhizal fungi the sugars they need to keep growing (since fungi can't photosynthesize to make their own sugars), and the fungi provide the plants with soil nutrients, particularly phosphorus, which their hyphae can extract from the soil more efficiently than the plant roots can.
When a large, vigorous network of mycorrhizal hyphae is associated with a plant's roots, it exponentially expands the "reach" and surface area of those roots, giving the plant greater access to the nutrients the soil has to offer. This symbiosis is, of course, great for plants, because the extra nutrients can fuel better growth and increase resistance to drought and disease. There are only two instances in which mycorrhizal fungi do not provide benefits to plants: (a) when the soil already has such ideal nutrient and moisture levels that the plants can scavenge enough on their own, or (b) when the plants are brassicas (members of the mustard family), which do not allow the mycorrhizal fungi to colonize their roots.
https://www.organicgardening.com/learn-a ... grown-ally

There is plenty of scientific study to confirm this. Here's just one as a sample:

A regional study was made to identify vesicular-arbuscular mycorrhizal (VAM) fungi effective in promoting plant growth in diverse plant and soil systems. Eight cooperators in six states of the eastern United States evaluated six VAM fungal isolates on soybean (Glycine max L. Merr.) and sorghum (Sorghum bicolor L. Moench) in a shared soil and in at least one regional soil from each location
In the shared soil, inoculation with two isolates of Glomus (GE329 and GENPI) resulted in the greatest shoot masses for soybeans, while the same two isolates and GE312 provided maximum response in sorghum. In the regional soils, GE329 and GENPI had the widest range of growth promotion with both soybean and sorghum; however, for both plant species the mycorrhizal response was greatest in soils with less than 10 mg extractable P kg−1
We conclude that VAM isolates exist which are effective in promoting plant growth over a range of edaphic and host conditions.
Journal of Soil Biology and Biochemistry
Volume 25, Issue 6, June 1993, Pages 705–713

See also information I posted earlier today, here: https://www.helpfulgardener.com/forum/vi ... 07#p349407

And how could somebody say nitrogen fixing bacteria don't help? The first year I used an inoculant on beans, I left about 1/3 of the row w/o inoculant, and the result was amazing. It looked like they had some sort of disease! I have been using it ever since, though the ground probably has a supply of its own, now, after 25 years or so of organic gardening. I haven't done that same test since then.

I'm wondering where that teacher got his PHD. Does Monsanto have a university?

You need to think more globally. The relationship between all living things is much more complex. The nitrogen cycle is a good example of a mini system.

Plants, animal wastes, organic fertilizers need to be broken down before they become available in a usable form to plants.
ammoniacal bacteria decompose the plant and organic material to produce ammonia, then the nitrifying bacteria convert the ammonia to nitrite, and to nitrate which is the usable form for the plants and bacteria to uptake. Nitrogen fixing bacteria convert nitrogen from the air via the nitrogen fixing nodules on certain legumes and synthetic fertilizers are already in a form that the plants can use. On the other side denitrifying bacteria reverse the process and convert the nitrate back into nitrogen gas that is released back into the atmosphere. When everything is in balance the system is perpetual.

Imbalances in inputs and outputs are usually caused by human activities. Intensive farming and applications of large amounts of synthetic or organic fertilizers (happens when a large number of animals are raised in a relatively small area), the pollution of greenhouse gasses and the burning of fossil fuels, and the leaching of excess nitrogen and phosphorus that pollutes waterways and can lead to algae blooms that use up the oxygen in the water creating massive fish kills. Other pollutants cause tumors on sea turtles and the greenhouse gasses thin the protective ozone layer, increasing cancer risk for everyone out in the sun as well as contributing to worldwide global warming affecting weather patterns, accelerating the rate of ice melting, rise in ocean levels, coral bleaching and changes in fish migration from rising ocean temperatures.

For humans to survive they need to develop crops that can tolerate heat and drought, use cleaner energy and decrease their carbon footprint. Here's the hard part, humans need to restore the natural environment and control their greed, otherwise they will have sown the seeds of their own destruction.

So much information in response to the OP!
It's great!

Rainbowgardener mentioned this in the discussion she linked to, but I'm just going to plunk the link for our Teaming with Microbe book discussion right here too https://www.helpfulgardener.com/forum/viewforum.php?f=43

I don't know what the purpose of the OP question was, but there are all kinds of symbiotic organism activities going on in the garden from micro to macro levels.

just a note. even though there are thousands of species of soil bacteria in every spoonful, 99.999% of them cannot be cultured in a lab. and thus, they can't be identified and described, especially their particular actions in the microecology. these bacteria simply cannot live and reproduce without direct interactions with large numbers of other organisms. we can't, for instance, sequence their genomes because it isn't possible to grow them in pure cultures. I know it seems odd, but the characteristics of the individual species of soil bacteria is an absolute mystery to modern science. nature, go figure...

I think instead of calling them symbiotic organisms. I just would think of them as a community. They are the organisms that inhabit the soil web and keep soil healthy. The soil web is just a microcosm of the larger world.

https://www.nrcs.usda.gov/wps/portal/nrc ... 2p2_053868

When this ecosystem is balanced inputs and outputs are roughly equalized and they all live in a state of equilibrium and harmony. The soil will be healthy and productive. There are nitrogen fixing bacteria to convert atmospheric nitrogen gas to ammonia nitrates. Other bacteria convert ammonia to nitrates nitrifying bacteria while still others take the excess nitrogen and convert it back to a gaseous form that is returned to the air. They are part of the nitrogen cycle

https://en.wikipedia.org/?title=Nitrogen_cycle

Human activity has been the largest factor influencing and in many ways interfering with the balance of nature.

Highly efficient synthetic fertilizers if abused add more nitrogen, phosphorus and or calcium to the soil. While in the short run this leads to agricultural productivity which has fueled our modern lifestyle, it has also caused much pollution as the excess builds up to toxic levels in the soil and leaches into the water table and rivers and oceans.

Chemicals like DDT took care of a lot of unwanted pests but impacted birds, especially birds of prey negatively driving them nearer to extinction. Bees and butterflies (monarchs) are threatened today by the dependence of many on the the use of insecticides instead of giving natural controls a chance to keep the problems in check (they will never be 100% effective and some people have zero tolerance for any damage). Monarchs are threatened by legislation that bans their primary food and habitat source.... milkweeds. And do we need to get into whose fault it is that has accelerated global warming. (although warming and cooling periods in geologic history is normal, the speed of this warming period is faster than normal.

Most of the organisms I would not call them symbiotic, for the most part they just do the job that they were created for they fill the niche. They do not intentionally try to benefit anything else, their goal is pretty much the same as everything else to survive as a species.

Not all symbiotic partnerships are welcomed by others.

Take the ants and aphids. The ants carry aphids to the tender parts of the plants and defend them from predators while they milk the honeydew from the aphids. It benefits their partnership but they are parasites to the plant and a bain to the gardener.

Nitrogen fixing bacteria live in the rhizosphere of the legume. The legume does benefit enough to get a little bit of the nitrogen that the bacteria fix from the atmosphere, but the bacteria really fixes the nitrogen for themselves and the benefit to the host is gravy. The soil and the crops do not benefit until the plant and bacteria die and they decompose (in place) and release their stored nitrogen back to the soil and the next crop.