Fungus vs Bacterial culture in mulch

I am reading Dave Jacke's book (2 volumes) "Edible Forest Gardens". In the book Edible Forest Garden, he describes the two different food webs. One is bacterial which is the "native" soil food web environment for annuals. This food web is dominated by bacteria which is capable of fully "digesting" the biomass produced by grasses and annuals. This bacterial environment also inhibits shrub and pioneer trees. Conversely, again according to Jacke, rough cellulose biomass (leaves, trigs, wood chips, and woody dead matter) is tailored for a fungus foodweb. This food web is antagonistic toward annual plants.

Now the question:

If this is true (bacterial is good for annuals and fungal is bad for annuals) why is the wood chip garden method seemingly so productive. Far be it for me to question Mr Jacje, but this seems to be a contradiction between theory and experience? - I'm just sayin'

Thoughts?

PS I cannot recommend the books more highly. It is quite expensive but worth every nickel!!!

BTW I'm still looking for a "perma-sweetie" for a perma-realtionship SWM 54 in Alabama

You should view the food web in the soil as a continuum that runs from bacterial dominated to fungal dominated, with a lot of stops in between rather than an either/or situation. The fungal dominated part of the soil food web is not antagonistic per se to annual plants, it's just that annual plants in that environment tend to get outcompeted over time. The reason our wood chip gardens stay productive is that we remove oak and willow and sweetgum and sumac invaders that would compete with our cabbages and tomatoes. Were we not to interfere, we know who would win that competition after a few years of neglect.

Mark, have you looked into Paul Stamets work ? Might tie up some loose ends for you as far as how the two interact?

John Eliot, or anyone who knows, the op mentioned that "the bacterial environment prevents shrubs and pioneer trees" is that really true? I was under the impression that grazing herds are what kept pioneer shrubs and trees from coming up and taking over a grassland, not really bacterial conditions. I realize it is a complex relationship but I have not been able to understand why there are forests and why there are grasslands and savanas, I see that grazing herds are huge players. If we removed them from the grassland eventually it would sprout trees and become forest right?

I'll toss my minimally educated opinion in the mix here. I think that we want lots of fungi, and lots of bacteria in our gardens. I dont see them as antagonistic or competitive to one another at all. They both have functions to perform. Gardens are not like native forests or grasslands, they are uniquely manmade disturbed areas. Utilizing both fungi and bacteria helps to keep the soil cycle cranking at maximum velocity, resulting in higher fertility and better prodcution.

Zach Muller wrote:John Eliot, or anyone who knows, the op mentioned that "the bacterial environment prevents shrubs and pioneer trees" is that really true? I was under the impression that grazing herds are what kept pioneer shrubs and trees from coming up and taking over a grassland, not really bacterial conditions. I realize it is a complex relationship but I have not been able to understand why there are forests and why there are grasslands and savanas, I see that grazing herds are huge players. If we removed them from the grassland eventually it would sprout trees and become forest right?

I think John points the way here--continuum is the model; few things in nature are all one thing or another. It would seem that among woody perennials the pioneer trees and shrubs are at the more adapted to compete in bacterially dominated soils because their niche is to gain a foothold in the grasslands with the result that certain fungal populations in the surrounding soil are advantaged and that changes the soil chemistry to the advantage of other woody perennials. While the grazers check the progress of the pioneers, many of them develop defenses, like thorns. Fire flashing across grasslands can do more damage to shrubs than to the grasses that have evolved to replace all their above ground growth each year. At the same time fire advantages the ponderosa pine--successor to the pioneer trees--which has developed thick bark as a defense, but also has seeds that are more viable after the fire clears out the undergrowth. Fire travels from clump of trees to clump of trees via the grass in between; if a large herd has just grazed the area, fire will bypass some outcroppings of trees, and species that benefit from brushy undergrowth are advantaged relative to the ponderosa.

The webs of cause and effect are much more complex than phrases like 'there are two types of soils' or 'bacterial environment prevents' allow for.

Zach Muller wrote:John Eliot, or anyone who knows, the op mentioned that "the bacterial environment prevents shrubs and pioneer trees" is that really true? I was under the impression that grazing herds are what kept pioneer shrubs and trees from coming up and taking over a grassland, not really bacterial conditions. I realize it is a complex relationship but I have not been able to understand why there are forests and why there are grasslands and savanas, I see that grazing herds are huge players. If we removed them from the grassland eventually it would sprout trees and become forest right?

"Does the bacterial environment prevent shrubs and pioneer trees?"

That's a question worthy of a long dissertation. If the balance in the soil is weighted to a lot of bacteria and few fungi, then pioneer trees are going to have a harder time getting established. I know in my own experiments with acorns that giving them a heavy dose of mycorrhizal boletes does wonders in getting them off to a good start. If the mycorrhizae aren't there then, well, was it the abundance of bacteria that prevented their growth or the absence of beneficial fungi?

You're right, it is a complex relationship. And if you remove one component from the environment (i.e., grazers from a grassland) then it can move in another direction and become a different environment.

Why does wood chip gardening work so well for annuals?

I don't put it down so much to the fungal/bacterial balance but the the improvements to soil structure that the mulch provides - greater water retention, a nutrient sponge near the surface etc... Our natural soil here bakes hard in summer and has comparatively little carbon matter. Under the wood chip the soil stays moist and the roots of my plants have much less competition for nutrients than when it was lawn.

Adam, John, and Walter - thanks for the thoughtful answers. Sometimes even when I can see that something is too intricate and variable I struggle to codify, categorize, and otherwise attempt 'understanding' in a mental way. As with all natural things it seems here that eventually you are faced with a chicken-egg scenario. One thing I just pulled up and found helpful is found on Tim Wilsons microbe organics site under the header "organic growing from a microbial perspective." It is kind of a play by play of the microbe cycle and he mentions how the microbe balance will change as the plant moves from growing into flowering. So indeed the microbe population is always changing because of roots releasing hormones, sun intensity, etc, etc.

Michael cox - yeah absolutely, modifying the soil structure to have increased diversity of particle size, and improved moisture capacity should not be overlooked when creating good soils.