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Soil Health

25K views 78 replies 6 participants last post by  Smallaxe 
#1 ·
#2 ·
This is an Ag related article, but it the context of lawn soils the following idea(from article) would also apply:

**"If crop nutrients are applied to the soil in excess, plants will not develop associations with soil organisms that help them acquire water and nutrients. After the "party is over" and the synthetic fertilizer is gone, the plants are left "high and dry" with few to no soil factory workers to help them access water and nutrients for the remainder of the growing season. The plants then give up valuable energy (sugars) in an attempt to make connections with microbes mid-way through the growing season when the plant should be putting that energy into flowering and seed development to produce a harvestable yield. By applying excess fertilizer, particularly nitrogen or phosphorus, we create plants that are very inefficient as they try to function without the support system of the soil with which they evolved."**

My concern would be, that if there was not enough SOM for the bacteria to work with, where would the 'nutrients cycle from'???
 
#3 ·
Another portion from the article:

* "Farms and ranches are provided with soil, water, and sunlight. The
challenge is to feed the soil, harvest sunlight and farm sustainably to make
a living now and in the future." *


This article seemed to forget about "AIR" being in the soil as a necessary component for the soil food web... do Ag crops not need air for the roots or the microbes?
 
#4 ·
How deep are the fungi able to generate nutrients through decay? and What happens after the OM in the depths of the soil is decayed and gone?
 
#5 ·
Another portion from the article:

* "Farms and ranches are provided with soil, water, and sunlight. The
challenge is to feed the soil, harvest sunlight and farm sustainably to make
a living now and in the future." *


This article seemed to forget about "AIR" being in the soil as a necessary component for the soil food web... do Ag crops not need air for the roots or the microbes?
Stable soil aggregates are critical for water infiltration and gas
exchange, both of which are essential to crop production.


Last time I checked Air was a Gas.
 
#6 ·
How deep are the fungi able to generate nutrients through decay? and What happens after the OM in the depths of the soil is decayed and gone?
When I inject mycorrhizae , I do so about 12" deep and the mix comes up.

When I am planting, I add a dry mix to the top 8 to 12" of the backfill. More and more reputable growers are now inoculating as well.

I mostly apply rhizobia in a nice mix of macro, micro nutrients, seaweed humate, yucca extracts and sugars to the lawn but the trees will respond too if you inject it in the top few inches.

It takes time for sure since most track homes have all the top soil stripped away, and compacted by construction. Aeration and top dressing helps speed it a long.
 
#7 ·
This is an Ag related article, but it the context of lawn soils the following idea(from article) would also apply:

**"If crop nutrients are applied to the soil in excess, plants will not develop associations with soil organisms that help them acquire water and nutrients. After the “party is over” and the synthetic fertilizer is gone, the plants are left “high and dry” with few to no soil factory workers to help them access water and nutrients for the remainder of the growing season. The plants then give up valuable energy (sugars) in an attempt to make connections with microbes mid-way through the growing season when the plant should be putting that energy into flowering and seed development to produce a harvestable yield. By applying excess fertilizer, particularly nitrogen or phosphorus, we create plants that are very inefficient as they try to function without the support system of the soil with which they evolved."**

My concern would be, that if there was not enough SOM for the bacteria to work with, where would the 'nutrients cycle from'???
On a lawn we mulch the grass and feed it with a mix on a regular basis as described above.
 
#10 ·
My concern would be, that if there was not enough SOM for the bacteria to work with, where would the 'nutrients cycle from'???
Well, to keep the party going, add more organic matter. In addition, much of the food for microbes is exuded by plant roots. In fact, the exudate will favor the microbes that are beneficial to the plant. Roots constantly slough of dead cells which add to SOM.

Microbes also are responsible for mining nutrients from the inorganic parent material of the soil. Mycorrhizea are critical for unlocking P and transporting it to plant roots. Certain nitrifying bacteria extract N from the air in soil pores and make it plant available.

The human part of the puzzle is to use practices which enhance rather than harm the process that builds soil health.
 
#12 ·
Disturbing the soil is bad, because it messes with the colonies of microbes... Should we be able to grow good healthy soils, without aeration??? Can we get the soil aggregates with gas exchange, w/out disturbing the soils???
 
#16 ·
I recommend aeration for the first year or so into a soil building program for turf grass because I think it will speed the process. After that, as long as you are able to maintain a healthy balance of life in the soil aeration should not be needed.

The exception is sports turf due to constant compaction from play.
 
#17 ·
Let the second and third level trophic organisms do it. :rolleyes:
The first trophic level is made up of the primary producers, that is the photosynthetic sources that turn the energy from sunlight and carbon dioxide into sugars or energy for the plants and the entire soil food web (usually a plant or tree, but photosynthetic bacteria and algae may also be included in this group). The second trophic level consists of the decomposers and mutualists: non-photosynthetic bacteria and fungi. The third trophic level is made up of the shredders, predators, and grazers (nematodes, protozoa and some arthropods), and the fourth and fifth levels are made up of higher-level predators. Ecological Landscaping Association
 
#18 ·
The first trophic level is made up of the primary producers, that is the photosynthetic sources that turn the energy from sunlight and carbon dioxide into sugars or energy for the plants and the entire soil food web (usually a plant or tree, but photosynthetic bacteria and algae may also be included in this group). The second trophic level consists of the decomposers and mutualists: non-photosynthetic bacteria and fungi. The third trophic level is made up of the shredders, predators, and grazers (nematodes, protozoa and some arthropods), and the fourth and fifth levels are made up of higher-level predators. Ecological Landscaping Association
so what did I miss?
 
#20 ·
This is an Ag related article, but it the context of lawn soils the following idea(from article) would also apply:

**"If crop nutrients are applied to the soil in excess, plants will not develop associations with soil organisms that help them acquire water and nutrients. After the “party is over” and the synthetic fertilizer is gone, the plants are left “high and dry” with few to no soil factory workers to help them access water and nutrients for the remainder of the growing season. The plants then give up valuable energy (sugars) in an attempt to make connections with microbes mid-way through the growing season when the plant should be putting that energy into flowering and seed development to produce a harvestable yield. By applying excess fertilizer, particularly nitrogen or phosphorus, we create plants that are very inefficient as they try to function without the support system of the soil with which they evolved."**

My concern would be, that if there was not enough SOM for the bacteria to work with, where would the 'nutrients cycle from'???
The article cited by the OP seems to be little more than an opinion piece and has little scientific background. If you're reading something without references following it, its nothign more than one person's opinion -- not scientific fact.

While the OP's article does a good job highlighting some practices that are important in production ag systems, many of those practices are detrimental in turf systems. That is why I hate it when organic fert salesmen tell me how good their stuff is for growign corn and soybeans. I'm growing lawns -- not corn and soybeans! If the salesman can't adjust between the differences in the two cropping systems, he surely doesn't know anything abotu my business.

Anyhow, if you're going to talk about soil "health" and soil microbial interactions, you need to learn from the experts. Please read the article linked here:

http://aggie-turf.tamu.edu/files-2005/D-Zuberer-SPORTSTURF-article-2005.pdf

Although the piece talks mostly about sandy soils vs native soils in athletic field management, the last paragraph is especially relevant to this discussion:

"So, do you need to add “beneficial microbes” to the soil to make it function properly? That’s highly unlikely! Many studies of turfgrasses, whether in sports fields, golf courses or home lawns, have shown that soil microbial populations are not compromised by normal management practices. The best thing that you can do to “manage” the soil microbes under your care is to grow a healthy stand of turf and pay close attention to the condition of the soil or root zone supporting it. Paying attention to the agronomics of grass culture, fertilization,aerification, drainage, etc., will insure that the microbial populations are not being adversely affected!"
 
#22 ·
With the advent of high-sand golf greens questions have arisen about the need for applying microbes during green construction and thereafter. Sand because of its lack of organic matter supports little microbial growth. However, when mixed with peats, composted rice hulls or other organic amendments it gains the microbial populations associated with those materials. Turfgrasses established from vegetative sprigs also bring their root-associated microbes with them! Once the turfgrass begins growing in the rooting medium of the green, microbes already present will colonize roots and the mechanics of soil organic matter formation will commence. A reasonable practice would be to add a small amount of normal pathogen-free soil to the greens mix as an inoculum. Thus far, there is little scientific evidence indicating the need to inoculate golf greens with selected microorganisms. The newly constructed green does afford us the possibility of customizing the soil population to some extent. Once we know what we want in these mixes it may be easier to add them "up front" than to add them into an established population already adapted to the prevailing conditions of a particular soil. As our knowledge of soil microbial biodiversity and the factors that control it increases we may find ways of tailoring microbial populations in given environments. At this point, we are limited in what we can do to this effect.
http://organiclifestyles.tamu.edu/soil/microbeindex.html

Unfortunately,most home track builders strip way the top soil and sell it. They do not use a soil mix either so there in our area most lawns are set on hard pan clay.
 
#23 ·
The article cited by the OP seems to be little more than an opinion piece and has little scientific background. If you're reading something without references following it, its nothign more than one person's opinion -- not scientific fact.

While the OP's article does a good job highlighting some practices that are important in production ag systems, many of those practices are detrimental in turf systems. That is why I hate it when organic fert salesmen tell me how good their stuff is for growign corn and soybeans. I'm growing lawns -- not corn and soybeans! If the salesman can't adjust between the differences in the two cropping systems, he surely doesn't know anything abotu my business.

Anyhow, if you're going to talk about soil "health" and soil microbial interactions, you need to learn from the experts. Please read the article linked here:

http://aggie-turf.tamu.edu/files-2005/D-Zuberer-SPORTSTURF-article-2005.pdf

Although the piece talks mostly about sandy soils vs native soils in athletic field management, the last paragraph is especially relevant to this discussion:

"So, do you need to add “beneficial microbes” to the soil to make it function properly? That’s highly unlikely! Many studies of turfgrasses, whether in sports fields, golf courses or home lawns, have shown that soil microbial populations are not compromised by normal management practices. The best thing that you can do to “manage” the soil microbes under your care is to grow a healthy stand of turf and pay close attention to the condition of the soil or root zone supporting it. Paying attention to the agronomics of grass culture, fertilization,aerification, drainage, etc., will insure that the microbial populations are not being adversely affected!"
Thanks for posting the relevant paragragh for review, as I'm heading out the door soon...

I too wonder about the bringing in a microherd to an area, since the microherd that is there already thrives for a reason... I like what the article says about: "The best thing that you can do to “manage” the soil microbes under your care is to grow a healthy stand of turf and pay close attention to the condition of the soil or root zone supporting it."

Looking into the soil and observing the conditions around the roots will tell me more in a minute than all the reading of symptoms in research papers...
The real question is in regards to that paragragh is: What is the best management practice of the tur?f??
 
#24 ·
Essentially, what Dr. Zuberer (and all the scientific literature) shows is that the concept of "building soil health" is unfounded nonsense! All the scientific literature tells us that soil microbial populations are naturally robust, but even inhospitable environments can be made more hospitable by doing what is necessary to grow a healthy turf. I understand the mycorrhizae crowd, but mycorrhizae are already in the soil, so adding more is of little benefit.

It all goes back to the basics of growing plants -- the right nutrients in the right amounts at the right time.

If you can show me any scientific literature that refutes Dr. Zuberer's results and the results of those whom he referenced, please post it here.
 
#25 ·
Essentially, what Dr. Zuberer (and all the scientific literature) shows is that the concept of "building soil health" is unfounded nonsense! All the scientific literature tells us that soil microbial populations are naturally robust, but even inhospitable environments can be made more hospitable by doing what is necessary to grow a healthy turf. I understand the mycorrhizae crowd, but mycorrhizae are already in the soil, so adding more is of little benefit.

It all goes back to the basics of growing plants -- the right nutrients in the right amounts at the right time.

If you can show me any scientific literature that refutes Dr. Zuberer's results and the results of those whom he referenced, please post it here.
I have seen the response to Mycorrhizae in urban landscapes.
Yes, it is present in abundance in old growth forest. If you have a transplanted tree or trees suffering from drought or damage the Mycor does help.

Again, many of the track homes built around here are in old farm locations and the top soil is completely stripped away. It is a great idea to stock pile it and reuse it but that seldom happens in track home development. So unfortunately we are often stuck with trying to develop subsoils for Turf.
 
#26 ·
I entirely understand the challenges of maintaining turf for new home construction. However, as Dr. Zuberer points out, microbial populations in harsh soils (even such unhospitable soils as kiln-dried sands) reach similar numbers after just a couple of weeks of plant growth (grass or otherwise). So, the compacted and nutrient devoid subsoils some of our customers have are NOT deficient in soil microbial populations and adding the things "soil health" advocates tout will NOT improve soil microbial function. This has been backed by numerous scientific studies. If you can find studies that say otherwise, please post them. Similarly, not one single study has shown that added mycorrhizae colonize plants. If any colonization has taken place, only the mycorrhizae that were already in place will colonize plants. Foreign or added mycorrhizae have never been observed to colonize plants when added to non-greenhouse situations.

Often, lawns grown in subsoils will perform better with conventional management, like core aeration and proper fertility.
 
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