Bacteria are a vital part of soil and the health of plants, so it is no wonder that there is a lot of talk about keeping soil bacteria healthy, increasing their numbers, having the right kind of bacteria, and so on. It only makes sense that if bacteria are important for plants, gardeners should (a) know more about them and (b) learn to manage them properly.
Unfortunately, along with good practical information, you will also find quite a few soil bacteria myths. The one I’d like to discuss today deals with the idea that you can figure out which type of bacteria you have. Armed with this information, you can then manage the populations to increase the ones that are most beneficial for your plants.
Soil Bacteria and Dr. Elaine Ingham
Dr. Elaine Ingham has become synonymous with the Soil Food Web. Her teachings include many good ideas about keeping soil healthy. She is a proponent of compost, and adding organic material to soil. She promotes the idea that microbes in the soil are very important for developing good soil structure.
Unfortunately, Dr. Ingham then takes these ideas to a ridiculous extreme. She recommends gardeners should look at the microbes with a microscope, and with this device, they will be able to identify the various bacteria in soil. Once you know which bacteria you have in your soil you can take steps to manage the herd, and increase the right ones which would make the growing conditions more favorable for your plants. She goes on to suggest that different plants need different populations of bacteria and gardeners can learn to customize their soil.
Here is a quote from the advertisement for one of her courses where a full day is dedicated to identifying microbes: “Get the necessary training to identify the bacteria, fungi, protozoa, and nematodes that drive the health and well being of our plants” Soil Food Web, Dr. Elaine Ingham.
I have no problem with the idea that microbe types in soil are important, and that their ratios might change over time, and that such changes influence plant growth. This is all very true.
What I have a problem with is the idea that anyone can control this situation in a quantitative way. To do this you need to be able to identify the current bacterial types that you have, and then influence their populations to make them more suitable for you plants.
Note: Added March 28, 2016. A couple of comments left at the end of this post said that Dr. Ingham does not promote the identification of species.
The commenters can’t imagine where I got such an idea. So I went back and looked at a lot of the promotion from Dr. Ingham, and looked at several online videos. In every case she talks about the ‘identification of microbes’. In the video she clearly differentiates between various types of bacteria, and nematodes and talks about the importance of identifying these various types, and how this can be learned using a microscope. Clearly she expects you to do much more than just count total bacteria and total nematodes as one commenter said.
From her web site: “we will develop a wider and wider base of knowledge as more people encounter all the myriad of organisms that exist in soil. Which in turns leads to a better understanding of what exactly is in different soils, in different climates, and with different organic matter and plants.” Sounds like a lot more than just counting bacteria, fungi, protozoa and nematodes!
The Soil Food Web also talks a lot about ‘increasing diversity’ of microbes. If you don’t know which species you have how can you know that your methods are increasing diversity? You can’t, which would lead a reader to think they are doing much more than just counting total bacteria.
I think this is a case of misleading the reader/viewer about her courses. I don’t think it is intentional.
What about the rest of this post? If identification of species is not the goal, are the comments still valid? I think they are. The post is mostly about gardeners using the information gained from the microscope.
I have just finished reviewing the book Teaming with Microbes, a gardeners Guide to the Soil Food Web and they say the following about using a microscope “when it comes to the microorganisms, we will be the first to admit that you will not be able to determine precisely what is in your soil, even with a powerful microscope.“ This comment comes from two strong proponents of the Soil Food Web, Jeff Lowenfels & Wayne Lewis. I agree with their conclusion.
Update Aug 2023: I just received a copy of The Compost Tea Brewing Manual, by Dr. Ingham. Under the section Compost Tea Organisms, she says, “Currently, a combination of selective media, enzymes and finger printing can serve to determine whether 20 specific beneficial species are present or not. In this way, you can determine whether your tea includes the beneficial organisms that you need.” Notice that microscopy is NOT included as one of the methods used to identify the bacteria in compost tea. She clearly agrees with the conclusion in this post, but continues selling the courses anyway.
Bacteria in Soil
Bacteria in soil carry out some very important functions. Some are nitrogen fixers which convert the nitrogen in the air, N2, into ammonia, nitrite and eventually nitrate, so plants can use the nitrogen. The decomposers are a large group of bacteria that decompose organic matter. This process releases nutrients for the plants and improves soil structure.
Bacterial pathogens cause diseases in plants. We don’t really want them around, but they are part of nature and play an important role. Normally, the good bacteria out compete the pathogens, and keep their numbers low enough so they don’t cause a problem.
Find out more about the bacteria found in compost at Compost Microbes – Good for the Soil?
Bacteria Species in Soil
How many species of bacteria exist in soil? You would think the question would have a simple answer, but the honest truth is that scientists don’t know. Most species of bacteria have not been identified which means no one knows how to identify them.
Estimates range between 2,000 and 8.3 million species of bacteria per gram of soil (ref 2).
Identifying bacteria is so complicated that the experts use approximation techniques to figure out the number of species. It is impossible to sit down in front of a microscope and figure out which species you have. For a glimpse at how soil scientists try to estimate bacteria communities see reference 3 .
A study (ref 4, Toward a Census of Bacteria in Soil) compared soil from Alaska and Minnesota and used computer models to identify species of bacteria because doing real identification was impossible. They found several thousand species, and 20% were endemic. So the soil bacteria from these two regions were quite different from one another.
The bottom line is that no one is able to identify bacteria species by looking at a soil sample. If the experts can’t do it, gardeners can’t do it – even if they take Dr. Ingham’s course.
Types of Bacteria
OK, so you can’t identify soil bacteria at the species level, maybe you can identify them as ‘classes’ of bacteria?
You can certainly see some bacteria cell structure under a microscope, and you can form classes of bacteria based on physical structure; rods, spheres, spirals etc., but that does not really tell you anything useful about which ones you want in the garden.
You can’t differentiate aerobic from anaerobic bacteria, based on physical appearance. You also can’t differentiate between beneficial and pathogenic bacteria. Identifying a bacteria as belonging to one or the other of these classes is critical to Dr. Ingham’s methods for the management of soil bacteria, and especially for the creation of compost tea.
You can count the number of bacteria you see, but I don’t know how accurate that is for a soil sample.
The average gardener can learn very little about the bacteria in soil by looking at a soil sample under a microscope.
Professional Labs
Let us assume that I have convinced you that you can’t identify the bacteria yourself. You then have the option of using one of the labs Dr. Ingham recommends on her web site, to do this identification for you.
Here is what one of them says “Complete Food Web Test (done by SFWNY) – Quantifies total and active bacteria, total and active fungi, and presence/absence of protozoa” , ref 5 Soil Foodweb Inc – Identifying Organisms. Your results will give you 4 numbers plus a yes/no for protozoa! Remember this is a ‘complete’ test, but it does not provide any information about the identification of bacteria. Odd – maybe the testing lab never took Dr. Ingham’s course??
So even the recommended professional labs don’t try to identify species, aerobic vs anaerobic, or even beneficial vs pathogenic. Why? It’s too complicated.
Managing Bacteria in Soil
The idea that someone can take a light microscope and find out critical information about their soil bacteria is ridiculous. You can certainly see bacteria, and you might be able to count some of them. That information is not very useful.
Even if you could get the information, what would you do with it? I don’t see how you would know which bacteria you should grow for each of your plants? No such table exists. How does this change for each plant you own? Nobody knows. We don’t even know which bacteria live in your soil!
Adding more organic matter will increase the number of bacteria – you don’t need to measure them to know this. Bacteria automatically increase in numbers when you supply a food source. Having active bacteria in soil is a good thing even if you don’t know which species you have. You don’t need a microscope.
In this discussion I have focused on bacteria in soil, but all of the comments also apply to bacteria in compost tea. Except for counting bacteria, a microscope will not help you to qualify your compost tea herd. Besides, there is no current evidence compost tea works any better than just compost.
References:
- Soil Food web with Dr. Elaine Ingham;
- Pyrosequencing enumerates and contrasts soil microbial diversity; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2970868/
- Empirical and Theoretical Bacterial Diversity in Four Arizona Soils; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC123964/
- Toward a Census of Bacteria in Soil; http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.0020092
- Soil Food web Inc – Identifying Organisms;
- Photo source: Filter Forge
QUESTIONS TO ELAINE INGHAM :
4. Why do you insist, in the 21st century, in saying that “aerobic is good and anaerobic is bad “, when everybody knows that some of the most important organisms in the soil are anaerobic and/or facultative like lactic acid bacterias, yeast and PSBs and PNSBs ?
Why do you never stress the importance of these groups of organisms ? Is it because they are part of a very efficient and world wide used organisms named SAM ( Synthropic Antioxidant Microorganisms ) ?
In Nature there is no “good and bad”. Margulis have shown that many years ago.
So then, why this Microbial Maniqueism ?
Here is the thing, Dr. Elaine Ingham was one of the first to point out that healthy soil is alive and in cooperation with others and the USDA created The Soil Food Web. The more diverse the microbiology the better in creating a harmonious and healthy balance. The more aerobic the environment the less likelihood of some of the harmful microbes becoming dominant. From a human perspective there are good and bad microbes or there would be no need for USDA recalls. In and with nature no, everything has its place in the big picture.
Anyone can create their own good microbes by learning how to create EMOs, Effective Micro-Organisms. Biodynamic gardening/farming has its ways, a little too esoteric for me but some swear by the formulas. There is DNA Sequencing that can tell which microbes you have in your soil just not quantitatively. The problem is we are now dealing with something that is alive rather than just a medium to grow in and we have much to learn but the good news is the data/information is coming in at a geometric progression.
You can after the fact, find fault with anyone’s initial premise, it is with time that a better understanding is always possible but without Dr. Elaine Ingham’s work, we wouldn’t be where we are now. Soil is alive and now we have to learn the best ways/methods to not only keep it alive but to thrive.
1) Actually DNA sequencing can’t ID most microbes in soil. We don’t even know how many species there are.
2) Soil is not alive. The living organisms in soil are not part of soil. They are part of the soil eco-system.
DNA Sequencing gives a representation of what types of microbes are there and if we take enough samples of the microbes that are in the soil at the time when plants are healthy and thriving then we will be at the beginning of being able to run a test to see from samples how healthy our soil are. The microscopy of teas is to confirm there is life and a quick peek of the different types. Basically a quick way to qualify the compost tea. We are at the beginning of the understanding of health in context to soils. Here is the hard part of IDing the microbiology, there are billions at the moment the sample was taken, so even if you could identify with the help of say super computers, you have no way of knowing if there has been a change or even how quickly change happens. It is why I said we need to learn methods and procedures to better care for the soil. We also need to learn what not to do. We should be learning to care for the soil as if it is a treasured family pet, even though it is far more important than that.
If you want to call soil as I understand it, the soil eco-system that is just a matter of semantics. As long as we agree that it needs to be alive and managed as such we are on the same page. I agree that if you add microbes before adding food for them, it would amount to the same as trying to graze cattle in the middle of the desert. I do think you can gather and maintain the microbiology needed for a healthy growing environment by cultivating the right food source with favorable environmental factors similar to making sour dough bread. If the right microbiology isn’t already around us we would have starved to death centuries ago. I am hoping that we get this agriculture thing down soon because I would like to move onto making the wheel rounder.
In one study, maybe. But I am not talking about a single study but about what is widely known in the Biologicals Industry.
Nobody, I mean nobody, in the whole world is multiplying Fungi in a commercial scale in a liquid medium.
USDA is currently doing research and I figure they ultimately will get it done but so far you cannot do it.
Even so, what is a double in 24 hours ? Not a big deal though.
In the case of bacteria we go from say 100 to 1.000.000.000 in 24 hours.
This is real multiplication.
In the case of Elaine’s recipe you are just fooling yourself.
Compost Tea has no real hard science backing it up. It is mostly wishful thinking.
Nobody said they are growing fungi on a commercial scale in liquid medium.
QUESTIONS TO ELAINE INGHAM :
3. Have you ever done a controlled study to prove that it is the compost tea and not all the ingredients added like Molasses, Humic acid, Kelp and Fish Hydrolizate that are running the show ?
How can someone guarantee that are the microbes and not all those products that are exerting their influence in soil and plants ?
How can we discount the effects of the ingredients from the effect of the microbes ?
QUESTIONS TO ELAINE INGHAM :
2. If we all know that the ambient of the great majority of the so called “Compost Tea Machines”, including the ones that your lab SFI have given your approval, are of very high aggitation and oxigenation, do not favour the growing and multiplication of the majority of soil organisms, but only some like Bacillus subtilis found in cattle manure, so WHY do you still insists in this practice that will do nothing more than reducing the numbers of the organisms found in the compost to just a few of them that will be more suited to high agitation, oxigenation and the feed choosen like molasses, humic acid, kelp and fish hydrolisate ?
It is my understanding that bacteria are a food source for some of the other microbes, prey perhaps. So supplying a tea to the soil high in bacteria would feed the microbes that we want to convert the nutrients in the soil into bioavailable form for plant uptake. There are bacteria on the market that can be purchased for this purpose, though I cannot comment on research to back up the marketing claim (specifically a few that convert nutrients even when pH levels are high). I do know there is research that in the human body bacteria/microbes in the human gut converts nutrients into a more biological form for absorption. So it’s not a huge leap of faith for me to think the same function occurs in the soil since I already am seeing structure/function similarities between our human body & planet Earth. I use science as but one tool to inform me in life and I understand a primary property of science is to question itself yet I know I will be drawn sometimes compelled to make decisions in life that hasn’t been scientifically validated. Sometimes even when things are scientifically validated I don’t choose it. I don’t allow science to be my gatekeeper.
“supplying a tea to the soil high in bacteria would feed the microbes” – the tea has high levels of microbes compared to water, but when you compare the amount to the huge amount in soil – it is essentially adding none.
QUESTIONS TO DR ELAINE INGHAM :
1. It is widely known, and the research of USDA and other Ag Research Centers demonstrate, that you cannot grow fungi in liquid over a period of 24 hours, even if that medium would have the proper conditions required by fungi, i.e. low agitation and low oxygen levels, why do you insist in making a fungal compost for Compost Tea extraction and multiplication ?
This study showed that fungi doubled during the tea making process using ACT.
https://www.gardenmyths.com/compost-tea-does-it-work/
To my understanding of Elaine’s work, she never emphasized categorizing the types of bacteria. She emphasizes honing in on beneficial hunters of bacteria. For some reason, you’ve overly focused on her preaching the deciphering bacteria. That is absurd in and of itself with a 400x microscope.
I think if you combine Elaine, Paul Stamets, and Josh Salatin’s work, with a Permaculture lense, you’d understand a little better? We are not identifying bacteria. We are identifying beneficial microbes and Fungi that consume bacteria.
Considering all life originated with Fungi, we might want to stop playing word games here and hone in on the basics. The excrement of beneficial microbes provides the nutrients to beneficial vegetation. Kind of simple. The hard part is preserving bacteria so that beneficial microbes have consistent food supply and are not leached away. The other hard part is dealing with the tons of disease causing microbes and Fungi that have gained increased footing via the actions of land mismanagement.
If you watch her videos she certainly promotes the idea of identifying bacteria.
How do you identify fungi? Can,t do that with a microscope either, nor can you identify which microbes are beneficial.
this may help you update and correct your assessment. Here’s the caase studies on her new website. https://www.soilfoodweb.com
this is a very good video in increasing your understanding of her research. https://vimeo.com/250723320 – Elaine Ingham- Reversing the Worlds Toughest Soil Problems (Soil Restoration Part 4)
Sorry – they are nice videos, but I did not see a single published study. If you have a link to a study I would like to see it.
This is a sad hit job, if you cant find Elaines publisshed studies, you are not looking at all
I have not been able to find them because they don’t exist. She has not published any research in many years.
But since you are sure they exist – why not add a link to one of them that disproves anything I said in this post?
Ingham, E.R. and M. Alms. (1999), The Compost Tea Handbook 1.1
Ingham, E.R. (2000) The Compost Tea Brewing Manual. Sustainable Studies Institute, Eugene, Oregon. 2nd–5th eds. Soil Foodweb Inc, Corvallis, Oregon.
Ingham, E. R. (1999). Chapters 1–5 in: The Soil Biology Primer. NRCS Soil Quality Institute, USDA.
Ingham, E.R. (2004). “The Soil Foodweb: Its Role in Ecosystems Health”. In: The Overstory Book: Cultivating Connections with Trees. Ed. Craig R. Elevitch. 2nd ed. Holualoa, Hawaii: Permanent Agriculture Resources.
Ingham, E.R. and M.D. Slaughter. (2005). “The Soil Foodweb–Soil and Composts As Living Ecosystems”. International SoilACE Conference in Soil and Compost Eco-Biology. Leon, Spain. 1: 127-139.
1) none of the references are links.
2) None of the references you list are research papers. The first 5 are articles that Dr. Ingham has written about her views. You can hardly use those as scientific support of her views.
3) The last items seems to show some research, but:
– it is a proceeding from a conference given in 2004. There is no evidence that this material was ever published in a scientific journal, but it may have been.
– as presented it would never be published in a journal since Dr Ingahm’s company Soil Food Web is listed as one of the researchers – a clear conflict of interest.
– It was presented in 2004, but it clearly states right at the top that this is data from Dr. Ingham’s graduate research and she obtained her PhD in 1981.
As I said in my last comment, she has not done any published research in quite some time – rehashing 1981 data in 2004 proves it.
4) For discussion purposes, let’s assume this last reference was properly published.
What does it conclude?
“There should be no question that properly made compost is actually mainly biomass of micro organisms, including bacteria, fungi, protozoa and nematodes. ” The study looks at the ratio of bacteria and fungi in compost. It also lists these ratios in some soil samples (seems this work was done by Soil Food Web).
Ok – so what. nobody, including me disagrees with this conclusion.
What did my post say?
a) A gardener, using a light microscope can’t identify bacteria.
b) There is no evidence that controlling the ratio or type of bacteria in soil is a viable process for gardeing.
You have given this research as evidence that my statements are wrong. But what does the paper say?
There is no attempt in this research to identify types of bacteria. In fact it only reports “total bacteria”
It does not use simple microscopy as promoted in her courses. She used DIC microscopy, with special staining and says “Training requires 6 to 12 months to be able to properly assess morphology” – and that is just to count total bacteria, not ID bacteria.
This paper does not show you can ID bacteria using a light microscope.
The presented data looks at the existing ratio of bacteria to fungi. It makes NO attempt to alter the ratio, nor does it measure any kind of plant response to a change in soil.
The paper clearly does NOT disagree with the statements I made in my post.
Many, perhaps all, of Dr. Ingaham’s studies on numbers of bacteria and fungi or their kinds deal with extracts of compost. Extracts do not necessarily measure numbers of certain organisms in a compost pile, just the ones most enable to extraction, which could also depend on details of the extraction process.
I recently watched Elaine Ingham present on YouTube. I found the soil ecology knowledge she presented to be basic and correct and as such to have profound implications concerning optimal practice in endeavours to grow plants. I researched further and found farmers such as Gabe Brown and Dave Brandt to have implemented the principles over a number of years with very good results.
That key mainstream agricultural practices harm soil biology which when unharmed naturally fertilises and develops plants so they can be healthy enough to not need any fungicides, or pesticides etc. This shows the natural and artificial systems to be in opposition to each other. (If one promotes and establishes a natural healthy soil ecology, one can completely avoid artificial chemicals. If one uses artificials the soil biology will be harmed and there will be a need for pesticides etc which can make one dependent on buying artificials to produce)
I did notice that Elaine promoted learning to look into soil for oneself so that people could be empowered by learning knowing and doing for themselves and so not have to rely on her own network to test their soil. The farmers who use her principles suggest a shovel and hands to know the soil health, but they do use and refer to her and others soil tests which they find useful.
The evidence of her knowledge when put into practice shows it to beneficial on many levels such as decreasing costs to farmers, decreasing erosion, increasing water penetration and ground storage, building soil organic matter and, according to Elaine, winning US yield awards but without the $$$ fertiliser and pesticides used in modern times.
The science from people like Elaine is becoming the new mainstream because economic, yield, sustainability, and nutrition benefits are superior. As such inferior knowledge industries, losing $$$ and diminishing due to a superior and cheaper product.
Re: “The science from people like Elaine is becoming the new mainstream” – some of the science is valid and has been proven. Some of her ideas can not be considered science since they have not been validated. Some of her ideas such as no-till are being adopted, but other like compost tea are anything but mainstream. Main stream farming uses synthetics.
A transition to a more optimal mainstream is happening in some places.
What is mainstream depends on where one is and at what time. In some places fertilizer is still a dominant paradigm but not in others. A couple of quotes from a pdf by Dr Christine Jones, shows that in some places farmers are discovering that much of the how they viewed soil, fertilizers, tilling, growing plants and farming was not optimal, so it is being adjusted accordingly. A couple of quotes from the article which is linked below.
“There is an extraordinary soil health revolution taking place in North America. This farmer-led movement is receiving increasing attention and support from the United States Department of Agriculture (USDA), particularly the Natural Resource Conservation Service (NRCS). …”
Pennsylvania farmer Jim Harbach has been using multi-species cover crops with highly beneficial results. Jim’s testimony … :
‘…I am very fortunate to have been part of agriculture for more than 40 years. I have witnessed the transition from conventionally plowed ground to no-till. Some of our fields have not been plowed for 40 years. We have seen first-hand the transformation of our soils, and the positive results when you farm in Nature’s image. In the last decade, with the addition of cover crops, and the belief that plants feed the soil, instead of soil feeding the plants, we have seen incredible results.
http://amazingcarbon.com/PDF/JONES-FrontiersInAg-Unlock-the-secrets-in-the-soil_Summer%202015.pdf
Awesome pic of you by the way!
Additionally, there are huge implications for this transition. The petro-chemical industry is significant and touches many people and businesses. That it has never really been optimal but rather anti life is not that surprising as I’ve heard that the industry came out of the munitions and some chemical warfare industries. I’m sure those in the industry are smart enough to see the writing on the wall and I’m sure they are also responsible enough to transition to a natural life supporting way of business also.
Cheers.
Well said, especially the last paragraph.
I find your stance regarding Dr. Ingham problematic as you are asking for something which is beyond the capacity of microbiology: certainty of quantitative analysis regarding microbiological activity. There are simply too many tiny things for all of them to be empirically verified. This is the crux of your critique and inasmuch you present a straw argument of Dr. Ingham’s position and the work which she has accomplished. Absolute knowledge is oxymoron, and yet with imperfect knowledge we build skyscrapers, bridges, send men to the moon and back, replace human hearts, etc. Instead of focusing on “meta” analysis of scientific literature, I strongly recommend that you peer review the work of Dr. Ingham as it will give you a more informed basis for the analysis of her claims and accomplishments.
I am not asking for quantitative analysis. Dr, Ingham was selling the ability to teach people to do quantitative analysis. I was simply pointing out that it was at the very least misleading marketing.
Dr. Ingham’s claims about things like the importance of the ratio of bacteria to fungi and the benefits of compost tea are not accepted by main stream science.
I think it’s fairly obvious that we have a problem relaying cause and effect. One come away from Dr Ingram’s seminars thinking the microbes are the cause of good soil rather than the effect of it and geology and climate play a larder role than she ever mentions. It’s like saying the desert is a desert because nothing lives there but WHY does nothing (or not much) live there? Because the environment is hostile to most of what we want to grow. Adding microbes will not help and it’s obvious. But it’s not obvious to housewives that adding microbes to your garden might not help anything but changing the climate and soil structure and fertility will and the increased biomass will be the signs of it and the above ground plants are a part of that biomass. We just have quit taking from the soil without returning what it needs to maintain the system. This is the model of Joel Salatin at Polyface Farms and he never talks about needing a microscope to asses the soil microbes.
Through deforestation, Rome helped create the deserts of North Africa. Restoring it is a long slow process, but deserts are not always deserts because nature made it that way. When we perform agriculture on land, we change it and the soil dramatically. Without plants to support the microbioms in the soil, it dies. Monoculture also stresses the soil, and our efforts to maintain a monoculture through manipulation of the soil with inorganic material, eventually leads to a killing of the soil microbioms, (the dustbowl). We’ve understood for hundreds (perhaps thousands in some cultures) of years that soil is fragile if we mistreat it. We are only now getting down to the science of understanding both plant nutrients AND how they are actually made available to plants (through the micorbioms). I believe you are giving too much credence to climate and not enough to the need for careful soil management or at least protection.
It is a very strange theory that without plants, living soil dies, and without living soil, plants die. But it is also a fact. I do not believe that microbes are merely present in the soil because it is convenient for them. They are a necessary part of nature’s plant life, and that is the core of Dr. Ingham’s research. Yes you can try to grow plants with only water, sun, and a plant available concoction of minerals in non-living dirt, but it is not a sustainable way of farming or gardening.