What’s in the soil anyway?
A lot more then you may have every imagined……..and it’s pretty exciting. Maybe you think it really isn’t a big deal and not so very important. Tell that to the Irish who experienced the Great Famine (Irish: An Gorta Mór or An Drochshaol, lit: The Bad Life). Something in the ground literally changed our history, reduced the population of Ireland by more then 25%, and resulted in a massive exodus to the US. If you think the late blight, the fungus responsible for that disaster is long gone never to be seen again…..you are wrong.
Plants and crops are essential for our well being and for our survival. They could do very well if we were not here, but we can not get along without them. Microbes and plants go together. One thing for sure ………is that plants and microbes depend one upon the other.
There’s a party going on and we’d like to get involved………..but the important party guests are the microbes and plants. They’ve been enjoying each other’s company for a very long time. Take one or the other out of the room and the party is over.
Once in awhile uninvited guests crash the party and cause a lot of problems. The “bad” microbes, like the example of the late blight fungus that caused the potato famine, get in the door……. and they then can really make a mess. And it can cause us a lot of trouble. We’ve got to figure out how to keep the “bad” guys out. We want to prevent unwelcome guests from spoiling the party. Maybe you want to grab the fumigant and give them a little blast. Resist that urge.
There is hope. We may one day come to realize that the “chemical” solution is non-sustainable. New thoughts are evolving. It is refreshing and very encouraging to note that those who really have been at the front line have come to realize that you’ve got to adopt a strategy of making it more difficult for pathogens (bad microbes) to get started.
Dr. Elaine Ingham, a soil microbiologist and founder of Soil Foodweb Inc, has nicely described the standard practices that result in sick soils and sick crops.
Soil-borne diseases result from a reduction of biodiversity of soil organisms (microbes). Restoring beneficial organisms that attack, repel, or otherwise antagonize disease-causing pathogens will render a soil disease-suppressive. Plants growing in disease-suppressive soil resist diseases much better than in soils low in biological diversity.
Traditional strategies at fighting plant disease involve the use of chemical fumigants, fungicides, and toxins targeting the pathogen after the pathogen’s effects were apparent. Or in many cases, the agents were used to suppress or prevent the pathogen’s emergence with a belief that higher crop yields or healthier plants were then assured. Chemical fertilizers, pesticides, fumigants, and fungicides are too broadly damaging. They change the environment and damage the soil. We’ve got to change our strategy if we want to enjoy the party.
We’re talking about microbes today. The gases in our atmosphere, the microbes, and the plants are all interdependent in some very interesting and surprising ways. And we need to understand how changes in one have effects on the other. The soil microbes are so important.
The simple definition of a microbe (short for micro-organism) is any living thing that spends its life generally in a form so small that it is only visible under a microscope. As it turns out, the number of organisms that meet that definition is very large. The organisms may be further classified into groups called bacteria, or fungi, etc. We don’t need to get overly technical in classifying the organisms for our purpose of understanding how they are so relevant and important. They are exceedingly numerous and quite diverse. They represent most of the life forms populating the planet.
Some microbes are pathogenic………that is to say they may be responsible for causing certain diseases. There are human, animal, and plant pathogens. But most microbes are non-pathogenic and they are literally found everywhere. A teaspoon of soil may easily be populated with nearly 1 billion living microbes and a cup of soil contains many more microbes in number then humans inhabiting the planet. A teaspoon of healthy soil will easily contain 10,000 or more bacterial species (types of organisms), 5,000 types of fungi, and 10,000 types of protozoa (organisms capable of moving about in the soil).
Most of the microbes in the world do a lot of good………..and you don’t want to destroy them because they assist plants promoting growth, digest and remove “dead” things eliminating nutrient material that could have supported the growth of pathogenic microbes, and in the process frequently produce valuable substances like antibiotics and vitamins that humans have been able to use effectively in treating diseases and staying healthy.
Different Microbes…..produce different gases:
Most of the microbes on the planet are very specialized. They may also be very sensitive to the local environment multiplying rapidly and thriving when conditions are just right and perishing when the conditions are ever so slightly changed. Bacteria are able to multiply very rapidly when there is a sufficient food source to feed upon and under ideal conditions can easily double their populations every 20 minutes.
The evolutionary pressures have resulted in these niches where one species survives whilst the other perishes. One of the important conditional factors that will impact which microbes survive has to do with the level of oxygen available. We’ve already talked about the process of composting when the conditions are anaerobic (low or no oxygen present) or aerobic (oxygen present).
We know either condition is bad if this is done by composting because gases are produced that escape into the atmosphere resulting in the heating up of the planet.
Advocates of composting like to think it is “green” to compost, but a careful analysis shows clearly it is unhealthy for the planet. Composting is a non-sustainable way of dealing with organic waste. Under anaerobic conditions we find a lot of methane, nitrous oxide, hydrogen, and ammonia gases are formed polluting the planet. That is why we’ve got to get that waste out of the landfills. Compost that is too wet decomposes anaerobically.
Aerobic composting, the preferred method done industrially diminishes the amount of methane and other noxious gases escaping into the atmosphere in exchange for a lot of oxidized carbon in the form of carbon dioxide, water vapor, and heat being put into the atmosphere. Microbes are involved in both anaerobic and aerobic composting.
Why do microbes produce gases of one kind when oxygen levels are low and of another kind when oxygen levels are normal (higher)? It’s because a different group of microbes are involved when the conditions of composting are altered.
We’ve talked about oxygen and its effect on microbes and already in an earlier discussion about carbon to nitrogen ratios and how they need to be correct to support microbial growth.
When the ratio of carbon to nitrogen is changed, the microbes change too. And we noted that microbes can not do their thing if the water content is off. The humidity must be controlled to get efficient oxidation under aerobic conditions. All of these seemingly small changes account for much of the wide variations in the compost end product.
So why don’t we anaerobically digest waste material that can then be converted to natural gas (methane)? We could use that gas to burn off and make electricity or run cars…right? That is exactly what many city planners and municipalities are planning to do. This is not a good idea.
The planners know that the material can be processed to produce gas that can be used as a fuel to make electricity. This process has been studied and advocated by many who believe it will convert waste to power. You can read about it and see how they plan to make the conversion (Biogas production using anaerobic digestion).
It has long been recognized that anaerobic fermentation at near neutral pH (where the acidity of sludge is neutral like the water in your faucet) is fast and more efficient then composting. But it is not simple because the system requires a lot of attention to keep the conditions just right so that the proper microbes that produce methane are supported.
They can do it and fully intend to have you pay for it to be done. This is a Landfill gas plan to generate an alternate source of energy. The microbes involved in this process produce other gases too. And these other toxins mixed in with the methane that can not be easily separated from the methane give off noxious toxins when they are burned polluting our air and planet. Because the waste feeding microbes is varied and inconsistent, the end product varies too.
Mike Ewall’s analysis is well worth a read. “Landfill gas” is not the same thing as “natural gas” or “methane.” They are three separate terms which mean different things. They should not be used interchangeably. The term “landfill methane” is deceiving as it’s usually used to imply that landfill gas is simply methane.
Bokashicycle Fermentation…produces virtually no gases
We’ve been talking about microbes, and how they are selected out by the conditions in the process. How can it be that anaerobic fermentation of organic waste with bokashi culture mix results in no measurable gases? We know already that anaerobic fermentation of organic waste in a landfill or in a biogas digester results in methane and other noxious gases being produced.
There are two factors that make it different. First, unlike the landfill or bio-digester where microbes are allowed to dominate the process by the conditions of fermentation, in bokashicycle fermentation a specific set of microbes is added to the organic waste. These pre-formed cultures rapidly take over the degrading process because they are dominant in numbers from the beginning of the process. It would be unlikely they could dominate the organic waste had they not been added early in the fermentation process.
The second factor has to do with the acidity. It turns out that few microbes can survive when the acidity is high. In bokashicycle fermentation the lactobacilli microbes produce acid as they work sustaining a relatively acidic environment that will inhibit competitors that might produce gases. The mix of microbes in the bokashicycle culture work symbiotically to break down proteins, plant cells, and other materials commonly found in organic waste.
Carbon is retained in its non-oxidized state as are the nitrogen products of fermentation and when these products are then placed in the ground, the soil microbes take over.
In our next blog, we will discuss in more detail how the soil microbes intimately convert the fermented products to nutrients plants can rapidly absorb.