(Green Ajah) Nature Week 2016: Earth - Dirty Facts: Soil and Society

[WildTaltos]

 

Dirty Facts: Soil and Society

 

This is an open discussion concerning what role soil plays in human society and culture. Open means that anyone can essentially post anything that comes to mind regarding this issue - from stories of mudslides that you found interesting or anything you recently read regarding soil or the creatures living in it, or just something in pop culture that had to do with soil/subterranean environments (any subterranean monster films in the recent past?). The main thing is to just exercise your intellectual curiosity and share with others whatever you wish to share. 

 

However, I will be periodically posting facts and theory about soil and its relationship to society in case anyone finds it interesting and hopefully learns something from it or wishes to discuss it. Again, do not let that dissuade you from posting something that does not have to do directly with the information posted - feel free to discuss whatever you want on the matter of soil, the ecology or the culture.

 

So to begin with...

 

#1: What is Soil?

 

It might seem like a silly question, but very few fully appreciate exactly what soil is. As a most basic definition, soil is a mixture of inorganic matter (such as sediments/pulverized rock and water) as well as organic matter, which ranges from microscopic insects, bacteria, fungus, and dead and decaying plants and animals. Many people tend to think of soil as something inorganic (just the sediment) but to do so essentially dismisses half or more of its definition, the living aspect without which soil would not exist. All other lifeforms on earth wouldn't exist without the organic aspect of soil - that is certainly not and understatement, and I hope the following posts I make give some idea as to why. 

 

To paint a picture of it, soil is essentially an extremely complex maze, the passages of which are made of a mixture not just of inorganic rocks/sand/clay but also of living roots and/or decayed organisms. That maze is maintained by tiny beings that live in the microscopic passages, maintaining the crucial aspect of healthy soil which is porosity. The pores in the soil allow water to pass through and allow other nutrients (like nitrogen) to pass into and out of the soil, making it amenable to plant life.  Here are some pictures I took of some of what I extracted from some soil samples over the summer:

 

 

Both of these come from leaf litter/top soil that probably all together is only the size of your fist, but in those samples, I found literally hundreds of insects. To get an idea of the size, those little brown dots you see all over both pictures are actually mites/ticks - you would almost not be able to see them with the naked eye, they would pretty much just look like a a speck of dirt that is literally smaller than the width of a pin. Any time you pick up a handful of dirt, you are probably picking up hundreds if not thousands of them without even knowing it!

 

A question to consider if you wish to answer:

 

How do you typically think of soil?

 

Did this information change the way you view it?

[LilyElizabeth]

How do you typically think of soil?

When I think of soil, two things come to mind - growing plants and the element of Earth. The Earth element represents stability and grounding to me. 

 

Did this information change the way you view it?

It definitely gave me a new way to see soil. I had no idea that THAT many things lived in soil. I always bought soil to grow plants in (in pots) but I suspect that is much more sterile and doesn't have bugs in it. 

[Ryrin]

When I think of soil, I think of growing things. When I lived in Monterey County in California, the rich soil is amazing. Lettuce is grown there, peppers, broccoli, strawberries, garlic, carrots, asparagus, artichokes and other things. To me, it's amazing that you can put a seed in the soil, and then come up with these things. I know that in my religious scriptures, the fields are to be left alone every 7th year. My book club read about farmers in the U.S. in the 30's, growing the same crops over and over, and stripping the soil of it's nutrients.

 

As far as things living in the soil, I had really only thought of worms in regards to fishing.

[WildTaltos]

In depends on what kind of potting "soil" you buy. From what I know, some of it isn't any definition of soil at all as it is made from synthesised compounds on top of lacking the biological component, while others get potting soil that is highly infested by pest insects and fungus (I have seen people specifically implicating "Miracle-gro" brands). 

 

It's always interesting to hear about the socio-cultural views others have about soil. Soil supports all terrestrial life, so definitely it plays the greatest role in stabilising an ecosystem. In my religion, one could divide the gods into gods of the land, the water, and the sky, with the ones of the land and water having the greatest relevance as it directly reflects the aspects of an ecosystem that has the greatest variability (air and climate under normal circumstances doesn't change much/takes a long time to change) and therefore often the limiting factor in determining what an area can support. Which will lead directly into another fact about soil...

 

(Which I will post in awhile, just got done writing two papers, need to sleep, sorry!)

[WildTaltos]

Here is the next little installment. As mentioned before, soil and water are often the limiting factor when it comes to determining what else can grow or live on an area of land, which brings us to one of the major functions of soil...

 

#2: Soil is responsible for biomass production

 

This essentially means the quality of a soil determines how many plants and animals (which together constitutes a biological mass - biomass) can live on it. Many are well aware that plants grow in soil - but surprisingly and increasingly, fewer are aware of how that ties into the wider food or trophic (essentially energy transferrance) web of life, more commonly known known as the "food chain." [someone I know who is a teaching assistant has quite a few horror stories about college students coming in who do not even realize they are eating plants or animals].

 

Microbes, fungi, and small animals living within the soil are responsible for breaking down dead plants and animals in a very complex web of chemical interactions. It basically boils down to, because all life is composed of proteins (which incorporate nitrogen) and carbon compounds (such as sugars and fats), these creatures can break down dead animals and plants into carbon and nitrogen compounds (such as CO2 and ammonia (NH3)) that can be used by plants to grow or else are further broken down and can be released into the atmosphere. These processes, part of the terrestrial Carbon and Nitrogen Cycles, are ancient and without which, terrestrial plants as we know them today wouldn't exist. Animals then of course feed on plants or plant products, and then higher predators feed on these, such that it is evident that, if one was to strip the soil of its properties that allow plant growth, everything higher up on the food web would die. Below is an example of a typical model of a food web for a particular ecosystem. Plants (and by proxy soil) typically form the base of such a food web.

 

 

Even an alteration to just one of the soils properties can cause drastic change to a food web. If a soil becomes too acidic or alkaline, only plants that are tolerant to those conditions will be able to grow in that soil and only animals that can eat those particular plants will be able to thrive there. If a soil becomes oversaturated with water because of poor drainage over an extended period of time, dead plant matter will take a much longer time to decay and so it may pile up into metres worth of the material known as peat. Soil that is frozen solid the entire year around can't support any major plant life and hence you will not find many terrestrial animal species in such places, while likewise, a place that has lost much of its top soil and is essentially just bedrock cannot support anything but the most primitive of plants. To summarize, the "poorer" the quality of a soil, the lower amount of biomass it may support (there are always exceptions, but this is the general trend).

 

 

A peat bog and the "Clonycavan man," an Irish bog body of a man who died between 400-200 BCE (extracted from a peat bog). The same slow decay that forms peat allows remarkable preservation of human and animal bodies. The man used pine resin in his hair as a form of hair stylant.

 

Modern human society is likewise wholly dependent upon soil quality. Societies have collapsed based solely on the depletion of suitable soil and water for practicing agriculture. We depend upon soil for almost all of our food, either through produce and grain or by supplying livestock with said produce (the only exception is marine life). A question relevant to the concept of sustainability is how we might devise an agriculture system that will not heavily degrade the soil and negatively impact the rest of the environment, as at present, all conventional agricultural systems in use result in substantial losses to top soil every year and/or degrading the nutritive value by disrupting the native ecosystems in place in the soil, on top of polluting our bodies of water and the air. Just like a species of animal, once the soil in an area is lost, either due to development, erosion, or pollution, it cannot be replaced or restored, as soils are a unique blend of weathering bedrock and the colonization and then concurrent evolution of soil fauna which took thousands of years to produce and which cannot be replicated.

 

Production of biomass is not the only function of the soil - it is also crucial to supplying us with drinkable water and breathable air, which will be discussed next time.

 

Some questions to consider...

 

How do you typically envision the food web (or "food chain")?

 

Does this information make you regard your food any differently?