Acalanes High school students hosted this chat with Steve Andrews,
Ph.D, the coordinator of the Environmental Sciences teaching program
at UC Berkeley. The focus of the chat was worldwide soil erosion, its
effect on agricultural prduction and possible solutions.
| Star: |
Are there any environmental
group people here? |
| Star: |
is there anyone here? |
| Harry: |
welcome sheshe |
| sheshe: |
Welcome yourself |
| Harry: |
something in |
| Harry: |
something aagain |
| Harry: |
again |
| Harry: |
dang |
| sheshe: |
o.k. |
| sheshe: |
o.k. |
| Harry: |
now? |
| Steve Andrews: |
Greetings All, |
| shio: |
Hello |
| Steve Andrews: |
The "Dirt Dude" is in on
cybersoil waiting to dig in with your thoughful questions on the
good earth. |
| Steve Andrews: |
So, let's dig in... Here's
a question for you. What is soil? Is it biotic? Abiotic? Is it an
ecosystem? What makes soil -- "soil"? |
| shio: |
Hmm, i thought we were
the ones with the questions, and you provide the answers |
| Steve Andrews: |
In the world of science,
questions work both ways -- asked and received. |
| Katherine: |
well our class came up
with some questions |
| shio: |
well, Katherine has a list
of questions our class wanted to know |
| Jeff: |
as do i |
| Katherine: |
ok jeff you can go first |
| Jeff: |
but i plan on more asking
whatever questions i feel are relevant at the time, and i'm eating
dinner |
| Jeff: |
but i'll start it off |
| Steve Andrews: |
Okay. Let's have the dirt... |
| Jeff: |
ok, something basic that
we probably know, but just to get things rolling: what kind of things
make up soil and which are most important? |
| Heather
Jackson: |
hi |
| Jeff: |
welcome |
| Heather
Jackson: |
who is the expert? |
| Katherine: |
steve is answering right
now |
| Heather
Jackson: |
ok |
| Steve Andrews: |
Technically speaking -
soil is comprised of three particles, known as soil separates. These
are sand, silt, and clay. Sand ranges in size from 2mm down to 0.05
mm, silt 0.05mm to 0.002mm and clay particles are smalled than 0.002mm. |
| Jeff: |
and ideally, you want a
mix, right? (for crop growing that is...) |
| Heather
Jackson: |
Does soil expand and contract?
My house always moves in the winter and the summer so doors don't
open correctly. |
| Katherine: |
ok guys.. let's make sure
we do one question at a time or it gets confusing |
| Jeff: |
i agree with that |
| Annie: |
good call |
| Heather
Jackson: |
sorry |
| Katherine: |
no prob :) |
| Katherine: |
is steve answering?? |
| Jeff: |
... |
| Steve Andrews: |
Yes. Most soils are comprised
of sand, silt and clay particles as well as organic matter. The
ideal agricultural soils fall into the textural class known as "loam".
Loam is the perfect "mix" of salt, silt and clay for agriculture. |
| Heather
Jackson: |
So, does soil expand and
contract? |
| Steve Andrews: |
Clays particles are responsible
for soil expansion and contraction. Specifically 2:1 clays which
shrink and swell. California has many such soils. |
| Katherine: |
k heres one.. |
| Katherine: |
can we succesfully grow
plants without soil? how? |
| Steve Andrews: |
Yes. Plants can be grown
hydroponically -- without the use of soil. This practice, however,
would not be sustainable. |
| Annie: |
What does soil in the Bay
Area seem to be lacking? Are there any trends that we can correct? |
| Katherine: |
wait what is hydroponically? |
| Katherine: |
I mean how does it work? |
| Jeff: |
ok, slow down everyone |
| Katherine: |
sorry but I never got my
question answered fully |
| Steve Andrews: |
Bay Area don't "lack" anything.
They followed a process that included evolutionary changes in vegetation,
animal life, and climate. The major issue in the Bay Area is human
development and the movement of soils by humans. |
| Annie: |
thanks |
| Jeff: |
so which type of soils
(those with what primary "ingredient") are the worst when it comes
to erosion? |
| Steve Andrews: |
Hydroponics is the process
by which plants are grown without soil -- using water and nutrient
solutions. |
| Heather
Jackson: |
What is your job, I mean
what do you do every day? |
| Steve Andrews: |
All soils erode over time.
There is not simple answer to erosion. It is a complex process involving
chemical and physical transformations brought about by wind and
water. To make life simple for my cybersoil scientists, let's say
that all BARE soil is subject to erosion. |
| sheshe: |
Do you know what is happening
in Russia with I think it is the Ural Sea |
| Steve Andrews: |
I am a soil scientist by
professional training and education. I specialize in a "hydric soils"
-- wetland soils. My research specialty is MUCK and the oxidation-reduction
reactions that occur in MUCK. I'm very interested in biogeochemistry
-- global nutrient cycling. |
| Heather
Jackson: |
wicked |
| Steve Andrews: |
The Ural Sea has been experiencing
a problem that's very similar to Lake Tahoe. The turbidity of the
sea has increased - probably due to N/P upset. |
| Katherine: |
which countries have the
best soil? why is that? |
| Jeff: |
caused by? |
| sheshe: |
What's N/P upset? |
| Jeff: |
nitrogen/phosphorous(i
think) nutrient upset i assume... |
| Heather
Jackson: |
Is there hope for the earth? |
| Steve Andrews: |
There is so such thing
as a best soil. The soil that forms in a given place around the
world is the "Best" for the climate, vegetation, topography, and
parent material of the area. |
| Steve Andrews: |
N/P is Nitrogen/Phosphorous. |
| Steve Andrews: |
Here's a soils factoid
for you. The BEST soil collections can be found in Russia and the
Netherlands. |
| sheshe: |
So if the ural Sea and
Lake Tahoe have N/P upset, what causes it and what can be done about
it? |
| Steve Andrews: |
To see a collection of
California soils from the Sierra to the Sea visit Hoagland Hall
on the UC Davis campus. There's a great transect of soils in front
of the building. |
| Heather
Jackson: |
Is there hope to be saved
from mass starvation and death that is bound to come upon us due
to soil erosion? |
| Jeff: |
ah...silence |
| Katherine: |
whoa that was a weird question |
| rupert: |
way to end with a bomb
there heather |
| Jeff: |
ok, i have a question |
| Annie: |
thats a question |
| Jeff: |
so in the general bay area,
if you were to do a restoration at, say, a creek, where erosion
was heavy, which plants would be best to prevent it, and what makes
them best? |
| Steve Andrews: |
The N/P problem at Ural
and Tahoe are related to human activities. Humans are burning fossil
fuels which produce nitrogen compounds that can be carried for 100s
- 1000s of miles. These compounds, react with P to create algae/aquatic
pplant blooms that increase the rate of eutrophication in lakes. |
| Steve Andrews: |
To turn back the effects
of N/P we need to reduce fossil fuel consumption. Stop buying SUVs! |
| Jeff: |
leading to the increased
bacT and subsequent loss of oxygen in the water, correct? |
| Steve Andrews: |
Regarding restoration and
erosion. Plants are excellent for curbing the effects of erosion.
Native plants - plants that have evolved with the soil of a given
area would work best. |
| shio: |
what are the native plants
to the bay area |
| Steve Andrews: |
Jeff is correct. |
| Jeff: |
so..give me an example
for east bay |
| Jeff: |
are we talking trees, shrubs,
grasses, what? |
| Steve Andrews: |
There are 100s of plants
known to be native to the Bay Area. Some are not extinct, others
threatered or of special concern. At the Dow site, where some of
youo may have been on Saturday we plant Elderberry, California Native
Rosa, Black Walnut, Yellow Willow, Red willow, Coyote bush... |
| Heather: |
Do you know which plants
are best to stop erosion in this area? LAMORINDA? |
| Jeff: |
i think he's addressing
that Heather. |
| rupert: |
come on now |
| Steve Andrews: |
Heather. Check with the
local Resource Conservtion District. |
| Katherine: |
ok I have a question |
| Heather: |
Thanks |
| Jeff: |
ok, now i'm on twice... |
| Jeff Martin: |
that's better |
| Katherine: |
how can we as individuals
prevent erosion? |
| shio: |
or on an larger view, how
can we have a lesser negative impact on our environment |
| Steve Andrews: |
Katherine. Good question.
First, focus on planting native species for landscaping. Use California
bunch grasses instead of Bermuda grass for example. |
| Heather: |
What are the best soils
to use in building sites? |
| Steve Andrews: |
Second. Be sure to cover
bare soil areas quickly. Rain drop splash is responsible for most
erosion caused by water. |
| Jeff Martin: |
how do you cover it? |
| Steve Andrews: |
Building sites with sandy
soils work best. Sand compacts easily, drains easily, and doesn't
shrink or swell.. Clay and organic soils should be avoided. Just
ask the people that live in Discovery Bay. |
| sheshe: |
You must really love to
be out of doors working in your field. What inspired you? |
| Steve Andrews: |
Soil is covered using a
cover crop. Also known as green manure - because it can be tilled
into the soil to improve N. The best cover crops are native grasse. |
| Jeff Martin: |
huh. interesting |
| Katherine: |
that was on our test..
green manure |
| Steve Andrews: |
My start in science came
early. I grew up in rural Massachusetts around cranberry bogs, swamps,
and ponds. The swamp was my playground then, and it still is today. |
| Heather: |
This is probibly out of
your field but :Do you know anything about soils on other planets,
have we learned anything from space exploration about soils? |
| Steve Andrews: |
I was also fortunate to
have teachers that inspired me. |
| Jeff Martin: |
sounds fun. so tell us
a bit about bogs |
| Steve Andrews: |
Bogs are wetlands created
during the last glacial period. Large blocks of ice were trapped
in moraine and slowly melted to form peat rich marshy environments
known as bogs. I love them because they have a unique plant community
-- Carnivoriouos plants like honey dews and pitcher plants -- these
require insects for essential nutrients |
| Jeff Martin: |
so how did those plants
evolve so they could survive without the essential nutrients? |
| Katherine: |
well they still need the
insects.. |
| Steve Andrews: |
Soils from outer space...
Think about it. What is SOIL? What needs to be present to have soil.
PLANTS! Without plants and the interaction of plants you don't have
a soil-- you have a sediment deposit. Beaches are sediment. Lake
bottoms are sediment. Fine textured materials on the moon, Mars
and elsewhere are sediments (until they find plants growing in them). |
| Steve Andrews: |
Soils from outer space...
Think about it. What is SOIL? What needs to be present to have soil.
PLANTS! Without plants and the interaction of plants you don't have
a soil-- you have a sediment deposit. Beaches are sediment. Lake
bottoms are sediment. Fine textured materials on the moon, Mars
and elsewhere are sediments (until they find plants growing in them). |
| Heather: |
They might be out there.................. |
| Katherine: |
how much does the CA coastline
erode each year on average?? |
| Steve Andrews: |
Bogs are oligotrophic --
they are nutrient sinks, slow processing environments, often acidic,
with a retarded decomposition process. As such, plants cannot obtain
all the essential nutrients they need from the soil -- so they evolved
to use unsuspecting insects as a nutrient source. They insects attracted
into the plant, fall into a trap, drown, and are slowly digested
by plant enzymes which provide the plant with nutrients. |
| Steve Andrews: |
Bogs are oligotrophic --
they are nutrient sinks, slow processing environments, often acidic,
with a retarded decomposition process. As such, plants cannot obtain
all the essential nutrients they need from the soil -- so they evolved
to use unsuspecting insects as a nutrient source. They insects attracted
into the plant, fall into a trap, drown, and are slowly digested
by plant enzymes which provide the plant with nutrients. |
| Jeff Martin: |
but does anything similar
exists for depleted soils elsewhere? |
| Steve Andrews: |
Erosion of the CA coast
is constant. The rate varies depending on annual weather. In somes
places it's inches per year, in others it's feet per year. |
| Heather: |
Right now what country
is in the most danger due toerosion? |
| Heather: |
to erosion |
| Steve Andrews: |
Jeff, yes, there are unique
plant communites elsewhere - like the tropical rainforest. Many
rainforest plants grow without soil -- pulling moisture and nutrients
from the forest microclimate. |
| Jeff Martin: |
huh. so why the big difficulty
with soil depletion from crops? or is that mostly just bad organization? |
| Steve Andrews: |
Erosion is a HUGE problem
worldwide. We are lossing soils globally at a tremendous rate --
inches per year. It takes anywhere from 1,000 to 10,000 years to
replace an inch of topsoil. |
| Heather: |
Are you called up to do
restoration work? |
| Heather: |
Who funds your work? |
| shio: |
what important organizations
are there that deal with this issue, globally |
| Steve Andrews: |
Repeated use of soil for
agriculture degrades the soil by reducing the soil's structure.
Plowing upon plowing turns good soil to dust. Remeber the DUST BOWL
of the 1930s? |
| Jeff Martin: |
yes |
| Steve Andrews: |
Heather. Yes, I do restoration
work. I'm generally hired as a consultant to do this. |
| Heather: |
I have a friend who works
for the government to consult on clean up and restoration before
they sell government owend land. What did you major in in college?
After college how did you startdoing what you do? |
| Heather: |
start doing |
| Steve Andrews: |
Here's an opportunity for
you. If you;re interested in soils and watershed issues you might
want to register for my summer sessions course at UC Berkeley this
summer. It will be offered during session 1 -- May 28 thru July
3 for 2 UC credits. The title of the course is Environmental Earth
Science. I often take qualified high school students who have completed
their sophomore year. |
| shio: |
i know this is not directly
related to soil, but as someone interested in the politics and making
sure the concern for the environment and a policy for protection,
politically, what what organizations seem to take an active and
balanced stance |
| shio: |
as in, i was reading in
the newspaper about the Hearst estate and conservation of CA coast
land |
| Steve Andrews: |
I major in natural resources
studies as an undergraduate. As a graduate student I specialized
in soil science and then wetlands - hydric soils. I got into teaching
and research while in college. I taught several undergraduate courses
as a graduate student. Students liked my classes, so I was hired
to keep teaching. |
| Steve Andrews: |
In my view, all organizations
have an agenda and a stance. Their is no such thing as a politically
"neutral" organization. All organizations exist to make a point,
push an agenda, stake out a claim. |
| Heather: |
What country or part of
our country has the most interesting soil in your mind?Why? and
what is it? |
| Steve Andrews: |
New England has the most
interesting soils in the US. They are called Spodisols. They are
very colorful. |
| shio: |
well, of course no organization
can acheive neutrality and objectivity, but what organizations do
you seem to really agree with |
| shio: |
and what organizations
seem like a joke |
| Steve Andrews: |
I believe in the strength
of my own thinking. I don't endorse or align myself with any particular
organization -- except perhaps for the University of California. |
| Heather: |
Is UC Berkley one of the
best places to study soil at? |
| Heather: |
ALSO GO Bears |
| Steve Andrews: |
Berkeley has a very solid
soils program -- at the graduate level. |
| Heather: |
Thankyou for chatting with
us. |
| sheshe: |
Thanks so much. Very impressed! |
| Steve Andrews: |
If you want to study soils
-- select a LAND GRANT college. |
| Jeff Martin: |
yep, thanks a lot Steve.
I'm out |
| Steve Andrews: |
Thanks! |
| $playa$: |
hello |
| $playa$: |
rktnoibs;etrghbnoids;zirhbvznofdj;o |
|
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