PDS APES 8th Period 2009-10

*This is a guest post by EmilyO in the other class.  Not sure everyone was there due to APs and not sure those that were there were very focused, so maybe this will be of use…

On Wednesday we reviewed some of the qualities of soil. To do this, we looked at a soil profile, and we also made our own edible version.

A soil profile is a view of the different layers of soil from the side, so it’s easy to separate each one. These layers are also called horizons, and there are four main ones that our text mentions- O, A, B, and C. Page 49 of our text has a good description as well. http://soils.usda.gov/education/resources/lessons/profile/profile.jpg

A soil profile that contains the basic horizons.

Each of the horizons have distinct qualities that separate them from the others:

• O- This is made up of the seasoned, dead organic matter known as “leaf litter.” It contains detritivores, and other small insects. The material we collected during the Davidson field trip was the O layer.
• A- This is the topsoil. Combined with the O and E, which isn’t necessary to know, layers it makes up the zone of leaching. Humus is also found in this horizon. Humus is the nutrient-rich soil that is dark brown in color.
• B- This is the subsoil and the zone of accumulation.
• C- This is the parent material, which is made up of weathered, larger rocks. The R horizon lies below the C and is known as bedrock, but it isn’t necessary to know this layer either.

We then went on to make our own ice cream version. First we added cookies, which were the R layer, next was the ice cream, which was the C layer. On top of that we put whipped cream as the B layer and pudding represented the A layer. The O layer was a combination of nuts, chocolate chips, and other toppings. This helped us to visualize what makes up each of the horizons.

We also reviewed a soil triangle; it might be nice to make sure you know how to read one- clay is read on the horizontal, and silt and sand are read on the diagonal.

A soil triangle, notice how each one is read on different angles.

http://www.oneplan.org/Images/soilMst/SoilTriangle.gif

A review over the qualities of sand, silt, and clay:

Sand- It is the largest of the three and is very permeable, so it doesn’t retain water well. This results in lots of leaching, which causes nutrients to be lost because they are “leached” downwards through the horizons. This causes sand to have poor nutrient retention. On the other hand, it has very good water infiltration (absorption), but poor aeration.

Silt- It is the second largest and retains water and nutrients fairly well. Its aeration and ability to absorb water are fair too.

Clay- It is the smallest of the three, and retains water and nutrients well. However, it has poor water absorption and aeration.

A combination of the three soils makes the “best” type of soil, which is known as loam. Loam exhibits the best qualities of all three particles, which is why it’s so good. That was about it, so I hope this helps anyone who needed a review of soil!

If you enjoyed “The Meatrix,” then you might like this parody too…

Yall can judge  if you want that I was looking at an aquarium website while I should be studying for my test but I found this recent news about finding in the Great Barrier Reef and it is related to what we have talked about.  They talk about how the reserves on the reef allow the bigger fish to survive and escape commercial fishing to create more offspring, making the reef more dense in fish populations.  It even talks about how these reserves can allow “spill over” into fished areas.  It also talks about some side effects associated with removing key aspects of the oceans predator prey relationships through either bycatch or targeting carnivorous species.  I thought it was interesting and worth sharing.

http://reefbuilders.com/2010/02/22/great-barrier-reef-marine-reserves-aiding-reefs-health/#more-15606

My question isn’t one that has a definite concrete answer, but I was wonder if anyone knew why the government subsidies “high-input” industrial agriculture when our book claims that “low-input” polyculture can be done organically, with minimal pesticides, and without significant reduction in crop yields? Maybe its just the books liberal bias, but if the later were just as good, then why don’t we do it? It certainly would be more economically and environmentally sustainable.

Hey guys. My lab group for the Soil pH lab got some weird data, so I had trouble with the lab’s analysis questions. Could some one help me out and give their findings about how pH affects nutrient levels? Thanks.

Hey, I just need a bit of clarification. In class we discussed techniques that could be used to preserve macronutrients in the soil. We talked about planting legumes every other year and planting a cover crop, like clovers, to help replenish the soil. But I don’t understand how these would aid in soil conservation. Wouldn’t they still diminish the soil of important nutrients? Also, wouldn’t this constant tilling of land lead to more waterlogging and erosion? I just need to understand how alternating crops would actually help the soil.

Thanks.

This may be a stupid question but i was confused on the difference between artificial selection and GMO.  I understand that GMos are genetically modified but when people artificially select for a certain gene are they almost doing the same thing? I have heard a lot of controversy over GMOs but never artificial selection and for some reason when i was reading through my book i got a little confused.  If someone could clear this up for me that would be great! thanks!

Traditional intensive agriculture is when farmers increase human and animal labor, fertilizer, and water to produce more food per area of cultivated land to the point that they have enough to sustain their families and still some for profit. Does this mean that  industrialized agriculture is just another form of traditional intensive agriculture? Or is there something different about this that makes it ‘traditional’?

Today we watched a good bit of the PBS documentary Empty Oceans, Empty Nets. Feel free to click around the movie web site if you want want to explore the issues further. What were the main points?

1. The Problem. Yes, we seem to be overfishing the oceans. In the last 4 years, numerous articles have come out predicting the collapse of most commercial fisheries by 2050. If you have 5 minutes, read this very current article cleverly titled, “Aquacalypse Now: The End of Fish.” This brief public service announcement give some reasons WHY this is happening and what we might do about it.

2. Causes. As mentioned in the PSA above, many of the “industrial” fishing methods used by large vessels or factory ships have the potential to remove fish from our oceans in massive quantities. Check out the animations at this Monterery Bay Aquarium web site of bottom-trawling, longlining, and purse-seine fishing techniques. Additionally, each of these method capture different types of bycatch (bykill). The movie we watched stated that for every pound of catch in the US fisheries, there may be five pounds of bycatch. Sometimes, it may include endangered animals like sea turtles.

US Fishing Methods

Image source: http://www.montereybayaquarium.org/cr/cr_seafoodwatch/sfw_gear.aspx

3. Solutions: We saw several solutions throughout the film.

• Since this is a commons issue (oceans fisheries), governments can regulate fisheries by setting quotas in their territorial waters. Anything involving species migrating across oceans and/or beyond those 200 miles offshore has to be addressed by international treaty, but enforcement becomes problematic.
• Governments can establish marine protected areas (MPAs), marine reserves, or marine sanctuaries in their territorial waters. Check this link for the US system of MPAs. These are safe areas for fish to hide and breed as fishing there is usually banned.
• Consumers can create more demand for fish taken from sustainable fisheries. You can download a pocket guide from this web site, or I can give you a printed pocket guide when you return. I gave them out in class for folks to keep in a wallet or pocketbook. I think there is also an app for mobile phones/ iPhones at that link!

Sustainable Seafood Guide

Image source: http://www.montereybayaquarium.org/cr/cr_seafoodwatch/download.aspx

Much of this is covered in your text, but I think it is hard to really appreciate the impact of these commercial scale fishing methods unless you SEE them. You are always welcome to borrow the DVD from me..

I told folks I’d handle scribe post duties yesterday (Thursday), so here goes.  We made lists of organic farming techniques that students viewed at green.tv in the Food for Life videos (homework).  While these videos were based on the UK’s Soil Association organic standards, they are almost the same as the USDA National Organic Program organic standards (established by the 1990 Organic Food Production Act).  For the test, you need to know the USDA definition of organic (I have a handout for you) and methods farmers must use to earn this label:

USDA Organic Label

Image source: http://www.ams.usda.gov/AMSv1.0/NOP

On the outside chance that today’s discussion was of interest and you want to know more, here’s what comes to my mind. This summer I finished The Ominvore’s Dilemma: A Natural History of Four Meals, by Michael Pollan (2006). Wow. What do you eat for dinner when you can eat anything-and how do you know it is safe? That, in a nutshell, is the omnivore’s dilemma. More importantly, Pollan tries to trace what we eat to the sources. Along the way, you discover some of the “why” we eat what we do…and the answers are sometimes quite unappetizing.

I was thrilled to move to a yard last fall that gave me the room to garden again. Our last lot was too small. Here is my 10 x 20 foot raised-bed garden at about 60 days after planting:

My Garden

My daughter helped me plant it in last April. We grew tomatoes, cucumbers, lettuce, onions, potatoes, corn, squash, carrots, and herbs (oregano, basil, rosemary, cilantro, mint)–all in this small space.  While I can’t grow all my veggies, I’m glad I can show my kids where food comes from, other than the grocery. I’ve read the average piece of produce in an American supermarket travels some 1,500 miles! It takes a tremendous amount of oil to ship out-of-season “fresh” produce to our grocery stores. So, my little garden is an attempt to save some oil in a way. People make a great deal of fuss about buying organic without realizing that large-scale organic (like Whole Foods) uses a lot of energy resources. Perhaps the MOST “environmentally-friendly” food choice one can make is to buy local.

Pollan also explores industrialized meat production (feedlots or CAFOs). I don’t want to get to far into that topic today as someone has already blogged on it in from your class. He affirms much of what was documented by Eric Schlosser in Fast Food Nation (2001). Another gripping read about the American diet–I think you guys did in 9th grade?  If the topic interests you, keep your eyes open for the documentary movie Food, Inc., which was in theaters this summer. I know Time Warner has it on DVR currently. Check out the trailer (it features Pollan and Schlosser):

So, do you know where your food comes from?