New Job!

Source: Wikipedia (c) University of Washington

Hello everyone,

As many of the followers of ColbyDigsSoil.com know, I’ve been working on my PhD in soil science at NC State for a while now. I’ll be finishing up in December, so I’ve been in the midst a thorough job search over the summer and the beginning of the fall semester. That job search is officially over now as I have accepted a position as a postdoctoral researcher in the University of Washington Civil and Environmental Engineering Department. I will be working with Dr. Rebecca “Becca” Neumann. I will be working on a project studying methane oxidation in the rhizosphere of wetland plants.

Methane is a greenhouse gas that is 20 times more effective at trapping heat in the atmosphere than CO2. Methane is produced in wetland soils. Plants can act as both a route for methane to move from the soil into the atmosphere, and as a way for oxygen to enter the soil and oxidize the methane in the rhizosphere (the zone of soil immediately surrounding roots). The objective is to put a solid number on the percentage of methane that’s oxidized in the rhizosphere in order to refine climate change models. We also want to predict how that number changes with different plant communities, and how those communities might change as the climate warms. The field site is about 40 minutes west of Fairbanks, Alaska. The field site has two types of wetlands – a bog and a fen. It is called the Bonanza Creek Long Term Ecological Research Station. I’ll be in Alaska for their growing season (June-September), and in Seattle the rest of the time working on laboratory experiments. 

Source: http://faculty.washington.edu/rbneum/opportunities.html

The position is exactly the type of postdoctoral research position I was looking for in my job search, so I’m really happy I got it. My wife and I are both excited to see what the West Coast is like, and we now have an excuse to visit Alaska.

My start date is January 6, so my wife and I will be moving over the holidays. This new stage of my career will affect this blog a little bit. My first priority is to finish and defend my dissertation on time in December, so I won’t be able to add many blog posts between now and the end of the year. However, once I make the move I should have all sorts of interesting material and pictures from Alaska to post on this blog.

Thanks for stopping by,

Colby

Citizen (Soil) Science: Predicting 17 Yr Cicada Arrival

Magicicada septendecim. Photo credit: Wikipedia Commons

The 17 year cicada (genus Magicicada) will emerge on the American east coast again this year in just a few days. As nymphs (grubs) they feed on the xylem fluid of deciduous tree roots. The xylem in plants is basically the tubes through which water and nutrients flow as it moves from the roots to the trunk, branches, and leaves. After staying in their nymph stage for such a long time, the emerged after 17 years as their adult form for four to six weeks. During this time their primary goal is reproduction. The buzzing sound you hear in the air during this time is their mating call as they desperately look for a mate. This genus of cicadas is one of the only insects that to follow such a lengthy and regular schedule.

Life cycle of the cicada. Photo credit: Wikipedia Commons

NPR’s affiliate, WNYC has a citizen science page called Radiolab. Radiolab has a great post regarding how you can track the emergence of the cicada. Cicadas emerge from the soil once the soil reaches a temperature of 64°F (18°C) eight inches (20 cm) below the surface.

If you go to Radiolab’s cicada website (http://project.wnyc.org/cicadas/), they have a spot in which you can enter the current temperature of the soil in your backyard. You can either measure it using a soil temperature thermometer you can purchase at a local garden center, or you can construct your own soil temperature monitor using some supplies available for purchase from your local Radioshack. Radiolab’s page says the parts all together cost about $80 total, and can be constructed in about 2 hours. Soil thermometers can be bought for around $10 to $20 at a garden supply store, but aren’t quit as fun as hacking your own soil thermometer.

Radiolab’s Soil Temperature Monitor

I thought this was a really fun and interesting citizen science project, mainly because it helps people get experience in soil physics, soil biology, entomology, and even engineering in a fun and exciting way. Let me know if you participate in this project by posting in the comments on this blog post page. If you take a picture of your project, send it to me and I’ll add it to the end of this post.

SWCS: Time Well Spent

SWCSnewlogoRGB_2829BDA961538Tonight the Soil and Water Conservation Society at NCSU (the NCSU student chapter of the SWCS) held our 2013 officer elections. For the first time since 2006 (seven years) I am not an officer or board member of the SWCS, or any affiliated chapters, whatsoever. I’ve really enjoyed my time as a leader in this society, but it’s finally time to step back, let others have a chance to lead, and focus on the next step in my own career.

The SWCS is an international professional society focused on the science of soil and water conservation. It’s mission is “to foster the science and art of natural resource conservation.” As a sophomore at Iowa State University, I attended my very first meeting of the Soil and Water Conservation Club (the ISU student chapter), and was immediately elected as the secretary of our chapter. I later became the chapter president, then the student representative to the Iowa Chapter of the SWCS. In 2008 I was elected as the student director of the SWCS, and served on the board of the directors for the society. Once my second 1-year term came to an end, I turned my attention to founding a student chapter at North Carolina State University. We were chartered in 2010, at which time I was elected as the founding chapter president. After that I became the treasurer in 2011, and the secretary-treasurer in 2012 (we merged the secretary and treasurer officer positions). Tonight, as I said, we held our 2013 elections, and I will finally be handing the ropes to the next generation of SWCS leaders.

I’ve had an incredible time in all of these officer positions, and it’s helped me build my network, learn new skills, and especially develop my leadership abilities. I’ve performed community outreach through teaching people of all ages about soil science and water quality. I’ve also had the chance to travel to many of our society regional and annual meetings, visiting places like Tucson, AZ; St. Louis, MO, Detroit, MI, Okalahoma City, OK, and of course Ankeny, Iowa (where the SWCS is headquartered). Of all of these experiences, I value the friendships I’ve made through the society the most.

I plan to stay involved with the society in the future, likely as an adviser role to a student chapter (if I get a job in academia), as well as a role more focused on the science end of the society – publishing and reviewing papers for the Journal of Soil and Water Conservation (that is, if they request that of me).

Here’s a couple of pictures from my SWCS adventures:

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Me teaching a little girl about hydrology, and water quality at ISU’s VEISHEA
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Me with a Saguaro cacti during the Tucson, AZ SWCS annual meetings in 2009.
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Me and my buddy Jerry Pearce at a Cardinals game during the 2010 SWCS annual meeting in St. Louis.
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Some SWCS at NCSU members during our first ever rain barrel builds (we build and sell rain barrels for a fundraiser).
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Me teaching FFA students about hydrology and water quality using the Iowa State Soil and Water Conservation Club’s groundwater flow model.

Test Time!

Hey everyone. I am in the middle of taking my PhD preliminary exams so I won’t be able to write a blog post until the end of January. I plans for my next couple of posts include a post on the Aridisol soil order (desert soils), the water cycle within soils and plants (how transpiration works), and more. I’m still somewhat plugged in on Twitter over lunch breaks and such. Stay tuned via the Twitter feed on the right side of this website. Stay tuned!

Nature Geosciences: Rare Earth Scientists

I came across an interesting article recently in Nature Geoscience called “Rare Earth Scientists” that discussed how there is a large demand for scientists in the earth science fields, yet the availability of scientists is falling short. Here are some interesting parts of the article:

As a result of these emerging job opportunities for geoscientists, the US Bureau of Labor Statistics predicts that employment of geoscientists in the US will grow disproportionately, by 21% between 2010 and 2020.

And this one:

Compared with other science subjects — physics, chemistry and biology — there are only a small number of Earth-science graduates. Registrations for undergraduate courses at US institutions are on the rise (http://www.agiweb.org/workforce/reports.html), but the job market globally is expanding even faster.

It then discusses how geoscientist need to speak with teachers and students to encourage them to enter the profession. I think being a “geoscientist”, or a soil scientists specifically, gives me the perfect opportunity to do computer and lab work, but add a healthy balance of field work. It’s not just doing the same repetitive things over and over like engineering, or other lab-only science professions.

Happy World Soil Day!

Webster Soil Series. Photo Courtesy of Iowa State University.

Webster Soil Series. Photo courtesy of the Iowa State University Extension and OutreachHappy World Soil Day everyone! I’ll be honest, I kind of forgot about it until I opened up Twitter this afternoon and saw all of my fellow soil scientist’s happy tweets about it. However, I celebrated by looking up the soil classification of the soil on which I grew up, i.e. the soil underneath my dad’s house. It was the Webster series – fine-loamy, mixed, superactive, mesic Typic Endoaquolls (Soil Taxonomy). It is a Mollisol, which is an organic-rich soil that formed under prairie in northern Iowa.
If you live in the US, and want to look up your soil, go to the Natural Resource Conservation Service’s (NRCS’s) Web Soil Survey, or click on the picturebelow. If you’re familiar with the web-based program you can find your soil’s classification, or you can just look up the soil series Official Series Description. Once you find it, please post it in the comments. I’m curious to read about all of them.

 

Soil Science In The News: “The Dust Bowl” by Ken Burns

Dust storm in Hooker, Oklahoma, June 4, 1937. Credit: Research Division of the Oklahoma Historical Society (via PBS.org)

PBS is currently broadcasting “The Dust Bowl” documentary film series by Ken Burns. It’s a series of movies about one of the most tragic environmental disasters to ever face the United States. The description of the films on PBS’s website reads:

THE DUST BOWL chronicles the worst man-made ecological disaster in American history, in which the frenzied wheat boom of the “Great Plow-Up,” followed by a decade-long drought during the 1930s nearly swept away the breadbasket of the nation. Vivid interviews with twenty-six survivors of those hard times, combined with dramatic photographs and seldom seen movie footage, bring to life stories of incredible human suffering and equally incredible human perseverance. It is also a morality tale about our relationship to the land that sustains us—a lesson we ignore at our peril.

I wanted to bring attention to the series, and to the fact that anyone can view the film series at this website. I haven’t had a chance to watch it yet, but if it’s anything like the other Ken Burns documentaries, I know it’s going to be good.

Here is the preview for the documentary:

If you would like to learn more about the dust bowl, I recommend reading the book The Worst Hard Time by Timothy Eagan (reviewed by me here), and also my previous posts The Shoulders of Giants: Hugh Hammond Bennett, and Erosion.

Root Humor

I appologize for the lack of posts recently. The fall semester is wrapping up, and one phase of a large field project is ramping up. This means I have no time at all. To make up for the lack of posts, here’s an awesome picture I saw on Facebook from I F*****g Love Science! As a scientist that studies roots, this just made my day:

Unlocking Ancient Maya Secrets With Modern Soil Science

Caana Caracol. Photo from Wikipedia Commons

When I see an interesting story involving soil science in the news, I like to post them here for my reading audience. One story I’ve seen in a variety of places is about a research article posted in the Soil Science Society of American Journal entitled Upland and Lowland Soil Resources of the Ancient Maya at Tikal, Guatemala (Burnett, et al., 2012). It is available as an open source research article for 30 days if you would like to read it. The Soil Science Society of American has a great summary of the research, and it’s historical significance. Here’s an excerpt:

Writing in the Nov.-Dec. issue of the Soil Science of America Journal (SSSA-J), an interdisciplinary team led by Richard Terry, a Brigham Young University soil scientist, now describes its analysis of maize agriculture in the soils of Tikal. Not surprisingly, the study uncovered evidence for major maize production in lowland areas, where erosion is less likely and agriculture was presumably more sustainable for this community of an estimated 60,000 people.

But the team also discovered evidence of erosion in upslope soils, suggesting that farming did spread to steeper, less suitable soils over time. And if Maya agriculture did cause substantial erosion, the soil loss could eventually have undercut the Maya’s ability to grow food, say the researchers.

It’s a pretty interesting story, and a mystery only solved by techniques of modern soil science. The researchers can tell what types of food was grown in the region based on the “fingerprints” left behind by the plants themselves. Broadleaf plants native to the area use the C3 photosynthetic pathway, while corn and other grasses are C4 plants.  Scientists can tell the difference between C left behind by C3 plants and C4 plants using C isotopes (C elements with different numbers of neutrons in the nucleus of the element). Using their methods, they could tell where corn was produced, and if they started growing corn on areas with steeper slopes – potentially causing erosion, and thus food shortages.

I love stories where science and history intersect, and this is a great example.

Maize. Photo from Wikipedia Commons

 

The Soil Orders – Spodosols

Left: A Spodosol soil profile. Right: Native vegetation over Spodosols. Photo courtesy of soilscience.info
This is the third of a series of blog posts where I will describe some of the interesting features of each of the 12 soil orders in Soil Taxonomy – the soil classification system developed for the US by the United States Department of Agriculture. Each order will be “profiled” (forgive the bad soils pun) in the order in which they are “keyed out” in Keys to Taxonomy.

The Spodosols soil order of Soils Taxonomy is a very interesting group of soils. Spodosols include many of the “Podzols” in other classification systems which was derived from the Russian “pod“, meaning “beneath”, and “zol” meaning “ashy”, i.e. “ashy underneath” in reference to the very light-colored E horizons of these soils (Buol, et al., 2003).

Entic Grossarenic Alorthod (sandy, siliceous, isohyperthermic). Photo: soilscience.info

Spodosols are most common in areas with coniferous trees as the primary native vegetation, and where the soil is coarse-textured. The driving force in the development of Spodosols is the translocation of iron (Fe), aluminum (Al), and organic matter.

U.S. Spodosol Distribution. Source: USDA NRCS

The needles of coniferous trees are very acidic. As they fall to the ground and decompose, organic acids percolate through the soil profile (with the movement of rain water). These organic acids strip off Fe and Al from the soil particles in the A and E horizons. These metals and organic acids are then deposited in the B horizon, just below the E horizons, in layers that appear to be yellow or brown (like coffee grounds) to red in color. The presence of a spodic horizon is confirmed chemically in a laboratory (by determining how much extractable Fe and Al is present). Spodic horizons tend to be yellow to red in color. In the case where large amounts of organic matter has accumulated, the horizon may be dark brown or almost black in color.

Ultic Haplorthod (Sandy, siliceous, thermic). Photo: soilscience.info

Suborders:

Spodosols are split into four suborders. Aquods are Spodosols that are very wet. They often have very grey subsoil colors (except for the Bs or Bhs horizons) with very dark colored A horizons. This is because saturation of the soil prevents the decomposition of the A horizon organic matter. Thus, organic matter accumulates and the A horizon gets really dark in color. Cryods are Spodosols that have evidence of freeze-thaw. Humods are Spodosols that have large amounts of organic matter accumulating in the subsoil (such as in a dark-colored Bhs horizon, h for humic material). Lastly, Orthods are all other Spodosols.

Leon series (Sandy, siliceous, thermic Aeric Alaquods). Photo: John A. Kelly via soilscience.info

Uses:

According to Buol (2003), Spodosols are used for forestry, pasture, hay, and cultivated crops. These soils are acidic in nature, and require large amounts of lime to neutralize the effect that Al has on roots (Al limits cell growth in the tips of roots). Because these soils are highly weathered, due to the organic acids, few minerals are present naturally. Thus, fertilize must be applied for agricultural use of these soils.

Spodosols are some of my favorite soils, partly because they are so beautiful and unique, and partly because my dissertation research involves the Leon sand (see picture above).

Some good Spodosol information sources:

Previously discussed soil orders:

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