Thursday, August 26, 2010

The dirt on turning soil into plants: August edition

OK, you got me:
"A plant's dry matter* consists mostly of carbon, hydrogen, and oxygen, which the plant obtains by photosynthesis from air and water, not from the soil.  (Reference #1)"
But the other macronutrients*, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, mostly come from soil solids.

As fascinating as soil is, much of my relationship with it is in the "benign neglect" category.  I'm hoping to change that!  But it is August and it is hot.  What to do in Central Texas?

Texas Agrilife Extension Service gives us a 2010 Travis County Planting Calendar, a list of vegetable varieties, and seed sources. Since today is August 26, the chart says I still have time to plant beans (lima and snap), cucumber, and summer squash.  And maybe I could squeeze in some Irish potatoes.  So I looked into my seed stash, and here is what I did:
How is your soil today?  How are you showing the soil your love?

Dry matter: "

the percentage of plant sample, which 

remains after all the water, has been removed (Reference: Cooperative Extension Service University of Kentucky and Kentucky State University)."

Macronutrients: "A chemical element necessary in large amounts (usually 50 mg/kg in the plant) for the growth of plants (Reference #1)."

    11 things you can do to increase water in Austin creeks

    This creek has high water flow during rain events; you can see the big pile of brush that the water carried.  But a day later,  it is sunny and the creek is dry (Fort Branch Watershed at Springdale Rd., I think).
    We talked earlier about how one of the problems in local Austin streams is that they have too much water when it rains [which renders our poor froggies and fish practically habitat-less from all that turbulence], but not enough the rest of the time.  This, in part, is caused by how we have developed impermeable cover on top of our soil.  Basically, we've become urban.  For more details, please read my post on Watersheds in a nutshell in a nutshell.  Thanks!  Now onto the proactivity...

    There are ways we can help those little froggies and fish keep their homes, and it doesn't have to be done by big groups of people.  Each yard can make a difference!  All we have to do is point water in a new direction, away from runoff and evaporation, and towards infiltration into the soil and groundwater.  When water is supplied to creeks by  groundwater recharge instead of runoff, creeks flow at a more constant rate.  A more constant flow rate helps preserve aquatic habitat.

    Below are some tips directly from the City of Austin's Watershed Protection Department and the EPA that will help our creeks flow.

    Structural improvements:

    • Select yard plants that have low requirements for water.
    • Preserve existing trees, and plant trees and shrubs.
    • Irrigate efficiently to avoid runoff from your yard (source).  For example, using "slow-watering techniques such as trickle irrigation or soaker hoses reduce runoff and are 20 percent more effective than sprinklers." (Thanks, EPA!)
    Ground cover:
    • Spread mulch on bare ground or restore bare patches in your lawn.
    • Use compost. Compost retains moisture in the soil and thus helps you conserve water.

    Increasing vegetation and ground covers are doubly effective.  They increase infiltration, and they also reduce evaporation!  Increased evaporation from impermeable ground surface is an often forgotten result of the increased urbanization of our watersheds.  By increasing shade, and thereby decreasing heat, we reduce evaporation (click here for more physic-sy evaporation details and terminology, just scroll down on the right side and look for terms).  This way, the water stays longer right where we want it, it our watershed!

    What about you?  Do you have other tips?  This is Austin, so we can be creative!


    Here is a 12th, amazing extra credit thing you can do: Create a green roof!  Thanks for the idea, Wildflower Center!

    Tuesday, August 17, 2010

    It was hot today: the dirt on the heat index.

    Fer reals.  The National Weather Service predicted that it would feel like 110°F (Fahrenheit) today.  Same for tomorrow, I hear.  This does not bode well for the following polar bear:
    Maryland: Where men are almost as tall as mountains.
    What are they saying when they predict it will feel like 110°F, even if it is only [only: ha!] 102°F?  They are talking about the Heat Index.  At first I thought it was the same as the term "effective temperature".  Oh, but no; when I looked up that definition, I got this from Columbia University: 
    The effective temperature of a planet is the temperature it would have if it acted like a black body, absorbing all the incoming radiation received at its surface and reradiating it all back to space.
    That's not what I want! This is what I was looking for, from NOAA's National Weather Service:
    The Heat Index (HI) or the "Apparent Temperature" is an accurate measure of how hot it really feels when the Relative Humidity (RH) is added to the actual air temperature.
    Please click on their link for all the details, it is pretty good text, but in the mean time, here is my favorite part:
    The body's blood is circulated closer to the skin's surface, and excess heat drains off into the cooler atmosphere by one or a combination of three ways...
    • radiation,
    • convection, and
    • evaporation.
    At lower temperatures, radiation and convection are efficient methods of removing heat. However, once the air temperature reaches 95°F (35°C), heat loss by radiation and convection ceases. It is at this point that heat loss by sweating becomes all-important. But sweating, by itself, does nothing to cool the body, unless the water is removed by evaporation (sweat changing to water vapor). The downside of this method of cooling is that high relative humidity retards evaporation.  (reference link)

    Considering their explanation, I'm surprised that wind speed isn't factored into it.   Doesn't wind promote evaporation?  Cuzzzzzz it blows the humidity away?  

    But here is a funny thing part: the heat index was first introduced by R.G. Steadman (1979) in his document called  "The Assessment of Sultriness, Parts 1 and 2." 

    Sultriness. Hee!

    Sunday, August 15, 2010

    Definitions are funny

    I wanted to talk about the difference between soil and rocks, but when I started looking up definitions, I remembered that there isn't a singular definition on which we all agree for these things.  The definition of a word depends on who you talk to, and the definitions bleed into one another.  

    For example, I happened upon the knowledge that the classic definition of geology is the study of the earth

    The study. 
    Of the earth.  (Doesn't that kinda mean everything? Doesn't the study of the earth also mean economics and anthropology and religion?)
    And its life forms, and the evolution of life.  
    Which now sounds more like biology.  

    To be honest, I like this definition.  Cuz I think that geology does include the study life and its evolution (for example, paleontology), but only as it has been recorded in the rock record.  But what are rocks?

    Please click here for the definition of "rock, " courtesy of the US Geological Survey (USGS).  Notice they use the word "mineral."  What are those?

    Please read the definition "mineral,"  by the Soil Science Society of America (SSSA)- "a naturally occurring homogeneous solid, inorganically formed, with a definite chemical composition and an ordered atomic arrangement."  

    Oh, but no! The USGS begs to differ.  They are more specific than the SSSA's "homogeneous solid," calling it an element or compound instead.  I like this better.  Also, "the ordered atomic arrangement" is called a "crystal form" by the USGS.   Same difference.

    I know.  Tedious.

    Anyways, here are soil definitions, courtesy of the NRCS.

    Here is some mica.  Common in the Glenelg silt loam in Maryland.  Use fingerprints for scale.
    What I get, is that soil has rocks in it, but soil is also an ecosystem.  There is air, liquids, and solids in soil.  There is water, there are minerals.  There is representation from all taxonomic kingdoms of life.  Oh and look, there is also my heart and soul (transcendent violins, please! And an angelic chorus).  

    Wednesday, August 11, 2010

    How to get in on tonight's Perseid meteor shower.

    Did you know that tonight (Texas Standard Time) is the best time to watch the Perseid "shooting stars"?  They come around every August.  I have some great memories of watching them with many a BFF.  So fun.  The good news is that, even A-town's night-light pollution won't block out the brightest comets in this meteor shower!  Of course, according to Bill Cooke of NASA's Meteoroid Environment Office at the Marshall Space Flight Center, the best show will be away from city lights.  "The greater flurry of faint, delicate meteors is visible only from the countryside," he says.

    Here is a pic from the same webpage.  Imagine lots of these at once [well you know, within an hour]! Weee!

    Further details lifted from NASA:
    Peak Activity: Aug. 12-13, 2010, approximately 50 meteors per hour. The crescent moon will set early in the evening, allowing for dark skies all the way up until peak viewing just before dawn.  Meteor Velocity: 61 kilometers (38 miles) per second.   
    Note: The Perseid meteor shower is one of the most consistent performers and considered by many as 2010's best shower. The meteors they produce are among the brightest of all meteor showers. 
    What is the Perseid meteor shower? I lifted this next info from the Discovery magazine  blog.
    WHAT: The height of the Perseid shower comes every August, because that’s the time our planet passes through a certain debris path.
    The Perseids are created by the tiny remnants left behind by comet Swift-Tuttle. The Earth passes through this material once a year, creating a spectacular show as the cometary particles burn up in the atmosphere.
     So,  in the spirit of pondering that which is greater than us, here is a youtube link.

    More links: