The word "Rhizotron" is an amazing sounding word by itself, today I stumbled across a group that have been burying mini-rhizotron scanners!
Jared Williams and Rob Mikkelsen started doing this years ago with their students and have put together a great presentation on it.
A few of his observations I found interesting:
Use of technology in this way is more engaging to students.
Students are so excited they end up sharing results on their own Facebook accounts.
He covers the basic build process in a way that can easily be done inside a classroom.
My current implementation has been buried outside. This provides different opportunities, but comes with a number of additional obstacles / difficulties.
Experimenting with the affects of fertilizer on root/plant growth
This is awesome. Being able to watch the difference both above and below ground.
So many questions come up as I crunch these videos together. The above is 34 days (~July 13th - August 16th) time lapsed down to 34 seconds. Below is a quick list of questions/observations that I think would be neat to edit into the video and provide clickable links for further info.
Did the fungus in the first few seconds target the grass, or did it just expand outward?
Can / Does / Why / How would fungus travel in a specific direction?
What goes after leaf/grass first, is it bacteria, fungus, bugs, a combination?
After the soil has been rained on and the leaf turns very dark there's a significant influx of skinny semi transparent worms? What are these?
What are ALL of the bugs that we can see? (another post coming soon)
Bugs eating roots. Tasty!
What are roots made of, what sort of nutrients do the bugs gain from eating them?
Fungus! Can we find any fungal traps for bugs?
Vertical Root Growth (Radishes)
When / why does it begin and stop?
Circumference change over time?
Secondary/Horizontal Root Growth (Radishes)
When / why does it begin and stop?
Circumference change over time?
Gravitropism & Phototropism
Leaf decomposition process
Mid rib last to go? In a few days all should be gone except that.
Can we find any worm casts?
Is that what we see in the first second of the video, above the left middle portion of the leaf?
I started reading "What a Plant Knows" by Daniel Chamovitz. Sufficiently awesome if you want a basic overview of plant senses. Last: Michigan Interlibrary Loan / MeLCat program FTW for making library books more accessible : )
A quick comparison of rain fall vs. brightness of the soil over the past 30 days. The numbers on the left represent inches of rainfall on a given day and are associated with the green lines. It's neat seeing the two largest points of rainfall corresponding to a change in the soil brightness (blue line).
Started experimenting with the compare tool of ImageMagick. Using this scanner has some interesting problems. It doesn't always start and stop at the same point. Doing a comparison between two images when they are shifted up or down a couple millimeters seems to throw the compare tool off quite a bit. Using the fuzz option so it ignores that level of change is probably enough to cause it to ignore most of the other small movements.
These small movements being that of bugs. It would be fascinating to quantify some level of movement / change influenced by the number of bugs crawling around. In order to do so I think I first need a stable image. Whether that means using a different scanner, correcting the start/stop position change, or correcting for by identifying one or two points to crop the images at. I'm not sure, or maybe something else.
Either way, this is awesome, and you should probably go hug a bug. Or at least listen to an amazing radio show named just that : )
This is a quick six second video that covers a 24 hour period. Around the half way mark (mid day) the rain begins and you can see the change in soil color/brightness(?). Images were taken every 15 minutes.
I used the program "Identify" from the software suite ImageMagick to get a rough idea of the average brightness of each image taken. Values below are from samples taken every hour. Over a 24 hour period this looks like:
The numbers on the left, 10200 thru 11400 are the values provided by identify when running the command:
identify -format "%[mean]" image.jpg
I am not familiar with the method identify determines the average brightness. When comparing percentage differences of luminosity histogram values in Adobe Photoshop CS2 with those of identify, they were quite close. Though only a couple images were compared
I am guessing the scanner affects this in a number of ways:
Scanner surface is very different than soil, may affect water path/flow
Light from the scanner, may (seems negligible) provide enough heat to evaporate water quicker?
Slight vibrations from the scanner operating may (seems negligible) affect water path/flow
Regardless, it's awesome to see this visually in terms of video and numbers/graphs.
So far images have been coming in at 300 DPI. My initial thoughts were that >300 DPI takes too long, would result in blurred movement and gigantic files. But so much of what I see moving at 300 DPI is too small!!
It's amazing just how many bugs are moving about down there. Many of the ones that we can see with our eyes are small enough, and move slowly enough that it would be difficult to see if we weren't speeding time up. Most of the videos that have been posted are sped up over 30,000 times.
But even so, scanning at 300 DPI isn't enough to reveal many of the details on most of what's moving down there. So I've added a second scan at 1200 DPI to target the area the leaf still (barely) occupies. The above image is the first scan, measuring ~5.75x3cm. Click it for a higher res version. I should have a very short video up of this early next week.
I've been on and off reading "The World Beneath our Feet" by James B. Nardi. I would love to learn more about what we're seeing, and be able to document within these images and videos the processes that are covered in the book. It also mentions things like Berlese Funnels, incredibly simple devices to discover more of what's in our soil.
Other random things learned today: The terms Pedology (the study of soils in their natural environment) and Edaphology (influence of soils on living things, particularly plants). Which reminds me, I should go learn from the crew over at Photosynq!
Over the past three weeks I have amassed approximately 2200 images. One image taken every 15 minutes. This is far too many files for me to handle with something like GIMP or Photoshop. Thankfully I am not the first person to have this problem, and the internet makes it very easy to find solutions to problems other people have already had.
Each image is approximately 2539 × 3507 pixels, and the orientation is not pleasant to view on a standard widescreen monitor. Further, there is so much activity that trying to view a series of images with everything visible tends to drown out any specific area of interest. So I've taken to cropping down to smaller 1280x720 or 1920x1080 pixel regions.
I've been using the software suite Imagemagick to handle the bulk of this. For example:
for file in *.jpg; do convert -crop 1920x1080+310+285 $file tc/zleaf_$file; done
This takes every jpg in a given directory: Move to a point 310 pixels in from the left and 285 pixels down from the top, and then crop out an area 1920 pixels to the right and 1080 pixels down.
It places each of these new images in a directory (previously created) called "tc" and labels the new images with the prefix "zleaf_" followed by the original file name. I preserve all the original files and have a separate directory with the new cropped images.
I have been using a few different programs to generate the videos. Originally I started with Apple's free iMovie '09 and an ancient version of Adobe After Effects. iMovie is a breeze to use and After Effects seems to offer more than I could imagine needing for this. However both require me to be involved in the process. They also won't run (easily) on a *nix system.
So I'm working to settle on Mencoder, a part of the Mplayer program used to play videos. Using two commands I'm able to easily (and so far much quicker than iMovie or Adobe After Effects) generate videos:
ls -1tr *.jpg | grep -v files.txt > video.txt
Creates and saves a files called video.txt, it contains a list of all the jpgs in a given directory.
Creates a video file that plays back at 30fps with no sound at the same resolution of the source images. It takes ~5 minutes to create a 1920x1080 video out of the 2200 image files, the file size of the resulting video is ~28MB. The original images totaled ~1.8GBs. Video below (recommended playback: Full screen at HD if possible)
The next step in this project (I think) involves
- Figuring out how to overlay 1cm grid lines
- Figuring out how to embed a timer
- Finding a few areas of interest so images can be automatically
- - Cropped and saved as they are captured (keeping the original intact)
- - Lists generated for each day of images
- - Videos generated for each day of images
- - Compiled video based on each daily video
- - - http://www.misterhowto.com/index.php?category=Computers&subcategory=Video&article=join_with_mencoder
Technology:
Adobe After Effects v7.0 doesn't have native support for Intel hardware. It works, but supposedly has limitations on available RAM.
Using a for loop and the linux software imagemagick (convert) to crop a specific region out of a series of images and save with a new file name. This was done to focus on the area of a germinating radish seed.
Using a script to include an hour timer within Adobe After Effects. This was used to show the time elapsed in the first 58 hours of the germinating seed.
It took approximately 13 hours after planting the seed for a visible change to occur within our view. This may have happened sooner, but we can't easily see the whole seed with this setup. It's possible it started much earlier in non visible area.
The video above shows a 1cm grid overlay, at hour:
13 = Seed bulges
24 = White of root barely visible on the top side of the seed
31 = White of root barely visible below the seed
39 to 48 = 1cm of root growth
48 to 54 = 1cm of root growth
53 = A second root is seen growing.
If we measure the root growth from the 39th to 54th hour, we have it growing at roughly 1cm p/7.5 hours. Woohoo!
There are numerous other time lapse videos of radish growth, very cool! All of the ones I have seen show the plants in containers of some sort, or above the ground. The video above is taken from the ground, the container being the earth.
