The NoIR Raspberry Pi camera comes with a blue filter to do near infrared photography – the blue filter ices the visible red but passes near IR which records as red, apparently.
NDVI image of something in the polytunnels. Should have made a not of what this plant is 😉 Anyway, more red and going to magenta white overload=more photosynthesis
Since I will be taking the sensor to the rock I’m going to temporarily give up on getting an absolute measurement, and take a leaf out of Bartington’s book from last time and use a flat coil. I will never be able to contain the sample in the magnetic field1 as I might be able to in a solenoid, to the effective susceptibility will always be lower than 1. One day I may be able to calibrate this and find a fixing factor, but for now I will look for relative differences.
There are two approaches to measuring paramagnetism that seem to be common. One is to use a balance to measure the slight attraction to a magnet – put sample in a balance, apply magnetic field, look for difference in weight of sample using a Gouy balance or use a torsion balance to observe the attraction in a horizontal plane which takes out the static weight of the sample.
The trouble with these two is the attraction due to paramagnetism is weak compared to the weight of the sample – these are lab bench instruments and the electromagnet consumes a lot of power. Although taking samples of soil is easy enough to bring back to the lab, one really shouldn’t be taking a hammer and chisel to ancient monuments to get a sample for a Gouy balance 😉
It’s not really right to go chiselling a lump off megaliths that have survived thousands of years to insert into a Gouy balance…
The other way of measuring volume magnetic susceptibility is to stick the sample into a coil and measure the inductance – with a different configuration of the coil as a search coil it can be used to measure susceptibility at the rockface.
Paramagnetism is a reasonably straightforward characteristic of materials – if there are unpaired electrons in the atoms then the element will be paramagnetic and weakly drawn to a magnet. This demo of oxygen being paramagnetic is great – so far so scientific. Compounds can change this – water is diamagnetic although H2O is clearly contains oxygen.
A lump of paramagnetic rock (the coin is ~2cm dia)
When applied to soil and the growth of plants, however, paramagnetic effects fall into the domain of the woo-woo rather than the analytic 🙂 Igneous rock and volcanic soils tend to be notably paramagnetic. Philip Callahan is the go-to source, and this extract from a 1995 Acres USA article is a high-level spin on his take : Continue reading “Paramagnetic soil ponderings and perambulations”
This is using Elaine Ingham’s microscopy techniques to investigate thermal compost – some of what I saw. I am at an early stage of being able to do this, so any errors are mine and not Elaine Ingham’s 😉 The principle is to classify organisms by their morphology – aerobic fungi tend to have a colour, diameter wider than 2.5µm and/or have uniform septa. Spiral structures are bad, indiciative of anaerobic conditions, and ciliates (hairs all over the body) also indicate anaerobic – bad- conditions. Apart form the spirochete most of these are good.
fungal hypha with septum 400x
fungal hypha 250x
fungal hypha 400x
spirochete – bad sort of bacteria. 250x
I saw only one and this one inactive!
misc protozoa 250x
fungal hypha 400x
fungal hypha 250x
This is on a 5x dilution, the recommended intial conditions (use 1ml of compost and make up to 5ml total with water left to stand so the chlorine has gone).
Sticking a Raspberry Pi camera exposed to the elements doesn’t do it any good over time, resulting in the hazy crazed lens problem.
Flare on the camera lens after a year in the open
The solution is to put some glass in front of the lens – and indeed this is exactly what this commercial outdoor spec little lipstick CCTV camera does
it’s hard to see, but there is a round glass against an O ring in gront of the camera lens on this weatherproof camera, which has spent several years outside and still works well
I discovered this when I took it apart to unscrew the lens a bit to make a close focus. And then cracked the glass refitting it as the lens stuck out too much. If you ever need a flat round piece of glass, search for watch crystal on ebay and they are to be had in lots of diameters. A watch crystal is apparently a term for the glass on a watch as well as the 32,768 Hz timing quartz crystal. A flat watch crystal repaired this camera.
The direct exposure of the camera lens to the elements is the biggest weakness of the now-defunct PICE weatherproof Pi case. But it is easily rectified now, using a piece of flat glass fitted with Sugru or Milliput putty. I used sugru and a cut down microscope slide, since I didn’t want to buy another watch crystal when microscope slides are optically flat and cheaper. It is a lot easier to cut glass under water, and you can remove the viciously sharp edges using a cheap diamond sharpening stone to smooth the cut edge and chamfer the corner.
Microscope slide fitted with Sugru to shed the water and seal the camera from the elements
The easiest and low-tech way of adding the microorganisms from compost is to extract them fro mthe compost using water and a mesh, then spray the water – in our case using watering cans. You can spread the compost itself, and there’s much to be said for that, but it’s more stuff to wrangle and needs to happen before you plant, ideally. Since we are going to test areas on already growing plants, extract it is. Compost tea is a way of getting more microbes out there, but it is technically harder and we don’t have the gear. Extract it is, then. The rate seems to be about a good handful per 5 gallons, we used half an IBC, ie about 500 liters, which is 110 gallons. So we need about 20 times as much
Start with a wodge of compost in a net curtainand 500 litres reasonably clean borehole water (so no worries on chlorine or chloramine)
We made a bag by putting the compost in the middle of the net curtain material and tying up the top with a releasable cable tie.
You can see the brown of the humic acid leaching out of the compost into the waterthe end result is a dark brown chocolate colour
The successful compost is ready – it has now fallen to roughly ambient temperature.
unfortunately the temperature logger failed when I was on holiday so I don’t know what the profile was as it cooled down. And yes, it didn’t spend three times three days above 55C – more like three days and two days. There’s still more to learn here.
Time to look at this and see what sort of microbial stuff is in it. I shook this up with about 20 times the amount of water and put a drop on a slide
fungal hypha and bacteria
According to Elaine Ingham’s rules of thumb this is probably a good sort of soil fungus, because if the little round cocci are 1µm in diameter the fungal hypha is about 4µm. I could see that this one was slightly tan coloured, but the incandescent lamp of the microscope plays havoc with the white balance of the camera, making everything bright yellow.
This next one is narrow and clear, so not good in the morphology rule of thumb that fungi < 3µm in diameter and clear are undesirable soil fungi.
I saw no protozoa or micro-arthropods. That’s either because there aren’t any or because I didn’t recognise them. The dilution is high, – it appears that Ingham starts at 5:1 so I’m four times less likely to see these at 20:1.
The high-nitrogen activator should typically be about 10% of the composting materials. These are typically animal wastes – I have used real chicken crap, pelletised chicken crap, and clover. With the chicken manure each time I have scored a fail, whereas the clover was a success.
pelleted chicken manure
I suspect the trouble is that it’s hard to mix a concentrated activator properly. For starters it’s not pleasant to do, which discourages it being turned in right. The pelletised stuff is easy to distribute evenly, but even then it seems to lead to localised action.
pellets seem to turn white
The pellets seem to go white, like dog crap used to go white when left on the footpath in the 1970s. This leads to a fast and furious burn on the composting front, but with no staying power
pelletised chicken crap – leading to a fast ramp up but no staying power – the dip was when it was turned
The clover was more evenly spread – somehow I need to find a way of spreading the others more evenly. Or maybe go for the urine, preferably from carnivorous humans (there is more N in protein). In Ben Easey’s Practical Organic Gardening (Faber, 1955) he says dilute this with water 1:20 which should make for a better distribution. So I’m going to steer clear of using crap, because I am a wuss and don’t like dealing with it and it’s too concentrated anyway. Clover or urine will be my activators of choice 😉
Joanne’s note Oct 2016:We subsequently (in later heaps) used pelleted chicken manure mixed with water and stirred into a slurry. It took a lot of water to do this! Poor old Richard has a very sensitive sense of small (tough on a small farm with animals!) so he had to leave the rest of the team to finish up building the heap when we started to add the slurry…
