Besides the fun of trying something new, and photo ops, we found a very clear indication of how fun soil chromatography can be:
Magic the black cat sniffing soil, Dec 2018.
Although we only had 5 good chromatograms out of the set of soil samples we tested, this process revealed several things:
- fun
- accessibility
- colours!
- ease of participation at different steps of the process
- darkroom construction does take some work
- soil qualities beyond the quantitative, chemical analysis
In this short article, we’ll take you through the steps (which we’ve documented in full here) so you can do your own soil chromatogram activity!
We give thanks to Europe-based HUMUSapiens, for their open wiki and inspiration across the world.
First of all, why make chromatograms with soil?
Soil chromatography was developed and introduced by Lilo Kolisko (visit the webpage! Highly recommended for a view to a woman scientist’s life and thinking in the early 20th Century), a woman scientist – who studied with the biodynamic thinker, Rudolf Steiner, in Germany.
Since then, it’s been played with as a mixture of artscience: by hackers, experimenting with non-traditional science, and by scientists and foresters: check out this resource from the University of Western Australia.
The chromatogram’s main strengths are what it doesn’t do: capture and quantify soil’s chemical properties into a number. What it does do, is transfer its properties onto a medium (filter paper) that allows the human eye to witness direct patterns emerging from the flow of chemical and other properties within the soil’s living system. In this, biodynamics considers qualities within each living organism. There are other words for this in other indigenous wisdoms (of which biodynamics is … really not). (In Singapore, we may hear of chi, prana, or semangat–different ways of looking at energy, within systems of holistic health and embodied vitality. The performance artist nor has a beautiful piece titled “Semangat in practice”, in Making Kin, published 2022 by Ethos Books.)
Chromatograms allow a human eye not accustomed to working with soil’s ecology, to see how soil is living and complex, to be understood qualitatively and viscerally and not only quantitatively or morphologically, as a vibrant, living matter.
Although we did want to understand how soils in two locations appeared, part of the process (which we didn’t do perfectly!) was also to see how this transformation of qualities occurs.
In the lab, chemical analysis these days is measured to a chemical standard; from there, a list of quantities of which chemical compound is generated.
When well done, chromatograms reveal not only proportions, but also vitality: jagged edges and sharp notches. Ours are just beginners in training. HUMUSapiens in Europe has much more on soil with their soil camps.
Although these resources exist, it was hard finding a simple workflow for non-hacker culture participants. So we made one ourselves (after our series of mini-success (chromatogram blooms!) and mini-missteps (questionable labelling, and AgNO3 blots on Huiying’s hands).
Select soil samples
First, find the spots you’d like. You can select any spots! Or consider comparing spots based on shade/non-shade, where you guess some soil may be doing better because you’ve added some compost, etc.
Prepare soil solution
- Mix soil with 5 times the amount of base solution. Some guides recommend 0.1% sodium nitrate solution. We used baking soda which is more easily available, adding in molar excess (until no more baking soda dissolves.)
- Leave soil solution to sit for at least 12 hours (Zuazagoitia & Villarroel, 2015)
Prepare darkroom
- Includes Red lights, tweezers, weighing scale, glass bottle for silver nitrate solution (1 per filter paper is best, or 5 if you are doing 10 sets for e.g.), filter paper fitted with wick, box for drying filter paper that ensures no light enters during the day
Prepare filter paper with silver nitrate solution
- This has to be done in a darkroom, with gloves. Always use gloves while handling silver nitrate solution. As a solution, silver nitrate stains hands permanently. While it eventually comes off as your skin renews itself and sheds, it forms jet black stains as silver oxidises under sunlight. It can be removed with strong toxic chemicals (e.g. some form of cyanide) but we recommend leaving it be until it comes off.
- Measure out enough silver nitrate to make a 0.5% silver nitrate solution. E.g. 0.5g to 100ml of water.
- [Optional] Mark out filter paper to be prepared in order of preparation. E.g. FP 1, FP 2, FP 3 or any other coding system that suits you. This is an additional step to track the consistency of the silver nitrate application.
- Place the filter paper with wick to the solution. Let the silver nitrate seep into paper a radius of 4cm. This takes approx. 20 minutes per filter paper, depending on the quality of the paper.
- Let filter paper dry overnight (still in darkroom conditions) or 2 nights during rainy season.
Wick soil solution onto prepared filter paper
- On prepared, now dry filter paper, add a new wick.
- Add 1 filter paper per soil solution. Each filter paper takes approx 15-20 minutes.
- [Observation step] Observe the changes on the paper as the solution is wicked up: does solution begin showing up? How fast does the solution take to be wicked up? Do this if your paper quality is not consistent or to catch light leakage in the darkroom.
So that’s it! We plan to do this again, sometime, in a different site…. when that will be will appear 🙂
Read/download the full step by step instructions here:
Written by Huiying.
Also as a testament to how qualitative and aesthetic understandings of ecology are seen today: you might like this passage from The Moon and Madness, written in 2011. Today we’ve moved a bit further on from the idea that moon cycles are completely separated from our human and ecological cycles of life and death. 🙂
