Soil burial test mycelium composites - Sequel I


Hello, as promised I would update my previous mentioned methodology and update how it works in practise. Small adjustments to the methodology have been made. Previous methodology can be retrieved here:

Soil Burial test mycelium insulation samples

Short recap of the methodology:
Cut, dead mycelium samples are measured, weighted and afterwards placed in soil. The pH of the soil is checked in the beginning and the end of the test. After 2 weeks the sample is retrieved, dried in an oven at 40°C and weighed. To maintain a continuous degradation, the samples are not re-buried.

For the test set-up, the following things are necessary:

  • sieve 2mm
  • soil
  • box that can be closed
  • scale
  • scaliper
  • mixer
  • pH-meter
  • liquids to calibrate the pH-meter
  • netting
  • destilled water
  • samples

Five different cases are created. In these cases, a distinction between sieved and remnants of the soil is made. This implicates a change in pH and moisture content of the soil. The sieved soil (< 2mm) has a pH of 6.426 and a moisture content of 60.976. The remnants of the sieved soil (> 2mm) has a pH of 6,026 and a moisture content of 77.726. To determine soil pH and its moisture content, the following references have been used respectively:

Further, the differences between the cases are in netting and sample size. Conceptually, the set-up is depicted in the following picture (cf. Figure 1):

Figure 1: Test scenario’s

Thus, the characteristics of each test is as follows:
T1.0/ sieved soil < 2mm - garlic netting - sample size small
T1.1/ sieved soil < 2mm - nylon netting - sample size small - in black bag
T1.2/ sieved soil > 2mm - garlic netting - sample size large
T2.0/ sieved soil < 2mm - nylon netting - samples size small
T2.1/ sieved soil > 2mm - nylon netting - sample size large

When retrieving the samples, they were washed and dried at 40°C for four days. The following table shows the weight loss (%) in a period of 2 weeks (cf. Table 1). The pH after the test still needs to be measured.

Table 1: Weight loss and pH difference

The following series of photos show the samples before (left) and after the test (right) (cf. Figure 2).

Figure 2: Samples before (left) and after (right) the test

When analysing the dried samples, hints of green and white marks are spotted. This is possibly fungi creation. The spots are however not perfectly clear yet.

1 Like

Nice start,

where are your controls? never hurts to have controls

Any plans on what to do if fungi grows in it?? it will probably distort your weight loss data, no?

Good luck, have fun.

Hi Gammarra,

sorry for the late response and happy festivities (new year and christmas). What do you mean with controls? Do you mean fixed paramters? If so, the fixed parameters will be the soil type, soil grain size (< 2 mm), pH of the soil, ambient temperature of the room, relative humidity of the room and (±) moisture content of the soil.

And good point about the fungi growth. I have not thought a strategy for this case yet. If a increase in weight would occur, this might also be a conclusion? I still need to think about it :slight_smile:

Thank you for the reaction!
Updates will follow,
Li Li

No I mean a sample thta has no contact with soil, it might have wight loss of its own even if minimal, since airborne bacteria and photoinduced breakdown are also a thing.

Aha! that is a very good point. I was going to take this into account for my final samples. But I didn’t do it for these test samples and the samples of the next test. Thank you for the reminder :).