Soil Reciprocities

1. Concept

Soil Reciprocities is an interactive clay installation that fosters a reciprocal relationship between human and soils. A living sculpture of clay and mycelium, partially buried in the earth, acts simultaneously as a site of ecological regeneration and collective ritual. Soil humidity sensors monitor mycelial activity and translate it into an evolving soundscape, while capacitive sensing allows human touch to reveal the sonic traces of ongoing bioremediation — as the soil heals, the sound grows richer and more layered. In turn, participants can speak to the soil, their voices converted into low-frequency vibrations that travel downward as gestures of care, stimulating mycelial growth and further enhancing bioremediation. Through this loop of listening, touching, and offering voice, the installation proposes that healing damaged soils and healing our estrangement from the living world are one and the same act.

2. Technical process

Material

The process of creating a sculpture consisted of main strategies: 1) preparing the clay mix which steps are: collecting wild clay from Valldaura Labs, filtering the clay, mixing the clay to grow mycelium in the following proportions:

• Wild clay = 100%
• Water = 40% (porque has usado el doble de la hidratación inicial del 15%)
• Sawdust = 6%
• Xantana = 1%
• Guar = 1%
• Mycelium = 8% (manteniendo la proporción de la receta anterior)

2) preparing the scaffolding with metallic mesh shaped in organic forms, adding a layer of plaster gauze to give it strenght and finally putting the mixed clay on top of the sculpture

After 2 days mycelium was starting to grow on the sculpture.

Electronics

An electronic system embedded into the physical sculpture allows humans to listen to the ongoing process of bioremediation (system 1), and in turn, to speak to the soil, sending human voices as sonic offerings that will stimulate mycelial growth, and further enhance the process of bioremediation (system 2). Both system 1 and system 2 were tested with smaller prototypes of the mesh and clay sculpture before calibrating the values to the actual 1:1 size of the installation.

System 1

Touch sensing connected to metallic mesh of sculpture --> Mini DFPlayer --> Speaker #1 plays pre-recorded sounds from SD card when a touch pin is activated.

System 2

Soil humidity sensor buried on site (data that composes music) + Capacity sensing values (control volume) ---> ESP32-S3 ---> MAX98357A ---> Speaker #2 generates sound continuously based on soil moisture values (sonification) and human touch

Design challenges

My main interest with this installation was to create a close feedback loop that will nurture a reciprocal relationship between humans and soil in the context of bioremediation. So the backbone structure was to be able to listen to the soil and speak to it. The possibilities of what was possible to listen and what sounds to broadcast changed in the iterations but the main system remained. For example, in the beginning I wanted to use a geophone to be able to transmit the sounds of vibrations of the soil to the surface but due to the cost of such device I dropped that idea, and instead thought that the humidity data could be a good proxy to listen to the process of bioremediation which the sculpture is meant to initiate with the mycelium. Similarly, the sounds to be broadcasted to the soil were initially just a music melody but then I decided to use human voices as the sound. For this iteration it was my own pre-recorded voice (poems to the soil), but I want to later make it that the voice of participants is the one that gets directly transmitted to the soil. The challenge would be how to edit those voices to low-frequencies in real-time, because at the moment I made those edits on audacity software.