This page provides background to the #SoundOfSoils project.
Between 19 November 2023 and 14 January 2024, audio field recordings were made of the soils on the peri-urban property of Kim V. Goldsmith, just outside the regional city of Dubbo, on Wiradjuri Country in Central West New South Wales (Australia). This project was initiated on an invitation from ecoartspace to join their Soil Dialogues and prepare soil-inspired works for the Centennial Celebration and Congress of the International Union of Soil Sciences (IUSS), 19-21 May 2024, Florence, Italy. At each #SoundOfSoils site, 100% cotton fabrics (homespun and muslin) were buried to a depth of about 8cm. Each fabric had a different treatment to gauge the effect this might have on microbial activity over the 8 weeks they were buried. The resulting work will be a soundscape composition of the soils and the environments they’re part of, along with poetic prose.
This was what was unearthed:
The gallery of images above shows the state of the fabrics unearthed from each site on 14 January. The level of degradation is an indicator of how active the microbial and soil fauna activity is. Cotton fibres are made of cellulose formed from glucose molecules strung together as a polymer. Soil bacteria and fungi have broken down the cotton fibres into glucose that then becomes a food source. Sound samples taken over the two months can be found further down the page. CLICK TO EXPAND THE IMAGES.
…results suggest that the temporal and spatial dynamics of the diversity and community composition of soil organisms can be predicted by the acoustic complexity of soil soundscapes.
Marcus Maeder, Xianda Guo, Felix Neff, Doris Schneider Mathis, Martin M. Gossner, Temporal and spatial dynamics in soil acoustics and their relation to soil animal diversity, 2022
The selected sites
The property is on undulating country on the northeastern edge of the Sappa Bulga range, west of the Wambuul Macquarie River. Geologically, it sits on the northern edge of the Lachlan Fold Belt and the southern edge of the Great Artesian Basin (Surat Basin). This is sandstone country, and the soils are described as rudosol and tenosol earthy sands. This is not considered productive farming country but it supports an abundance of life — birds, bats, insects, frogs, fish, marsupials, reptiles and billions of microorganisms that call these soils home.
Tenosols (tenuous soils) have only weak soil profile development with limited B horizon development (less than 15% clay content) but more than Rudosols, including possible bleached layers and colour changes. Rudosols (rudimentary soils) have the least profile development of all soils. They are often just shallow soils with little more than some minor organic matter accumulation on the surface and weathered parent material
The two burial sites are 126 metres apart (direct line), one on the top of a slope, one below near an ephemeral waterway that only runs when there’s heavy rain. The property has never been heavily grazed and no domestic animals have been on either site for 12 months.
Site 1: A disused chicken/goat yard and orchard, pH 4.5, light red, compacted sandy soils with some organic matter.
Site 2: A shallow gully running across a slope on ungrazed land inhabited mostly by kangaroos, pH 4.5, grey, sandy silted soils with little to no organic matter.
DNA tests and nutrient tests were not conducted before the burial on either site.
Fabrics buried at each site
1. Homespun/muslin – unwashed, untreated (store handled)
2. Homespun/ muslin – washed, untreated
3. Homespun/ muslin – washed, soaked in worm juice from the worm farm
4. Homespun/ muslin – washed, soaked in sugar solution
Method
Each site was monitored, documented and audio recorded on 19 November, (25 November – during a rain event), 3 December, 17 December, 31 December and 14 January. On each date, general observations were noted about the site, and readings of air temperature, soil temperature and soil moisture were documented, along with rainfall two weeks prior to the recording. Notes were made about the sounds heard using two sub-surface microphones – a Jez riley French hydrophone and a LOM geofón. Atmospheric recordings were taken at each site (except on 17 December due to barking dogs nearby) using a Sonorous Objects ultrasonic omni mic placed on top of the burial sites at ground level.
Keep scrolling down the page to hear the sound of the soil during the rain on 25 November (a week after burial).
Observations
Each fortnight, about 45 minutes were spent at each site, listening, observing, documenting temperatures, plant, animal and insect activity, and audio recording the soils with different microphones.
19 November, 8.30am – BURIAL OF FABRIC AND FIRST RECORDINGS
Rainfall 2 weeks prior: 36.4mm; average max temp for Nov – 30.1°C.
Site 1: air temp 29°C; soil temp 36°C; soil moisture very low
Site 2: air temp 29°C; soil temp 38°C; soil moisture very low
General observations: Site 1 soils very compacted – required a crowbar to dig the hole. Previous week had been in the A lot of black ant activity at both sites, a lot of bees on the Paterson’s Curse in the roo paddock. Difficult to penetrate either site with the 10cm probe on the geofon. Wind, plane and airport noise evident.
3 December, 1.30pm
Rainfall 2 weeks prior: 38.2mm
Site 1: air temp 18°C; soil temp 26°C; soil moisture moist
Site 2: air temp 20°C; soil temp 25°C; soil moisture moist
General observations: Big drop in air and soil temperatures since rain. Even more ant activity than before, problems with ants getting into recording equipment. Geofon probe easier to use on both sites. Noted blue-banded bees on Paterson’s Curse.
17 December, 7.00am
Rainfall 2 weeks prior: 4.2mm, as well as a 10-day heatwave reaching maximums of over 40 degrees between 5-14 December.
Site 1: air temp 16°C; soil temp 23°C; soil moisture dry
Site 2: air temp 19°C; soil temp 28°C; soil moisture dry top/ moist below top 3cm
General observations: Less ant activity at Site 1 since last recording, pigweed growing over Site 1, grasses have shot up, still a lot of ant activity at Site 2, no regrowth over Site 2. Lots of dogs barking in area and a lot of plane activity. No atmospheric recordings due to dogs barking. Scratching sounds picked up by hydrophone.
31 December, 9.00am
Rainfall 2 weeks prior: 61.1mm (total for period – 104mm); average max temperature for December was 33.8°C
Site 1: air temp 22°C; soil temp 27°C; soil moisture dry top, moist below 5cm
Site 2: air temp 23°C; soil temp 33°C; soil moisture dry top, moist below 8cm
General observations: Soil temperature at Site 1 significantly lower than Site 2 – groundcover effect with pigweed grown right over Site 1, roo activity evident at Site 2 (roo poo), a lot of gusty wind, less ants at both sites (much less at Site 2), Paterson’s Curse finished flowering – fewer bees. Crackling sounds, not rhythmic, movements can be heard when wind dies down.
14 January, 8.30am – FINAL RECORDINGS + UNEARTHING
Rainfall 2 weeks prior: 82.4mm (total for project period – 186.4mm); average max temperature for first 2 weeks of January was 32.9°C
Site 1: air temp 23°C; soil temp 27°C; soil moisture very moist – wet
Site 2: air temp 25°C; soil temp 30°C; soil moisture – wet
General observations: Both sites received heavy storm rain two days prior to final recordings/observations – water had run across Site 2. Much more grass and weed growth on Site 1, and increasing regrowth happening at Site 2. A lot of wind, less ants. White curl grubs found in both burial pits – a small one at Site 1, larger one at Site 2. Most likely both are Yellowheaded cockchafer (Sericesthis harti), commonly known as Scarab. The fabrics at Site 1 had almost completely disintegrated – only fragments left. Rubber bands and plastic bread tag labels were not present either. Site 2, all four fabric samples were intact, with rubber bands and labels attached.
…the impact of anthropogenic noise on invertebrates has largely gone unstudied. Although invertebrates comprise 97% of animal species on Earth, and are important in most ecological processes, only 4% of the work on noise and wildlife has been on invertebrates.
Maggie Raboin, Damian O. Elias, Anthropogenic noise and the bioacoustics of terrestrial invertebrates, 2019
Picture gallery
CLICK TO EXPAND THE IMAGES
Conclusions
This isn’t a science project but it is informed by science. The soundscape composition and poetic prose that are now in development will encapsulate the conclusions drawn from this two-month project, along with the narrative around these soils. This is fertile ground (pun intended) for creative exploration, requiring deep engagement with the subject and time to listen to not just what we think we can hear, but to the potential that lies deep within.
Thanks
Patricia Watt – ecoartspace founder and convenor for the invitation to join the Soil Dialogues; Dr Rhonda Janke (USA) – for guiding the fabric burial process and her role as lead convenor of the IUSS congress session; Anne Yoncha (USA) – for her interest and time spent working on developing an abstract and presentation of the results of our projects that reveal the power of sound and data sonification as creative and expressive mediums for not only sharing the story of and life contained within soil, but as an indicator of soil health; and to all the amazing field recordists across the globe whose works constantly inspires me to listen more actively and more deeply to the incredible world that exists beyond the bubbles we live in.
…whilst there are myriad complex layers of sound everywhere, understanding how they interact, when presented, with narrow surfaces and power dynamics within the arts (and sciences) can be part of the process…because it is listening also.
Jez riley French, Instagram, November 2023