Introduction

Academics, public practitioners and government entities have demonstrated a burgeoning interest in the potential of citizen/community science (CSFootnote 1). CS examples feature abundantly in a range of scholarship, including critiques on science productivity, policy, democratisation, educational opportunities, and philosophy and practice (e.g. Bonney et al. (2014); Strasser et al. 2019). Ultimately though, to achieve more equitable outcomes, and we argue, better outcomes for the multiple planetary crises that CS might work to understand and alleviate, researchers must study topics with meaning for society. Further, CS has an obligation to engender ownership for participants, which requires commitments of time, finances, and effort in getting to know participants’ values (what they care for) and how these values manifest (how participants practice that care).

CS, which “poses questions about who participates in science, what it means to participate in science, who gets to decide what scientific questions to investigate, and even what kind of knowledge and practice count as science” (Pandya et al. 2018), offers an opportunity to examine diversity in knowledge production. While much of the literature is notably uncritical, CS approaches can create challenges that are not present in conventional, dominant modes of research. Our discussion builds on scholarship of CS and diversity through the case study of Soilsafe Aotearoa (SA), a CS programme in Aotearoa New Zealand (Aotearoa NZ) that engages with communities through diverse and inclusive approaches to participants and participation. SA’s primary objective is to generate a dialogue on a diversity of soil meanings and value(s) so that communities in Aotearoa NZ are cognisant of what soil might represent to others while contextualising what (a lack of) soil care might mean for them and society more broadly (Sharp 2024). We draw our insights from mixed (arts and social, environmental and earth sciences) methods of enquiry, education, and engagement (Sharp et al. 2024; Tsang et al. 2023).

Here, we aim to outline the opportunities and challenges that arise with a strong commitment to diversity in CS projects. This includes diversity in the participants and participation, and therefore the values, knowledge bases, and representations of data incorporated into the scientific process and, therefore, the outputs.

Background

Origins of citizen/community science

Richard Bonney’s and Alan Irwin’s early works in the 1990s (e.g. Bonney, (1996); Irwin 1995) laid claims to the intentions of CS. These have evolved and been captured variously in the Ten Principles of Citizen Science developed in 2015 and through the European Citizen Science Association (Robinson et al. 2018), with key principles listed as: (1) active engagement in new knowledge production with citizens as contributors, collaborators or project leaders; (2) genuine science outcomes; (3) mutual benefits for all parties; (4) citizen participation at multiple stages of the process; (5) citizen scientists receiving feedback; (6) recognition of limitations and biases; 7) public availability of data; (8) citizen scientists acknowledged in results and publications; (9) citizen science evaluation for output, quality, experience and societal/policy impact; and, (10) consideration of legal and ethical issues around copyright, intellectual property, data sharing, confidentiality attribution and environmental impact (for complete wording of the principles, see Robinson et al. 2018). Over time, there have been some shifts around vernacular reflecting various contentions in the terminology, particularly over the use of ‘citizen’ in citizen science. Firstly, the term ‘citizen’ in CS has, in some spheres, been perceived to problematically represent the ‘citizenship’ status of amateur scientists, thus effectively excluding non-citizens of any particular state. It is recognised that terminology matters to participants, and it affects the production of knowledge (Eitzel et al. 2017). Secondly, there have been performative efforts to shift the locus of power in some projects away from the scientist and towards community (as collective rather than individual). Despite a still frequent conflation of ‘citizen’ and ‘community’ science in less critical literature, a more deliberate use of community science has emerged in the last decade to capture efforts towards more inclusive engagement and epistemic practice (Strasser et al. 2019).

Robinson et al. (2018) – as illustrated in their 10 Principles of Citizen Science – and Sauermann et al. (2020) have published important, recent provocations on how scientists might engage citizens in scientific endeavours. In the sections below, we illustrate how the two key drivers for CS, productivity and democratisation, proposed by Sauermann et al. (2020), present both opportunities and challenges for what Robinson et al. (2018) have advanced around a different framing and practice of CS.

Science productivity: participation in, and promotion of science

CS is perhaps most recognisable in its deployment to emphasise engaging public in data collection, analysis, and interpretation, where the term citizen was initially used to distinguish recreational scientists from professional scientists. Often public engagement uses technology or theory that is otherwise exclusive to scientific specialists, giving the public insights into scientific method and process, thus broadening their experience through practical education. This is consistent with Bonney’s version of CS, as “public participation in scientific research and a tool to promote the public understanding of science” (Strasser et al. 2019, p. 53). Bonney’s vision and implementation of CS offered a neat solution to the launch of the U.S. National Science Foundation (2002) Informal Science Education initiative to engage public in science, finding consistency in messaging between science and science agenda.

From a scientist’s (and potentially funder’s) perspective, there are compelling reasons to involve the public in scientific projects. By ‘productivity’ Sauermann et al. (2020) mean the enrolment of more, spatially-distributed data collectors to enable more data collection, more analysis, and more interpretation over time than otherwise possible. This is visible in, for example, the increased sampling power and public benefit of coastal litter in a CS marine conservation project (Van Brussel & Huyse 2019). Critiques of this productivity-focus are that scientists reserve the privilege of research design, and therefore the outputs of the research narrative, and its audience (where determining actual research practices is seldom enabled for public participants (Kleinman 2000a p. 6)). Arguably this approach erases public participants from the production and dissemination process and often assumes that the outputs will have a positive contribution to society, belong in the public domain, and/or generate increased social license to continue implementing such projects, none of which are guaranteed aspects of a CS project.

Democratised science? For the people, and by the people

Irwin’s (1995) initial people-centred approach to CS highlighted two key democratic interests: that CS was “science for the people” and was “science by the people”. The intention was that it would help usher in a more democratic science policy system that was more responsive to the “understanding” and “concerns” of the public (Irwin 1995, p. 69–80). Further CS was intended to be democratising – a declaration influenced by feminist academic interest in the social construction of science and technology, which identified privilege, politics, and exclusion in (artefacts of) science (Lengwiler 2008). Practically, this approach broadened CS’s take on ‘the people’ to include otherwise marginalised populations who typically have reduced involvement in scientific knowledge production. CS was seen here to have a role in capturing local contingency and knowledge, which is acknowledged to “differ qualitatively” from knowledge produced following the “norms and values of institutional science” (Strasser et al. 2019, p. 54). Uncomfortably, this type of knowledge capture has been regarded warily from within science with concerns for its potential to decentre scientific expertise, ‘scientist as expert’, and, associated credibility (Riesch and Potter 2014).

Public in science: diversity in, and of, participation

We have outlined intrinsic benefits of public participation in science–broadened understanding of funding and policy decisions, research process, and education in science for public. Public science also includes extrinsic benefits, for example, taking part in CS has been proven to enhance well-being and connectedness with nature (e.g. Pocock et al. 2023). Diversity in the target CS (public) participants, as well as diversity in ways of participating in CS, are important to make these benefits available to those who are interested in pursuing them.

What participation?

Participation methods vary across projects, but oftentimes not within the same project. There have been different perspectives in the CS community of scholars regarding models of participation. Bonney et al. (2009, p. 11) offer a typology of involvement types, which classes projects as contributory (designed by scientists with data contributions from the public) to collaborative (with some design input, data analysis, or science communication done by the public), or co-created (jointly designed by professional scientists and public, with sustained engagement by public participants). Indeed, scholars like Kleinman (2000b) have developed a continuum of participation to document different types of engagement, spanning from the oft-observed versions of CS where participation is relatively low-engagement, to lesser-found projects where participation is high-engagement (e.g. public participation in research design and practice) thus “challenging the rules of scientific methods” (p. 140f). This conceptual ‘ranking’ encounters difficulties when projects demonstrate overlaps between methods and, therefore, levels of involvement; or, when there is a bias against projects with ‘alternative’ data types; or, when participation is more exclusive (e.g. requiring more advanced competence or skills and access to take part in particular analysis).

Progressively, Strasser et al. (2019, p.55) assess CS models differently, thinking through non-hierarchical “epistemic practices involved in participatory research – sensing, computing, analysing, self-reporting, making” as a set of diverse practices that are involved in knowledge-making. They, therefore, offer the potential of privileging otherwise marginalised types of knowledge, supporting the idea of ‘more-than-science’ CS projects. Such thought experiments expand notions of what is legitimate knowledge production, broadening CS socio-cultural inclusivity, educational and pedagogical rigour, and diversity of the types of values and valuations of the world that might be made with such an approach. To this end, Senabre Hidalgo et al. (2021, p.199) maintain that “the citizen science research design process should be inclusive, flexible, and adaptive in all its stages, from research question formulation to evidence-based collective results” potentially to include co-creation techniques from a multitude of disciplines and methodological inspirations.

What value(s) and which ones represented?

Data generated from diverse participants and forms of participation offer opportunity for different representation, beyond conventional scientific formats that connect with other diverse potential learners/participants in different ways. Typically, social science methods are used to examine potential impact on individual citizens (Gommerman and Monroe 2012). But beyond instrumental examinations of ‘impact’, the use and analysis of less familiar modes of multimedia, images, art and language can narrate and critique aspects of the world as a form of ‘community humanities’ (Heinisch et al. 2021), not only to “bring to light new research questions but also new ways of analysing, combining, visualising, presenting, storing, and sharing pre-existing data as well as new ways of [information sharing, with diverse publics] and collaboration among scholars” (p. 98).

As Sauermann et al. (2020) discuss, diverse participants and participation in CS shapes science: “when citizens get involved in identifying problems and setting research agendas, their identity will shape what projects are pursued” (p. 9). It follows then, that a lack of diversity in participation will be mirrored in research priorities, reflecting “primarily the preferences and assumptions of those who participate rather than society at large, contrary to the premise of the “democratization view” of CS” (Ibid.). Recently, there has been an upswing in the emergence of community-designed and -led initiatives (Ballard et al. 2018), leading to greater reassurances around perceptions and realities of data/knowledge sovereignty and engendering trust through more proximate relationships to professional scientists. This supports Bonney et al.’s (2016, p. 12) provocation that if CS is to be genuinely democratising, then “it must strive to reach a wider range of audiences and participants”.

Which participants?

While there is a lack of detailed analysis of who takes part in CS (Paleco et al. 2021), socio-cultural aspects of gender and race are examined most regularly. CS projects seem likely catalysts of science capitalFootnote 2 growth given that ideal project recruitment and engagement efforts invite the widest variety of people, “with an emphasis on involving children, young adults, and families with low science capital” (Edwards et al. 2018). Actually realising participant diversity in CS is not that straightforward. Increasing the diversity, levels, and intensity of participation is, as observed by some scholar-practivists, the number one challenge (e.g. Sauermann et al. 2020 p. 9).

On a solely (notably outdated) binary axis of gender, we note the concern that in the Global North participants of CS projects are more likely to be (cis-) men (Pateman et al. 2021; Edwards et al. 2018; Allf et al. 2022). Looking at ethnicity in isolation, data on CS participation shows typically homogenous demographics (Pateman et al. 2021) unless the project is intentional about diversity e.g. UK-based Open Air Laboratories (OPAL showed greater diversity where 23% of participants were people of colour compared to 16% non-whiteFootnote 3 in UK (Open Air Laboratories (OPAL) 2023). It has been demonstrated that gender (e.g. Jones et al. 2000) and ethnic identity (Greenall et al. 2023) have impacts on the ways in which people experience, value, and participate in. Such findings have provoked a swathe of literature on feminist, (more-than-) humanist approaches to what has been traditionally perceived of as the ‘natural’ sciences (e.g. Carey et al. 2016; Sharp et al. 2022).

Inclusiveness in participation should therefore be core to CS; thus, an eye on the effects of intersectionality, or multiple axes of identity (see Okune et al. 2018) and how they assemble to define hierarchies and power relations, should be considered. For example, statistical representativeness in US CS projects shows predominantly white, younger than average, middle class, and male participants (Curtis 2015; Reed et al. 2013; Raddick et al. 2010). Yet more studies note higher participation by higher education graduates working in science, technology, engineering and mathematics (STEM)-related fields (Allf et al. 2022). Of particular relevance to our work on domestic garden soil, a US study suggests domestic food gardening is typically done by higher-income, white, males (Das and Ramaswami 2022). While recruiting for diversity increases inclusivity in CS, the pressure for ‘robust science’ (c.f. the productivity model of CS) is a driver for the deliberate targeting of conventional participants: entry barriers for CS are in principle intended to be low, but practically, participants’ competence with and access to technology is often a requirement, potentially posing an obstacle to participation. Potential participants list scientific or other literacy as barriers to engaging, where schools, in particular, list a lack of time, space, staff, and other key resources as key obstacles (Roche et al. 2020).

This limits the scope of meaning, socio-cultural and scientific value, and interest incorporated into CS, for public and professionals alike. Lesser regarded considerations of diversity of participants include age. In a “paradox of neighbourhood participation” elderly people tend to be more present in their neighbourhoods, yet are systematically overlooked in participatory processes that relate to their environments (e.g. King et al. 2020). Further, there is a relative paucity of CS studies that consider children and youth, which seems paramount as today’s youth inherit the legacy of degradation and environmental contamination of the past and today. Further, to our knowledge, there has not been a systematic overview of people with disabilities in CS projects. It is clear though that there are some groups – low income, people of colour, migrant populations, the young and the elderly, those with disabilities (and these demographics intersect along a number of planes) – who are under-engaged in CS.

CS recruitment for diversity

To attend to these participation imbalances, toolkits encouraging progressive team composition practices have been established (e.g. ECSA (2015); Biodiversa+ 2022). One example recommendation is that women hold leadership roles in CS projects (Puy, Angelaki (2019)). Additional learnings can be gained from children’s educational agency scholarship, which seeks to empower and increase children’s representation and voice in research (Ergler 2017), for children’s interests to inform research practices (Tisdall 2017), and for children to determine their preferred ways of learning (Cincera et al. 2020). These priorities also emphasise the provision of enabling children to collaborate to co-produce their own methods of educational outputs (Lemos et al. 2018; Edwards-Maas 2023; Edwards-Maas et al. 2023). An example of how one project has enabled diverse age participation is D-NOSES study on odour pollution through the use of both analogue and digital methods (D-NOSES 2023), which appeals to sensory-based methodology. Further, the Intergenerational Learning for Nature Conservation Volunteers programme has features where elders and experts share their knowledge about historical, social, economic, and ecological features of the area, participate in field trips together, and practice local conservation activities, documented through photos, videos, and storytelling (Papageorgiou 2015) consistent with citizen humanities approaches (Heinisch et al. 2021).

Democratisation assumes a levelling of access to distribute power among all participants. This assumes that all citizens participate, an ideal of CS, but as illustrated above, this is not a reality. It assumes a goal of public participation to expand the range of people involved in science to increase scientific literacy. Increasing scientific literacy is often an aim that is considered only from the perspective of the scientist, that scientists must educate the public. While education is almost certainly critical to the process, especially to democratise science, the educational benefits of CS are often narrowly defined, typically instrumental, and not always explicitly advertised even while they are often listed as a project outcome. If looking to expand its reach, Strasser asks, should it not “reach out to people with little or no previous experience of science”? (2019, p. 62). Scrutinising the role of education in CS also, however, leads to questions about whether public wish to participate or be educated in ‘science’, particularly if it does not represent or reflect their reality.

Given that many CS projects are scientist-designed, -facilitated, and -narrated in public spheres, CS has been critiqued for its principle of scientists giving feedback to citizens while rarely allowing for equivalent feedback from citizens to scientists, despite the clear benefits for both science and participants, and the knowledge that all CS projects will have aspects that participants will find challenging or have problems with (Vohland et al. 2021). Further, there is an expectation of CS projects to generate genuine scientific outputs without equivalent ‘genuine social outputs’. The promises of CS, to: democratise science, increase scientific literacy, and make scientific breakthroughs (Strasser et al. 2019), therefore require critique.

A diversity in knowledge and values via diversity in participants and participation benefits all learners (Pandya (2012)). Encouraging CS participant diversity is claimed to benefit scientific outcomes too, by delivering them to a wider population, and even leading to positive effects for complex thinking (Lising et al. 2004). The subsequent growth in science capital is of benefit for the whole of society, with the potential for a pathway into a science career if encountered at a point in one’s life appropriate to them. Thus, enabling wide societal participation in science is not only an egalitarian endeavour, but also leads to “collaborative knowledge creation [that] is urgently needed to address the complex global challenges that humanity faces” (Rayne et al. 2023, p. 1034) where scientific progress also benefits from the diverse perspectives offered by heterogeneous teams (Kandola & Fullerton 1998).

Context: Aotearoa New Zealand

Aotearoa NZ’s diverse public

Today, Aotearoa NZ has a unique bicultural (and trilingual – te reo Māori (Māori language), English language, and NZ sign language) foundation and increasingly diverse demographics. Of the national population, 16.5% identify as Māori, and of the Tāmaki MakaurauFootnote 4 Auckland population, 23.4% (Statistics NZ 2018). Recognising the nation’s bicultural, and historically marginalised Indigenous Māori, honours Te Tiriti o WaitangiFootnote 5 (the Treaty of Waitangi) principles and Māori values, while enriching knowledge production everywhere. There is a diversity of perspective around knowledge production of ‘science’ amongst individuals and communities, though te ao Māori (Māori worldview) origin stories are in common as they relate to ancestral relationships to environment and, specifically to our project, oneone (soil) or whenua (land). The education system is witnessing a resurgence for te ao Māori (Ritchie 2012) by including subjects such as te reo Māori, Māori performance and arts in school curriculum revisions, and offering specialised learning about Māori models of well-being as subjects grounded in mātauranga Māori (Māori knowledge), though there is simultaneously systemic trauma for learners and their families, as well as ongoing conservative pressure to halt such projects. There are observable disjunctures in exposure to, and participation across curricula, where, for example, participation in Aotearoa NZ school (mainstream) science fairs has been examined to be low for Māori, rural students, and (underfunded, less appreciated) smaller schools (Wehi et al. 2014).

The concept of ‘co-production’ for Māori is considerably more nuanced than previously discussed in much of CS literature. Certainly, Smith’s (1999) foundational work Decolonising Methodologies challenges the concept that Eurocentric approaches to research benefit all people, laying the ground for co-production practices in Aotearoa NZ. Indigenous scholars in Aotearoa NZ and globally have reflected that a key CS outcome is strengthened relationships rather than prescriptive or intervention-focused ones (Larkins, 2024; Tengö et al. 2021). Closer attention to sincere, relationship-focussed co-production could enable and prioritise accelerated Māori development aspirations via iwi (Māori tribal group), and Māori authorities’ influence in the co-design of policies and programmes that concern their people and their own resources (McKenzie et al. 2008). This approach would offer knowledge production in CS in directions not often realised.

Soil, in place

Soil contains a variety of metals, minerals and nutrients which occur naturally and are an important part of what makes soil so valuable (Doran, 2002). There are also some metals that we might have concern about when they are present above levels that we consider safe for human and/or ecosystem health (Martin et al. 2023). These metal values might be natural (geogenic) in origin (Martin et al. 2016) though there is copious global evidence for anthropogenic signatures in soil that result from past industrial practices, such as adding lead to gasoline and paint (Markus and McBratney 2001). In Aotearoa NZ, soil is often discussed in an agricultural context, and through this lens, there is a dominant narrative of soil being valued for its productivity and economic gain (Minami, 2009).

Working with soil in domestic spaces has a long history in Aotearoa NZ where domestic and community gardening has been a way of life to sustain an affordable, adequate, and culturally appropriate food supply. In Aotearoa NZ, gardens associated with marae (meeting grounds belonging to an iwi, hapū (clan), or whānau (family)) provide a sense of community, an opportunity to practice Tino rangatiratanga (self-determination) and Tikanga (cultural protocol), as well as a connection to the whenua (land, placenta), tīpuna (ancestors) and atua (creators) (Stein et al. 2017). For Māori, soil health has therefore been explored from a perspective of health, considering its human, social, and cultural dimensions (Stronge et al. 2023), as having its own mana (integrity, power) and mauri (life essence, energy) (e.g. Hutchings et al. 2018). While there is some capture on how public land or industrial soils have been ‘cared for’ or not, via data on soil contamination, biodiversity, or fertility, there is little to tell us about domestic soil quality, and what its care looks like.

Soilsafe Aotearoa

Soilsafe Aotearoa (SA) (Soilsafe Aotearoa 2024) is an interdisciplinary CS programme that was established by environmental, social and earth scientists at the University of Auckland and GNS Science | Te Pū Ao (an Aotearoa NZ Crown Research Institute), in Aotearoa NZ in 2020. It is perhaps best known now for its most enduring activity – a screening programme for domestic garden soil that provides participants with results for a suite of metals and metalloids such as lead or arsenic, free-of-charge. It was inspired by the work of the Vegesafe (Vegesafe 2022) project, launched in 2013 by Macquarie University in Sydney (Rouillon et al. 2017) which was successfully providing backyard soil metals testing to gardeners in Australia.

SA’s core interest is in a diversity of place-based soil values that span scientific, environmental, cultural, economic, political, and social aspects of soil. These values might be quantitative and qualitative, natural, and social, and understood through a mix of scientific and humanities lenses. The inception of SA was motivated by an interest in the intersections of the diverse types of soil values that we as physical and social scientists had identified, but first it was critical to understand what was important for different communities in Aotearoa NZ, and potential participants.

Methodology and methods

The first stage of the programme entailed spending the best part of a year undertaking foundational social science activities to establish community values of care and concern for soil. Community partners in food production, education, and policy-making have been active in feedback and development, leading to the informed design of the programme, including a mandate for the soil chemistry screening and approach (Fig. 1).

Fig. 1: Stage one of Soilsafe Aotearoa’s programme development.
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Programme preparation and the continued programme informed design from 2020 until the soil metal screening launch in February 2021.

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This was followed by the development of (again, mandated by public feedback) educational engagement activities (Fig. 2).

Fig. 2: Stage two of Soilsafe Aotearoa’s programme development.
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Ongoing educational and outreach programme development committed to diverse participation, values and knowledge production starting from when our soil metals screening programme launched in 2021, to date.

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SA’s various programme activities are disseminated through a website www.soilsafe.auckland.ac.nz, fliers at public libraries around the country, social media (mostly Facebook), a school programme, and talks at academic and non-academic events. Reflecting the principles of diversity in the programme’s work is paramount and so commonly marginalised groups (mana whenuaFootnote 6, people with disabilities, young and elderly people, people of colour, and low-socio economic groups) have been a focus in engagement work. Specifically, working in Aotearoa NZ, the programme needed to be attentive and responsive to obligations and commitments to Te Tiriti o Waitangi, given that PākehāFootnote 7/tauiwiFootnote 8 researchers lead the programme. The full list of methods is listed in Appendix I along with their different contributions and challenges around diversity.

Baseline of social values (meanings and perspectives) of soil

Our first year of work prior to launching the soil metal screening aspect of our programme (Fig. 1) concerned work that established qualitative baseline values for the SA programme, on which future projects in the programme would be dependent. Our initial research questions aimed to understand:

  1. a.

    What are the diverse values and meanings of soil for Aotearoa NZ’s public?

  2. b.

    In what ways do Aotearoa NZ’s public care for, and have concerns for, soil?

To achieve this, the project used predominantly social science methods of interviews, an anonymous online questionnaire on values of care and concern for soil and gardening practices, and informal personal communications with public. Fifteen interviews were undertaken with participants who were publicly searchable online as being organisational representatives who were familiar with/practitioners of soil on an everyday basis; they were organisers of community gardening and māra kai (Māori food garden) activities, council and government policymakers and scientists on soil issues, horticulturalists, geoengineers, food waste managers, and community composters. Māori participants were intentionally invited to participate where their online identity was associated with Māori gardening practices or places) (see community composters’ responses in Wing and Sharp 2023). Participants were approached via email and social media. As pointed out by Larkins (2024), evaluating how learning and empowerment of participants relates to wider societal impacts is often overlooked by researchers but has the potential to yield insights into the long-term sustainability, transferability of practices and data to different contexts, and the influence on policy and decision-making processes to increase the overall societal and scientific impact of CS endeavours.

Responses from the fifteen interviews with soil practitioners helped to inform the questionnaire’s focus on identifying respondents’ concerns about and care for soil. The questionnaire was distributed in English and te reo Māori language between September 2020 and July 2021 (overlapping with some periods of Covid-19 lockdowns in Aotearoa NZ), distributed via email directly to warm contacts, and via social media through invited community pages, including purposively to populations of diverse ethnicity including Māori groups (like for the interviews, where their online identity was associated with Māori gardening practices or places). The questionnaire would have been put in front of perhaps a thousand potential participants and yielded 354 (English language and te reo Māori) initial responses. Funds were committed for back-translation of te reo Māori responses. The questionnaire included a photo-elicitation component for respondents to upload photographs of their interactions with soil for visual analysis, as a set of alternative data/values, more consistent with citizen humanities work (Heinisch et al. 2021), and 65 participants engaged in this activity. We did not collect data on which participants of this questionnaire were Soilsafe Aotearoa soil metals testing participants, as this was not the purpose of the questionnaire and largely preceded the metals testing initiative.

Baseline of physical values (metals) in domestic soils

The nation-wide soil metal screening programme required consultation on human ethics protocols and legal aspects of the soil collection process for participants. Participants gather the soil samples and send them to our lab themselves, according to a protocol provided on the website (Soilsafe Aotearoa 2024). SA initially tested for eight trace elements in domestic soils using portable x-ray fluorescence (pXRF) according to protocols in Rouillon et al. (2017). The metals selected were arsenic, cadmium, chromium, copper, manganese, lead, nickel, and zinc (now only arsenic, lead, copper, and zinc, post-quality assessment). The elements were initially chosen because: arsenic, cadmium, chromium, copper, and lead are identified by the New Zealand Ministry for the Environment as priority contaminants with histories of contamination in Aotearoa NZ and non-negligible effects on human health (Ministry for the Environment, 2012); and, copper, manganese, nickel, and zinc are all essential elements for plant growth at lower concentrations. All eight elements occur naturally in Aotearoa NZ soils (Martin et al. 2016). Participants take part in the soil testing to find out the levels of metals (particularly lead), in their soil with consequences for their backyard food gardening and recreation. As of September 2024, SA has provided >5100 free soil metal tests to >1100 homes.

Once their soil is tested, the participant is emailed a report with levels of the eight metals and metalloids in their soil (e.g. Fig. 3), displayed next to the associated national soil guideline values. The report links to resources to help participants understand metal concentrations in their garden, and how to take action in case of exceedances over threshold values. Results from testing help participants to choose where (not) to plant food crops or play in the garden (particularly for children), identify house maintenance issues (e.g. where leaded paint might be flaking into soil), and contribute scientifically to the first baseline of domestic soil metals for Aotearoa NZ.

Fig. 3: Example report showing the levels of the eight metals and metalloids in a participant’s soil.
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<LOD: below the lower method detection limit of the pXRF.

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Recruitment for soil testing began (and has continued) as a general appeal through social media. Once pilot-testing issues were worked through, the approach was targeted to be more inclusive, to specific Māori gardening groups and rural communities, including dropping/sending fliers and posters at locations of interest, like garden centres and community gardens. A recent soil metal screening post-participation evaluation revealed that more than a quarter of participants came to the programme via word of mouth, then about a sixth via social media, and next, our website (Eugenio et al. 2024). The programme website contact form generated community engagement possibilities too: early childhood education soil science sessions, ‘women in science’ talks with the Girl Guides association, participation in annual kids’ outdoor education events with national partners, and invitations from other industry partners to collaborate. After launching the soil metal testing, attention turned to other aspects of soil care and concern values provided through the interviews, questionnaire responses, and our website contact form. Our many respondents from schools/community groups requested educational resources, school activities, and workshops for children, as well as the general public. This created a mandate to develop Soilsafe Kids (SK), dedicated to educational engagement for diverse soil values in Aotearoa NZ, reaching diverse ages and communities.

Children’s engagement activities

In 2021, we presented an interactive soil science workshop in nine classrooms across Tāmaki Makaurau Auckland, where the social scientist at the University of Auckland was based. These activities led to the development of resources targeting early primary school students (~5–10 years old). Teachers supported by the Royal Society of New Zealand Teacher Leadership Fellowships assisted in aligning the resources to the English-medium New Zealand Curriculum. While these pilot activities were outreach activities only and did not require ethics approval, the subsequent research activities at schools described below, did.

Through 2022 and 2023, further resources were developed as part of the diverse soil knowledge 3-day workshops designed and delivered under the NZ Ministry of Business, Innovation and Employment (MBIE) Unlocking Curious Minds programme which funds projects that support New Zealanders, particularly those that have fewer opportunities, to learn about and engage with science and technology (Ministry of Business, Innovation, and Employment MBIE (2023)). The workshops feature 8 interrelated modules that sit across multiple curriculum requirements: numeracy, literacy, science, arts, and mathematics, and that inspire different lenses of enquiry on soil (Fig. 4). The ‘What is soil?’ module run at the start and end of the modules established differences in perceptions/ values of soil after students participated in the interdisciplinary programme that promoted diverse knowledges (Tsang et al. 2023).

Fig. 4: Soilsafe Kids 3-day school workshops.
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The modules shown here illustrate an example of content order, and ways of teaching/learning diverse values of soil.

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Public art exhibits

The two SA art exhibits were opportunistic around the timing of Covid-19 lockdowns in Auckland at different periods in 2021, and they were advertised on social media. Interactive displays (that particularly appealed to children) included: microscopes with interchangeable slides with thin sections of various rock types, graphed data of soil trace elements, video interviews of the SA team members and their roles, participant narratives of soil care and concern (quotes gathered from the SA questionnaire) on a revolving slideshow, and children’s artwork from our school visits, to represent diverse values of soil. All contributions were displayed anonymously. We also engaged with a community photographer, a clay potter, an artist focused on atua Māori, a local soil pigment artist, and a fine arts specialist to create community artist interpretations of soil to the collection (Fig. 5). The soil pigment artist held live soil painting workshops with the resulting artworks donated to the community as murals.

Fig. 5: Examples of artworks at the Soilsafe Art Exhibits, showing the variety of artistic practice and contributes to ‘soil work’.
figure 5

Illustrated here is a variety of artistic practice contributing to ‘soil work’.

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Findings and discussion: committing to diverse participants, participation, and knowledge production for human, environmental and scientific benefits

Below we comment on areas of our programme that demonstrate a diversity of participants, participation types, and in knowledge production.

Diverse participants

We saw diverse geographical, age, and ethnicity participation in our baseline soil values questionnaire that generated initial understandings of the public’s values of soil, and simultaneously, their potential interest in engaging with a screening programme on metals in soil. Surprisingly, given the plethora of studies that suggest low participation in CS by women, at least for this questionnaire, almost two thirds self-identified as women. 8.5% self-identified as Māori, more than a quarter were older than 60 years old (yo) and more than two-thirds were older than 40 yo (Appendix II), a contrast to the trend for gender, ethnicity, and age participation in typical CS projects. Acknowledging this questionnaire represents just a segment of societal perspectives on soil care and concern and given it was implemented via an online platform which limits participation to those who can access the technology, its demographics suggest progressive statistics around usually marginalised participation in CS.

In a separate soil screening post-participation questionnaire undertaken by SA, we identified similar demographic results: we found that, out of 175 responses (post data-cleaning), 68% of respondents identified as women, 5% identified as Māori, and more than a third were at least 60 yo (Eugenio et al. 2024). Like for the baseline questionnaire on care and concern, diverse age participation is suggested to include a significant number of retired participants who are more active, often in their gardens, and have the time and inclination to test the soil they produce food in. This older age participation was irrespective of socio-economic status. Despite overseas studies to the contrary, we suggest this is a consequence of the place-based nature of gardening, and the gendered and age-based trends in domestic and community gardening in Aotearoa NZ where it is a popular and thrifty activity for retiree gardeners, with associated wellbeing benefits (Wiles et al. 2009).

In 2022–23, the school workshops purposively invited schools that were: located in lower socio-economic neighbourhoods; had high Māori and Pasifika student ratios (guided by the New Zealand Educational Review Office statistics and collected by the school at the classroom level); and/or, were rural (as evidenced by cartographic boundaries) on the basis that inequalities remain for rural students' access and participation (Wehi et al. 2014) (see Appendix III). 3-day workshops engaged students of whom 27% (across all participants) were Māori. All workshops (3-day and condensed versions) engaged 1083 students from preschool to 11 years old. Children themselves participated, but also engaged their family and communities: children were invited to submit soil samples from home which would require parental or caregiver assistance (there was uptake up of this invitation by 29.4% of children in the 2023 iteration of the 3-day workshops), and children reflected that they had discussed their learnings on the programme with their household and people outside of the classroom (Edwards-Maas 2023). This suggests that these children had a role in soil’s meaning-making through their participation, translation of their understanding to their wider family and communities, and through actual practice (James & Bixler 2008).

Diverse participation

Diverse participation has been described many ways including as encompassing a diversity of academic disciplinary approaches, both community- and science-led enquiry, and diverse community participation (i.e. a range of intersectional demographics). Recognising the diverse socio-cultural contexts of this work, SA brings together academic, public, iwi, industry, government, community (artists, social enterprise), individual, and school (teacher, principal, student and child-caregiver) partners. The knowledge produced, as a culmination of these contributors, is therefore novel. This requires diverse communication styles and languages for diverse learners and collaborators.

The range of methods of enquiry implemented across academic disciplines (art using soil, science experimentation, photography, interviewing, practical learning with hands in the soil) mean that diverse values – quantitative (e.g. typologising and counting worms), and qualitative (e.g. sensing soils through colour, texture, smell, and notions of ‘beauty’) – were utilised to express soil meaning, appealing to a diversity of learning acuities. The qualitative aspects in particular, allowed the programme to access emotive connections with soil, and to observe actual demonstrations of soil care. Further, contributing participants in the school workshops included teachers who offered reflections on the activities and the learning. Particular value in this practice is the accountability and commitment by taking on participant feedback (Ortlipp 2008).

Community-led enquiry as generated out of the baseline questionnaire responses showed ‘contamination’ was a top concern about soil (in response to ‘what concerns do you have for the soils you interact with?’. ‘Uncontaminated soil’ was a top criteria for values of ‘good soil’. We received many responses like “our house is an ex-state house and was repainted before we bought it. I know that there are flakes of lead paint in the soil which concerns me for my family’s health…in particular my…one year old. I worry she may get lead poisoning from eating the soil”, and “The house I live in was originally constructed in the 1950s, and has had lead-based paint used on weatherboard in the past. Also, neighbours recently built a retaining wall next to my fruit and vegetable garden using treated timber, and I worry about arsenic leaching”. From the social values baseline data, it was clear that the public saw an emotive and practical need, and concern for the protection of soil and wanted information on soil contamination data to be collected and communicated back to the public. There was therefore a mandate to establish a soil screening programme in NZ that is responsive to community need and consistent with CS principles. This came with some conditions, for example, early interviews with Indigenous participants indicated that some participants would want their soil samples returned to them, so this option was added during the submission process, following a protocol of geoethical study design (Sharp et al. 2022) that is attentive to cultural needs.

A key finding from participation in the school programme was that children learned most about their soil (via food gardening) from older family members. This tells us that there is intergenerational knowledge exchange happening in domestic and community spaces, as well as more formally in schools. This fits with Papageorgiou’s (2015) noted benefits of intergenerational CS that include the integration of human aspects with technological ones, and the novel sharing of experiences and capacities.

Consistent with our interest in making our work diversely interesting and digestible for the public, particularly through visual and tactile experiences, we exhibited diverse soil ‘data’ in the art exhibits as vignettes, slide shows with anonymous responses about soil care values, mapping of similar response snippets, and children’s art. This mode of citizen humanities (Heinisch, et al. 2021) was a way of collecting and feeding back to the public what they had told us about their perceptions of soil. Not only did this offer transparency to the public about how their data are used by researchers, but also enabled the public to interpret the data themselves to co-produce their own soil knowledge (Lemos et al. 2018). All of these media were intended to highlight a variety of representations of a variety of soil values, and encourage curiosity about, and awareness of the need for, this resource’s protection. For one of our exhibits, we invited a low-resourced school class from the local area. The purpose here was to encourage participation in this project of diverse soil values of students who might not otherwise have the opportunity to do so. They participated in our associated soil art workshop and attended our soil science talk and mixed-medium exhibit. This novel work added a new dimension to our exhibits that was captivating and brought in a different sector of public interest.

Diverse knowledge production

Diverse knowledge production refers to the outputs and outcomes of the diverse participants and participation above. Considerable intention in, and attention to, Māori participation in the programme (e.g. in social value baseline interviews and questionnaires, and in workshop development and school student’s participation) meant that there was an opportunity for Indigenous participants to identify themselves, and Indigenous perspectives to be identified, in the knowledge presented. This was seen in the soil education workshops and co-designed activities, and in the art exhibits where participants’ qualitative questionnaire responses (quotes) were displayed on rotating slides. This emphasis centred Māori participants as experts in their own soil knowledge, in domains typically dominated by Western academia (McKenzie et al., 2008).

Educational engagement resources to date include five soil experiment posters (on testing soil pH, colour, water holding capacity, biodiversity via worm indicators, compost-in-a-jar), replicating some activities delivered in class; a series of 3–5 minute Ask-A-Soil-Expert videos that interview different soil actors (with NZ Sign Language translations) with associated student workbooks (in English and Māori languages) and answer keys, and teacher lesson plans. An interactive 30-minute slideshow and educational games are also offered.

The combination of community and science-led enquiry has led to, for example, co-production aspects of the soil educational programmes where children are recognised co-producers of knowledge (Lemos et al. 2018). This leads to unpredictable outputs, particularly where, in the ‘knowledge communication workshop’ at the end of their 3-day workshop series, they design and deliver a knowledge communication output about soil for their school community and whānau. Educating students and communities about soil quality and health therefore reaches into aspects of wellbeing, spiritual and Indigenous values, as well as chemical, geological, biodiversity, and fertility properties of soil. The diversity of worldviews of the bicultural/multicultural rights-holders and stakeholders of Aotearoa NZ means that the environment is not measured or learned about in uniform ways; where CS is concerned with scientific, environmental, cultural, economic, political, and social aspects of our world, these values might be captured quantitatively, or qualitatively. Some examples are inferred from Strasser et al.’s (2019) epistemology that deliberately includes different forms of knowledge making such as oratory or other sensory means not regularly captured in dominant scientific modes of data collection.

Collaboration with community organisations led to the development of a soil kete (basket of knowledge) for schools which includes all resources used in the 3-day workshops, plus Indigenous-designed gardening tools for kids (included in the kete thanks to design studio Paku www.paku.nz, with their bespoke storybook to explain their origins and importance). These were given to all classes participating in the 3-day workshops, enabling teachers to reproduce the workshops for other classes and, thus, creating an intergenerational ‘learning legacy’ of soil knowledge building over time. Partnership with other community organisations like Garden to Table (school food gardening and cooking organisation), OKE (school food garden-building organisation), Artgrounds (community art), as well as another national CS programme ‘The Great Kiwi Earthworm Survey’ (AgResearch 2023) which facilitates data collection on worm diversity transects, offered interactive opportunities for diverse learning styles. Further, they engendered a place-based connection to soil where students often participated outdoors, which in turn offers its own wellbeing benefits (Mann et al. 2022). A combination of diverse collaborators and participation types have led to resources like the Ask-a-Soil-Expert videos that broaden the notion of soil expertise beyond the scientist to other facets of society. With some videos still in production, they feature scientists as well as a māra kai matua (in this sense, a father-figure/leader of māra practice), an artist, and an educator on soil delivering soil expertise in their own knowledge domains. The school engagement activities had real effect in responding to diverse learners, languages, and learning needs, representing diverse disciplines and simultaneously enhancing more mainstream STEM teaching and learning access for students/teachers around the subject of soil, engendering the flow of knowledge and habits through to households, whānau, and wider community (Damerell et al. 2013).

The range of activities, in particular the baseline values questionnaire about soil care and concerns, and the interactive workshops and associated activities provided extrinsic benefits for public that included the opportunity to observe and reflect on aspects of nature that they otherwise might not have had. One respondent remarked “Not having access to and connection to earth (and good soil) to me means that people won’t care for it…so would be less inclined to worry about wastage that occurs in supermarkets”. Another linked their soil guardianship to concerns for “insect apocalypse, oil consumption, climate change, etc.’ Another asked “Are we ensuring we are caring for Papa[tuanuku (earth mother)] adequately. Is it sustainable? Is it kind? Are we being exploitative?” and another “Kaitiakitanga [stewardship] – we care for it, it cares for us. Soil is the ngakau [soul] of the garden really.” We found through our questionnaire responses that that they were connecting with soil through their own contextual more-than-human subjectivities (Siimes et al., 2023), nature connectedness, and pro-nature conservation behaviours.

Challenges

While interview subjects on baseline soil values were purposively invited based on the diversity of work in soil, there were limitations in the soil values questionnaire participation. The timeline and ethics of engagement around soil metals results was an important consideration. For our mainstream soil testing programme we decided to only communicate individual results directly to participants. At the inception of the programme, we were presented with the opportunity to publish live soil testing results on our website, which would be immediately available to the public for consultation. The risk of this was that some results may be misinterpreted and/or taken out of context. It was important to us that we managed the public message as the intention of the programme is not to concern the public unduly about contaminants, but rather to put the information in the hands of the people directly affected by the results, and we do this by providing results directly to participants.

This also amounted to considering our ethics of communicating scientific results – e.g. who can access what information, whether it could be taken out of context, and whether that is in the interests of the public and the programme. Defining our scope and focusing on doing that well meant it was a simple message to communicate. For ideas outside that scope, finding ways to connect with credible partners was useful for expanding our work. These feedbacks were vital for effective CS engagement.

Conclusions

SA’s collection of initiatives demonstrates the multidimensional approach of the programme, integrating community engagement with scientific data on metal contaminants in soil. The emphasis on educating communities across various dimensions, from wellbeing to Indigenous values, offers a depth of enquiry lending itself to social and humanities aspects of CS as well as what have been more regularly practiced natural science approaches. While CS best-practice guidelines typically cater for exclusively scientist-designed projects, and start with the scientific aims, we suggest that starting with the diversity of people in the community, in their place-based contexts, is an approach that has the best potential to generate meaning for society in CS and engender a sense of ownership for public participants. Representing community’s diverse value(s) of their world is critical to reflect and feed back what communities have offered to CS. Giving community the opportunity to feed back to (diverse) scientists is also key to confirm meaning and better support participation. SA is, therefore, an example of mostly informed design (soil metal screening), and in some aspects, co-design (SK’s 3-day workshops, art exhibits) and implementation of education, and community engagement aspects of a diversely scientific CS programme.