Deliverable 4.7 - Smartphone use for Soil Citizen Science – initial version

On-farm soil health assessment is an important approach that complements other sources of information available to farmers, such as (i) results from soil samples tested in a laboratory (typically aiming on soil nutrient supply for optimizing fertilization, and (ii) remote sensing data from satellites that provide information on the crop vigour which is, among others, responding to the status of soil-related growth factors (e.g., water, nutrients). Digital smartphone tools are intended(i) to standardize and guide visual assessments of the state of soil, and (ii) to provide image-analytics-based (semi)quantitative data on soil (e.g., soil colour) and/or soil status-related observations (e.g., indicator plants). With the improvement of smartphone imaging quality (hardware side) and advances in image analytics (software side), there is currently a dynamic development intending to provide novel digital tools for soil assessment (e.g., Aitkenhead et al., 2016; Fan et al., 2017; Gupta et al., 2023). Within NBSoil we aim to explore the use of mobile apps for soil health monitoring to provide tools to nextgeneration soil health advisors on relevant measures that are considered responsive to nature-based solutions, in particular soil organic carbon and soil structure. For the initial version of smartphone digital tools, we screened for currently available tools and their capabilities in order to (i) provide an overview and identify current capabilities and potential knowledge gaps (section 2), and (ii) make an initial selection of tool(s) to be prioritized for testing on NBSoil demo-sites and inclusion into MOOC and further advanced training courses (section 3).