Soils, Science and Community ActioN (SoilSCAN): a citizen science tool to empower community-led land management change in East Africa

Abstract

Pastoralist communities worldwide face complex challenges regarding food and feed productivity. Primary production systems are under stress, nutritional choices are changing and the relationship between development and agriculture is undergoing profound transformation. Under increasing pressure from climate and land use change, East African agro-pastoral systems are approaching a tipping point in terms of land degradation. There is an urgent need for evidence-led sustainable land management interventions to reverse degradation of natural resources that support food and water security. A key barrier, however, is a lack of high spatial resolution soil health data wherein collecting such information for each individual community is beyond their means. In this context, we tested whether bridging such data gaps could be achieved through a coordinated programme at the boundary between participation and citizen science. Key outputs included a community-led trial of a hand-held soil scanner, which highlighted a range of positive benefits and practical challenges in using this technology in this context, with identification of some potential solutions; and a high-resolution soil organic matter and nutrient status dataset in a small catchment-based community setting. The results show that if the practical challenges can be resolved, use of portable soil scanner technology has the potential to fill key knowledge gaps and thereby improve resilience to the global threat of land degradation through locally responsive farmer and community decision-making.

Smallholder farms have and can store more carbon than previously estimated

“…Such a database might follow the model of continental iSDA, which aggregates data from across government, nonprofit, and for‐profit stakeholder sources (Hengl et al, 2021), but in contrast with iSDA's extensive reliance on legacy data, focus specifically on contemporary samples collected recurrently from agricultural soils. Such a momentous data collection effort could be facilitated by advancements in soil testing and data aggregation through smartphone‐enabled crowdsourcing and low cost, field‐portable instrumentation (Ewing et al, 2021; Herrick et al, 2013; Kelly et al, 2022). Doing so could create a robust and broad set of ground measures from samples taken across the region (Paustian, Collins, et al, 2019; Snapp, 2022).…”

Novel use of portable gamma sensors to rapidly assess soil status and recovery in degraded East African agro-pastoral land

“…• Principle components analysis (left) of NORM data and basic soil properties, determined by Near Infra Red Spectroscopy (NIRS; Amasi et al, 2021;Kelly et al, 2022), supports modification of NORM signal in this landscape by SOM wherein influence of other factors needs exploring. • Negative correlation (centre and right) between specific radioisotopes and soil properties suggest that in this context the closest proxy to SOM/SOC is negative correlation with Th-232, which is also closely correlated to cps.…”

“…• This provides (i) visual information that enables local communities (as citizen scientists, Kelly et al, 2022) to take local sustainable land management action to mitigate land degradation and (ii) quantitative evidence to inform policy makers for longer-term planning and regeneration of soil health…”