Policy demands for robust soil health monitoring are steadily growing. Given that soil biota are critical to the ecosystem services soils provide, biological properties are well-suited as relevant indicators, complementing physicochemical characteristics. However, biological properties are highly dynamic across spatial and temporal scales, which presents a challenge when using them for monitoring purposes.
As part of AI4SoilHealth project, we conducted a comprehensive soil health assessment in the experimental grasslands of NEIKER, where a rotational grazing system has been in place since 2013, compared to a free grazing system. Our objectives were to test innovative methods for measuring soil health and to analyze the temporal dynamics of soil biological properties in relation to climatic and pasture conditions.
Plant and soil samples were collected every three weeks from April to November 2024 at two depths (0-20 cm and 20-50 cm). A broad array of descriptors related to pasture quality, production, and soil physicochemical and biological properties were assessed. Novel methods tested and compared to conventional approaches included: (i) DigitSoil – a tool that measures enzymatic activity, providing real-time data on organic matter decomposition and other key biological processes; (ii) microBIOMETER – a portable kit measuring microbial biomass and the fungi-to-bacteria ratio; (iii) Slakes – assessing aggregate stability through a mobile app; (iv) eDNA and eRNA metabarcoding of 16S rRNA and ITS, to differentiate total and active prokaryotic and fungal communities; (v) remote sensing from Planet to provide data on vegetation growth and greenness.
The novel diagnostic tools provided cost-effective and high quality soil health assessments. Nevertheless, preliminary results suggest that differences in soil biological properties were more pronounced across soil depths and over time than between grazing types. Therefore, their spatial and temporal variability must be considered when designing a soil health monitoring program.

Boermarke-Zeijen is a 350-year old farmers collective in the North of the Netherlands. The farmer collective
owns 1200 hectares of land and consists of five dairy farms, four arable farms, two mixed farms, and one chicken
farm. The farmers are developing economically and ecologically sustainable farming practices to strengthen soil
fertility and biodiversity at company and regional scale. The soils are sandy with peat patches, which is
representative of the soils of the Netherlands. The farmers producing agricultural crops face subsoil compaction
and soil crusting, leading to decreased infiltration capacity. Some of the dairy farms face phosphate deficiencies.
As part of AI4SoilHealth project, Planet Labs is teaming up with the farmer collective and the regional water
board Noorderzijlvest, to correlate in-situ measurements with Planet’s satellite data products to demonstrate its
value for monitoring and decision making. The farmers have a specific interest in monitoring nutrient fluxes, soil
moisture, land surface temperature and biomass conditions, specifically for the sustainable application of
fertilizer.
The in-situ monitoring network collects location-specific, real-time information about the weather outlook, the
level of surface water and groundwater, the moisture content of the topsoil and the water quality. Legacy data
includes in-situ samples and soil profiles covering a range of soil parameters. A field sampling campaign is
planned in April 2025 to collect the AI4SoilHealth baseline indicators (texture, SOC, pH, CEC, nutrients, density)
and additional indicators (e.g. enzymatic activity, eDNA, Macrofauna, NIR-spectroscopy).
We have used Planet’s high spatial and temporal resolution satellite data [Planet Product] to monitor and
characterize the landscape of Boermarke Zijen, by looking at Vegetation health [PlanetScope, Crop Biomass];
Water balance [Soil Water Content]; Environmental stresses [Land Surface Temperature]; Soil health [Tanager,
Sentinel, PlanetScope] and Above ground carbon [Forest Carbon, Crop Biomass]. With the recent launch of
Planet’s Hyperspectral Mission Tanager, the pilot at Boermarken Zijen will also facilitate investigations into the
feasibility of soil property estimation using spaceborne hyperspectral sensors. Using our satellite data products
in combination with the in-situ sample data, will evaluate the water regime and the potential and effects of
year-round greenery to address some of the challenges that the farmers at Boermarke Zijen are facing.