Dutch soil field campaign successfully finished
PhD candidates Anatol Helfenstein, Cynthia van Leeuwen and Doina Mani have completed their field campaign to collect soil samples from 68 locations across all 12 provinces of the Netherlands, including a broad range of soil and land use types.
Anatol (SGL & BWL) will use the collected data to validate 3D space and time maps, as part of his project to develop a high-resolution, 4-dimensional soil modelling and mapping platform for the Netherlands (BIS-4D). In order to assess changes over time, they specifically returned to locations that have previously been sampled (see bodemdata.nl) between the 1950s – 1990s as part of the “Bodemkundig Informatie Systeem (BIS)”. “I am very curious to see whether we can link temporal changes in land use and soil types to changes in quantitative soil properties over the last 70 years and to what extent these can be captured in our model”. The primary focus for his research will be soil organic matter, since this is a soil property that is essential for soil fertility and climate change mitigation and is expected to change over time due to strong anthropogenic influences in the Netherlands.
Cynthia (ISRIC & SGL) will use the collected data to determine how measurement error in cation-exchange capacity (CEC) calibration data will lead to uncertainty in mid-infrared (MIR) spectroscopic models. Uncertainty analysis of these models is typically limited to the predictor values and the model itself. The measurement error in wet chemistry data used for calibration of the spectroscopic model has been acknowledged but not quantified. To assess the contribution of laboratory measurement error, it is important to have a dataset where all soil samples are analyzed both via traditional wet chemistry methods, as well as via MIR spectroscopy. Furthermore, to quantify the error in calibration CEC data, about 40% of the samples should be measured in duplicate. These requirements for the experimental measurement design limit possibilities to work with existing datasets, since duplicates are generally missing. “Collecting and analyzing soil samples myself, gave me the freedom to play around and create the optimal experimental measurement design for my research aims”.
Doina (SGL & SBL) will be studying the effect of land-use on the functional diversity of soil biota. Functional diversity describes the range of functional traits that are present in the soil community. These traits can be linked to the role soil organisms play in providing soil functions that are essential for agricultural production, such as nutrient cycling, carbon sequestration, water retention and disease suppression. Understanding how land-use practices affect the functional diversity of soil organisms could thus be an important step towards quantifying and predicting the effect of our land-use on these soil functions. During the fieldwork Doina has sampled earthworms, nematodes, fungi and bacteria, at sites with different types of land-use, ranging from forests to intensively managed arable fields. “I’m especially interested to see whether the effect of land-use differs for the different soil types that are present in the Netherlands. Perhaps the soil community is much more sensitive to land-use practices in some soils than others.”
Combining efforts and working together has made their research more interesting, allowing for a holistic assessment of soil processes, while also making it more efficient, manageable and fun!