Quantifying Landscape Variability of Dynamic Soil Properties in the James River Valley, Eastern South Dakota

Dynamic soil properties (DSP) are a great tool for monitoring land-use change, and they are frequently used as soil health metrics. The NRCS and other soil researchers often use repeating, single-point or nested-point DSP studies to monitor and better understand the effects of land management decisions. While these studies capture the temporal variability of DSPs, they overlook the field-scale spatial variability of DSPs. Soil organic carbon (SOC) provides critical services to the ecosystem and other environments. These traits, as well as its susceptibility to management decisions, make SOC an important soil health indicator and DSP. Measuring SOC is often time consuming and costly. This study researches the spatial variability of SOC in two different fields under different management systems, while investigating a non-destructive, quick, and budget friendly dual-wavelength spectral probe to estimate SOC in-situ. The results show that spatial distribution of SOC varies significantly, whether along catenas or transects, and is highly impacted by microtopography and management decisions. We also discovered that while using a dual-wavelength sensor, management systems and inherent soil properties can cause differences in estimation accuracy. Although spectral sensing using the dual-wavelength probe shows promise, the relationship between adsorption and SOC is not equal for differences in landscapes, management systems, and soil types. The spatial variation in DSPs is not covered in modern DSP methodology, this study fills in the missing knowledge for some glaciated eastern South Dakota landforms.