Challenges in linking soil health to edge‐of‐field water quality across the Great Lakes basin

Abstract

To better understand agricultural nutrient losses, we evaluated relationships between management (e.g., manure and tillage), soil health measurements, and resulting edgeof-field (EOF) surface water quality. This work was conducted before or early into conservation implementation at 14 Great Lakes Restoration Initiative EOF sites spanning Wisconsin, Michigan, Indiana, Ohio, and New York. Analyses of site characteristics (hydroclimate, management, catchment properties) along with 3 yr of soil health measurements (chemical, biological, and physical properties) showed EOFnutrient export depended on both site and soil properties. A pattern emerged whereby sites not receiving manure and sites with manure defined opposite ends of several gradients for soil and water data. Sites receiving manure had increased microbial activity, organic matter (3.2 vs. 2.7%), and soil test phosphorus (P) (2.8 times more) relative to sites without manure. Suspended sediments (SS), total P (TP), and total nitrogen (TN) in EOF surface runoff varied over three to five orders. Multivariate analysis among sites showed covariant linkages between soil nutrients, soil C, microbial properties, and nutrients in EOF water. There were positive univariate relationships between water-extractable soil P and annual EOF-water concentrations and yields of orthophosphate, TP, TN, and SS (p < .01). Some soil physical properties (e.g., bulk density and infiltration) also covaried among sites but were not consistently related to runoff index or water yield variables. Given the observed among-site variability, we were not able to isolate desirable soil health signals on EOF surface water quality.

Addressing conservation practice limitations and trade‐offs for reducing phosphorus loss from agricultural fields

“…Soil properties (e.g., texture, mineralogy, and structure) and landscape factors (e.g., slope grade, shape, and position) influence the dominant P transport process for a given field (Table 1). Due to these complex and interrelated factors (e.g., Fermanich et al., 2022), the extent and magnitude of CP trade‐offs can be different when the same practice is applied in different ecoregions or during different weather conditions in the same ecoregion (Macrae et al., 2021). As a result, combining multiple CPs (also referred to as “stacking practices”) can be an effective means of minimizing trade‐offs and improving the effectiveness of watershed mitigation strategies (Law et al., 2020; Tomer et al., 2014).…”

Enhancing the Soil Health–Watershed Health Nexus: Introduction

“…Physical indicators of soil health measured by Fermanich et al. (2022) were less consistent or predictive relative to the findings of Gutknecht et al. (2022).…”

“…An additional study conducted by Fermanich et al. (2022) verifies that increases in soil nutrients, soil carbon, and microbial properties were also linked to greater edge‐of‐field nutrient losses. Physical indicators of soil health measured by Fermanich et al.…”

“…Interactions among field management, hydrology, and edge‐of‐field water quality are the theme of three research articles (Osterholz et al., 2021; Williamson et al., 2021; Fermanich et al., 2022). The research of Williamson et al.…”

Connecting soil health and water quality in agricultural landscapes

“…Similarly, Gutknecht et al (2022) did a small set of rainfall simulation experiments wherein cover crops also did not change runoff, sediment, or nutrient loading. Fermanich et al (2022) examined from a set of 14 edge-of-field monitoring sites unique for their spread across five U.S. Great Lakes states. They relate field catchmentscale runoff and water quality metrics directly to soil health measures in addition to land management factors.…”