Soil health and the hydrologic cycle

Authors: WYATT, BRIANA - Texas A&M University; HATFIELD, JERRY - Retired ARS Employee; Wacha, Kenneth - Ken; LAL, RATTAN - The Ohio State University; ARENAS, ANTONIO - The Ohio State University; BIRGE, HANNAH - Nature Conservancy; SCHNITKEY, GARY - University Of Illinois; PETERSON, TODD - Retired Non ARS Employee

Submitted to: Council for Agricultural Science and Technology Issue Paper
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2023
Publication Date: 5/1/2024
Citation: Wyatt, B., Hatfield, J.L., Wacha, K.M., Lal, R., Arenas, A., Birge, H., Schnitkey, G.D., Peterson, T. 2024. Soil health and the hydrologic cycle. Council for Agricultural Science and Technology Issue Paper. 76. https://doi.org/10.62300/QEOG5785.
DOI: https://doi.org/10.62300/QEOG5785

Interpretive Summary: The hydrologic cycle in healthy soils is dramatically different from that in conventionally managed and degraded soils. Healthy soils have higher water infiltration rates and contain more water-stable aggregates, thus result in reduced runoff and soil erosion during rainfall events. While widespread adoption of soil health practices can improve production efficiency, resiliency, food security, and help combat climate change, soil health studies have failed to connect fundamental relationships between soil health and the hydrologic cycle across field and watershed scales. This paper seeks to address this knowledge gap, summarize pertinent literature regarding the impacts of soil health practices on different components of the hydrologic cycle, and provide clear evidence and guidelines for policy- and decision-makers regarding the impacts of soil health practices on the hydrologic cycle. Given the rapid recent and projected changes to Earth’s hydrologic cycle due to climate change, understanding the influence of soil health practices on agricultural production, flooding, and drought resilience is likely to become increasingly important.

Technical Abstract: Research interest in soil health has grown in popularity in the past decade as scientists and producers seek to determine the best methods of soil management for optimizing crop production, ecosystem function, and biodiversity. Soil health is defined as “the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans”. This includes the capacity of the soil to filter contaminants, cycle nutrients, provide physical support for infrastructure and habitats, and regulate water movement. Many approaches have been suggested for quantifying soil health, and often those techniques rely on measurements of chemical, physical, or biological soil properties, or in some instances a combination of those properties. A growing number of scientists have acknowledged the need for a more comprehensive, integrated approach to measuring soil health. While measurement and quantification of the impacts of soil health are somewhat new, soil and water conservation practices that enhance soil health have been recognized and promoted for decades. In agricultural systems, the primary methods of increasing soil health involve minimizing disturbance by using no-tillage or reduced-tillage, maximizing biodiversity of both macro- and micro-organisms, maximizing soil cover using cover crops or plant residues, and maximizing the amount of living roots within the soil. Benefits of increasing soil health on agricultural soils can generally fall into three categories: (1) improvements to the hydrologic cycle, (2) greater crop yields, resilience, and food security, and (3) reducing greenhouse gas emissions to lessen climate impacts of agriculture. Often when summaries of soil health are documented, emphasis is given to the second and third categories above, with little attention paid to changes in the hydrologic cycle resulting from the implementation of soil health practices. This paper seeks to address this knowledge gap, summarize pertinent literature regarding the impacts of soil health practices on different components of the hydrologic cycle, and provide clear evidence and guidelines for policy- and decision-makers regarding the impacts of soil health practices on the hydrologic cycle.