Extreme soil surface temperatures reflect need to rethink agronomic management

Authors: O'Brien, Peter; Hatfield, Jerry

Submitted to: Agricultural & Environmental Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2019
Publication Date: 2/19/2020
Citation: O'Brien, P.L., Hatfield, J.L. 2020. Extreme soil surface temperatures reflect need to rethink agronomic management. Agricultural & Environmental Letters. 5(1). https://doi.org/10.1002/ael2.20002.
DOI: https://doi.org/10.1002/ael2.20002

Interpretive Summary: Soil surface temperature plays an important role in the rate and quantity at which water, energy, and nutrients cross the soil-atmosphere interface, as temperature regulates numerous physical, chemical, and biological processes. Many current management practices manipulate soil surface temperatures, especially through tillage or residue removal, to create conditions suitable for early-season crop growth. However, these conditions persist beyond plant establishment and have the potential to develop extremely high temperatures. We present maximum daily soil surface temperatures in central Iowa, USA, demonstrating that extreme temperatures may be present even in an historically mild climate. We discuss how soil surface temperatures may impact soil water availability and crop development, and we suggest that extreme soil surface temperatures may be an indicator of other undesirable processes, such as soil C losses or soil erosion. This commentary may be useful to land managers by identifying an unintended consequence of common agronomic practices and guiding them to consider agroecosystems holistically.

Technical Abstract: The soil surface exists at the soil-atmosphere interface and is critical in regulating transfer of water, energy, and nutrients in agroecosystems. Soil surface temperature plays an important role in the rate and quantity at which these resources cross the interface, as temperature regulates numerous physical, chemical, and biological processes. Many current management practices manipulate soil surface temperatures, especially through tillage or residue management, to create conditions suitable for early-season crop growth. However, these conditions persist beyond plant establishment and have the potential to develop extremely high temperatures, even in historically mild climates. We show the potential for extreme maximum soil surface temperatures in Iowa, USA after crop establishment but before canopy closure and discuss possible direct impacts of those temperatures. Given the conditions required to develop extreme maximum temperatures, we contend that soil surface temperatures may be an indicator of conditions that are inconsistent with highly productive, sustainable, efficient agroecosystems.