Impacts of long-fallow wheat stubble management on soil water,microclimate, and wheat yield in a Mediterranean climate

Authors: Durfee, Nicole; Wuest, Stewart; Williams, John; Robertson, David

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2025
Publication Date: 9/25/2025
Citation: Durfee, N.M., Wuest, S.B., Williams, J.D., Robertson, D.S. 2025. Impacts of long-fallow wheat stubble management on soil water,microclimate, and wheat yield in a Mediterranean climate. Agrosystems, Geosciences & Environment. 8(4):1-15. https://doi.org/10.1002/agg2.70214.
DOI: https://doi.org/10.1002/agg2.70214

Interpretive Summary: In semiarid dryland agricultural systems, sufficient soil water for crops is a key concern. More research is needed to understand the effects of wheat residue management on soil water evaporation and crop production in the inland Pacific Northwest. This study examines the impacts of wheat residue management approaches and row orientation on wheat yield, fallow soil water, and key factors associated with soil water evaporation, such as windspeed and near-surface air temperature. Row orientation had minimal impact on the factors examined in this research. While differences were found in windspeed, air temperature, and shallow soil temperature during the fallow season, no significant treatment differences were found in wheat yield, reference evapotranspiration, or soil moisture. The results of this study suggest the importance of considering soil conservation, seeding conditions, and other factors when implementing residue management in these systems.

Technical Abstract: Inadequate soilwater for timely crop establishment in dryland agricultural production systems of the inland Pacific Northwest is a key limiting factor in crop production. It is important to identify management practices that reduce soil water evaporation in the long fallow season prior to seeding wheat (Triticum aestivum L.) in the fall. In a 2-year study, we assessed the impacts of four residue management approaches (conventional stubble height, high stubble left standing, high stubble mowed in spring, and residue removed) in conjunction with two row orientations (north-south vs. eastwest) at low and intermediate precipitation dryland agriculture sites. Soil cores to a 120-cm depth were collected at the beginning and end of each fallow season. Nearsurface microclimate data (relative humidity, air temperature, soil temperature, and windspeed) were collected. Taller stubble had significantly lower windspeed compared to short residue heights. Higher soil temperatures were observed where residue was removed, but higher air temperatures were observed in high stubble. Differences in snow capture were noted during one snowfall event with high winds. Row orientation demonstrated little impact on any of the parameters. No statistically significant (p< 0.05) differenceswere found between treatments inwheat yield, fallowsoilwater storage, or reference evapotranspiration. The results of this study suggest that while residue management can have effects on microclimate, it did not lead to differences in soil water storage or wheat yield in a climate where little precipitation is received for the last 3 months of the fallow season.