EGU22-8258
https://doi.org/10.5194/egusphere-egu22-8258
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Soil pH Influences on Microbial Functional Responses to Crop Rotational Management and Field Translocation

Jack Horne1, Paul D Hallett1, Fiona C Fraser2, and Catriona Willoughby1,2
Jack Horne et al.
  • 1University of Aberdeen, School of Biological Science, Plant and Soil Science, United Kingdom of Great Britain – England, Scotland, Wales (jack.horne96@gmail.com)
  • 2SRUC Aberdeen, Crop and Soil Systems, United Kingdom of Great Britain - England, Scotland, Wales

Structural disturbance of soil such as that caused by tillage or translocation for infrastructure projects can induce changes in soil microbial functions eliciting large fluxes of CO2. Soil pH, often referred to as a master variable in the context of soil biology, exerts a strong influence on both the structure and function of microbial communities as well as the physical structure of the soil. In order to better understand the interaction of soil pH and large-scale physical disturbances in controlling these fluxes, we took the opportunity presented when moving an entire experimental field to a new location to look at how changing soil structural conditions influenced the activity of the microbial community. Soils under long-term (60 years) pH manipulation were dug from the original experimental site (Woodlands Field, SRUC, Aberdeen) and transported to a new experimental site less than 1 mile away (Aberdeen Cropping Experiment (ACE), Aberdeen), excavated soils were thoroughly mixed before reinstatement. This produced a significant decrease in bulk density and concomitant increase in macroporosity as expected (p = 0.027 and p = 0.021 respectively), with more pronounced changes at lower pH. There were consistent increases in the fraction of water-stable aggregates from the soil translocation, where the field averages of Woodlands and ACE were 91% and 95% respectively (p < 0.001). However, there were no discernible differences across the pH range (p = 0.641), despite greater changes occurring at lower pH treatments. We also observed changes in respiration rates of soils after translocation, rates were slightly increased at low pH, reduced at mid-range pH, and stable at high pH, although none of these were significant changes (p = 0.081). Soil pH was a dominant factor in controlling some aspects of the soil physical properties. Soil pH had variable magnitudes of influence, in particular, more acidic soils were more vulnerable to changes in the physical structure, where the volume of large pore spaces increased dramatically. This could explain the increased CO2 efflux in acidic soils, however, microbial communities in mid-range pH treatments demonstrated the greatest vulnerability to large-scale physical disturbance, which is likely due to the threshold pH determining their respiration pathway. This research demonstrates that soil management in large-scale disturbance should have altered management, guided by the soil pH. 

How to cite: Horne, J., Hallett, P. D., Fraser, F. C., and Willoughby, C.: Soil pH Influences on Microbial Functional Responses to Crop Rotational Management and Field Translocation, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8258, https://doi.org/10.5194/egusphere-egu22-8258, 2022.

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