Global Geochemical Thresholds and the Boundaries of Soil Fertility
Please note this event occurred in the past.
October 07, 2024 3:30 pm - 4:30 pm ET
In person in Paige 202 or virtually via Zoom:
https://umass-amherst.zoom.us/j/97102939495?pwd=SFYwMFNhN2xxdGQ1Z1REWHYvYlE1UT09
Meeting ID: 971 0293 9495
Passcode: Seminar
Dr. Eric Slessarev, Yale University Department of Ecology and Evolutionary Biology
Abstract: Earth’s soils sustain productivity on land by regulating nutrient supply. In this talk I will show how two important aspects of soil fertility—soil pH and soil organic matter content—are constrained by a global-scale geochemical threshold. I will show using a global data synthesis that soil pH responds non-linearly to climate. When water inputs from precipitation are less than atmospheric water demand, base cations released by mineral weathering accumulate in soil, alkalizing soil pH. Conversely, when precipitation exceeds atmospheric water demand, base cations are lost and soil acidifies. At the abrupt transition between these two climate domains geologic inputs of base cations are a dominant control on soil pH. Using a simple process-based model, I will advance the hypothesis that elevated geologic inputs of base cations in this climatic transition zone can explain the high soil organic matter content of grassland soils. This hypothesis stands in contrast to traditional explanations for the carbon-richness of grassland soils focused on below-ground allocation. These results suggest that managing soil base cation budgets could be an important tool for conserving soil fertility and carbon storage in grasslands and croplands.
There are still a few openings in Dr. Slessarev’s schedule. Please let me know if you would like to meet with him. For graduate students, there is also a lunch from 12:30-1:30. If you are interested in attending, please let me know your dietary restrictions before 12 pm on 10/3.
Thanks,
Rachel Hestrin
rhestrin@umass.edu
https://umass-amherst.zoom.us/j/97102939495?pwd=SFYwMFNhN2xxdGQ1Z1REWHYvYlE1UT09
Meeting ID: 971 0293 9495
Passcode: Seminar
Dr. Eric Slessarev, Yale University Department of Ecology and Evolutionary Biology
Abstract: Earth’s soils sustain productivity on land by regulating nutrient supply. In this talk I will show how two important aspects of soil fertility—soil pH and soil organic matter content—are constrained by a global-scale geochemical threshold. I will show using a global data synthesis that soil pH responds non-linearly to climate. When water inputs from precipitation are less than atmospheric water demand, base cations released by mineral weathering accumulate in soil, alkalizing soil pH. Conversely, when precipitation exceeds atmospheric water demand, base cations are lost and soil acidifies. At the abrupt transition between these two climate domains geologic inputs of base cations are a dominant control on soil pH. Using a simple process-based model, I will advance the hypothesis that elevated geologic inputs of base cations in this climatic transition zone can explain the high soil organic matter content of grassland soils. This hypothesis stands in contrast to traditional explanations for the carbon-richness of grassland soils focused on below-ground allocation. These results suggest that managing soil base cation budgets could be an important tool for conserving soil fertility and carbon storage in grasslands and croplands.
There are still a few openings in Dr. Slessarev’s schedule. Please let me know if you would like to meet with him. For graduate students, there is also a lunch from 12:30-1:30. If you are interested in attending, please let me know your dietary restrictions before 12 pm on 10/3.
Thanks,
Rachel Hestrin
rhestrin@umass.edu