The role that roots play in building soil organic matter and soil health - Dr. Christine Sprunger, OSU - SENR, from the 2020 Conservation Tillage and Technology Conference, held March 3-4, 2020, Ada, OH, USA.

1. The role that roots play in building
soil organic matter
and soil health
Dr. Christine Sprunger
Assistant Professor of Soil Science and
Rhizosphere Processes at OSU

2. Why should we care about roots?
• Roots provide nutrients for
plants and microbes and
feed the soil via
decomposition.
• Roots and root exudates
are major sources of
carbon
• Root production and decay
are major regulators of the
global carbon cycle and
important for C fluxes and
pools

3. Strong connection between roots and soil
organic matter build up!
• Roots have been shown to be the most
important factor for increased soil
carbon in natural ecosystems (Chen et
al., 2018)
• A meta-analysis found that root derived
C lasts 2.5 times longer in the soil
compared to aboveground material
(Rasse et al., 2015).
• Most soil organic matter consists of
belowground material rather than
aboveground material. (Greater
quantity)

4. Unknowns facts about roots!
• Which crops have the capacity to build soil C through their
roots?
• How does management influence root production and soil
health?
• How long does it take to detect changes in soil carbon and
soil health?

5. How does tillage and crop rotational diversity
influence root production and
soil health?
• No-Till trials established in 1962
• Wooster and Hoytville locations
• No-Till vs. Chisel vs. Moldboard
• Monoculture corn vs. corn in
rotation
• No-till and crop diversity lead to
increased soil carbon.

6. Measuring Fine Roots
July Aug. Sep. Oct.
Core
Installation
Core
Removal
• In-growth cores used to compare relative estimates of
fine root production.
• 2 mm mesh cores filled with root free soil:sand mixtures
and buried in the root zone to 15-cm depths.

7. Chisel No-Till
NorthwestWooster
CC CS CAA CC CS CAA
0
500
1000
1500
0
500
1000
1500
Rotation
FineRootProduction(g/m2
)
Long-term management impacts on
root production (2019)
Martin et al., in prep
CC=Continuous Corn
CS= Corn-Soy
CAA= Corn-Alfalfa-Alfalfa
*
*

8. Long-term management impacts on soil health

9. Chisel No-Till
NorthwestWoosterCC CS CAA CC CS CAA
0
50
100
150
0
50
100
150
Rotation
MineralizableC(mgkg-1
soil)
Long-term management impacts on
Respiration (2019)
CC=Continuous Corn
CS= Corn-Soy
CAA= Corn-Alfalfa-
Alfalfa
Martin et al., in prep
*
* *

10. Long-term management impacts on
Active C (2019)
Chisel No-Till
NorthwestWoosterCC CS CAA CC CS CAA
0
300
600
900
0
300
600
900
Rotation
POXC(mgkg-1
soil)
CC=Continuous Corn
CS= Corn-Soy
CAA= Corn-Alfalfa-
Alfalfa
Martin et al., in prep
*
*
*

11. Long-term management impacts on
Soil protein (2019)
Chisel No-Till
NorthwestWooster
CC CS CAA CC CS CAA
0
3
6
9
0
3
6
9
Rotation
SoilProtein(mgg-1
soil)
CC=Continuous Corn
CS= Corn-Soy
CAA= Corn-Alfalfa-
Alfalfa
Martin et al., in prep
*
*
*
*

12. Summary
• Roots are key contributors to soil organic matter
• How can I get more roots and nutrients in my rotation?
• Root production appears to be greater in the corn-alfalfa-
alfalfa rotation
• Soil health indicators consistently greater under corn-
alfalfa-alfalfa rotations

13. Seeking farmer collaborators for soil
health study
Questions?
Sprunger.29@osu.edu
• Objective: Understand how soil
health testing can be valuable to
farmers in light of heavy precipitation
• Sampling:Two selected farmer fields
• Soil health test: 10+ chemical,
biological, and physical soil health
indicators
• Conversation: Explanation of
management history and
Interpretation of results