Great Lakes Big Rivers Climate
Workshop
Cover Crops and Resilience
Dean Baas, MSU Extension
December 11, 2018

Definition of resilience
An ability to recover from or adjust
easily to misfortune or change
T. Tervonen, et al.,2015, A multi-
criteria inference approach for anti-
desertification management,
Journal of Environmental
Management, Volume 162.

Climate
resiliency -
Midwest is
getting 37%
heavier
precipitation

Days with heavy precipitation
Ball and Andresen, MSU, personal communication

Palmer Drought Severity Index

• Do they contribute to/detract from water
quantity?
• Do they:
• Conserve water or use water in dry years?
• Conserve water in wet years?
• Increase resiliency to extreme climate
conditions?
Soil health, cover crops and water
quantity

• NRCS definition:
• A healthy, fully functioning soil is balanced to provide
an environment that sustains and nourishes plants, soil
microbes and beneficial insects.
What is soil health?
Source: Agriculture.com
{ }
Pore
space
50%
Solids
50%
25% Water
25% Air 5% Organic Matter
45% Inorganic
(mineral materials)

• Stabilized organic
matter acts like a sponge
and can absorb six times
its weight in water
• The active organic matter,
and the microbes that feed
on it, are central to nutrient
cycles
What is soil health?
Source: Agriculture.com
• Soil organic matter (SOM) is where the action is:

Soil health, SOM and water quantity
Hudson, 1994
0.0
0.5
1.0
1.5
2.0
2.5
0 1 2 3 4
InchesofWater
% Soil Organic Matter
Inches of Water in the top 8 Inches of Soil
vs SOM
Sand Silt loam Silt clay loam

Soil health, SOM and water quantity
• Water capacity from SOM:
• Is not a one time advantage
• Increases the size of the “container”
• More volume to hold large rain events
RunoffRunoff

Soil health, SOM and water quantity
• Water capacity from SOM:
• Is not a one time advantage
• Increases the size of the “container”
• More volume to supply crops
Drought
Crops Crops

Soil health, SOM and water quantity
• Water capacity from SOM:
• Is not a one time advantage
• Increases the size of the “container”
• More volume to refill with the next rain event
RunoffRunoff

• Do they contribute to/detract from water
quantity?
• Do they:
• Conserve water or use water in dry years?
• Conserve water in wet years?
• Increase resiliency to extreme climate
conditions?
Cover crops and water quantity

• A rye cover crop increased water storage (plant available
water) in the top 30 cm by 18%
• Equivalent to an extra 0.75 cm of water every time the
upper 30 cm of soil was rewetted with rainfall.
• The rye cover crop does use water in the spring, but in 5
out of 7 years this was replenished by the time of main
crop planting.
• In most years after cover crop termination water contents
in the upper 30 cm were higher following a rye cover
crop in the summer.
Basche et al., 2015
Rye cover crop effect on plant available
water after 12 years (Iowa)

Cover crop water use replaced by
planting in 5 of 7 years
Basche et al., 2015

Cover crop water use not replaced by
planting in 2 of 7 years
Basche et al., 2015

In a dry summer, a rye cover crop
increased soil water content
Basche et al., 2015

In a wet summer, a rye cover crop also
increased soil water content
Basche et al., 2015

CTIC survey for 2012, a drought year
CTIC/SARE 2012 Cover Crop Survey

Water quality and climate resilience
• Agriculture is under
continued pressure
to reduce its impact
on water quality
• Climate change
adds to the problem

0
10
20
30
40
50
60
0
10
20
30
40
50
60
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Avg.
Precipitation(in)
Tileflow(in)
Annual Tile Drainage Flow and Precipitation for Corn-Soybean
Rotation near Ames, IA with or without a Cover Crop
No Cover Crop
Rye Cover Crop
Precip.
Kaspar – USDA ARS
Cover crops help – Iowa example

20 19.1
24.9
19.8
21.6
16.4
14.9 14.5
7.1
7.6
7.1
12.0
12.5
10.8
5.8
13.9
5.8
11.9
9.3
8.0
5.1
8.1 8.1
5.5
4.8
1.8
2.3
3.5
4.2
2.0
5.7
0
5
10
15
25
Annual Flow-wt NO3 Concentration of Tile Drainage for Corn-
Soybean Rotation near Ames, IA with or without a Cover Crop
30
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Avg.
AnnualFlow-wtNO3Conc.(ppm)
Year
No Cover Crop
Rye Cover Crop
Kaspar – USDA ARS
Cover crops help – Iowa example

Total Nitrate-N Lost 2002-2015 in Tile Drainage
Treatment Nitrate-N Lost in Drainage
14-yr total
lbs/acre
14-yr avg.
lbs/acre
Corn-soybean no-till 488 35
Corn-soybean no-till w.
rye cover crop 211 15
Reduction 277 20
% Reduction 57
Kaspar – USDA ARS
Cover crops help – Iowa example

• Increasing SOM increases AWC which can
improve resiliency in both wet and dry years.
• Some years, cover crops reduce available water
at crop planting, but it is usually replenished
during the season.
• In a dry spring, early termination can reduce cover
crop water use.
• Long-term cover crop use increases SOM and
can increase available water most years.
• Cover crops can reduce nutrient loss from
extreme events.
Conclusions

Dean Baas, PhD
Extension Educator
Ag and Agribusiness Institute
Michigan State University Extension
612 E. Main Street
Centreville, MI 49032
Office Phone: 269-467-5646
Cell Phone: 269-967-9672
Email: baasdean@anr.msu.edu
Thanks!!!
Questions?

MSU is an affirmative-
action, equal-opportunity
employer. Michigan State
University Extension
programs and materials are
open to all without regard
to race, color, national
origin, sex, gender, gender
identity, religion, age,
height, weight, disability,
political beliefs, sexual
orientation, marital status,
family status or veteran
status.