Restoring Degraded Soils and Improving Soil Health with Cover Crops

59 Pages·2016·8.57 MB·English

Restoring Depleted Soils & Improving Soil
Health With Cover Crops
Bob Kremer
University of Missouri

[email protected]
Integration
 of
 cover
 crops
 in
 diverse
 management
 systems
 is
 a
 primary
 means

for
 protecting
 our
 soil
 resource,
 maintaining
 soil
 function,
 improving
 soil
 health.

R.J. Kremer
Cover crop screening trials - MU Bradford Farm - 1997 2
Covers
 crops
 can
 aid
 in
 reducing
 soil
 degrada1on
 on
 fragile
 landscapes
 converted
 to

large-­‐scale
 commodity
 crop
 produc1on

Responsible
 integra1on
 of
 conserva1on
 prac1ces
 remains
 a
 cri1cal
 issue.

Need
 to
 limit
 off-­‐site
 movement
 of
 inputs,
 soil.

Photo: R.J. Kremer
Example:
 soybean
 on
 highly
 erodible
 loess
 soils
 of
 Missouri
 River
 uplands

(Howard
 County,
 MO
 -­‐
 2010)
Covers
 crops
 can
 be
 included
 in
 riparian
 buffer
 strips
 to
 reduce
 soil
 loss
 on
 alluvial

landscapes
 under
 intensive
 crop
 produc1on

Photo: R.J. Kremer
Photo: D. Hemmelgarn
Example:
 corn
 on
 alluvial
 soil
 resul1ng
 in
 soil
 loss
 due
 to
 sloughing
 into
 river

(Gasconade
 River,
 MO
 -­‐
 2013)
Cover Crops X Soil Health
Spring oats + berseem clover mixture Biodiversity in a hypothetical block of field soil --

Source: Reganold et al. 1990.
Important biological attributes of ‘healthy soils’
are influenced by vigorously growing plants

•S  oil Microbial Diversity (Biodiversity)
• Soil Carbon Content & Quality -- Plant root contributions
•  (SOM ≈ 58% C)
Rhizobacteria on plant root surface metabolize
Crimson clover provides Carbon and
plant-derived C and interact with plant.
Nitrogen to soils
5000X magnification
Soil Microbial Diversity (Soil Biodiversity)
[biodiversity = most valuable property of any ecosystem; E.O Wilson, 1999]

Accommodates diverse soil processes (i.e., nutrient cycling)
• 
 Diverse
 microbial
 communi0es
 (“Consor0a”)

carry
 out
 soil
 processes
 completely
  Earthworms
•  Ecosystem stability and resistance to stress

Nematode
Example of Structural Diversity: Bacteria

Algae
Fungi
Opera1onal
 food
 webs
 are

essen1al
 for
 op1mum

environmental
 func1oning

and
 “ecosystem
 services”
Mi#er,
 B.
 et
 al.
 2013.
 Advances
 in
 elucida8ng
 beneficial
 interac8ons
 between
 plants,
 soil,
 and
 bacteria.

Advances
 in
 Agronomy
 121:381-­‐445.
Crop residue
SOM
Components
Bacteria
Actinobacteria
Fungi
SOM
CO
2