Transcript PowerPoint Presentation - Soil and Agroecosystem Health

Soil, Agroecosystem
and Landscape Health
Martha E. Rosemeyer
April 10, 2003
Rachel Corrie’s Birthday
Creating a sustainable food system: Step
1- sustainable food production
Earthfriends 1995
“The Whole Story
of Food”
Outline
 Soil health: basis for sustainability
 Agroecosystem health: Mimicking the
natural system
• Land Institute: Designing a new system
• Slash Mulch System: Assessing a traditional mimic
• Restoration of oak savanna with Highland cattle:
Substituting domesticated for wild
 Landscape health: connecting the
agroecosystems

Re-wilding the farm
• Nature Conservancy Cosumnes River Project, CA
John Doran defn of soil quality or soil
health (often used interchangeably)
 “Quality” academics vs. “health” by nonacademics
 “The continued capacity for soil to function
as a vital living system, within ecosystem
and land-use boundaries to:



sustain biological productivity
promote quality of air and water environments
maintain plant animal and human health”
Doran and Safley 1997
Soil provides “ecosystem
functions or ecosystem services”
 Cooperband: Infiltration, water retention,
absorption of nutrients, degradation of
pesticides, pollutants, stabilizing soil
temperatures
 Sequestration of carbon dioxide,
decomposition of organic substrates
 Other ecosystem services can be predation
of insect pests and pollination (not nec.
Soil)
Indicators of soil quality
 Physical


water infiltration - percolation tests
texture and structure
 Chemical


Organic matter
pH (“the master variable”)
 Biological

earthworm population (25/ft3)
Zimmer,G. 2000.
Soil health associated with
organic matter content
 Organic matter in soil is basically the
compost that Leslie talked about
 Organic matter is about all
that we can easily change
 Neutral pH needed for
earthworms
Human health dependent on
Plant and Animal health, which is
dependent on
Soil Health
 Mismanagement of soil has lead to poverty,
malnutrition and economic disaster
Soil, plant, human linkage:
The case of Selenium




Naturally found in soil and water
Irrigation of Central Valley in CA  [Se]
Certain native and other plants accumulate
Essential nutrient in animals and humans
and can be deficiency


Cofactor in antioxidant enzymes
Important in Vitamin D absorption
 In large quantities is poisonous to livestock
and humans causing muscle tremors, etc.
Cihacek, Anderson, Barak 1996
Soil is totally critical
But there is more...
 Not so linear
 What sustains plants and animals is not just
soil
Mimicking the natural system
 Agroecosystem mimic the native ecosystems
 Only ecosystems that are present that
1. maintain or build their ecological capital,
2. fix and hold their nutrients,
3. are adapted to periodic stress, such as
drought and fire, and
4. manage their weed, pest and pathogen
populations.
Tropical Ecosystem mimic:
Traditional slash mulch system
 Pre-Hispanic, swidden (migratory)
 Bean, corn, root crops also sorghum and rice
 Key characteristic is mulch of secondary
vegetation (not primary) that is not burned
 Fallow part of system
 System produces 30-40% of Costa Rica’s beans
(1994)
 Costa Rica beans: household use 40%,
commercial 60% of production (1994)
Experimental site: Farm in south
Costa Rica
Finca Loma
Linda
Canas Gordas
Slash mulch mimic of rainforest
root-litter mat
Appropriate second growth vegetation
for slash mulch system
After sowing seed, vegetation cut down
and distributed to form a mulch
Slash mulch beans
Unmulched
Slash mulch
Volcanic ash soil (Andisol) with
high capacity for P-fixation
The slash mulch system on steep
hillsides in Costa Rica
Near Ciudad Neilly
Finca Loma Linda, Caas Gordas
No further management until
harvest and drying of the bean plants
Threshing and winnowing
Winnowing with turkey wing on Guaymi reservation,
near San Vito, Coto Brus, Costa Rica
Root systems
Slash mulch
Unmulched
u g / g a v a i l a b l e P (m e m b ra n e ) 4 w
50
Available P in soil and mulch of slash
mulch system,*Los Arcos 1995-1997
40
30
20
10
0
1995
1996
Soil 0-5cm
1997
Slash Mulch
*Unfertilized
Bean diseases: Effects of the mulched
and unmulched systems
 Anthracnose
With Mulch
- significantly less
(Colletotrichum lindemuthianum)
 Fusarium-type root rot
significantly less
 Root knot nematode
(Meloidogyne spp.)
 Rhizoctonia-type root rot
-
-significantly less
-
Biological impact summary
 Less foliage and root disease with exception
Rhizoctonia root rot in mulched system
 Different nematode communities in
mulched and unmulched systems, less
morphospecies diversity in soil of mulched
 Greater arthropod diversity in soil of
mulched systems
In summary
 The traditional system appears to be
sustainable because it imitated the natural
system root-litter mat


limiting nutrient more available
avoidance of disease
Land Institute
“Natural Systems Agriculture
is a new paradigm for food
production, where nature is
mimicked rather than subdued
and ignored. Because we are
located in native prairie, we
look to the prairie as our
model for grain crops. As a
result, we are investigating the
feasibility of perennial
polycultures or mixtures of
perennial grains.”
Ecosystem function follows structure
 Have identified four functional groups in prairie:
cool-season grasses, warm-season grasses,
legumes and composites. Has identified
perennials in all groups:




cool-season grasses: wild rye, perennial wheat,
warm-season grasses: bunchgrass (3x higher in protein
than corn),
legumes (Fabaceae): Illinois bundleflower (38%
protein),
composite (Asteraceae): Maxmillian sunflower (oil)
Tall grass prairie:
perennial and polyculture
Perennial polyculture at the Land Institute
Maxmillian sunflower and Monarch Butterfly (upper)
Polycultures
-Land Institute
 Do perennial
polycultures outyield
perennial
monocultures?
Perennialization
Marty Bender and Jerry Wild (KSU)
looking for sunflower moths
 Breed perennial characteristics into existing
grains like wheat
 Breed edible grain characteristics into
perennials
 Suggests genetic engineering may be a
useful approach
Genetic Engineering: what is it?
 Genetically Engineering (GE): Transfer of
genes from one organism-- plant, animal or
microbe-- to another using biotechnology, not
conventional breeding.
 Genetically Modified Organism (GMO) is a
term that is somewhat misleading since the
process of plant adaptation or conventional
breeding can be a genetic modification
 Transgenic
GE is not hybridization
 Hybrids are conventionally bred from two
inbred parents
 Advantage is the the F1 generation (the plants
from the bought seed) is uniform and recessive
genes are unexpressed
 Issues are the the seed saved is variable in
quality so that it is not useful to save
 Need to continually buy seed
 Has supplanted open-pollinated varieties
Assembling the agroecosystem
 synthetic communities of plants, animals,
and micoorganisms that are stable,
productive, and close enough in form to the
native community that the essential
functions of pest resistance, soil stability,
and nutrient cycling are preserved.
What maintained oak savanna and
prairie? --fire and browsers/grazers
Can livestock substitute for natural grazers
and browsers? we meet conservation goals
and produce livestock too?
Scottish Highland cattle
foraging on brush and grass
Can we manage the animals so that
the rare herbaceous oak savanna plants
are impacted positively?
Farming with the wild
 Beyond organic
 “We cannot have healthy farms in a
degraded landscape. Quite apart from the
problem of drift-- whether chemical or
genetic-- there is the fact of the biodiversity
necessary to produce the ecosystem services
on which our organic farms depend can
only be restored and maintained on an
ecosystem level”-- Kirschenmann and
Gould
 “The idea that organic farms are enclaves of
purity-- that everything within their
boundaries is God-like and everything that
lies outside their boundaries is evil-- is a
patch ecology perspective that must be
reconsidered.” --Kirsh. and Gould
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
identify ecological neighborhoods
how can agriculture fit into them by effectively
using the ecosystem services they provide
• microorganisms and soil quality; predators of
insect pests and native pollinators
The Nature Conservancy- Cosumnes
River Landscape Level Project
 42,000 acres
 Agencies 


State Fish and Wildlife
EPA
UC Davis
 Organic rice farmers
livestock grazers in
buffer areas
Egrets and cattails
Sandhill cranes in winter rice fields
Other Wild Farm pioneers
 Wildlands corridor Coon Mt. to Split Rock
Wildway to link Lake Champlain to
Adirondacks. Land trusts and Black Kettle
Farm- maximizes biodiversity
 Chile Parque Pumulin- viable rural
economies with demonstration organic
farms (800,000 acres)
 Costa Rica- Palo Verde National Park- cattle
used to clear vegetation
 Paseo Pantera Mesoamerican corridor
Restoration of soil fertility at level of
a country: case of Cuba
Type
Erosion
Area
(M ha)
3681
% Rehabil.
1990
86.1*
Saliniz.
780
0.1
Acidity
1133
26.5
Poor drain 100
6.7
Low SOM 3000
94.1
* principally via agronomic methods like contour plowing etc.
Methods to maintain and restore soil
fertility in Cuba
1) Soil Amendments
a) Organic matter- leaf-cutting ant refuse, leaf
litter, compost, green manures, cover crops,
worm compost (from vermiculture), urban
garbage, crop residues, processing of
agricultural by-products
b) Crushed rock and lime
c) Physically moving eroded soil and organic
matter from lowlands to highlands
d) Biofertilizers
 N-fixing organisms:
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symbiotic-Rhizobium (bacteria) Cuba- 80% N
supplied for legumes
free-living-Azotobacter (bacteria) Cuba- 4050% of N supplied in non-legumes
 P-solubilizing-Bacillus (bacteria)
 VA Mycorrhizal Fungi
Available commercially in Cuba (and US)
For sustainable food systemfood production:
 We need to restore soil
 We need to restore connectivity of
landscape
 Work from landscape level perspective for
sustainable food production and quality of
life
References
 Imhoff, D. 2002. Farming with the Wild.
In: Fatal Harvest.
 Soule, J.D. and J.K. Piper. 1992. Farming in
Nature's Image. Island Press
 Jackson, L. and Jackson, D. 2002. The
Farm as Natural Habitat Island Press
 Cihacek, Anderson, Barak. 1996. Linkages
between Soil quality and plant, animal and
human health. In: Methods of Assessing
Soil Quality. SSSA Spec. Pub. #49
 Zimmer, G. 2000. The Biological Farmer:
A Complete Guide to the Sustainable and
Profitable System of Farming