Soil, Agroecosystem and Landscape Health

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Soil, Agroecosystem and Landscape Health

• Martha E. Rosemeyer
• April 10, 2003
• Rachel Corries Birthday

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Creating a sustainable food system Step 1-
sustainable food production
Earthfriends 1995 The Whole Story of Food
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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

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John Doran defn of soil quality or soil
health (often used interchangeably)

• Quality academics vs. health by non-academics
• 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
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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)

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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.

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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

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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

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Soil, plant, human linkageThe 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

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Soil is totally critical But there is more...

• Not so linear
• What sustains plants and animals is not just soil

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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.

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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 Ricas beans
  (1994)
• Costa Rica beans household use 40, commercial
  60 of production (1994)

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Experimental site Farm in south Costa Rica
Finca Loma Linda Canas Gordas
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Slash mulch mimic of rainforest root-litter mat
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Appropriate second growth vegetation for slash
mulch system
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After sowing seed, vegetation cut down and
distributed to form a mulch
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Slash mulch beans
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Unmulched Slash mulch

• Volcanic ash soil (Andisol) with high capacity
  for P-fixation

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The slash mulch system on steep hillsides in
Costa Rica

• Near Ciudad Neilly

• Finca Loma Linda, Ca?as Gordas

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No further management untilharvest and drying of
the bean plants
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Threshing and winnowing
Winnowing with turkey wing on Guaymi
reservation, near San Vito, Coto Brus, Costa Rica
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Root systems Slash mulch Unmulched

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Unfertilized
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Bean diseases Effects of the mulched and
unmulched systems

• With Mulch
• Anthracnose - significantly less
• (Colletotrichum lindemuthianum)
• Fusarium-type root rot - significantly less
• Root knot nematode -significantly less
• (Meloidogyne spp.)
• Rhizoctonia-type root rot - significantly
  more

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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

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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

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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.

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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)

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Tall grass prairieperennial and polyculture
Perennial polyculture at the Land
Institute Maxmillian sunflower and Monarch
Butterfly (upper)
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Polycultures -Land Institute

• Do perennial polycultures outyield perennial
  monocultures?

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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

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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

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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

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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.

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What maintained oak savanna and prairie? --fire
and browsers/grazers
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Can livestock substitute for natural grazers and
browsers? we meet conservation goals and produce
livestock too?
Scottish Highland cattle foraging on brush and
grass
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Can we manage the animals so that the rare
herbaceous oak savanna plants are impacted
positively?
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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

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• 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
• 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

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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

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Egrets and cattails
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Sandhill cranes in winter rice fields
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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

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Restoration of soil fertility at level of a
country case of Cuba
principally via agronomic methods like contour
plowing etc.
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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

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d) Biofertilizers

• N-fixing organisms
• symbiotic-Rhizobium (bacteria) Cuba- 80 N
  supplied for legumes
• free-living-Azotobacter (bacteria) Cuba- 40-50
  of N supplied in non-legumes
• P-solubilizing-Bacillus (bacteria)
• VA Mycorrhizal Fungi-
• Available commercially in Cuba (and US)

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For sustainable food system- food 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

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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

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• 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