- Количество слайдов: 50
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 l 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: l l l 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 l l water infiltration - percolation tests texture and structure § Chemical l l Organic matter p. H (“the master variable”) § Biological l earthworm population (25/ft 3) 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 p. H 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 l l 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
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 - significantly
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 l l 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: l l cool-season grasses: wild rye, perennial wheat, warm-season grasses: bunchgrass (3 x 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 F 1 generation (the plants from the bought seed) is uniform and recessive genes are unexpressed § Issues are 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 l l 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 l l l 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 * 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: l l 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 Fungil Available commercially in Cuba (and US)
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
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