Download Sustainable Agriculture: An introduction

Sustainable Agriculture
An introduction……
Sustainable Agriculture
• The practice of farming using principles of ecology, the
study of relationships between organisms and their
environment.
– It has been defined as "an integrated system of plant and animal
production practices having a site-specific application that will
last over the long term:
• Satisfy human food and fiber needs
• Enhance environmental quality and the natural resource base
upon which the agricultural economy depends
• Make the most efficient use of non-renewable
resources and on-farm resources and integrate, where
appropriate, natural biological cycles and controls
• Sustain the economic viability of farm operations
• Enhance the quality of life for farmers and society as a
whole.
Sustainable agriculture integrates
three main goals
• Environmental health
• Economic profitability
• Social and economic
equity.
© bank ESA 2010
Environmental health
• Sustainable Agriculture refers
to agricultural production that
can be maintained without
harming the environment.
• Environmentally Sustainable
Agriculture should be:
– Bearable
– Equitable
– viable for the farmer
• AND - produce the best
quality food for the
consumer, nurture the
environment & preserve
energy.
© bank ESA 2010
Economic profitability
• Ecological economics is:
– the interdependence of
‘human economies and natural
ecosystems’.
• It treats the economy and
society as a subsystem of
the ecosystem:
– with emphasis on preserving
natural capital
• recognizes
– That social and economic
systems cannot exist
independently from the
environment.
© bank ESA 2010
Social and economic equity
• There is a natural market
premium
• If successful
– Equity will be recognized by
the farmer as beneficial for
this commitment to quality
food output.
• In addition farmer may get
– Government favorable
interest rate financial
incentives and solution
support.
© bank ESA 2010
Sustainable agriculture
• Sustainable agriculture in the United States was addressed
by the 1990 farm bill.
• More recently, as consumer and retail demand for
sustainable products has risen, organizations such as Food
Alliance and Protected Harvest have started to provide
measurement standards and certification programs for what
constitutes a sustainable grown crop
What is Sustainable
Agriculture?
• Agriculture has changed
dramatically, especially since the
end of World War II.
• Food and fiber productivity
soared due to new technologies,
mechanization, increased
chemical use, specialization and
government policies that favored
maximizing production.
• These changes allowed fewer
farmers with reduced labor
demands to produce the majority
of the food and fiber in the U.S.
What is Sustainable
Agriculture?
• Has had major social and
ecological impacts, which have
drawn intense praise and equally
intense criticism.
• In fact, many regions of the
world peaked in food production
in the period 1980 to 1995
• Are presently in decline, since
desertification and critical
water supplies have become
limiting factors in a number of
world regions.
What is Sustainable
Agriculture?
• Although these changes have had many positive
effects and reduced many risks in farming, there
have also been significant costs.
•
•
•
•
•
•
Prominent among these are:
Topsoil depletion,
groundwater contamination
decline of family farms,
continued neglect of the living and working
conditions for farm laborers,
increasing costs of production
disintegration of economic and social conditions in
rural communities.
What is Sustainable
Agriculture?
• A growing movement has emerged during the past
two decades to question the role of the agricultural
establishment in promoting practices that
contribute to these social problems.
• Today this movement for sustainable agriculture is
garnering increasing support and acceptance within
mainstream agriculture.
• Not only does sustainable agriculture address many
environmental and social concerns, but it offers
innovative and economically viable opportunities for
growers, laborers, consumers, policymakers and
many others in the entire food system.
The Biosphere
• The atmosphere sustains
life and is sustained by life.
• The Gaia hypothesis
– The entire planet is a
living breathing
organism and will
protect itself –
homeostasis of the
whole planet!!!
• The biosphere works in
“cycles”
• Nitrogen
• Carbon
• Water
•
Some greenhouse
emissions related to
agriculture are
embedded in other
sectors
•
fossil fuels to produce
chemical fertilizers and
pesticides
•
Processing
•
Packaging
•
Refrigeration
•
transport of food
•
land conversion from
biodiverse ecosystems to
giant, monoculture food
plantations
Rodale Institute study
• projects that the planet’s 3.5
billion tillable acres could
sequester nearly 40 percent of
current CO2 emissions if they
were converted to “regenerative”
organic agriculture practices
• Remember:
• Via photosynthesis, over 100 billion
metric tons of CO2 and H2O are
converted into cellulose and other
plant products
Many studies have drawn similar
conclusions.
• India
– organic farming research shows increases in carbon
absorption by up to 55 percent (even higher when
agro-forestry is added into the mix), and water holding
capacity is increased by 10 percent.
• California
– study of 20 commercial farms found that organic fields
had 28 percent more carbon in the soil than industrial
farms.
Water
• In some areas, sufficient
rainfall is available for crop
growth, but many other
areas require irrigation.
•
For irrigation systems to
be sustainable they require
proper management (to
avoid salinization) and must
not use more water from
their source than is
naturally replenished
taken from an article by Robert Service in Science
Magazine. “Energy demands on water resources”
Indicators for sustainable water
resource development are:
• Internal renewable water resources.
– This is the average annual flow of rivers and groundwater generated
from endogenous precipitation.
• Can be expressed in three different units:
– in absolute terms (km3/yr),
– a measure of the humidity of the country (mm/yr)
– as a function of population (m3/person per yr).
• Global renewable water resources.
– sum of internal renewable water resources and incoming flow
originating outside the country.
– can vary with time if upstream development reduces water
availability at the border.
Indicators for sustainable water
resource development are:
• Dependency ratio.
– This is the proportion of the global renewable water resources
originating outside the country, expressed in percentage.
– It is an expression of the level to which the water resources of a
country depend on neighboring countries.
•
Water withdrawal.
– When expressed in percentage of water resources, it shows the
degree of pressure on water resources.
– A rough estimate shows that if water withdrawal exceeds a quarter
of global renewable water resources of a country, water can be
considered a limiting factor to development.
– Therefore, the pressure on water resources can have a direct
impact on all sectors, from agriculture to environment and fisheries.
The Soil
• The biggest ecosystem on
Earth!
• Animals:
– micro-organisms mix soils as they
form burrows and pores, allowing
moisture and gases to move about.
In the same way, plant roots open
channels in soils.
• Plants:
– deep taproots can penetrate many
meters through the different soil
layers to bring up nutrients from
deeper in the profile.
– fibrous roots that spread out near
the soil surface have roots that are
easily decomposed, adding organic
matter.
The Soil
• Micro-organisms:
– including fungi and bacteria, effect
chemical exchanges between roots
and soil and act as a reserve of
nutrients.
•
Humans:
– impact soil formation by removing
vegetation cover with erosion as the
result.
– Also mix the different soil layers,
restarting the soil formation
process as less weathered material
is mixed with the more developed
upper layers.
Soil Erosion
• Fast becoming one of the worlds greatest problems. It is
estimated that more than a thousand million tonnes of
southern Africa's soil are eroded every year.
– Experts predict that crop yields will be halved within thirty to
fifty years if erosion continues at present rates.
• Not unique to Africa but is occurring worldwide.
– The phenomenon is being called Peak Soil as present large scale
factory farming techniques are jeopardizing humanity's ability to
grow food in the present and in the future.
• Without efforts to improve soil management practices, the
availability of arable soil will become increasingly
problematic.
Soil Management techniques
• No-till farming
– soil is left intact and crop residue is left on the field.
– soil layers, conserving organisms and layers in their
natural state.
• Keyline design
– maximizes beneficial use of water resources of a piece of
land.
– refers to a specific topographic feature linked to water
flow
• Growing wind breaks to hold the soil
– Planting trees and hedges
– Prevent wind from blowing away top soil
Soil Management techniques
• Incorporating organic matter back into fields
– Composting! Puts Carbon, Nitrogen, Oxygen, Water and
microbes back into the soil!!! Can also add Urine –honest!!
• Stop using chemical fertilizers (contain salt)
– Remember Algal Blooms? Also, the salt kills natural
micro-organisms in soil – contaminates water!!!!!
• Protecting soil from water runoff
– Careful placement of rocks and trees.
• Soil Steaming
– sterilize soil with steam in open fields or greenhouses
– Destroys pathogens
– Destroys weeds, but dead plant material is left in soil as
compost
Bottom line
• Grow crops which are
best suited to local
environment
• Have a plentiful, and
renewable local water
supply
• Protect the soil
• Good crop management
techniques
Good crop management techniques
• Grow a variety of crops.
– spreads economic risk and are
less susceptible to the radical
price fluctuations associated
with changes in supply and
demand.
• Crop rotation
– used to suppress weeds,
pathogens and insect pests.
Good crop management techniques
• Cover crops
– stabilizing effects by holding soil
and nutrients in place
– conserving soil moisture with
mowed or standing dead mulches,
increasing the water infiltration
rate and soil water holding
capacity.
– The use of vineyards can buffer
the system against pest
infestations by increasing
beneficial arthropod populations
and can therefore reduce the
need for chemical inputs.
Bottom line
• Low cost and effective
local storage of food
stuffs
• Low environmental
impact transport
system
• Local market and a
steady and growing
customer base.
So what about backyard
Agricultural Sustainability?
• Grow only crops which mature within the local growing
season.
• Only grow crops selections which will work together in such
a limited space.
• Think about nutrient needs.
• Think about water demands.
• Think about long time storage of successful crops.
Water barrel
• Free (clean) water!!!!!!!
• Rain barrel kit
– www.earthminded.com
– Trash can
– $40.00!!!
• Set up next to garden. Fills up
fast!
– Melting snow will also fill it up.
– Can connect many together.
• Consider county, city, and
state laws!
Composting
• Turning kitchen waste into
natural fertilizer
• Any container will work
– Need air holes
•
Can buy bacteria cultures to add
to container.
– Can add worms to increase
efficiently
• When setting up, layer soil and
kitchen waste.
– Takes approx. one year to get
going from scratch.
The start of composting
• Bacteria are the smallest living
organisms and the most numerous
in compost.
• They make up 80 to 90% of the
billions of the microorganisms
typically found in a gram of
compost.
• Bacteria are responsible for most
of the decomposition and heat
generation in compost.
• They are the most nutritionally
diverse group of compost
organisms, using a broad range
of enzymes to chemically break
down a variety of organic
materials
By: Nancy Trautmann and Elaina Olynciw:
Cornell University
As composting goes on…..
•
At the beginning of the composting
process (0-40°C), mesophilic bacteria
predominate. Most of these are forms
that can also be found in topsoil.
•
As the compost heats up above 40°C,
thermophilic bacteria take over. The
microbial populations during this phase
are dominated by members of the
genus Bacillus. The diversity of Bacilli
species is fairly high at temperatures
from 50-55°C but decreases
dramatically at 60°C or above.
•
When conditions become unfavorable,
bacilli survive by forming endospores,
–
thick-walled spores that are highly
resistant to heat, cold, dryness, or
lack of food.
– They are ubiquitous in nature and
become active whenever environmental
conditions are favorable.
By: Nancy Trautmann and Elaina Olynciw:
Cornell University
And at the end……
• Once the compost cools down,
mesophilic bacteria again
predominate.
• The numbers and types of
mesophilic microbes that
recolonize compost as it
matures depend on what
spores and organisms are
present in the compost as well
as in the immediate
environment.
• In general, the longer the
curing or maturation phase,
the more diverse the microbial
community it supports.
By: Nancy Trautmann and Elaina Olynciw:
Cornell University
Actinomycetes
• The characteristic earthy smell of soil
is caused by actinomycetes, organisms
that resemble fungi but actually are
filamentous bacteria.
• Like other bacteria, they lack nuclei,
but they grow multicellular filaments
like fungi.
• In composting they play an important
role in degrading complex organics
such as cellulose, lignin, chitin, and
proteins.
• Their enzymes enable them to
chemically break down tough debris
such as woody stems, bark, or
newspaper.
Institute of Soil Biology České
Budějovice, Czech Republic
Actinomycetes
• Some species appear during the
thermophilic phase, and others
become important during the cooler
curing phase, when only the most
resistant compounds remain in the last
stages of the formation of humus.
• Actinomycetes form long, thread-like
branched filaments that look like gray
spider webs stretching through
compost.
• These filaments are most commonly
seen toward the end of the
composting process, in the outer 10 to
15 centimeters of the pile. Sometimes
they appear as circular colonies that
gradually expand in diameter.
Institute of Soil Biology České
Budějovice, Czech Republic
Fungi
• Fungi include molds and yeasts,
and collectively they are
responsible for the
decomposition of many complex
plant polymers in soil and
compost.
• In compost, fungi are
important because they break
down tough debris, enabling
bacteria to continue the
decomposition process once
most of the cellulose has been
exhausted.
• They spread and grow
vigorously by producing many
cells and filaments, and they
can attack organic residues
that are too dry, acidic, or low
in nitrogen for bacterial
decomposition.
Permission from University of
California Museum of
Paleontology.
Fungi
• Most fungi are classified as
saprophytes because they live
on dead or dying material and
obtain energy by breaking down
organic matter in dead plants
and animals.
• Fungal species are numerous
during both mesophilic and
thermophilic phases of
composting.
•
Most fungi live in the outer
layer of compost when
temperatures are high.
• Compost molds are strict
aerobes that grow both as
unseen filaments and as gray or
white fuzzy colonies on the
compost surface.
Permission from University of
California Museum of
Paleontology.
Don’t forget worms!
• These are heterotrophs that obtain
nutrients by
consuming detritus (decomposing
plant and animal parts as well as
organic fecal matter).
• By doing so, they contribute
to decomposition and the nutrient
cycles.
• They should be distinguished from
other decomposers, such as many
species of:
– bacteria
– fungi
– protists
• which are unable to ingest discrete
lumps of matter
– but instead live by absorbing and
metabolizing on a molecular scale.
Conclusions
• Converts raw organic matter into humus, feeds the soil
population of microorganisms and other creatures, thus
maintains high and healthy levels of soil life.
• Decomposition of dead plant material causes complex
organic compounds to be slowly oxidized or to break down
into simpler forms which are further transformed into
microbial biomass.
• The biochemical structure of humus enables it to moderate
– or buffer – excessive acid or alkaline soil conditions.
• The dark color of humus (usually black or dark brown)
helps to warm up cold soils in the spring.
Wood ash
• In addition to composting,
can use wood ash from a log
burning fireplace.
• Ash is full of the essential
nutrients required for plant
growth and development.
• Even contains a higher % of
these nutrients than
commercially available
growth supplements.
• Cheap, natural, and fantastic
for the environment and soil
health
Component
Normal agar (ppm)
Ash Agar (ppm)
Arsenic
<0.1
0.1
Barium
<0.1
3.3
0.1
2.2
Calcium
37.9
1409.9
Chlorine
2.1
2.1
Chromium
<0.1
0.1
Cobalt
0.1
0.1
Copper
0.1
2.2
Iron
0.5
27.4
Lead
0.1
0.2
Lithium
<0.1
0.2
Magnesium
11.6
107.6
Manganese
0.2
3.8
Molybdenum
<0.1
0.1
Nitrogen
21.5
21.5
Phosphorus
3.6
109.4
Potassium
35.6
552.1
Sodium
83.7
90.7
Sulfur
268.3
335.8
Tin
0.1
0.1
Zinc
0.1
1.1
Boron
Canning
• So, you grew hundreds of tomatoes.
What to do with them?
• Great preservation technique.
– Allows you to store food stuffs
outside of the growing season
– Can use them for cooking for the rest
of the year
– Better than just freezing food stuffs
• Can store ANYTHING by this
method.
• Not a new technology, just a (mostly)
forgotten one, which is making a
comeback.
Final Summary
• Sustainable Agriculture is:
– The practice of farming using principles of ecology, the study of
relationships between organisms and their environment.
– refers to agricultural production that can be maintained without
harming the environment.
• Not only does it address many environmental and social
concerns, but it:
–
–
–
–
–
offers innovative and economically viable opportunities for:
growers
Laborers
Consumers
policymakers.
The End!
Any Questions?