4. Agroecology
Why is there a course in agroecology?
Sustainability
Threatened by conventional agricultural principles
5. Agroecology
Why is there a course in agroecology?
Sustainability
Threatened by conventional agricultural principles
What are those principles?
6. Agroecology
Why is there a course in agroecology?
Sustainability
Threatened by conventional agricultural principles
What are those principles?
Let’s discuss the Wendell Berry essay
9. Conventional Agriculture
Central ideas:
Maximize production
Maximize profits
Intensive Tillage Chemical pest control
Inorganic fertilizers
Irrigation
Monoculture
Genetic manipulation of crop plants
24. Conventional Agriculture
Synthetic Fertilizer
High yield increases, uniform application, rapid uptake/use
...but in large quantities can be leached from the soil and
cause damage through groundwater contamination,
collection in larger bodies of water, variable costs
25. Conventional Agriculture
Synthetic Fertilizer
High yield increases, uniform application, rapid uptake/use
...but in large quantities can be leached from the soil and
cause damage through groundwater contamination,
collection in larger bodies of water, variable costs
Did you know that the worldwide average Nitrogen
Use Efficiency is 33%?
29. Conventional Agriculture
Irrigation
Yield increases (water is a limiting factor)
16% of the world’s ag land is irrigated
30. Conventional Agriculture
Irrigation
Yield increases (water is a limiting factor)
16% of the world’s ag land is irrigated
...and it produces 40% of the world’s food
31. Conventional Agriculture
Irrigation
Yield increases (water is a limiting factor)
16% of the world’s ag land is irrigated
...and it produces 40% of the world’s food
What are problems with heavy irrigation?
32. Conventional Agriculture
Irrigation
Yield increases (water is a limiting factor)
16% of the world’s ag land is irrigated
...and it produces 40% of the world’s food
What are problems with heavy irrigation?
Replenishment, ecological effects of dams, increases
fertilizer leaching
36. Conventional Agriculture
Pest & Weed Control with Chemicals
Short-term pest removal
...but what happens to food chains? Resistance?
Leaching? Human health?
39. Conventional Agriculture
Plant Gene Manipulation
Selection has been practiced a
long time, but here we’re talking
about genetic manipulation
40. Conventional Agriculture
Plant Gene Manipulation
Selection has been practiced a
long time, but here we’re talking
about genetic manipulation
High-yielding hybrids,
pesticide use reduced
41. Conventional Agriculture
Plant Gene Manipulation
Selection has been practiced a
long time, but here we’re talking
about genetic manipulation
High-yielding hybrids,
pesticide use reduced
...and hybrids require optimal
conditions (fertilizer & water),
seed is dissimilar to the parent
(why is this important?)
58. Why Conventional isn’t Sustainable
Soil Degradation
erosion
waterlogging
compaction
contamination
structure problems
Erosion
4 T/A/Yr can be
“acceptable”
59. Why Conventional isn’t Sustainable
Soil Degradation
erosion
waterlogging
compaction
contamination
structure problems
Erosion
4 T/A/Yr can be
“acceptable”
Conventional Ag
often leaves soil bare
69. Why Conventional isn’t Sustainable
Water Use
Water rights are a big deal
Agriculture accounts for 2/3
of worldwide water use
70. Why Conventional isn’t Sustainable
Water Use
Water rights are a big deal
Agriculture accounts for 2/3
of worldwide water use
Plant water use efficiency is
around 50%!
71. Why Conventional isn’t Sustainable
Water Use
Water rights are a big deal
Agriculture accounts for 2/3
of worldwide water use
Plant water use efficiency is
around 50%!
Ag water use has a broader
ecological effect
72. Why Conventional isn’t Sustainable
Water Use
Water rights are a big deal
Agriculture accounts for 2/3
of worldwide water use
Plant water use efficiency is
around 50%!
Ag water use has a broader
ecological effect
Microclimate effects
80. Why Conventional isn’t Sustainable
Dependence on External Inputs
Now, think about this. Do people who
practice organic agriculture use inputs?
81. Why Conventional isn’t Sustainable
Dependence on External Inputs
Now, think about this. Do people who
practice organic agriculture use inputs?
irrigation, fertilizers, pesticides cost energy
that is not renewable (fossil fuels)
82. Why Conventional isn’t Sustainable
Dependence on External Inputs
Now, think about this. Do people who
practice organic agriculture use inputs?
irrigation, fertilizers, pesticides cost energy
that is not renewable (fossil fuels)
Now, think again. Is it morally wrong to use
something that is not renewable?
83. Why Conventional isn’t Sustainable
Dependence on External Inputs
Now, think about this. Do people who
practice organic agriculture use inputs?
irrigation, fertilizers, pesticides cost energy
that is not renewable (fossil fuels)
Now, think again. Is it morally wrong to use
something that is not renewable?
The inputs come from outside the relative
ecosystem, so now you depend on an
uncontrollable resource. The longer they are
used, the more you depend on them
86. Why Conventional isn’t Sustainable
Loss of Genetic Diversity
In the past, agriculture has relied on local
diversity (adapted traits) and recruiting
wild species into the gene pool
87. Why Conventional isn’t Sustainable
Loss of Genetic Diversity
In the past, agriculture has relied on local
diversity (adapted traits) and recruiting
wild species into the gene pool
We know that now only around six
varieties of corn account for 70% of
the world’s corn crop
88. Why Conventional isn’t Sustainable
Loss of Genetic Diversity
In the past, agriculture has relied on local
diversity (adapted traits) and recruiting
wild species into the gene pool
We know that now only around six
varieties of corn account for 70% of
the world’s corn crop
About half the wheat varieties in the
US are descendants of lines produced
by Norman Borlaug and collegues
89. Why Conventional isn’t Sustainable
Loss of Genetic Diversity
In the past, agriculture has relied on local
diversity (adapted traits) and recruiting
wild species into the gene pool
We know that now only around six
varieties of corn account for 70% of
the world’s corn crop
About half the wheat varieties in the
US are descendants of lines produced
by Norman Borlaug and collegues
Anything wrong with that?
92. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (continued)
This loss is a result of the desire for short-term
productivity gains
93. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (continued)
This loss is a result of the desire for short-term
productivity gains
The plants that are replaced could have really
desirable or potentially desirable traits
94. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (continued)
This loss is a result of the desire for short-term
productivity gains
The plants that are replaced could have really
desirable or potentially desirable traits
Homogeneous crop ‘germplasm’ (parentage) are
now more vulnerable...vulnerable to what?
95. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (continued)
This loss is a result of the desire for short-term
productivity gains
The plants that are replaced could have really
desirable or potentially desirable traits
Homogeneous crop ‘germplasm’ (parentage) are
now more vulnerable...vulnerable to what?
It is important to have a large genetic reservoir as
we look to possible future problems or diseases
98. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (some more)
Greenbug (aphid) and sorghum example
99. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (some more)
Greenbug (aphid) and sorghum example
$100 million
in damages
$50 million
in pesticides
the following
year
100. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (some more)
Greenbug (aphid) and sorghum example
$100 million
in damages Sorghum
variety was
$50 million
discovered with
in pesticides
tolerance
the following
year
101. Why Conventional isn’t Sustainable
Loss of Genetic Diversity (some more)
Greenbug (aphid) and sorghum example
$100 million
in damages Sorghum
variety was
$50 million
discovered with
in pesticides
tolerance
the following
year
BOOM
104. Why Conventional isn’t Sustainable
Loss of Local Control over Ag Production
Everybody knows that there’s fewer farmers farming bigger
fields now
105. Why Conventional isn’t Sustainable
Loss of Local Control over Ag Production
Everybody knows that there’s fewer farmers farming bigger
fields now
Business-farming often does not take part in local place-
based knowledge
106. Why Conventional isn’t Sustainable
Loss of Local Control over Ag Production
Everybody knows that there’s fewer farmers farming bigger
fields now
Business-farming often does not take part in local place-
based knowledge
But, with the rise of Organic Foods, there is a parallel rise in
niche producers
111. Why Conventional isn’t Sustainable
Global Inequality
People are still starving
Developing countries tend to become satellite
producers for the developed world, relying on
high-yielding varieties and non-renewable inputs
114. Why Conventional isn’t Sustainable
Having said all that...
High-yielding agriculture has done real good in the world
115. Why Conventional isn’t Sustainable
Having said all that...
High-yielding agriculture has done real good in the world
But, it can’t be relied on for the long-term
116. Why Conventional isn’t Sustainable
Having said all that...
High-yielding agriculture has done real good in the world
But, it can’t be relied on for the long-term
Oh, and we don’t have a lot more land to develop
117. Why Conventional isn’t Sustainable
Having said all that...
High-yielding agriculture has done real good in the world
But, it can’t be relied on for the long-term
Oh, and we don’t have a lot more land to develop
...But a lot of this topic used to be in the context of a huge
increase in population worldwide, which according to Albert
Gore won’t actually happen
125. Sustainability
Can you define it?
Minimal negative effects on the environment & local ecology
126. Sustainability
Can you define it?
Minimal negative effects on the environment & local ecology
Preserve and rebuild soil fertility, prevent erosion
127. Sustainability
Can you define it?
Minimal negative effects on the environment & local ecology
Preserve and rebuild soil fertility, prevent erosion
Use water so that aquifers are restored and other water
needs are met
128. Sustainability
Can you define it?
Minimal negative effects on the environment & local ecology
Preserve and rebuild soil fertility, prevent erosion
Use water so that aquifers are restored and other water
needs are met
Rely on resources within the agroecosystem
129. Sustainability
Can you define it?
Minimal negative effects on the environment & local ecology
Preserve and rebuild soil fertility, prevent erosion
Use water so that aquifers are restored and other water
needs are met
Rely on resources within the agroecosystem
Work to conserve biodiversity
132. Agroecology
A fancy word for wise agriculture
We cannot ignore the problems of conventional ag, but we
cannot just abandon it
133. Agroecology
A fancy word for wise agriculture
We cannot ignore the problems of conventional ag, but we
cannot just abandon it
Traditional (old), resource-conserving, local, small-scale
134. Agroecology
A fancy word for wise agriculture
We cannot ignore the problems of conventional ag, but we
cannot just abandon it
Traditional (old), resource-conserving, local, small-scale
Definition:
The application of ecological concepts and principles to the
design and management of sustainable agricultural systems
136. Thought Questions
What are the issues of greatest importance that
threaten the sustainability of agriculture in the
town or region in which you live?