University of Michigan Guest Lecture E

LECTURE 17

Food
Farming
Agriculture

ENVIRON201 SCHEDULE
Lecture: Professor Webb returns next week!
Lab: Exploring an Environmental Issue – continue to work in
groups, bring together various delegated individual tasks (from
proposal), advance overall project, ask questions

HUMAN EXPERIENCE

FOOD

  Agriculture: Yield –
  Varieties
  Pest Control
  Soil
  Water

  Fertilizer

  Agriculture: Energy
  Case Study: UM Sustainable Food Program

AGRICULTURE: LAND
  Supply of land for agriculture use is limited
  In 2011, 1.5 billion hectares are already under cultivation
  Or, 3.7065x10 9 acres
  This number is projected to increase over the next 50 years, especially in
developing nations with less stable food production

source: indianagrain.com

AGRICULTURE: LAND

The Millennium Ecosystem Assessment:
-  Commissioned by UN Secretary General
Annan in 2000
-  Goal: To assess the consequences of

ecosystem change for human well-being
and the scientific basis for action
needed to enhance the conservation
and sustainable use of those systems
and their contribution to human wellbeing
-  Anthropocentric

AGRICULTURE: LAND
 I n the past 50 years,
humans have
changed ecosystems
more rapidly and
extensively than in
any comparable
period of time in
human history
- M i l l e n n i u m E c o s y s te m A s s e s s m e n t

AG R I C U LT U R E :

LAND
M o r e l a n d wa s
c o nve r te d to
cropland in the
3 0 ye a r s a f te r
1950 than in
t h e 1 5 0 ye a r s
b e t w e e n 17 0 0
and 1850
C u l t i va te d
s y s te m s c ove r
25% of Earth’s
te r r e s t r i a l
surface

FOOD
  Agriculture: Land

  Agriculture: Energy
  Green Revolution

  Agriculture: Subsidies
  Agriculture: Climate Change
  Organic Farming and Beyond

AGRICULTURE: YIELD
PRESSURE TO USE LESS LAND IN FUTURE
 W ith less and less land
available for food
production, there is
pressure to intensify
 B ut there are competing
goals of multifunctional
agriculture

AGRICULTURE: YIELD
COMPETING GOALS
  Avoid farming marginal lands
  Restore grasslands on steeper slopes
  Restore wetlands for water quality improvement
  Allow for 100-300 f t riparian stream buffers

  Increase crop diversity
  5-year crop rotations
slash-and-burn ag in South America
  Row crops planted with cover crops
  Managed intensive rotational grazing

B o o d y e t a l . 2 0 0 5 B i o S c i . Vo l . 5 5 ( 1 ) ; 27 - 3 8

RESTORE
GRASSLAND
ON SLOPES
Te r r a c e d
Agriculture
Common in
Asia
Erosion
H a r d to
maintain

RESTORE

WETLANDS
We t l a n d s
p r ov i d e h u m a n s
with natural
wa te r
purification
H a b i t a t fo r r a r e
species
Po o r l a n d fo r
a g r i c u l t u r e ( l ow
yield)

Wetland that was farmed upon then abandoned
Poor habitat for farming, but available

G o o d to
i n c o r p o r a te
p r e s e r ve d
wetlands with
b u f fe r z o n e

CROP
ROTATION
Plant species
a f fe c t s o i l
composition
d i f fe r e n t l y
Ro t a te w h a t
yo u p l a n t to l e t
s o i l s r e j u ve n a te
Lots of
te c h n i q u e s –
n e e d to k n ow
what kind of
s o i l yo u ’ r e
working with

IMPLEMENT
COVER
CROPS

L e s s i n te n s e
direct sunlight
C ove r e d c r o p s
require less
frequent
wa te r i n g s
Manage soil
fe r t i l i t y
M i t i g a te p e s t s ,
diseases,
weeds, erosion
of soils

MANAGED
INTENSIVE
ROTATIONAL
GRAZING
Ro t a t i o n o f
a n i m a l s to
a l l ow fo r

r e g r ow t h
Can be used
w i t h c ow s ,
sheep, goats,
p i g s , c h i c ke n s ,
ducks
Some farmers
h ave te m p o r a r y
fe n c e s

AGRICULTURE: YIELD
MAKING LAND WORK HARDER
 C AFO –
Concentrated Animal
Feeding Operation
 Animal feeding facility
with no natural
vegetation (feed)
 Animals grow
(fattened) in confined

space for > 6 weeks
 Increase in yield

ENVIRONMENTAL IMPACTS OF CAFO S

CAFOs replacing small-scale farms

Point-source pollution from CAFO

AGRICULTURE: YIELD
SOCIAL CONTEXT OF YIELD
 Europe and US –
concerns for animal
welfare
 Developing markets –
less/no concern
 Unlikely to meet
global meat demand
without CAFOs
(TechnoGarden

scenario, MEA)

AGRICULTURE: LAND
MAKING LAND WORK HARDER
  https://www.youtube.com/watch?v=-LjW6eIFYpo
  A happier alternative (for the animals AND environment):
https://www.youtube.com/watch?v=z9HF93LfBDw

  Visit Niman Ranch website for more information:
http://www.nimanranch.com/Index.aspx

AGRICULTURE: YIELD
  Yield = biomass achieved per unit area
  Wheat:
  11,032 pounds/acre – best modern plants, best fertilizer, best
husbandry
  5,511 pounds/acre – best yield from 1970s after Green Revolution
  2,755 pounds/acre – typical practices in Argentina and India

AGRICULTURE:
YIELD
  There are two sources of increasing crop yield without
increasing amount of land used:
  1) Increase in cropping intensities
  Shorter fallow periods

  2) Modify system through increased inputs
  More biomass via increased nutrient inputs, denser plantings

WHICH OF THESE COULD POTENTIALLY HAVE AN ECOLOGICAL ISSUE
ASSOCITED WITH ITS IMPLEMENTATION?

AGRICULTURE: YIELD
  Yield depends on:
  Crop/livestock variety – species and traits
  New varieties generated through selective breeding, genetically modified
organisms, and pests

  Soil
  Micro-organisms in soil biomass > dirt biomass

  Water
  Up to 80% may be wasted. Often subsidized. Over-watering water-logs
soils. Agricultural Runoff.

  Fertilizer
  Responsible for > 50% of doubling of crop production in last 50 years.
Over fertilization leads to aquatic ecosystem pollution.

AGRICULTURE: YIELD
VARIETIES
 Until recently there
were numerous
varieties from selective
breeding by humans
 Selective breeding of
battery chickens
reduced input food
requirement from 4kg
of food/kg of eggs to
just 2kg food/kg eggs!
 Turkeys so bloated they
cannot walk. Chickens
grow so fast they suffer
stress fractures.

WHICH KIND OF EGGS DO YOU BUY FROM
THE STORE?

AGRICULTURE: YIELD
GENETICALLY MODIFIED ORGANISMS
 PROS
 Accelerates genetic
modification by faster
selection for desired
traits
 Insertion of novel
genes
 Increases yield,
resistance to
pathogens, ability to
process fertilizers,
freeze resistance

 CONS
 Accelerates
development of pest
resistance
 Higher herbicide use for
GMO high tolerance
varieties
 Reduce survival/growth
and diversity of wildlife
 Gene jumping
 Dilution of wild genome
and genetic diversity

READ: A GROWING THREAT DOWN ON THE FARM

AGRICULTURE: YIELD
GENETICALLY MODIFIED ORGANISMS
 Ethical concerns:
 Are we tampering with
nature?
 Where’s the stopping
point?
 Lots of information out
there on this topic –
know what you’re
reading!

INTERMISSION

AGRICULTURE: YIELD
PESTICIDE USE
  Direct advantage – increase yield by killing competitors
(pests)
  Disadvantages –
  Pesticide resistance and pest resurgence (pesticide treadmill)
  Non-target species: 90% misses
  New pests
  Bioaccumulation (Rachel Carson, Silent Spring)

“But man is a part of nature, and his war against nature is inevitably a
war against himself.” – Rachel Carson

AGRICULTURE: YIELD
ALTERNATIVES TO PESTICIDES?
  Farming Practices:
  Crop rotation
  Green manure
  Natural, organic fertilizers
  Polyculture
  Vary planting times
  Burning before planting
  Flooding before planting
  Surrounding habitat
diversity

Source: wikimedia commons

AGRICULTURE YIELD:
ALTERNATIVES TO PESTICIDES?
  Biological Control
  Predators, pathogens attack pests
  Interplanting with pest deterrents
  Sterile males/females
  Sex attractants to traps

  Integrated Pest Management
  Organic Farming

Source: wikimedia commons

AGRICULTURE:

YIELD
SOIL
>15,000 soil
types in US
A c c r u e 10 to n s /
a c r e , ye a r
Erosion 50% of all synthetic N
fertilizer ever used has
been used since 1985
 60% increase in the
atmospheric
concentration of CO2
since 1750 has taken
place since 1959
 What’s happening?

AGRICULTURE: YIELD
FERTILIZER
 P lants also need
phosphorus in small
amounts, but these
elements are also
limiting
 E ffects of runoff with
nutrient loads of N &
P
 D EAD ZONES
Lake Erie

AGRICULTURE: YIELD
DEAD ZONES
  Gulf of Mexico Case Study
  https://www.youtube.com/watch?v=ahOmeTOIrRg

FORMATION OF DEAD ZONES

AGRICULTURE: YIELD
FERTILIZER
  Over-fertilization
  Produces “yield insurance”, add more to ensure maximum current
yield
  Excess enters water table – “Blue baby alerts” in Iowa

  Salinization
  Toxic
  Soils untenable

  Dead Zones
  Hypoxia – excessive O2 demand
  Eutrophication – nutrients are single biggest water quality problem
worldwide (Carpenter et al., Ecol App 1998)
  Non-functioning ecosystem

AGRICULTURE YIELD:
FERTILIZERS
  Alternatives?
  Animal manure
  Interplanting (legumes = N fixers)
  Crop rotation
  Green manure

AGRICULTURE YIELD:
FERTILIZERS
  Alternatives?
  Use animal waste as fertilizer/soil improvement
  Interstate regulations limit the transport of wastes and toxic material
  Would reduce odor, dust, and
escape of waste into system

FOOD
  Agriculture:
  Agriculture: Yield
  UM Sustainable Food Program

AGRICULTURE: ENERGY
Which of the following is an example of direct energy use
involved in the processing and distribution of farm products?
A.  The manufacturing of fertilizer
B.  Storage of the products
C.  Running the farm machinery
to harvest the products
D.  Cooking the food
E.  Eating the products

AGRICULTURE: ENERGY
  Energy is another raw material used for farming
  Two types of use:
  Direct
  Indirect

AGRICULTURE: ENERGY
  Another Raw Material for Farming - Energy
  Fossil fuel – key ingredient for increased global food production and
distribution.
  Direct use that is going to become more and more expensive as oil
becomes a very limited resource!

“The U.S. expends roughly 10 units of fossil energy to produce one unit
of food energy.” -Webber 2012. More Food, Less Energy. Scientific
American Jan, pp. 74-79

AGRICULTURE: ENERGY
 D IRECT USE
 Operating machinery
 Lights, and heating on
the farm

 I NDIRECT USE
 Fertilizer manufacturer
 Pesticide
manufacturer
 Storage
 Cooking
 Distribution