TODAY

1
TODAY

• Food Futures Will there be enough food for the
  21st century?
• Opportunities to improve output
• Feeding the World A Challenge for the 21st
  Century. 2000. Vaclav Smil. MIT Press.
• Institutional Policy Changes to end hunger
• Ending Hunger in Our Lifetime. 2003. CF Runge, B.
  Senauer, PG Pardey, MW Rosegrant. IFPRI Johns
  Hopkins U. Press.

2
Reasons for Concern

• Population growth
• To 8-10 billion by 2050 (50 more than today!)
• Dietary transitions
• Moving up on the food chain
• Changes in agriculture/environment
• Potential for slowing growth or even stagnation
  or decrease

3
Food Crisis now

• World food prices are up 50 since last year
• The World Food Programme announced a 500 million
  deficit for 2008
• http//www.freerice.com/
• Low-income countries that are net food importers
  have been hit hardest
• Already, 37 countries--21 of which are in
  Africa--are in a food security crisis according
  to the FAO
• The World Bank recently announced that the
  current food situation could push 100 million
  people into deeper poverty
• Poor households spend between 60 to 80 of their
  income on food, compared to only 10-20 in most
  industrialized countries.

4
Raising Output 4 major issues

1. Photosynthesis and crop productivity limits (last
   time)
2. Land, water/irrigation, (last time) and nutrient
   (NPK) limits
3. Agroecosystems and biodiversity
4. Environmental change

5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
2) Nutrient limits I

• Crop nutrient (NPK) limits
• Typically need 10s of kg P K and 100s kg N per
  ha in modern high output agriculture
• Complete recycling of ALL organic residues from
  all harvested land and confined animals NOT able
  to supply all the NPK needed for high-yield
  agriculture (i.e., more removed by harvesting
  than could be replaced)
• Only way to feed 10 b this way (all organic)
  would be to increase cropped area 2 - 3 times
  (e.g., all tropical rainforests)

10
2) Nutrient limits II

• Nitrogen is the key element
• We do not know annual rates of biofixation of N
  with certainty
• Clover alfalfa etc. fix about 150-200 kg/ha
• Beans about 70-100 kg/ha
• Bacteria in rice fields 30 kg/ha
• Earth may be able only to support 3-4 billion w/o
  synthetic N added

11
2) Nutrient limits III

• Nitrogen continued
• 50 gm protein/capita/day for 6 b people in 2000
  gt only 19 m tons Nitrogen/yr removed from soil
• Current synthetic nitrogen production about 80 m
  tons/yr
• Energy cost to produce N
• 40 giga joules/ton of N fertilizer (40 energy
  60 feedstock)
• This equals only 7 of world's total natural gas
  -- so energy is not a limit in the short run

12
2) Nutrient limits IV

• Phosphorus (P)
• Complete recycling not able to support high-yield
  farming
• But - mined rock not in short supply
• Potassium (K)
• Needed in even smaller quantities
• Thus only N is a nutrient bottleneck

13
3) Agroecosystem Biodiversity

• Basic ecology
• gt Increased species diversity gt increased net
  primary productivity and nutrient retention
• But NO clear link between natural system
  stability and diversity

14
3) Agroecosystem Biodiversity II

• Concern a very narrow biotic base of modern ag
• Traditional systems use far more species than do
  modern monocultures (e.g., wheat in USA plains)
• 250,000 higher plants known 30,000 edible 7,000
  have been cropped
• Only 15 major crop species
• 15 species produce 90 of all food
• Corn, wheat, rice produce 2/3 kcal and 1/2 plant
  protein!

15
3) Agroecosystem Biodiversity III

• Crop rotations, intercropping, and new crops
• Perfected rotations gt better yields, soil
  protection, reduce pests (but not all are so
  good)
• Introduction of legumes in rotations can be very
  helpful
• Microorganisms (soil flora an fauna primarily)
• diversity apparently NOT down overall but this is
  NOT a well studied field
• correct applications of modern inputs does not
  seem to hurt soil microbes (but not well studied)

16
4) The last major concern is Environmental Change

• Changing soils
• Environmental pollution
• Climate change

17
Changing soils I

• Erosion - most talked about issue
• Mismanagement gt excess erosion on 180 m ha crop
  fields (about 1/5 of all cropped land)
• Data are uncertain and scarce
• Varies with soil type and cropping type
• BUT evidence is lacking to prove widespread
  productivity loss

18
Changing soils II

• Qualitative soils degradation - often subtle and
  long-term
• Even more difficult to prove or gather data
• Again little hard data to prove widespread
  problems (but vice versa)
• Salination is easier to show - but not
  significant in global sense
• Loss of productivity hard to see because of
  changes cultivars, fertilization, irrigation,
  etc.
• Retention of soil organics via using crop
  residues etc. probably key here

19
Environmental Pollution I

• Has been implicated in reducing crop yields
• Agriculture is a major polluter itself
• Nitrogen issues
• Compared to pre-industrial era humans now have
  doubled all inputs of nitrogen to soils
  atmosphere
• Nitrates are widespread contaminates in surface
  and sub-surface water
• Atmospheric deposition of nitrogen should gt
  increased production but good data are scarce

20
Environmental Pollution II

• Ozone
• Loss of stratospheric ozone gt higher levels of
  ultraviolet radiation gt damage to crops
• High levels of surface ozone also degrades
  agriculture production in places like W Europe E
  North America E Asia

21
Climate Change I

• Mostly due to increase in greenhouse gasses
• Key issues for agriculture
• Surface heating ( 2º C - greater more pole-ward)
• Intensified water cycling (more in high
  latitudes)
• Uncertain local effects but droughts, storms, or
  surplus water quite possible

22
Climate Change II

• Probably increasing instability in climate system
  (i.e., storm intensity and variability)
• Agriculture is a major contributors to greenhouse
  warming
• Releasing CO2 form biomass and soils
• N2O emissions from fertilizers
• Methane from rice fields and cow farts

23
Foods contribution to climate change

• Worldwide, agriculture contributes to nearly 14
  of total greenhouse gas emissions.
• In the U.S., the food we eat accounts for 17 of
  our total fossil fuel consumption (which is huge
  per capita).
• The annual carbon footprint of an average
  American diet is 0.75 tons CO2-eq, without
  accounting for food transportation.
• On average, food travels 1,500 miles between the
  production location and the market.
• Meat products have a larger carbon footprint than
  fruits, vegetables, and grains the carbon
  footprint of the average meat eater is about 1.5
  tons CO2-eq larger than that of a vegetarian.

24
CO2 emissions due to land use
25
Climate Change III

• Consequences for agriculture
• Overall agriculture output may not change much in
  near term but regionally there may be problems
• Increased CO2 gt increased crop yields (assuming
  no other constraints) lower water loss thru
  leaves (transpiration) better ability to
  withstand env. pbms. etc.
• Doubled CO2 should boost yields in well
  fertilized crops of about 7-30 (C3 species
  benefit most - all staple cereals except corn and
  sorghum)

26
Climate Change IV

• Consequences for agriculture II
• Rising temps
• Improve efficiency of C3 plants (if too high gt
  lower yields)
• Temporal timing also key (all in summer? all in
  winter? all this is unclear) but too hot could
  gt drought-like stress
• Increase cropping area overall in higher latitudes

27
Climate Change V

• Consequences for agriculture III
• More rapid water cycling
• More water available for irrigation but
  regionally much more uncertain
• Changes may be gradual so adaptation may help
• Regional scenarios high latitude areas may
  benefit (Canada, Russia) drier tropics and
  sub-tropics may be big losers (SS Africa etc)

28
Opportunities to improve things I(see details at
end)

• More efficient fertilization
• Reduce losses
• Proper timing
• Choosing varieties that need less
• More natural N fixation
• Better use of water
• Pricing to reduce waste
• Better irrigation loss control
• Precision farming and low till
• Rationalizing animal food production

29
Opportunities to improve things II

• Precision farming and low till
• Within field adjustments (GPS/GIS technology)
• No till ag to reduce nutrient and CO2 losses
• Rationalizing animal food production
• No real need to eat animals (but humans seem to
  be omnivores)
• More efficient use of animal products (in order)
• Milk
• Eggs
• Chickens
• Pork
• Fish
• Beef

30
Opportunities to improve things III

• Reducing harvest storage losses
• 15 lost in traditional ag
• Post-harvest storage losses
• Maintain vitamins etc.

31
Opportunities to improve things Higher cropping
efficiency via more efficient fertilization

• Late 1990s global use of N fertilizers (80 m
  tons/yr) about 60 to 3rd world in future will
  account for more (predicted to grow at 2/yr)
• Most need in SS Africa where soil losses in NPK
  are not matched by fertilizer applications

32
More efficient fertilization II

• Asia is reverse HYVs and heavy fertilizer use
• Problem is much applied nutrient does not serve
  plants at all (leaching, and erosion especially
  of N) and pollutes
• N losses are commonly 10-15 of applied ammonia
  and 30-40 of manures (aggregate perhaps 45-50
  loss in rain-fed and 30-40 loss in irrigated)

33
More efficient fertilization II

• Reducing fertilizer losses
• Soils testing
• Use of more stable fertilizers
• Unbalanced (excessive) N use is a main problem
• Proper timing
• Proper application

34
More efficient fertilization III

• Increased reliance on biofixation (rotation with
  legumes primarily and use of green manures) and
  nutrient recycling
• N recovery from green manures is higher than for
  synthetic N fertilizers
• Problem is needed output is forsaken by growing
  of green manures
• Choosing cultivars that require less (e.g,
  Brazils choice of soy with low N need gt low use
  of N fertilizers)
• Possible to inoculate fields with N-fixing
  bacteria to set up self-sustaining N fixation

35
Better use of water

• Water seldom priced appropriately to regulate use
• Irrigation efficiencies
• Losses maybe 60-70 of initial total 20-30
  improvements possible gt enough water to feed 100
  m more people
• Reduce loss in canals
• Plant more water efficient crops
• Better timing of water application
• Simple devices to judge soil water need
• Manage tillage to reduce soil water loss
• Use new efficient pumps and motors

36
Rationalizing animal food production

• Justification for animal use
• There is no need to eat animals to lead healthy
  lives
• But humans seem to be adapted to omnivory by
  evolution
• Globally humans eat 10-20 kg meat annually - a
  quite small amt. by US standards (70-110 kg
  annually 300 kg milk)
• Adding meat and milk to diets is an easy way to
  improve protein, calcium, vitamin, and etc.

37
Animal food production II

• As long as animals eat foods we cannot they do
  not compete with humans
• But the problem is that increasingly we feed
  grain to animals in 1900 10 of grain to
  animals by late 1990s 45! gt 60 in USA
• If all grain fed to animals were devoted to
  humans gt 1-3 billion could be fed!!

38
Animal food production III

• Efficiencies and resource use of animals
• Milk inherently efficient energy conversion
• feed 30-40 of feed to edible energy 30-40 of
  feed to protein
• land need about 1-1.5 sq meter land per million
  kcal 19-28 sq meter land per kg protein
• water 10-15 gm water/kcal 200-300 gm/g protein
• Eggs
• feed 20-25 feed to edible energy 30-40 of
  feed to protein
• land need 1.5-2 sq m / m kcal 19-25 sq meter
  land per kg protein
• water 1.5 gm water/kcal 15 gm/g protein

39
Animal food production IV

• Efficiencies and resource use of animals
• Chickens
• feed 15-20 feed to edible energy 20-30 of
  feed to protein
• land need 2.5-3 sq m / m kcal 13-15 sq meter
  land per kg protein
• water 6 gm water/kcal 50 gm/g protein
• Pork inherently efficient due to low basal
  metabolism rapid reproduction and growth
• feed 20-25 feed to edible energy 10-15 of
  feed to protein
• land 5 gm water/kcal 150-200 gm/g protein
• water need 2.0-2.5 sq m / m kcal 80-100 sq
  m/kg protein

40
Animal food production V

• Efficiencies and resource use of animals
• Fish
• feed farmed carp etc. 15-20 feed to edible
  energy 20-25 of feed to protein
• farmed salmon 35-40 feed to edible energy
  40-45 of feed to protein (but carnivorous gt
  need high protein feed)
• Beef US-style feedlot
• feed 6-7 feed to edible energy 5-8 of feed
  to protein
• land need 6-10 sq m / m kcal 180-310 sq
  meter/kg protein
• water 25-35 gm water/kcal 700-800 gm/g protein

41
Opportunities for meat and milk

• Benefits of animal food are the ability to turn
  non-edible stuff into relatively high quality
  protein
• Improved feeding fine-tune feeding quantity and
  quality to improve efficiencies (as has been done
  in US over past 50 yrs)
• Major costs/problems are wastes (e.g., 1 dairy
  cow produces 20 tons feces urine annually)
• Can be reused as manure especially in places
  with concentrated industries
• But cheap synthetic nitrogen fertilizers and
  transport/storage costs etc. make manures less
  attractive

42
Opportunities for meat and milk II

• Strategies
• Milk efficiency of milk gt a good place to put
  efforts
• Pigs since they are 40 of ALL meat consumed
  worldwide and are omnivorous and can gain on many
  foods (e.g., cassava, bananas, brans, brewery
  byproducts, etc.)
• Water buffalo since they are more efficient
  converters of roughage to protein than cows

43
Opportunities for meat and milk III

• Strategies
• Fishing
• Yield is poor in open ocean far better inshore
  on continental shelves due to greater nutrient
  availability
• As of late 1990s the ocean is fully fished (no
  opportunities for expansion, probably contraction)

44
Opportunities for meat and milk IV

• Strategies
• Aquaculture
• Now provides about 20 of all fishes 80 of all
  mollusks 1/5 of all shrimp 1/3 of all salmon
• Total greater than all mutton and lamb and 1/3
  all chicken
• Tilapia is especially attractive likes warm
  climates is omnivorous an be raised intensively
  or extensively mild taste
• Has many advantages improved diets can be
  integrated into agriculture systems (e.g., rice)
• e.g., Chinese carp polyculture system is good
  2-4 tons/ha (700kg protein) of fish plus other
  vegetables etc. on very small farms (0.2-.05 ha)

45
Opportunities for meat and milk V

• Strategies
• Aquaculture problems
• Humans have less experience raising fish
  (especially outside Asia) so predicting expansion
  is harder
• More intensive production is possible
• But pollution problems already

46
Changes in crop yield by the 2080s, under
scenarios of unmitigated emissions
Rosenzweig, C., M. L. Parry, G. Fischer, and K.
Frohberg. 1993. Climate change and world food
supply. Research Report No. 3. Oxford University
of Oxford, Environmental Change Unit.
47
(No Transcript)
48
Changes in crop yield by the 2080s, under
scenarios of stabilization of CO2 at 750 ppm
49
Changes in crop yield by the 2080s, under
scenarios of stabilization of CO2 at 550 ppm