Organic Agriculture
Michael Bomford, PhD
Organic Agriculture
Michael Bomford
Kentucky State University
Food production
• Past 40 years:– Doubling of grain yield
– 700% increase in fertilizer use
– 70% increase in irrigated cropland
• Now – ~40% of land surface
1960 1970 1980 1990 20000
2
4
6
8
10
12
14
Mean yield of 23 main food crops(million kCal/ha)
Developed worldDeveloping world
Adapted from Green et al. 2005. Farming and the fate of wild nature. Science 307: 550-555.
Agricultural land use
Adapted from Green et al. 2005. Farming and the fate of wild nature. Science 307: 550-555.
1960 1970 1980 1990 2000
5
10
15
20
25
% of usable land
Cropland
1960 1970 1980 1990 2000
25
30
35
40
45
% of usable land
Pasture
Developed worldDeveloping world
WorldWatch, 2000
Agriculture threatens bird species
225 951039 687
0
10
20
30
40
50
60
70
Threatened Near Threatened
Percentage of
threats
attributable to
agriculture
Developed world
Developing world
Adapted from Green et al. 2005. Science 307: 550-555.Data from World Bird Database, BirdLife International.
N and P fertilizer use
0
10
20
30
40
50
60
70
1950 1960 1970 1980 1990 2000 2010
N fertilizer
use (Million metric tonnes)
Developed world
Developing world
0
5
10
15
20
25
30
1950 1960 1970 1980 1990 2000 2010
P2O5 fertilizer use (Million metric
tonnes)
Developed world
Developing world
International Fertilizer Industry Association. 2006. http://www.fertilizer.org/ifa/statistics.asp
Nitrogen groundwater contamination
USGS. 2001. http://water.usgs.gov/nawqa/wcp/wcpfig1.html
High vulnerability:
• Shallow groundwater• Well-drained soils
• Little forest
Water pollution
0
5
10
15
20
25
30
35
1910 1930 1950 1970 1990
Farmers (millions)
Farm fuel use (petajoules)
Changing Face of US Agriculture
Animal
Production
8%
Irrigation
13%
Transportation
16%
Machinery
Operation
19%
Fertilizer
Manufacturing
31%
Misc.
3%
Pesticide
Production
5%
Crop Drying
5%
Agricultural Energy use
Household storage
and preparation,
2.3 calories
Farming,
1.6 calories
Transport,
1.0 calorie
Processing,
1.2 calories Packaging,
0.5 calories
Food retail,
0.3 calories
Commercial food
service,
0.5 calories
Energy inputs per food calorie
M.C Heller and G.A. Keoleian (2000). Life Cycle-Based Sustainability Indicators for Assessment of the U.S. Food System. University of Michigan
Albert Howard (1873-1947)
• British agricultural scientist.
• 25 years in India.
• Critical of reductionistagricultural science and specialization
• Blamed fall of past civilizations on unsustainable agriculture
• Wrote An Agricultural Testament (1940)
Howard on Chinese agriculture
• “The small-holdings of China, for example, are still maintaining a steady
output and there is no loss of fertility
after forty centuries of management.”
Howard on Eastern
agriculture• Small farms
• Mix of people, plants and animals; wastes recycled as nutrients
• Human and animal labor, not machines
• Food crops, not cash crops (subsistence)
• Nitrogen fixed by legumes
• Reduced cultivation
• Composting
• Mimic natural ecosystems
Howard on Western
agriculture- Large, growing farms
- Monocultures
- Mechanization
- Synthetic fertilizer dominates
- Increasing crop disease
- More processed and preserved foods
- Success judged by profit
- Too much food (low prices force farmers off land and into cities)
Lady Eve Balfour
(1899-1990)
Soil Association (2003) / Mary Erstman
• Among first women to graduate from University of Reading (agriculture)
• 1939 – began long term experiment comparing conventional and organic production
• 1943 – wrote The Living Soil
• 1946 – founded the Soil Association
“Healthy soil, healthy plants, healthy people.”
J.I. Rodale
• Bought farm in PA to test Howard’s ideas
• Popularized term ‘organic,’ through his Organic Gardening and Farming magazine
• Relationship with science
– Presented reader testimonials as research (“science for the people by the people”)
– Solid long-term research trials continue
Lady Eve
Balfour
(1899-1990)
Jerome Irving
Rodale (1898-1971)
Organic agriculture is “a production system that is managed in accordance with the Act and regulations in this part to respond to site-specific conditions by integrating cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity.”
Organic Production Standards
USDA
ORGANIC
USDA
ORGANIC
Organic Production Standards
• Land is certified by gov’t-approved agencies
• Farmer develops and follows organic farm plan
• Synthetic substances prohibited– Includes synthetic organics
• Natural substance allowed– Includes natural inorganics
• Maintain or increase soil organic matter content
• Separation from conventional products– In time – 3 year transition period
– In space – buffer zones, barriers, separatecontainers, equipment cleaning etc.
• $10,000 fine for misuse of word
• U.S. organic food sales have grown between 17 and 21% each year since 1997 (total U.S. food sales over this time have grown in the range of 2-4% a year)
• Organic food sales represent approximately 2% of U.S. food sales.
– (Organic Trade Association’s 2004 Manufacturer Survey) 0
5
10
15
20
25
1991
1994
1997
2000
2003
2006
2008
Billions
of dollars
US Organic Farms, 2006
Clear Boundaries & Buffers
Organic
Buffer
Conventional
Conventional
Soil Fertility: Cover Cropping
• Rye/vetch mix adds ~135 lb N/ac
• Slow release
• Organic matter
• Erosion control
WVU organic research project
4
4.5
5
5.5
6
6.5
7
1998 2000 2002 2004 2006
Soil
organic
matter
(%)
Winter rye & vetchcover crop
Cover crop +compost @10t/ac
Soil Fertility: Animal Waste
Soil Fertility: Animal Waste
• Raw manure pre-harvest interval:
> 90 days if edible portion does not contact soil
> 120 days if edible portion contacts soil
Soil Fertility: Compost
• No pre-harvest interval
• Strict requirements for manure-based compost– 131-170°F for 15 days in
windrows
– C/N = 25-40
Pest Management:Solarization and Biofumigation
Pest management:Resistant varieties
Pest Management:
NaturalEnemies
Pest Management: Farmscaping
Pest Management: Botanicals• Chemicals derived from plants
– Rotenone
• rat poison, very toxic to fish, linked to Parkinson’s
• allowed under NOP; temporary ban in Europe
– Pyrethrum
• neurotoxin, quickknock-down
• chemistry inspiredsynthetic pyrethroids
– Neem
• inhibits moulting
Pest Management:Microbials
• Bacteria
– e.g. Bacillus thuringiensis
• Fungi
– e.g. Coniothyrium minitans
• Nematodes
– e.g. Steinernema
Pest Management: Oils & Soaps
• Oils
– Petroleum / vegetable based
– kill through suffocation
– most widely used insecticide, by weight
• Soaps
– kill through desiccation (penetrate protective waxy covering)
– mainly kill soft-bodied insect
• No resistance observed to these modes of action