This document discusses the history and impacts of agriculture, as well as approaches to more sustainable agriculture through agroecology. It begins with a brief history of ancient Egyptian and bonanza farm agriculture. Tables show major structural changes in U.S. agriculture over the 20th century, including decreasing farm and rural population shares. Figures depict increasing world food production and the large percentage of global land used for agriculture. The impacts of conventional agriculture are then summarized, such as reduced biodiversity and soil impacts. The document introduces agroecology as an integrative approach and discusses examples of biodiversity management, pest management, and integrated soil management techniques.

1. Caroline Wrobel
ES8912 – Applied Ecology
March 7th, 2012

2. History of Agriculture
Ancient Egypt

3. History of Agriculture
Ploughing on a bonanza farm

4. Changes in Agriculture
Table 1. One hundred years of structural change in U.S. agriculture.
1900 1930 1945 1970 2000
Number of farms 5.7 6.3 5.9 2.9 2.1
(millions)
Average size of farm 146 151 195 376 441
(acres)
Average number of 5.1 4.5 4.6 2.7 1.3
commodities
produced per farm
Farm share of 39 25 17 5 1
population (%)
Rural share of 60 44 36 26 21
population (%)
(Dimitri & Effland, 2005)

5. Figure 1. World food production from 1960 to 2000
measured as the sum of cereals, grains, and root crops.
(Tilman, 1999)

6. % of land area
Figure 2. Percentage of global land area that is used for agriculture.

7. Impacts
• Reduction in biodiversity
• 30,000 edible plant species
• 20 species in current food load
• 3 species account for more than 50%
• Decreased soil fertility
• Eutrophication
• Soil erosion
• Impaired soil biota
• Salinization
• Loss of important species
• Encroachment on surrounding ecosystems

8. Case Study: Kesterson Reservoir,
San Joaquin Valley, California

9. Agroecology:
The integrative study of the ecology of the entire food
system, encompassing ecological, social and
environmental dimensions (Francis et al., 2003)
OR
The application of ecological concepts and principles to
the design and management of sustainable
agroecosystems (Altieri, 2004)

10. Agroecology in Action
 Biodiversity
Figure 3. A biodiversity experiment at the Cedar Creek Ecosystem Science
Reserve (a) demonstrates the relationship between the number of planted
species and ecosystem stability (b) or species stability (c).
(Tilman et al., 2006)

11. Agroecology in Action
 Biodiversity
Figure 4. Number of studies that show organic farming having a positive
(green bar), negative (red bar) or no effect (number in white circle) on
biodiversity of various animal and plant groups in comparison to non-
organic farm management. Summary of 95 scientific publications.
(Hole et al., 2005)

12. Capacity of organic conversion
Trait-based ecology
Levels of biodiversity
Additional food crops

13. Agroecology in Action
 Pest Management
 Integrated Pest Management (IPM)

14. How to make it easier to follow
Impacts of particular biocontrol
agents
Detailed impacts of pests
Ecological data needed in
framework

15. Agroecology in Action
 Soil Management

16. Agroecology in Action
 Soil Management
 Integrated Soil Management (ISM)
Soil Tillage &
Conservation
Management
Crop Water
Management Management
Integrated Soil
Management
Land Use Nutrient
Management Management

17. Agroecology in Action
 Soil Management
 Integrated Soil Management (ISM)
Techniques Minimum tillage
Cover cropping
Slope barriers
Microbial inocula and biocontrol
Maintenance of organic and inorganic nutrients
Bioremediation
Mulching and manuring

18. Decomposer ecology
Organisms and ecosystem
function
Productivity of soil biota

19. • Mosaic plots
• Green manures
• Fallow areas
• Polycultures

21. References
• Altieri, M. (2004). Linking ecologists and traditional farmers in the search for sustainable agriculture. Frontiers in Ecology and the
Environment, 2(1): 35-42.
• Brussaard, L., Caron, P., Campbell, B., Lipper, L., Mainka, S., Rabbinge, R., et al. (2010). Reconciling biodiversity conservation and food
security: scientific challenges for a new agriculture. Current Opinion in Environmental Sustainability, 2: 34-42.
• Chen, L., Lee, D., Song, Z., Suh, H., & Lu, B. (2004). Gene Flow from Cultivated Rice (Oryza sativa) to its Weedy and Wild Relatives. Annals of
Botany, 93(1): 67-73.
• Dale, V., & Polasky, S. (2007). Measures of the effects of agricultural practices on ecosystem services. Ecological Economics, 64(2): 286-296.
• De Clerck-Floate, R., & Bourchier, R. (2000). Ecological Principles of Biological Control: From Population Theory to Wedd Biocontrol Practice.
Proceedings of the X International Symposium on Biological Control of Weeds (pp. 517-520). Bozeman, MT: Montana State University.
• Dover, M., & Talbot, L. (1987). To feed the earth: agroecology for sustainable development. Washington, DC: World Resources Institute.
• Drinkwater, L., & Snapp, S. (2007). Nutrients in Agroecosystems: Rethinking the Management Paradigm. Advances in Agronomy, 92: 163-186.
• Ehler, L. (2006). Integrated pest management (IPM): definition, historical development and implementation, and the other IPM. Pest
Management Science, 62: 787-789.
• Ewel, J. (1999). Natural systems as models for the design of sustainable systems of land use. Agroforestry Systems, 45: 1-21.
• Fagan, W., Lewis, M., & van den Driessche, P. (2002). Invasion theory and biological control. Ecology Letters, 5: 148-157.
• Fitter, A., Gilligan, C., Hollingworth, K., Kleczkowski, A., Twyman, R., Pitchford, J., et al. (2005). Biodiversity and ecosystem function in soil.
Functional Ecology, 19: 369-377.
• Francis, C., Lieblein, G., Gliessman, S., Breland, T., Creamer, N., Harwood, R., et al. (2003). Agroecology: The Ecology of Food Systems. Journal
of Sustainable Agriculture, 22(3): 99-118.
• Gilpin, M., Gall, G., & Woodruff, D. (1992). Ecological Dynamics and Agricultural Landscapes. Agriculture, Ecosystems and Environment, 42:
27-52.
• Hajjar, R., Jarvis, D., & Gemmill-Herren, B. (2008). The utility of crop genetic diversity in maintaining ecosystem services. Agriculture,
Ecosystems and the Environment, 123: 261-270.
• Hobbs, R., & Morton, S. (1999). Moving from descriptive to prescriptive ecology. Agrofrestry Systems, 45: 43-55.
• Hole, D., Perkin, A., Wilson, J., Alexander, I., Grice, P., & Evans, A. (2005). Does organic farming benefit biodiversity? Biological Conservation,
112: 113-130.
• Jackson, W., & Piper, J. (1989). The Necessary Marriage Between Ecology and Agriculture. Ecology, 70(6): 1091-1093.
• Jordan, C. (1995). Conservation: Replacing Quantity with Quality as a Goal for Global Management. Chichester, UK: John Wiley and Sons.
• Jorgensen, S., & Nielsen, S. (1996). Application of ecological engineering principles in agriculture. Ecological Engineering, 7: 373-381.
• Killham, K. (2011). Integrated soil management - moving towards globally sustainable agriculture. Journal of Agricultural Sciences, 149: 29-
36.
• Lefory, E., Hobbs, R., O'Connor, M., & Pate, J. (1999). What can agriculture learn from natural ecosystem? Agroforestry Systems, 45: 423-436.
• MacRae, S., Hill, B., Henning, J., & Bentley, A. (1990). Policies, programs, regulations to to support the transition to sustainable agriculture in
Canada. American Journal of Alternative Agriculture, 5: 76-92.
• Main, A. (1999). How much biodiversity is enough? Agroforestry Systems, 45: 23-41.

22. References
• Miller, F. (2008). After 10,000 Years of Agriculture, Whither Agronomy? Agronomy Journal, 100: 1-13.
• Natarajan, M., & Wiley, R. (1986). The effects of water stress on yield advantages of intercropping systems. Field Crops Research, 13: 117-131.
• Neher, D. (1999). Soil community composition and ecosystem processes. Agroforestry Systems, 45: 159-185.
• Nielsen, S. (2007). What has modern ecosystem theory to offer cleaner production, industrial ecology and society? The views of an ecologist.
Journal of Cleaner Production, 15: 1639-1653.
• Paul, E., & Roberston, G. (1989). Ecology and Agricultural Sciences: A False Dichotomy? Ecology, 70(6): 1594-1597.
• Roberston, G., & Swinton, S. (2005). Reconciling agricultural productivity and environmental integrity: a grand challenge for agriculture. Frontiers
in Ecology and Environment, 3(1): 38-46.
• Robertson, A. (2000). The Gaos Between Ecosystem Ecology and Industrial Agriculture. Ecosystems, 3: 413-418.
• Rosset, P. (2000). Cuba: A Successful Case Study of Sustainable Agriculture. In F. Madgoff, J. Foster, & F. (. Buttel, Hungry for Profit: The
Agribusiness Threat to Farmers, Food and the Environment (pp. 203-213). New York, NY: Monthly Review Press.
• Shi, T. (2002). Ecolgical agriculture in China: briding the gap between rhetoric and practice of sustainability. Ecological Economics, 42: 359-368.
• Stirzaker, R. (1999). The problem of irrigated horticulture: matching the biophysical efficiency with the economic efficiency. Agroforestry Systems,
45: 187-202.
• Swinton, S., Lupi, F., Robertson, G., & Hamilton, S. (2007). Ecosystem services and agriculture: Cultivating agricultural ecosystems for diverse
benefits. Ecological Economics, 64: 245-252.

23. Ecological Agriculture in
China
Historically Modern Reforms Reversion to Past
Taoism – harmony Western practices Ecoagriculture –
with nature adopted melding of past
and present
4000 of years of Major impacts 51 counties have
cultivation realized shown favourable
improvement
Soil fertility 35% of total land
maintained experiencing Legal proposal
desertification drafted to shut
down GE rice

24. Ecological Agriculture in
China