Agriculture and Food Supply

1. Agriculture and Food Supply Soil Degradation & Sustainable Agriculture 2) Trends in Agriculture and Food Production 3) Solutions to Sustain a Global Food Supply

2. Maintain the Humus, Sustain Soil Fertility • Partly decomposed organic matter. • Typically found in O & A horizons. • High capacity for holding water and nutrients. • More biologically active soil increases nutrient cycling.

3. Humus: To Be or Not to Be Erosion processes exacerbate topsoil loss. Root systems addhumus too!

4. Soil Degradation • Activities resulting in humus loss : • Deforestation • Removal of forest litter source (trees) • Burning of slash and O-horizon humus • Overgrazing • Surface litter completely removed. • Loss of productive root system organic inputs. • Over-cultivation • Over-harvest (remove all crop biomass) • Tilling soil (accelerates soil organic matter oxidation) • Factors that facilitate erosion: • Loss of living ground cover and humus • Susceptibility to wind and water forces

5. Extreme Soil Degradation:“Desert Pavement”

6. Causes of Soil Degradation 40% of global agricultural lands

7. Soil degradation is made worse by poor agricultural practices on already low fertility soils.

8. Golden Rules of Sustainable Agriculture • Organic mulch for nutrients • Maximize biomass production • Maximize biodiversity of crop plants • Cover the soil (cover crops; agroforestry) • Minimal or zero tillage • Protect from natural erosion forces • Wind (shelterbelts) • Water runoff (contour farming)

9. shelterbelts

10. contour farming & strip crops

11. Historical Trends in Agriculture and Food Supply • Subsistence Farming: • Objective is family food security and some profit. • Pre-Industrial Revolution in developed countries. • Largely uses sustainable agricultural practices. • Human and animal labor intensive – low tech. • Deficit met by natural harvest (e.g. wild game). • Still dominant in developing countries. • Population growth dominant in developing world. • Resort to non-sustainable practices that promote environmental degradation (esp. soil loss).

12. Subsistence Farming Today: Answer More, Less, or the Same as in the Past? • Labor intensive • Technologically based • Use of marginally productive lands • Clearing of tropical rainforests • Over-cultivation • Over-grazing

13. Modern Industrialized Agriculture • Bringing additional land into cultivation • Increasing use of inorganic fertilizers • Increasing use of herbicides and pesticides • Increasing use of irrigation • Substituting old varieties with genetic hybrids • Fewer kinds of crops (reduced biodiversity) • Less recycling of animal wastes • More grain used for animal meat production

14. U.S. Corn Yields

15. The Green Revolution (1943) • Hybrid Mexican Wheat heat resistant and high grain production. • Temporarily closed the gap between food production and need in some developing countries. • Heavy reliance on fossil fuels, herbicides, irrigation, fertilizers, and pesticides. • Negative impact on small farmers and culturally specific crops.

16. Status of the Global Food Supply: Per Capita Food and Grain Production No global shortage on average today. But what about in 20 years? Can we increase by 40%? Why is there still hunger today?

17. The Food Trade versus Food Aid • Profit over need in a global market economy. • North America is the major exporter of food. • Asia, Africa, and Latin America have become the major food importers in the past 45 years. • 20% are still hungry! • Food aid needed for famine. • Broader us of food aid today.

18. Food Aid: True or False • Alleviates chronic hunger • Helps local agriculture • Disrupts local economy • Contributes to ecological deterioration Give a man a fish; you have fed him for today. Teach a man to fish; and you have fed him for a lifetime." --Old Chinese Saying

19. Solutions to Sustain a Global Food Supply • Why not simply cultivate more land? • Eat lower on the food chain & convert animal crops (feed grain) to human crops. • Convert cash crops to food crops • Consume less per capita & fewer pets • Increase crop yields: • Restoration of soil fertility • The promise of genetically engineered foods

20. Promises of this Biotechniology • Engender resistance to disease and pests • Engender resistance to herbicides • Increase tolerance range: • Drought • Salt • Increase nutritional value • Incorporate vaccines to human disease What’s the advantage of each?

21. Problems with this Biotechnology • Environmental problems: • Promote pesticide resistance in pests • Unwanted spread of toxins • Unwanted spread of traits • Food Safety • Allergic reaction of transgenic proteins • Access to the new technology • Large agro-industry ownership & profit motive • Illegal to propagate expensive patented seed