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

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.

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

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

Extreme Soil Degradation: “Desert Pavement”

Causes of Soil Degradation 40% of global agricultural lands

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

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)

shelterbelts

contour farming & strip crops

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).

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

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

U.S. Corn Yields

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.

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?

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.

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

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 foodsgenetically engineered foods

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?

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