Ag Production and the Environment Text adapted from The World Food Problem Leathers & Foster, 2009 ttp:// Toward-Undernutrition/dp/

Erosion Soil removed by –Wind –water Agricultural cause: –Plowing –bare fields Absence of roots

Wind Erosion

Water Erosion

Chemical Degradation of Soil Nutrient depletion –Especially if same crop grown every year Salinization –Irrigation with low levels of salt Salt build up when dries Acidification –Too much fertilizer –Drainage problems –Pollutants –Oil –Pesticides Salinization

Physical degradation of soil Less porous –Compaction by Heavy machines Animals Water logging –Roots die –Due to Over irrigation Poor drainage Soil compaction

Extent of Land Degradation 38% total cropland degraded worldwide –2 billion hectares 83% by erosion 12% chemical 5% physical 5-10 million new hectares –degraded each year New land must be put into production to compensate –Generally poor quality Overgrazed degraded soil

Irrigation Problems Water Quality degradation –Salt-water intrusion in coastal areas due to lower water table –Leeches salt into groundwater: unusable –Runoff carries fertilizer, pesticide residues Land degradation: –SoilErosion –Waterlogging –Salinization –acidification Irrigation in Uzbekistan

Ag Chemicals Can lead to –Land degradation –Water pollution –Health problems Chemical manufacture can be dangerous –Explosion at fertilizer plant in Bhopal India in 1984 Killed thousands Union Carbide Chemical Plant, Bhopal India

Fertilizer Runoff: Hypoxia Hypoxia –Dead zone in rivers, lakes, oceans –N and P fertilizer runoff cause algae growth –Algal bloom removes dissolved oxygen –Result: nothing grows

Carrying Capacity How many people can earth support? –Carrying capacity Limitations on –Agricultural land –Fresh water –Waste assimilation

David Pimentel Believes carrying capacity has already been exceeded Earth can support 2 billion – at high standard of living Current yields not sustainable

Julian Simon Optimistic about future ag production –Technology will solve problems –Drip Irrigation –Fish Farming –GMOs for Pest resistance Drought resistance Salt resistance

Fish: the Blue Revolution World fish stocks fully exploited –No future increases in wild capture Aquaculture increasing –Developing nations China –Developing nations by % World population 77% World fish consumption country_2010.png Aquaculture

Fish: the Blue Revolution

Global Warming Agriculture contributes to global warming: –CO 2 released from plant decomposition CO 2 = 80% greenhouse gases No-till Ag releases less CO 2 –Methane released from rice paddies Methane: 23 x warming impact of CO 2 –Nitrous Oxide (NO) released from fertilizer use NO: 296 x warming impact of CO 2

Global Warming Livestock contribute to GW –Produce 18% of total greenhouse gasses (Cars, Airplanes, Trains, Boats total 13%) –Cattle Belching produces methane 200L/d/cow methane –1.3 billion cattle in world –Occupy 1/3 earth’s landmass 5% of planet’s greenhouse gasses –Manure produces Nitrous Oxide (NO) –Deforestation to support livestock Grazing land Crop land to grow feed 70% of former forest in Latin America is grazing land

Global Livestock Distribution Global cattle production is projected to double by

(2000)

CO 2 Emissions

Global Warming Impact on Agriculture: –Flooding of coastal land ½ of world population lives within 120 miles of the coast –Affect crop yields Increase CO2 –Boosts crop growth –Increase water-use efficiency Increase extreme weather Increase insects, disease Shift climate zones –Northern regions better –Tropical regions worse Developing countries

Impact on Agriculture

Impact on Agriculture

Ethical Issue Global warming is caused primarily by CO2 –from industrial development in the first world Is it morally acceptable that the developing world will suffer more negative effects from global warming –Without having benefited from the fossil fuels that caused the problem.

Solving Global Warming

Bioenergy Potential: –Reduce CO2 emissions Plants fix CO2 –Sustainable If use perrennial switchgrass –Profits for farmers Worldwide –Energy for poor Worldwide

Bioenergy Problems Competes with food production –Agricultural land diverted –Food prices rise worldwide –Hurts poor hardest Undernutrition Ethanol from maize increases CO2 production –Farming uses fossil fuel –Less soybeans planted in U.S. Tropical forests destroyed to plant soybeans in Brazil. Net loss of ability to fix CO2 Biodiesel from oil palm and soybeans destroys rainforests –Oil palm plantations in S.E. Asia –Soybean planting in Brazil Oil Palm Plantation, Indonesia undated-photo-sh-509.jpg

Bioenergy plusses and minuses