Agriculture and the Environment Study Notes

Agriculture and the Environment

Introduction

  • Fundamental question: How can we provide nourishment for people while protecting the environment?

Historical Context of Agriculture

  • Agricultural Success: Agriculture has been greatly successful since the Neolithic Revolution 12,000 years ago.

    • Introduced agriculture and animal husbandry.

    • Humans have effectively managed to provide food.

  • Food Production: Over the last 50 years, world food production has approximately doubled.

    • Food production has increased at a pace faster than population growth.

    • Greater availability of food particularly in developing nations.

    • World food trade has become a critical economic driver for many countries.

Types of Agriculture

  • Subsistence Agriculture: Common in the developing world.

    • Characterized by traditional agricultural methods.

    • Focuses on growing enough food for personal family needs.

    • Inputs mainly involve labor and land.

    • Can be sustainable if managed well, particularly in low-population areas.

    • However, it struggles in regions with rapid population growth.

  • Slash-and-Burn Agriculture in Brazil:

    • Can be sustainable if managed appropriately.

    • Involves shifting cultivation in tropical forests.

      • Cleared land supports crops for a few years, after which the farmer moves to a new plot.

    • Utilizes Oxisols, a type of soil found in tropical areas.

Yield Gap in Agriculture

  • Cereal Yields: Yield of corn by region from 1960-2014 indicates substantial disparities.

    • High yields observed in developed regions (North America, European Union).

    • Lower yields particularly notable in sub-Saharan Africa.

Modern Industrialized Agriculture

  • Historical shift in the early 1800s:

    • Most people in the U.S. worked on small farms.

    • The mid-1800s Industrial Revolution drastically changed agriculture by:

      • Increasing farming efficiency.

      • Decreasing the number of farms while increasing farm size.

  • Key Components of Agricultural Modernization:

    • Infrastructure development: rural electrification, roads, university programs, markets, transportation, loans, and subsidies.

    • Technological improvements: Shift from animal labor to machinery.

      • Increase in fossil fuel energy inputs allowing farmers to cultivate larger areas.

Energy and Food Production

  • Dependency on Fossil Fuels:

    • “The principal raw material of modern U.S. agriculture is fossil fuel.” - David Pimentel et. al., 1974.

    • More energy derived from oil is used compared to solar energy in food production.

Agricultural Technology

  • High-Yielding Varieties (The Green Revolution):

    • Initiated by Norman Borlaug in 1943 with the development of dwarf hybrid wheat, recognizing both benefits and external costs.

  • Use of Fertilizers and Pesticides:

    • Current agricultural practices account for 70% of total global water use.

    • Significant use of fertilizers and pesticides is crucial for increasing crop shortfall:

      • Grows 40% of the world’s food on just 18% of cropland.

  • Livestock Farming:

    • Utilizes 33% of cropland for livestock feed.

    • CAFOs (Concentrated Animal Feeding Operations) are used extensively in the U.S., housing over 50% of livestock.

    • Contributes to various environmental challenges:

      • Pollution from millions of tons of manure entering waterways.

      • Spread of diseases such as Salmonella in densely populated animal farms.

      • High usage of antibiotics (accounting for 80% of U.S. usage), adversely affecting human health and livestock.

      • Livestock production contributes 14% of total global methane emissions.

Biofuels and Food Production

  • Biofuels: Fuels derived from crops aimed to mitigate climate change without releasing new CO₂.

    • Ethanol production from corn in the U.S. and sugar in Brazil, using 40% of U.S. corn for this purpose.

Genetic Engineering in Agriculture

  • Gene Revolution: Implements genetic engineering to insert desired traits into plants and animals, leading to the production of GMOs (Genetically Modified Organisms).

    • Enables gene exchange among bacteria, animals, and plants.

    • Majority of commercial GMO production consists of cotton, soybeans, canola, and corn.

    • Notably, half of U.S. farmland is planted with bioengineered crops.

  • Aims of Agricultural Biotechnology:

    • Add disease and pest resistance to crops.

    • Increase tolerance to drought and salinity.

    • Improve nutritional quality of crops.

    • Develop crops for pharmaceutical production.

  • Bt Cotton: Example of bioengineered cotton that incorporates a gene from Bacillus thuringiensis, aiding in pest resistance.

  • Golden Rice: Genetically engineered rice high in beta-carotene (pro-vitamin A), addressing nutritional deficiency issues.

Concerns Associated with GM Crops

  • Food Safety and Environmental Safety: Concerns involve allergic reactions, secondary pest emergence, ecological impacts, and increased monocultures.

  • Regulatory Measures:

    • The Cartagena Protocol allows countries to prevent the entry of GMOs considering a precautionary principle.

Food Distribution and Trade

  • Shift from self-sufficiency to globalization of food systems sparked by the Industrial Revolution.

    • Historical interruptions like climate impact and wars affecting agricultural production and leading to famine.

    • North America remains the major exporter of grains.

Global Food Crisis and International Response

  • Food Price Growth: Between 2006-2008, food prices soared by 100%.

  • The 2009 UN World Food Summit addressed hunger and food price issues.

  • Rio+20 Conference: Focused on sustainable development progress and emphasized food and agriculture. Set a goal to eradicate hunger.

Hunger, Malnutrition, and Food Aid

  • Millennium Development Goals (MDGs): Aimed at reducing hunger by 50% by 2015, successfully achieved.

  • Definitions:

    • Hunger: lack of food for energy and normal life.

    • Undernourishment: lack of calories.

    • Malnutrition: lack of essential nutrients (amino acids, vitamins, minerals).

    • Overnutrition: excess caloric intake leading to obesity.

Global Food Aid Trends

  • Global food aid provided to nations unable to sustain themselves has declined consistently since 1999.

Sustainable Agriculture Prospects

  • Addressing the future of food production involves:

    • Increasing crop yields through new technologies.

    • Expanding diets to include diverse food sources.

    • Prioritizing food production over livestock feed, biofuels, or cash crops.

    • Emphasizing local food consumption (locavores).

    • Enhancing farming efficiency and exploring urban agriculture.

Urban Agriculture and Innovative Farming Systems

  • Urban Agriculture: Project examples include community-supported agriculture and urban gardens.

  • Polyculture Practices: Integrating diverse crop species alongside traditional farming methods to promote biodiversity.

  • Organic Farming: Focus on small farms, traditional methods avoiding chemical usage, producing slightly lower yields, yet maintaining ecological balance.

Pesticides in Agriculture

  • Pesticides are chemicals deployed to kill or control agricultural pests.

    • Common categories include herbicides (57% of weight used), insecticides, fungicides, nematicides, and rodenticides.

    • Economic impact: pests destroy a significant portion (37%) of U.S. agricultural production annually.

  • Pesticide Use Trends:

    • Significantly increased from 1964 to 2007.

Resistance Development in Pests

  • Genetic Adaptation: Some pests develop resistance due to genetic variation and selective pressure from pesticide exposure.

  • Pesticide Resistance Development explained through genetic variation leading to successful reproduction and resistance traits.

Human Health Implications of Pesticides

  • Acute Health Effects: Include nausea, abdominal pain, and respiratory failures among others.

  • Chronic Health Effects: Link to serious conditions like cancer, neurological disorders, and endocrine system disruption.

Historical Context of DDT Usage

  • DDT (Dichlorodiphenyltrichloroethane): Once considered a ‘magic bullet’ in pest control, now recognized for its toxicity to wildlife & humans.

    • Used effectively in agriculture, led to the decline of various bird species including the Bald Eagle due to eggshell thinning caused by DDE (a breakdown product).

  • Legislative Action: DDT was banned in 1972, leading to recovery efforts supported by environmental regulations.

Bioaccumulation and Biomagnification

  • Concepts:

    • Bioaccumulation: Organisms absorb pesticides from the environment, resulting in increased concentration in their tissues.

    • Biomagnification: Pesticide concentrations increase up the food chain.

Education and Policy Considerations

  • Integrated Pest Management (IPM): A sustainable approach to managing pest populations utilizing ecological factors and minimizing synthetic pesticide use.

    • Comprises monitoring, action thresholds, and preventative measures.

  • Economic Threshold Definition: The population level of pests where control costs exceed crop value loss.

Environmental Impacts of Fertilizers

  • Impact on water quality leading to eutrophication and nitrogen pollution.

    • Maximum Contaminant Level (MCL) for nitrates set at 10 ppm (nitrate-N) or 45 ppm (nitrate).

  • Fertilizers significantly contribute to greenhouse gas emissions, representing a considerable portion of methane (CH₄) and nitrous oxide (N₂O) emissions.

Goals of Sustainable Agriculture

  1. Maintain productive topsoil.

  2. Ensure food safety and wholesomeness.

  3. Reduce dependency on chemical fertilizers and pesticides.

  4. Sustain the economic viability of farms.

Conclusions: Changing Trends in Agriculture

  • Attitude shifts alongside management changes in the agricultural sector, including the adoption of Environmental Management Systems (EMS) for sustainability.

Review Questions for Evaluation

  1. The impact of the Green Revolution is characterized by:

    • A. Doubling the land for crop production |

    • B. No significant productivity increase |

    • C. Requirement for high levels of fertilizers and pesticides |

    • D. Contribution to ozone layer damage |

  2. The development of pesticide-resistant insects is primarily due to:

    • A. Mutations caused by pesticides |

    • B. Increased biotic potential of insects |

    • C. Learning to avoid pesticides |

    • D. Survival and increase of naturally resistant pests over generations.