The Effects of Agriculture

Effects of Agriculture Soil Erosion Desertification Loss of Biodiversity Water Pollution Air Pollution Human Health

Soil Erosion Soil Erosion Video – Kenya Causes: plowing, deforestation, planting on bare slopes, overgrazing. Leads to infertile, flat land. Contributes sediments to waterways – destroying functionality of wetlands Leads to death of crops, livestock, poverty, hunger.

Desertification Desertification - 2007 Video Year of the Desert

Ways to reduce soil erosion: Contour Plowing – perpendicular to slopes and as horizontal as possible. No-Till Agriculture – not plowing, using herbicides to make room for plants, but letting some weeds grow.

Pest Management Estimated that 1/3 of all harvests are lost to pests. Remember that Farming: Holds back natural succession. Prevents migrating organisms from entering an area. Prevents natural interactions: parasitism, predation, competition. (Boll weevil)

DDT and Rachel Carson Rachel Carson : Silent Spring

Integrated Pest Management (IPM) Uses a variety of methods to control pests: chemical, biological, planting. Goal is for control rather than complete elimination of pests. Attempt to move away from monoculture. No-till agriculture

Integrated Pest Management

Air Pollution Hydrogen Sulfide is a gas that limits the ability of cells to use oxygen. Exposure to hydrogen sulfide in high levels can cause skin, eye, and respiratory irritation, neurologic and cardiac disorders, seizures, comas, and death. Chronic exposure at lower levels can cause low blood pressure, headache, chronic cough, and psychological disorders.14 Hydrogen sulfide is generally associated with hog production facilities. Ammonia can cause irritation of the eyes, skin, and respiratory tract.15 It is released in large quantities by chicken and hog CAFOs. Particulate matter is a leading cause of bronchitis and asthma in people who are regularly exposed to it and can also be a cause of cardiac disorders including arrhythmia and heart attacks.16 Endotoxins, poisons produced by dying bacteria, are found in high concentrations on factory farms, but can cause respiratory problems even in extremely low concentrations.17 Carbon dioxide is a byproduct of decomposing manure that causes shortness of breath and dizziness in humans, and often kills confined animals by asphyxiation.18 Methane is a major contributor to climate change. According to the EPA, methane is 23 times as potent as carbon dioxide and is the second most important contributor to the greenhouse effect, now accounting for 16 percent of global greenhouse gas emissions from human activity.19 http://www.sustainabletable.org/issues/airpollution/#major

Water Pollution - Types Nutrients Nutrients, such as nitrogen and phosphorous, are the minerals in fertilizer that promote plant growth. But due to the over-fertilization of cropland, far more nitrogen and phosphorous are applied to fields than are removed by crops.ix Excess nutrients in water cause harmful plant growth—commonly referred to as “algal bloom,” which can cause fish kills.x

Water Pollution…. Ammonia and Nitrates Livestock manure is high in ammonia concentrations, xiv and dissolved ammonia in water is not only highly toxic to fish, xvi but can also be converted to dangerous nitrates.xvi Elevated nitrate levels in drinking water are highly poisonous to humans, causing potentially fatal oxygen levels in babies (known as “blue-baby syndrome”), spontaneous abortions, and possibly

Water Pollution…. Antibiotics and Hormones Antibiotics and artificial growth hormones are commonly used on industrial farms, either injected directly into the livestock or added to their feed.. Large amounts of both substances end up being excreted by animals and can thus pollute water along with everything else in livestock waste. Some hormones can remain functional in manure up to 270 days after excretion, and there have been many documented cases of hormones discovered miles downstream of farms.xxiv Although it is unclear whether these hormone concentrations can be high enough to affect humans, they have been shown to compromise the reproductive processes of fish.xxv

Water Pollution…. Pathogens and other microorganisms Manure contains a high level of pathogens (disease-causing microorganisms). When the waste is applied to fields, those pathogens can be transferred to local water supplies during a run off from either irrigation or rainfall.xx Some other waterborne microorganisms do not originate on farms, but develop as a result of eutrophication caused by high nutrient levels. Pfiesteria piscicida, for example,thrives in many areas where algal blooms grow, and causes lesions in fish and large-scale fish kills.xxii It can also cause a range of symptoms in humans, including respiratory and eye irritation, gastrointestinal problems, fatigue, as well as skin problems and cognitive symptoms such as memory loss and confusion.xxiii

Water Pollution…. Heavy Metals and Salts Some heavy metals, such as copper and zinc, are essential nutrients for animal growth—especially for cattle, swine, and poultry.xxx However, such elements are often present in animal feed in concentrations far higher than necessary for animal health, along with other heavy metals such as chromium, lead, arsenic and cadmium.xxxi Farm animals excrete excess heavy metals in their manure—which in turn gets spread as fertilizer, leading to soil and water pollution.