Major Macronutrients
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Nitrogen
A limiting nutrient because it is often found in very low quantities in natural systems and is an essential component of proteins, RNA, and DNA
Nitrogen Cycle
The movement of Nitrogen around the biosphere.
Nitrogen Fixing Bacteria (Biotic)
Turn N2 into ammonia (NH3), which is rapidly converted into ammonium (NH4+), a form that is readily used by producers.
Nitrogen Fixation Abiotic Processes
Lightning strikes and the combustion of wood or fossil fuels.
Convert N2 into nitrate NO3- which carried to the Earth’s surface in precipitation and is then readily used by plants.
Nitrification
The process by which ammonium (NH4+) is converted into nitrite (NO2-) and then into nitrate (NO3-).
Assimilation
Plants absorb N from the soil and incorporate it into their tissues.
N is passed up a food chain then eliminated in waste.
Ammonification
Conversion of organic nitrogen compounds back into inorganic ammonium.
Dentrification
Conversion of NO3- into N2O or N2 gas, which then returns to the atmosphere.
Conducted by denitrifying bacteria that live in anaerobic environments.
Leaching
The movement of dissolved minerals through soil via groundwater.
Oligotrophic
Low nutrient load, low BOD
Mesotrophic
Mid-level nutrient supply, mid-level BOD
Eutrophic
High (sometimes excessive) nutrient input, high BOD
Eutrophication
Excess nutrients in a body of water, frequently due to runoff from the land.
Natural Eutrophication
Occurs when small amounts of naturally occurring, Nitrogen-based compounds enter bodies of water.
Cultural Eutrophication
Occurs when large amounts of nutrients enter bodies of water as a result of human activity.
Cultural Eutrophication Process
Nutrient pollution
Explosive plant growth
Algal blooms block sunlight
Plants die off and decomposition skyrockets
Hypoxia = death of the ecosystem
The phosphorus cycle
the movement of phosphorus around the biosphere.
Undernutrition
The condition in which not enough calories are ingested to maintain health.
Malnourished
Having a diet that lacks the correct balance of proteins, carbohydrates, vitamins, and minerals.
Food security/ insecurity
A condition in which people have access to sufficient, safe, and nutritious food that meets their needs for an active and healthy lifestyle.
Overnutrition
The ingestion of too many calories and a lack of balance of foods and essential nutrients.
Green Revolution
a set of global agriculture policies introduced from 1940-60 that emphasized the planting of high-yielding hybrid crops, intensive irrigation, mechanization, and the widespread use of synthetic pesticides and fertilizers.
Industrial agriculture
Agriculture that applies the techniques of mechanization and standardization (agribusiness).
Energy subsidy
The fossil fuel energy and human energy input per calorie of food produced.
Mechanization
Agriculture is extremely labor intensive. In countries with cheap, abundant fossil fuels it can be economically advantageous to replace people with machines.
Economies of scale
With mechanization, large farms growing commodity crops have become more profitable than small, diverse farms.
Irrigation
Massive irrigation programs have allowed for the rapid expansion of industrial agriculture.
Salinization
Soil degradation that occurs when the small amount of salts in irrigation water becomes concentrated in the soil surface.
Waterlogging
Soil degradation that occurs when soil remains underwater for prolonged periods.
Organic fertilizer
Compost and manure
Synthetic fertilizer
NPK fertilizers produced on an industrial scale, more biologically available.
Monoculture
An agricultural method that utilizes large plantings of a single species.
Pesticide
any substance that is specifically designed to kill a living thing → biocides, herbicides, insecticides, fungicides, etc.
Organophosphates
Organophosphates attack the nervous systems of animals (including humans) → they were developed from nerve gas after WWII. (MOST COMMON FORM OF PESTICIDES IN THE US).
Roundup
made of a chemical called Glyphosate and is applied to 90% of all soybean crops in the US.
Organochlorines
Highly persistent and highly toxic to sensitive organisms.
Atrazine
The most common organochlorine in the US - applied to 96% of all corn crops in the US.
Neonicotinoids
Originally developed in the 1990s, now the most common pesticides in the world.
Extremely powerful - even when applied in small amounts, neonics are transferred to the fruit, nectar, or pollen of plants.
Colony collapse disorder
the global disappearance of honey bees.
Pesticide Resistance - “Pesticide Treadmill”
Over time, species become increasingly resistant to pesticides (survival of the fittest) leading to increased use or increased toxicity.
Persistent Organic pollutants
Accumulate in the environment and take decades or centuries to break down.
Bioaccumulation
The buildup of toxic substances in the fatty tissues of animals.
Biomagnification
The increase in concentration of POPs up a food chain.
Grasshopper Effect
Due to global atmospheric patterns, toxins tend to accumulate in the polar regions → disproportionately affecting Inuit people and arctic wildlife.
Acute Exposure (pesticides)
Poisoning and illness that result from accidents
Chronic Exposure (pesticides)
Cancer, birth defects, immune dysfunction, endometriosis, neurological dysfunction, Parkinson’s disease, etc
Genetically modified organism (GMO)
An organism whose genetic material has been altered using the techniques of genetic engineering (i.e. gene replacement, CRISPR, genetic transformation, etc).
Sustainable Agriculture
Agriculture that fulfills the need for food and fiber while enhancing the quality of the soil, minimizing the use of nonrenewable resources, and allowing economic viability for the farmer.
Polyculture
The opposite of monoculture, growing and producing diverse crops (maintains biodiversity on all 3 levels)
Agroforestry
Producing crops within and amongst trees (often fruit bearing trees like coffee, cacao, almonds, apple, etc)
Permaculture
Production of perennial plants (as opposed to annual plants) that do not require the farmer to disturb/plow the soil every season.
Integrated Pest Management (IPM)
An approach to food production that exists between conventional and organic.
Organic Agriculture
The production of crops without the use of synthetic pesticides or fertilizers. There has been a 17% increase in the number of certified organic farms in the U.S. between 2016 and 2019.
CAFO
Intensive animal feeding operation in which over 1,000 “animal units” are confined for over 45 days a year.