Unit 7 Test - APES

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

1. Nutrient pollution
2. Explosive plant growth
3. Algal blooms block sunlight
4. Plants die off and decomposition skyrockets
5. **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.