Exam 1 Agro Study Set

Nitrogen fixation

Bacteria that contains nitrogenase convert nitrogen (which is a gas) from the atmosphere so that it become ammonia.

Nitrification

Bacteria in the soil coverts the ammonia to nitrogen dioxide. Another type of bacteria then adds an oxygen atom, which creates nitrate.

Ammonification

When plants and animals die the ___ process causes the nucleic and amino acid to turn back into ammonia and nitrates. They are then released back into the soil.

Denitrification

Bacertia coverts nitrates back into nitrogen, which is then released back into the atmosphere.

Assimilation

Plants convert nitrate to chemicals they need, such as nucleic and amino acids. Animals that eat the plants then utilize these substances.

Immobilization

Inorganic forms of N are taken up by microorganisms or plants, by which it is prevented from being accessible to target plants

What is the dominant narrative around the need for industrial agriculture?

The world’s growing population requires ever‑greater food production through large‑scale, high‑yield, commodity‑driven industrial agriculture, and that without it, global hunger will worsen

Productivism

The notion that food insecurity is primarily the result of insufficient food/production and increasing production and efficiency will solve the issue.

Why does Vic believe productivism is a flawed narrative?

We have enough food, the amount of food is not the problem, we are simply wasting tons of food.

Proximate Cause

A generally short term or immediately causes some observed outcome.

Ultimate Cause

The “root" cause for an observed outcome.

Nikolai Vavilov

The father of seed banks.

Identified the importance of “centers of origins” for crop species

These regions harbor the highest percentage of genetic diversity per taxa

Why did Vavilov stress the importance of maintaining seed diversity?

He believed it was the foundation for preventing famine, improving crop resilience, and enabling future plant breeding.

What were some of the governent responses to the dust bowl?

• The U.S. government, after the dust bowl, ecologically and economically, realized we weren't preserving the land well enough/soil science, floods, irrigation, plant nurseries, and water supply. 

• Invest in research and universities to support farmers (Soil Conservation Act)

What did the soil conservation service do?

Created in 1935, after the Soil Conservation Act, to fight soil erosion and depletion due to the Great Depression

Protect the nation’s soil resources

Economic policies

• Soil Conservation Act

• demonstration projects showing conservation techniques;

What is this economic intervention? Price Support

(Farmers produce more, sell more)

What is this economic intervention? Deficiency payment

• _____ makes the difference between what the consumer is paying to the farmers. The government takes the burden of paying the farmers. Where is this money coming from?, taxes

What is this economic intervention? Direct Payment

• If you have a history of farming and have a bad year, such as a drought, the farmers are paid what they have historically made. Investing in farmers and focusing on the trend it is going)

• What is this economic intervention? Insurance

• Government provides farmers with the opportunity to buy ____ at a reduced rate. It is difficult for farmers to have justice when it comes to receiving money they lost from ____. Most farmers do not have ___ because it is not worth losing all that money

What are some of the other economic interventions besides that are smaller?

• soil science research;

• management of plant nurseries;

• flood surveys and flood control plans;

• support for drainage and irrigation work;

• snow surveys and water supply forecasts; and more.

What is this economic intervention? Demand Expansion

• Take the supply and find new uses for it. Ex “Got Milk”, marketing expands usage. Ex “Ethanol” in gas, high fructose syrup in food. Reduce the amount we have to buy giving others products to expand the business. 

Energy Conversion (What is this economic intervention?)

You can maximize ________ by… Chemicals, fertilizer, irrigation, pesticides, weeds. This costs money, environmental impacts, and justice in the food system

Market expansions

• Prices were crashing, community prices rising in 1920 being the highest, then wall st crashed. 

• Not just commodities crashed but the economy crashed

Domestication Syndrome

The human selection of traits in agriculturally relevant organisms

Often many plants (and animals) become less defended and more susceptible to predations, herbivory and/or disease.

Zero sum game

any change in an organism, plant or animal, to select for one trait will lead to some loss in other traits (e.g. less defensive chemicals in high yielding plants or animals, etc.).

What are some other ways that investment in yields and growth rates has made domesticated plants and animals less resilient

Higher vulnerability to pests and diseases

Reduced genetic diversity

Dependencies on specific agricultural practices or environments.

The Recipe of Evolution

“Change passed on through generations”

Variation provides the raw materials (traits)

Selection does the choosing

Inheritability = passes trait onto the next generation

Characteristics of healthy soil

High Organic matter (keep it alive and spongy)

Erosion Control (keep it there)

Soil Structure (keep it aerated and porous)

High organic matter

• Adds organic materials to the soil.

• Adds diverse sources of organic materials to the soil.

• Minimize losses of native soil organic matter.

Erosion control (keep it there)

• Provide plenty of soil cover

  cover crops and/or surface residue

Soil structure (keeo it aerarted and porous)

• Minimize tillage and other soil disturbances.High Fertility (keep it healthy)

• Manage soil fertility status to maintain optimal pH levels for your crops and a sufficient supply of nutrients for plants without resulting in water pollution

How can you maintain or increase organic matter in the soil?

By knowing the organic carbon content in a soil

Drainage (why it’s important for soil fertility)

You have to maintain the physical, chemical, and biological aspects for example, you must have water, nutrients, and organic matter, making ____ crucial to maintaining all three aspects. 

What conditions lead to denitrification and why?

____ only takes place in anoxic environments where oxygen consumption exceeds the oxygen supply and where sufficient quantities of nitrate are present.

How is organic matter lost from the soil?

A great advantage of the water-holding capacity of organic matter is that the matter will release most of the water that it absorbs to plants.

What are the factors that determine the potential amount of soil organic matter?

Living organisms (Soil engine)

partially decomposed plant and animal residues, unaltered material (potential food of organisms)

transformed products, non-humic substances (food and energy “glue”)

humic substances (Nutrient Bank Buffer)

How does tillage affect organic matter?

____ aerates the soil causing a large increase in oxygen which leads to an overabundance of bacteria that “burn up” the organic material

What are cover crops and how do they support soil organic matter?

• Any plant that is living in the soil that contributes to soil organic matter. 

What is the nitrogen cycle?

_____ is when nitrogen is excreted through decomposition, residues become mineralized, bacteria gets immobilized into nitrate (lighting would have to strike to break those bonds)

What is the nitrogen cycle?

The cycle that nitrogen is excreted through decomposition, residues become mineralized, bacteria gets immobilized into nitrate (lighting would have to strike to break those bonds)

What is nitrogen fixation and what types of plants/organisms are best known for it?

_____ is the process of converting atmospheric nitrogen (N₂), which plants cannot use directly, into ammonia (NH₃) or related compounds that plants can assimilate for growth and protein synthesis.

mediated by specific microorganisms such as Rhizobium, Frankia, Azospirillum, and Azotobacter, which possess the enzyme nitrogenase.

What is nitrifcation and denitrification?

• Well altered soil is aerobic

• Water logged soil is anaerobic

Mineralization

The process where organic matter is broken down by microorganisms into inorganic minerals

the green revolution

The idea that we can solve hunger through developing technologies to produce more food

What is a commodity

• A basic, raw material or agricultural product 

• Ex. Wheat, coffee, soybeans, gold, copper, coal, natural gas

• Homogenous so they can be traded

Norman Brolaug

Joined Rockefeller Foundation team in Mexico in 1944

increased yield and rust resistance in wheat

the biggest contributor to the Green Revolution

won the Nobel Peace Prize in 1970.

Haber-Bosch

Created the Haber-Bosch Process, the most transformational, technological, development of the modern age.

Believed that air becomes nitrogen/natural gas and water that becomes hydrogen which converts to Ammonia

believed that oil is just “really long chains of carbons/hydrocarbons”.

This improved the agricultural technology of Hybrid plants

What are cultural controls?

• The everyday growing conditions you control without chemicals (ex. Crop rotation or weed management)

Mechanical controls

• Physical, non-chemical methods to prevent, remove, or reduce pest populations (Ex. pest traps or manual removal of pests)

Biological control

Using living organisms to reduce or eliminate pest populations without chemicals (ex. Parasites, predators, or pathogens)

Augmentative

• By mass-releasing a beneficial organism to increase its impact in the field

Classical

• By introducing a natural enemy from the pest’s native area to control an invasive pest

Conservation biological control

• By managing the environment to protect and encourage natural enemies. 

• Shelter: Conserve overwintering Habitat

  Safety: Provide refuge from other natural enemies and pesticides

  Resources: Plant flowering plants that provide nutritional resources (pollen & nectar) and Alternative prey for generalists

What is this economic intervention? Supply Control

We had a surplus of things like grains and meats that needed to be controlled. There’s no incentive to make less food. High prices all around

Is feeding 10 billion people on earth possible?

Yes through sustainability

Lamarck’s Idea and the problem with it

Proposed that organisms evolve through the inheritance of acquired characteristics.

• “Inheritance of acquired traits” was incorrect

• Blacksmiths’ children did not inherit muscles

What is the Tragedy of the Commons?

Individuals acting in their own self-interest can ultimately deplete shared resources, leading to negative consequences for the entire group.

What makes up the soil texture (%)

20% Clay, 30% Silt, 50% Sand