Environmental Science Exam 2, Lecture 14 | Ecological Niches

Key Concepts, Terms & Ideas

Summarize the 5 ways agroecosystems are unique:

kept in early succession, little biodiversity, manmade growing patterns, plowed soils, GMOs

Agroecosystem

farm ecosystem

Describe how agroecosystems are kept in early ecological succession:

native species removed, conditions maintained for crops to stay, prevent succession

Describe how biodiversity and food webs are limited in agroecosystems. What impact does this have in terms of disease?

1 species, reduce competition, disease wipes out

Describe the impact of manmade growing patterns

straight lines, packed tightly, easy disease spread

Describe the impact of plowing soils

dilutes nutrients, increases erosion

How should you remember the impact of plowing soils?

sundae, hot fudge on top versus mixed, harder to get

Describe the impacts/consequences of GMOs

unknown effect on food webs, can be invasive to natural environs

What are two main agricultural products?

crops, livestock

Which 6 crops make up ___ of the calories we eat?

80%, corn, rice, wheat, potatoes, sweet potatoes, yuka/casava

Forage Crops

crops grown for animals

What is the main forage crop in the US? How much of this crop is produced in US?

alfalfa, 1/2 of wordwide

What are the three grain crops? What determines what grain crop will grow?

wheat, corn, rice, geography

There are more ____ on the planet than people

livestock animals

What is the effect of massive amounts of livestock animals on agricutural production?

massive strain

Rangeland

land for grazing, not plowed/planted

What does a rangeland need to have/provide to livestock?

food & water, natural water supply

How can a rangeland be environmentally harmful?

trample water bank, release waste into river

Pasture

planted & harvested to livestock

Feedlot

animals are fattened up before market

Where do animals typically move from as they age?

rangeland -> feedlot

How can a feedlot be environmentally harmful?

density = pollution, runoff of waste

Nutrient Migration

crops take nutrients, crops shipped to other place

What is the impact of nutrient migration in the middle of the US as compared to the coast?

forage in middle depleted, feedlots on coasts nutrient polluted

What technological advancements did the Green Revolution (1940s - 1960s) bring?

irrigation water, chemical pest/herbicides, synthetic fertilizers, crop breeding

What was an unintended consequence of the Green Revolution? What became tied together?

energy needed surpassed yield, food & energy prices

As the cost of fuel increases…

cost of food increases

How much land, excluding Antarctica, is used for agriculture worldwide?

38%

What is the current goal of agriculture?

grow more food per acre

What are the present limitations agriculture faces?

lack of nutrients, water, improving organic matter, predators/competitors

Describe how solutions to agricultural limitations present new issues: fertilzier, pesticide, irrigation, adding organic matter

nutrient pollution, pesticide accumulation, need drinking water, bringing foreign microbes

What is the most important agricultural resource?

soils

What is an analogy to remember why the top layer cannot tell us everything about a soil?

top of person’s head versus full body

Horizons

layer within the soil

O Horizon

organic, decomposing matter

A Horizon

minerals & organic material, dark

E Horizon

leached, water sucks nutrients, grey/white, rain

B Horizon

zone of accumulation, oxide deposition, colors vary

C Horizon

minerals, actively form soil, parent rock present

R Horizon

rock, bedrock, unaltered

What is a mnemonic to remember the order of soil horizons?

only americans eat bacon covered raisins 

What is important to remember about the presence of soil horizons?

potential layers, not all present

Summarize the important soil properties:

texture, color, organic matter, pH, nutrients, metals

Soil Textures

sand = largest, silt = middle, clay = smallest

Soil Colors

dark = carbon & organics, red = iron, white/grey = depleted

The ____ organic matter, the healthier the soil

higher

Soil pH is often too ___, a pH of ___ is often best

low, 7

Nutrient balance is important for…

growing specific crops

What does testing a soil for metals tell you?

common metals, PCBs, solvents

Leibig’s Law of Minimum

growth of plant affected by 1 limiting nutrient at a time

What is a solution to Liebig’s Law of Minimum?

add multiple limiting nutrients at once

We need a second ____ _________ to combat widespread famine

green revolution

Summarize what a new Green Revolution might entail:

increase production per acre, more farmland, new GMOs, eating lower

How can we increase more production per acre to be more efficient?

target fertilizer, crop rotation, irrigation

How do we increase our farmland

varietals in inhospitable, stop converting farms

What is a possibility of GMO breeding programs?

increasing calories per crop

Why would eating lower on the food chain increase crop production?

less forage crop, more people crop