Plant Sceince Exam 3

what is the driving force behind climate

the sun’s energy

T or F: Climate is mainly incluenced by soil type

false - its dirven primarily by solar energy

what three things affect how much solar energy is received?

Latitude, season, time of day

does the earth’s daily spin or yearly orbit have more effect on seasons?

both matter, but season are mainly due to the earth’s tilt + orbit

what three aspects of light affect plant growth

quality, duration, intensity

what does ight quailty refer to

wavelenght

which wavelenghts are most important

420-460 and 620-680

T or F: more light intensity always increases plant growth

false - too much can damage plants

how far does the atmospehere extend

about 70 miles

name the four main layers of the atmosphere

troppsphere, stratosphere, mesosphere, thermosphere

which layer do we live in

troposhere

give two fuctions of the atmosphere

protection

define climate

typical long-term weather in a region

T or F: climate and weather mean the same thing

false- weather is short-term and climate is long term

what are two ket climare factors for agriculture

temperature and precipitation

what causes global warming

increase in greenhouse gases

T or F: global warming only affect temperature

false - also affects weather pattern and crop regions

what system classifies climated based on tempature and precipitation

koppen system

name the five major climare types

tropical, dry, mild mid-latitude, cold mid-latitude, polar

what are the four precipitation regions?

humid, semihumid, semiarid, arid

T or F: semiarid regions recieve more than 40 inches of rain

false - only 10-20 inches

what are two extremes of precipitation

drought and flooding

what is temperature a measure of

heat intensity or energy

what three factors influence temperature

latitude, altitude, proximity to water

T or F: temperature has little effect on plant growth

false - it strongly affects growth and processes

what are three temerature adaptation categories

temperate, tropical, subtropical

what are the three moisture adaptation types

hydrophytes, mesophytes, xerophytes

T or F: xerophytes need a lot of water

false - they are adapted to dry conditions

what is fallowing

leaving land uncropped in rotation

what is irrigation

supplementing precipitation

what does drainage do

removes excess soil water

T or F: crop residues decrease soil moisture

false - they help retain moisture

ehat directly influence plant processes: light or temperature?

both

Why are 420–460 nm and 620–680 nm important for plants?

Because they are the wavelengths most efficiently absorbed by chlorophyll for photosynthesis

What does ecology study

relationships among organisms and their enviroment

T or F: ecosytemns are defined only by the organisms living in them

false; ecosystems include organisms and their enviroments functions together

what are agroecysystems managed to produce

food, fiber, or other agricultural products

T or F: agroecosystems naturally maintain themselves without human input

false - they require high inputs and high management

in a food chain, what are plants classfied as

primary producers

what do secondary consumers eat

primary concsumer

T or F: Human are always primary consumers

false - humans are secondary consumers when eating meat

what process converts atmospheric N₂ inot usable nitrogen

fixation

what process converts organic N into inoganic forms

mineralization

T or F: Leaching moves nitrogen upward in the soil profile

False - leachnig moves nitrogen downward, often out of reach of plants

what is competitive exclusion

two species cannot occupy the same niche simultaneously

T or F: Plant succession happens quickly, usually within a year

false - it occurs over ong peroids

what is the first stage of succession listed in the slideshow

Pasture (0years)

What is the final stage of succession shown

Pine Forest (100 years)

T or F: Aspen forest appears before grass-shrub communities

false - grass-shrubs comes first

which (ecosystems or agroecosystems) has higher diversoty

natural

which system (ecosystems vs agroecosystems) has higher inputs

agroecosystems

T or F: natural ecosystems have high breeding control

false - they have none

name one disaster caused by simplifed agriecosystems

irish potato famine

T or F: simpifies food chains make agroecosystems more resilient

false - they make them more vulnerable

what must sustainable agriculture maintain for future generations

soil, water, and air resources

T or F: sustainable agriculture ignores profitability

false - it must be profitable for good land stewards

what are silds made of

a mixture of minerals, organic matter, liuids, and gases

T or F: soild forms quickly - usually within a few years

false - it takes up to 500 years to form soil in a distrubed area

what is soil fertility

the ability of a soil to supply nutrients

what is the A horizon

topsoil - high in nutrients, minerals, and moisture

what is the parent matieral for most soild

rock

name the three types of rock

sedimentary, igneous, and metamorphic

T or F: igneous rock forms for melted lava

false - hot in pressurized not melted

what happens to soil color as organic matter increase

it becomes darkers

list functions of organic matter

nutrient sequestration

T or F: organic matter includes living organisms

false - it includes plant and animal residues (not living)

Which material has the highest C:N ration in the table

sawdust (400:1)

T or F: a high C:N ratio means fast decay

false low C:N ratio = faster decay

what do earthwords contribute to the soil

aeration, decomposition, nutrient cycling

T or F: soil organisms decreases soil productivity

false - they increase productivity

which type of water is availabe to plants

capillary water (held in mcropores)

which type of water drains out of the root zone

gravitational water

T or F: hygroscopic water is available to plants

false - it is not available

what three particles determine soil texture

sand, silt, clay

which particle has the greatest water retention

clay

T or F: sand has the smallest particle size

false - clay is smallest (<0.002 mm)

what s soil structure

the clustering of soil partcles into shaes

what is tilth

soil qualities that benefit crop growth

what does CEC measure

the amount of exhangable cations a soil can sustatin

what does soil pH influence

nutrient availability

T or F: all plants grow best at pH 7

false - plants vary widely in optimum pH

what do the number 20-10-5 represent on a fertilizer bag

Percent N-P-K

name two fertilizer application mehtods

broadcast

T or F: organic fertilizers are alwyas fastre acting than inorganic ones

false - organic fertilizers release nutrients more slowly

what is erosion

accerlerated loss of soil by wind or water

how much soil is lost to water erosion in the U.S. year

3 tons/acre/year

T or F: wind erosion removes more soil than water erosion

false - water erosion removes more

Minimum soil cobvergae for conservation is ?

30%