Chapter 8 Flashcards
Photosynthesis from plants is the fundamental source of food and energy for all other complex life of Earth.
True
The reaction for photosynthesis is as follows: C6H12O6 + 6O2 = 6CO2 + energy (heat and ATP)
False
Many crop plants contain 80-95 % water
True
Chlorophyll converts chemical energy into light energy
False
Carotenoids are one type of plant pigment
False
ATP and NADPH are produced in the carbon-fixation steps of photosynthesis
False
The light reactions are the only part of photosynthesis that require light
True
One of the functions of transpiration is uptake of mineral nutrients
True
The Krebs cycle is part of photosynthesis
False
Water is absorbed from the soil by root hairs
True
The rate of transpiration increases with higher temperatures
Treu
Leaf curling can be a sign of moisture stress
True
It is important to recognize crop development stages in order to apply sound management practices
True
The Growing Degree Day base temperature for soybeans is 32 degrees F
False
In which organelle does photosynthesis occur?
Chloroplast
Plat pigments absorb visible light in this range?
400-700 nm
Plant pigments are least effective in absorbing which color of light?
green
The two energy compounds used in carbon-fixation reactions are:
ATP and NADPH
Which type of photosynthesis is inefficient about 25 degrees C ?
C3
What percentage of the world’s plants are C4?
10
Which type of cell controls the opening and closing of stomata?
guard
Rhizobia bacteria convert atmospheric nitrogen into:
NH3
The plant response that is most important for triggering flowering in the spring is:
vernalization
The process by which plats differentiate from seedling to vegetative to flowering would best be described as:
development
The index of heat accumulation (or heat units over time) used to estimate how corp development will progress and when a crop is predicted to mature is:
Growing Degree Days
Half of the yield grains in cereal crops is due to genetic improvement
True
Strict cross-pollinators do not require an outside source of pollen
False
Yield is an example of a quantitative trait
True
Flower color is an example of a quantitative trait
False
Peas are an example of a cross-pollinating species
False
The resulting phenotypic ration of the cross-pollinating species
True
A genotype of GG would be Homozygous
True
Lodging resistance is an example of a harvestability trait
True
Persistence is a tria that would most often be improved in annuals
False
Plant breeding strategies do not depend on pollination systems
False
High amounts of genetic variation in germplasm are desired at the start of a breeding program.
True
The USDA is not currently conducting plant explorations
False
Cross-pollinated species tend to be more uniform than self-pollinated species
False
Hybridization is generally a better technique than mass selection for cross-pollinated species
True
Agrobacterium tumefaciens can transmit its DNA to other cells
True
In 2007, the majority of cotton, alfalfa, and corn planted was genetically modified
False
It is possible to transfer a single gene using traditional breeding methods
False
The maximum number of genetic traits that can be transferred to a single cultivar in four
False
Most modern crop varieties are patented to protect the intellectual property of those who developed them
True
When pollen is transferred to the stigma of the same flower, it is:
self-pollination
DNA is organized into units called
genes
Plants that have two copies of each chromosomes are:
diploids
The total genetic makeup of a plant is known as its
genotype
the term that describes a group of genetically similar plants that can be distinguished from other groups within the same species is:
cultivar
Which of the following is NOT an sample of a harvestability trait
increased leafiness
The development of a new cultivar averages how many years?
5
The advancement of which of the following crops is considered America’s greatest achievement?
corn
Which of the following crops have had their genome sequences?
rice
How are transgenic plants generated once genes have been transferred into new cells using biotechnology?
by tissue culture
What is the most prevalent trait that has been incorporated into transgenic crops?
herbicide resistance
Saving seed that is patented and then growing or selling it is called:
seed piracy
Day length varies with latitude
True
The latitude at the equator is 90 degrees
False
There are five named lines of latitude
True
It is possible for the sun to be at its zenith at the Arctic Circle
False
The two layers of our atmosphere that influence biological activities are the troposphere and mesophere
False
Earth’s average air temperature has increased by 1 degrees F in the past 100 years
True
A state by the ocean such as New Jersey has more fluctuation in air and soil temperature than a landlocked state such as Minnesota
False
The orographic effect causes wet conditions on the leeward side and dry conditions on the windward side
False
Less than 0.5 percent of Earth’s water is in the form of groundwater
True
Naturally low rainfall is also known as drought
False
Chilling injury occurs at a lower temperature than freezing injury
False
Fallowing involves land in rotation that is not cropped for a season or more
True
Drainage systems can lower the water table of a soil
True
Relative maturity (RM) is a system that denotes that averages days to physiological maturity for a particular hybrid
True
The Colorado River and its reservoirs are being depleted due to increased agricultural use and population growth in the Southwest
True
What percentage of the sun’s energy reaches Earth
1%
How much of the portion of the sun’s energy that reaches Earth is absorbed or reflected by the atmosphere?
50%
Energy is the greatest at which wavelengths?
short
Which is NOT a great influence on the amount of quality of light received on Earth?
the orbit of the moon
Because of which of the following do we experience seasons?
the inclination of Earth
At what angle does the sun’s radiation strike at the equator?
90 degrees
When were the concepts of altitude and longitude developed?
200 BCE
The layer of the atmosphere closet to Earth is the:
troposphere
Which of the following is NOT known as a greenhouse gas?
O2
Which type of air mass tends to be hot and dry?
continental tropical
The Koppen climate classification system how has many major climate types?
5
Which of the following is NOT a major climate type of the Koppen classification systems?
Mediterranean
Montana would be part of which general precipitation region?
semi-arid
Which natural catastrophe cost the United States the most on a yearly basis?
drought
Which temperature adaptation type would corn be categorized at?
tropical
Which temperature adaptation type would wheat be categorized as?
temperate
Which moisture adaption type would rice be categorized as?
hydrophyte
Which moisture adaption type would soybean be categorized as?
mesophyte
The living portion of an ecosystem is called the abiotic component
False
Bioremediation is an example of a service that an ecosystem can provide
True
The ecological pyramids of most terrestrial systems have a minimum of five levels
False
Simple ecosystems are less vulnerable to destruction compared to complex ecosystems
False
Carbon tends to be the limiting elemental nutrient in terrestrial systems
False
The entire process of ecological succession requires up to 20 years to complete
False
Non-nitrogen-fixing terrestrial plants take up nitrogen mostly as NH4+
False
Tillage helps release mineralized nitrogen in the soil
True
Deserts are never utilized for agricultural purposes
False
One of the most common agroecosystems in the United States is the corn-soybean rotation
True
Alfalfa can be a common component of an animal-based agroecosystem
True
Modern agriculture has resulted in greatly accelerated rates of erosion
True
Wetlands are no longer being drained in the United States
False
Which of the following would be considered an abiotic factor of an ecosystem
water
Which component is the start of every food chain?
sun
In a food chain, an eagle would be an example of a:
secondary consumer
In a food chain, a plant would be an example of a:
primary producer
How much energy is generally transferred to each successive level of an ecological pyramid?
10%
The chemical formula for atmospheric nitrogen is:
N2
Which of the following is NOT one of the pathways through which atmospheric nitrogen is converted to a usable form for plants?
denitrification fixation
Which is the first product in industrial fixation?
NH3
Performed by microbes, the reverse of the immobilization process is called:
mineralization
The average percentage of nitrogen in the soil is in the range of:
1-10%
Which of the following biomes once occupied 80% of North and South America
forests
How much of the world’s area is occupied by cultivated cropland and managed pastures?
40%
Modern agriculture is also called:
All of the above are correct
One of the reasons the Dust Bowl occurred was:
tillage of an arid region prone to droughts
Agricultural operations can cause modifications to the C horizon
False
SOils in wet tropical regions tend to have high organic matter and distinct profiles
False
Weathered rock can be a source of essential minerals for plants
True
Plants with low C:N ratios decay rapidly
True
Sawdust added to soil can cause nitrogen deficiency
True
Organic matter has a positive charge
False
Higher earthworm populations are achieved in conventional tillage in comparison to no-till
False
Plants infected with mycorrhizal fungi can absorb phosphorus better than noninfected plants
True
Productive soils are densley packed
False
A plant will extract water at field capacity until it reaches the permanent wilting point
True
Sandy soils drain at a faster rate than clay soils
True
Soils that are fertile and hold nutrients will have a low cation exchange campacity
False
the pH of a soil is important because it influences the availability of plant nutrients
True
Most crops grow well in soils with high salinity
False
Synthetic fertilizers are used to provide organic matter to the soil
False
Geologic erosion occurs at a faster rate than soil formation
False
Erosion can leave behind less fertile subsoils
True
How thick does the soil layer tend to be in agricultural regions?
3 to 4 feet
A vertical section through the soil extending from the surface to an unweathered rock is best described as the:
profile
The topsoil is also known as the:
A horizon
the subsoil is also known as the:
B horizon
Which horizon has the highest amount of organic matter?
O horizon
Which of the following is one is the most important soils in agricultural production
mollisol
Which is the predominant parent material for soils?
sedimentary rock
The fineness or coarseness of a soils is called:
soil texture
Sand and silt are chemically composed mostly of:
silica
Which soil particle contributes most to plant nitrogen
clay
The clustering of soil particles into various shapes is called:
soil structure
The pH range that most field crops grow best at is:
6-7
Which of the following is an index that rates soil for intensive agricultural production on a 0-100- value scale
Crop Productivity Index
One distinction between organic and inorganic fertilizers contain:
Carbon
Which of the following fertilizer nutrients is NOT obtained from mining?
nitrogen
Limestone is applied to soil to:
increase soil pH
When biodiversity is considered, the concept of richness refers for the distribution or relative abundance of the individuals of a species
False
Increased biodiversity is generally desirable in an agroecosystem
True
Continuous cropping is the planned sequence of different crops grown over years on the same land
False
A 2-year rotation is generally adequate to control pests
False
By cropping corn continuously, producers can expect 10 percent yield grains over corn in rotation
False
The nitrogen from legumes can provide enough nutrition for a subsequent corn crop
False
Corn and soybean are crops that tend to be grown in monocultures
True
Polyculture systems are easier to manage than monoculture systems
False
Hay mixtures using species such as alfalfa and grasses are an example of mixed intercropping
True
Living mulches have only been used to a limited extent due to management challenges
True
Multiple cropping is often practiced in areas with short growing seasons
False
Green manures can be used as a substitute for synthetic fertilizers
True
One way to diversify the landscape is through conservation plantings
True
Farmers who have CRP plantings receive a one-time payment for enrollment
False
Studies have not shown a positive environmental impact as a result of the CRP program
False
A common example of a 2-year rotation in the Midwest is:
corn-soybean
A common companion crop to alfalfa is:
oats
Growing two or more crops together in the same place during a growing season are called:
polyculture
The agroforestry system where trees are grown in rows with an annual or perennial crop between is called:
alley cropping
The polyculture system where annual grain crops are planted into a suppressed perennial sod is:
living mulch
An example of a double crop system that would be grown in a state such as Illinois is
wheat planted in fall with corn planted in spring
The type of multiple cropping system where a crop is planted (but not for harvesting) during or following the cash crop is:
cover cropping
A common crop grown in rotation with cotton is:
peanut
Cover crops are killed using which method?
All answers are correct
Which of the following crops is known to have allelopatic effect?
rye
What percentage of the Corn Belt is planted with corn and soybean?
95%
Which is a type of agroforestry system that combines trees with pastures for livestock utilization?
silvopasture
The incorporation of plant residues into soil increases their rate of decay
True
Moldboard plowing leaves adequate residue cover to protect the soil
False
Excessive plowing can lead to the loss of organic matter
True
Primary tillage smoothes the seedbed for planting
False
Conventional tilling requires less time and energy than conservation tillage
False
No-till is commonly used on wet soils in northern regions
False
A benefit to the ridge till system is earlier planting
True
Fall plowing can facilitate earlier planting
True
Good soil-to-seed contact is important for planting success
True
Oxygen is not a factor in seed germination
False
Light is a requirement for germination for most crop species
False
The mechanism of dormancy can result in germination being staggered over years
True
Seed of some cereal crops undergoes after-ripening before germination
True
The initation of metabolic processes in the seed occurs after germination
True
At low seeding rates, plant populations are not utilizing resources optimally
True
Typical row spacing of corn and soybean have increases since the 1950s
False
On approximately how much planted land is conventional tillage used in the United States?
1/3
Which piece of equipment shears off sections of soil and flips them over?
moldboard plow
How much residue does moldboard plowing typically leave?
0-15%
Which of the following crops leave the most residue after harvest?
corn
Most farmers get their seed by:
buying from private seed companies
Seed planted too deep will:
exhaust their energy reserves
The general rule for planting depth is to go no deeper than:
10 times the seed diameter
Which crop is more likely to be negatively affected by crusting of the soil surface?
soybean
In which soil should seed be planted the deepest?
sand
Dormant seeds usually have around what percentage of moisture?
15%
Hard seed is an example of what type of barrier to germination?
physical
Hard seed must undergo what process before planting?
scarification
Broadcast seedling is most likely to be used with which of the following crops?
alfalfa
Which of the following would most likely be used to plant a restored prairie?
no-till grassland drill
Which of the following would most likely be used to plant corn?
row crop planter
Which of the following would be planted earliest in the year?
small grains
