weed management exam 1 ACTUAL UPDATED Questions and CORRECT Answers
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Terms in this set (68)
What is a weed? A plant that interferes with the growth of desirable plants and is unusually
persistent.
Why is the definition of a weed as 'a plant out of place' It relies solely on a plant's physical location without considering its impact on
insufficient? crops.
What are volunteer crops? Crops that emerge the next year after planting in the subsequent crop, such as
corn in a soybean field.
What is a major flaw in defining weeds as plants with no Many plants without clear uses can still be significant weeds due to their impact
clear use or purpose? on crops.
What characteristics make a weed successful? Ability to germinate in various environments, rapid development, continuous seed
production, and easy dispersal.
How many total plant species exist in the world? Approximately 250,000 plant species.
What percentage of total plant species are considered About 0.08%, or roughly 200 species.
weedy in agriculture?
What percentage of crop loss is caused by these 200 90% of all crop loss in the world.
weedy species?
What are some examples of newly introduced weed Bush Honeysuckle, Hydrilla, Kudzu, Palmer Amaranth, Tropical Spiderwort.
species?
What is the estimated loss in yield due to weeds in the 12% loss, equating to significant financial losses in agriculture.
US?
What percentage of weeds in the US are non-native 73 percent.
species?
What is Witchweed and where was it identified? Witchweed (Striga asiatica) was identified in North Carolina in 1955.
What is the significance of the quarantine enacted for It reduced the affected area from 450,000 acres to less than 5,000 acres.
Witchweed?
What is the definition of soil according to the Yearbook of Soil is a dynamic three-dimensional natural body on the surface of the earth in
Agriculture (1957)? which plants grow, composed of mineral and organic materials and containing
living organisms.
, What does the new definition of soil (SSSA, 2017) Soil is layers of generally loose mineral and/or organic material affected by
emphasize? physical, chemical, and/or biological processes at or near the planetary surface,
usually holding liquids, gases, and biota, and supporting plants.
List some properties that make soil a complex and Texture, Depth, pH, Organic Matter, Porosity, Slope, Cation Exchange Capacity
dynamic system. (CEC), Potential to Erode, Water Holding Capacity.
How does particle size affect surface area in soil? Larger particles of smaller size result in greater surface area, which holds more
water and nutrients.
What is the charge of soil and organic matter? Soil and organic matter typically have a negative surface charge, allowing
negative charged particles to stay in solution and positive charged particles to
adsorb to soil.
How does the pH of organic matter differ from mineral The pH of organic matter can change, while the pH of mineral particles is fixed.
particles?
What is the surface area comparison between solid soil A solid 6 cm^2 cube has a surface area of 6 m^2, while larger colloidal particles
and colloidal particles? can have a surface area of 60,000 m^2, and smaller colloidal particles can reach
up to 6,000 m^2 (1.5 acres).
What factors contribute to the development of soil The integrated effect of climate, topography, and living organisms acting upon
properties over time? parent materials.
What is the significance of water holding capacity in soil? Water holding capacity is essential for supporting plant growth and maintaining
soil moisture levels.
How does slope affect soil properties? Slope can influence erosion potential, drainage, and the distribution of soil
moisture and nutrients.
How many seeds can a single Palmer Amaranth plant From 10,000 to 250,000 seeds.
produce?
What conditions allow weed seeds to remain viable? Weed seeds can produce viable seeds under poor fertility, low water supply, and
late germination.
What is Primary Dormancy in weed seeds? Primary Dormancy refers to the phenomenon where most seeds of summer
annuals and perennials do not germinate in the fall of the season they are
produced.
What is Secondary Dormancy in weed seeds? Secondary Dormancy allows seeds to 'wait' in the soil during adverse conditions
such as hot, dry, cold, or flooded environments.
How long can weed seeds remain viable in the soil? Weed seeds can remain viable for years, with some able to germinate after
several decades.
What adaptations do weed seeds have for survival? Weed seeds have thick coats and protection that allow them to endure extreme
environments.
C
Terms in this set (68)
What is a weed? A plant that interferes with the growth of desirable plants and is unusually
persistent.
Why is the definition of a weed as 'a plant out of place' It relies solely on a plant's physical location without considering its impact on
insufficient? crops.
What are volunteer crops? Crops that emerge the next year after planting in the subsequent crop, such as
corn in a soybean field.
What is a major flaw in defining weeds as plants with no Many plants without clear uses can still be significant weeds due to their impact
clear use or purpose? on crops.
What characteristics make a weed successful? Ability to germinate in various environments, rapid development, continuous seed
production, and easy dispersal.
How many total plant species exist in the world? Approximately 250,000 plant species.
What percentage of total plant species are considered About 0.08%, or roughly 200 species.
weedy in agriculture?
What percentage of crop loss is caused by these 200 90% of all crop loss in the world.
weedy species?
What are some examples of newly introduced weed Bush Honeysuckle, Hydrilla, Kudzu, Palmer Amaranth, Tropical Spiderwort.
species?
What is the estimated loss in yield due to weeds in the 12% loss, equating to significant financial losses in agriculture.
US?
What percentage of weeds in the US are non-native 73 percent.
species?
What is Witchweed and where was it identified? Witchweed (Striga asiatica) was identified in North Carolina in 1955.
What is the significance of the quarantine enacted for It reduced the affected area from 450,000 acres to less than 5,000 acres.
Witchweed?
What is the definition of soil according to the Yearbook of Soil is a dynamic three-dimensional natural body on the surface of the earth in
Agriculture (1957)? which plants grow, composed of mineral and organic materials and containing
living organisms.
, What does the new definition of soil (SSSA, 2017) Soil is layers of generally loose mineral and/or organic material affected by
emphasize? physical, chemical, and/or biological processes at or near the planetary surface,
usually holding liquids, gases, and biota, and supporting plants.
List some properties that make soil a complex and Texture, Depth, pH, Organic Matter, Porosity, Slope, Cation Exchange Capacity
dynamic system. (CEC), Potential to Erode, Water Holding Capacity.
How does particle size affect surface area in soil? Larger particles of smaller size result in greater surface area, which holds more
water and nutrients.
What is the charge of soil and organic matter? Soil and organic matter typically have a negative surface charge, allowing
negative charged particles to stay in solution and positive charged particles to
adsorb to soil.
How does the pH of organic matter differ from mineral The pH of organic matter can change, while the pH of mineral particles is fixed.
particles?
What is the surface area comparison between solid soil A solid 6 cm^2 cube has a surface area of 6 m^2, while larger colloidal particles
and colloidal particles? can have a surface area of 60,000 m^2, and smaller colloidal particles can reach
up to 6,000 m^2 (1.5 acres).
What factors contribute to the development of soil The integrated effect of climate, topography, and living organisms acting upon
properties over time? parent materials.
What is the significance of water holding capacity in soil? Water holding capacity is essential for supporting plant growth and maintaining
soil moisture levels.
How does slope affect soil properties? Slope can influence erosion potential, drainage, and the distribution of soil
moisture and nutrients.
How many seeds can a single Palmer Amaranth plant From 10,000 to 250,000 seeds.
produce?
What conditions allow weed seeds to remain viable? Weed seeds can produce viable seeds under poor fertility, low water supply, and
late germination.
What is Primary Dormancy in weed seeds? Primary Dormancy refers to the phenomenon where most seeds of summer
annuals and perennials do not germinate in the fall of the season they are
produced.
What is Secondary Dormancy in weed seeds? Secondary Dormancy allows seeds to 'wait' in the soil during adverse conditions
such as hot, dry, cold, or flooded environments.
How long can weed seeds remain viable in the soil? Weed seeds can remain viable for years, with some able to germinate after
several decades.
What adaptations do weed seeds have for survival? Weed seeds have thick coats and protection that allow them to endure extreme
environments.
