Basic Agronomy/Plant Biology

Question 1

What is required for photosynthesis?

Answer 1

sunlight, chlorophyll, water, CO2, heat, nutrients, structure (usually soil)

Question 2

What are the stages of plant growth?

Answer 2

1. planting
2. care of the growing, vegetative plant
3. development of seeds
4. harvesting and storage

Question 3

What is dormancy?

Answer 3

seed won’t germinate even in favorable conditions

Question 4

What is quiescence?

Answer 4

stage of inactivity in the seed, will end if conditions are favorable

Question 5

What is imbibition?

Answer 5

water uptake

Question 6

What is needed for a seed to germinate?

Answer 6

water, proper temperature, nutrients (N&P), energy source (CHO, lipid), proper depth

Question 7

What happens if you plant a seed too deep?

Answer 7

it might run out of energy before reaching the surface where it can become an autotroph

Question 8

What happens if you plant a seed too shallow?

Answer 8

it might blow away , get eaten, or dry out

might not be able to use soil moisture, especially if the seed-soil contact is poor

Question 9

What is an autotroph?

Answer 9

an organism that can meet its own nutritional requirements through inorganic compounds (CO2)

Question 10

What is a heterotroph?

Answer 10

an organism that needs organic compounds to meet its nutritional requirements

Question 11

What are the parts of a seed?

Answer 11

seed coat, endosperm, embryo

Question 12

What is a monocot?

Answer 12

has one leaf upon emergence, grasses
makes it easier to break through the soil surface
ex) corn, barley, wheat

Question 13

What is a dicot?

Answer 13

has two leaves upon emergence, broadleaf
bends more upon emergence
ex) soybean, peas, legumes

Question 14

How do C3 and C4 plants differ?

Answer 14

have different affinities for CO2
C3 has a lower affinity

C3 - cool season (rye, small grains)
C4 - warm season (corn, sorghum)

Question 15

What conditions influence photosynthesis?

Answer 15

CO2 concentrations, light intensity, temperature, water availability in the soil, plant architecture

Question 16

What are photosynthates?

Answer 16

products from photosynthesis

ex) leaves, silks, grains

Question 17

When does photosynthesis stop?

Answer 17

when the stomata closes - when there is a lack of light and water

Question 18

Why do plants keep their leaves at an angle?

Answer 18

to make the largest surface for sunlight

Question 19

What is Langleys?

Answer 19

a measure of light intensity to rate of photosynthesis

has regions of deficiency, saturation and damage

Question 20

What is LAI?

Answer 20

leaf area index
area of leaves/area of soil surface (shadow area)
different plants use different architecture to maximize sunlight

Question 21

Why is a closed canopy desirable?

Answer 21

closed canopy = overlapping between rows

it shades out weeds, captures more sunlight (isn’t hitting the ground)

Question 22

What are the steps of seed development?

Answer 22

flowering –> pollination –> seed set

Question 23

Why is moisture content important for harvest and storage?

Answer 23

grain/seed can be damaged during harvest if too dry or wet
ex) corn - 26% or less, soybeans - no lower than 14%
grain/seed can spoil if too wet during storage
ex) corn - 14%, soybeans - 12%

Question 24

What are the steps of harvesting grain?

Answer 24

cutting
threshing - loosening grain from husks and straw
winnowing - separating grain and chaff

Question 25

How is perennial forage for silage stored?

Answer 25

harvested moist
clippings packed airtight into a bunker silo
anaerobic respiration pickles silage (fermentation)

Question 26

How is hay harvested and stored?

Answer 26

cut, loosened, drys out to 15% moisture content, then baled

stored outside or in a pole barn

Question 27

What are the two tissue types?

Answer 27

woody, herbaceous

Question 28

How can plants be categorized?

Answer 28

botany - seedling morphology, tissue type, photosynthetic pathway
reproductive method
parts of the plant that are used
lifespan - annuals, perennials, biennials
planting pattern
market use

Question 29

What are the possible market uses of plants?

Answer 29

commodity, specialty crop, food (vs feed)

Question 30

What are annuals?

Answer 30

one growing season

winter (require cold period) and summer annuals

Question 31

What are perinneals?

Answer 31

live for years

ex) trees, alfalfa

Question 32

What are biennials?

Answer 32

two years to complete cycle

ex) artichokes, garlic

Question 33

What are the different planting patterns?

Answer 33

row crop
narrow or solidly seeded
sod (stolons, rhizomes, hay)

Question 34

What is a rhizome?

Answer 34

continuously growing horizontal underground stem that puts out lateral shoots

Question 35

What is a stolon?

Answer 35

creeping horizontal plant stem or runner that takes root at points along its length to form new plants

Question 36

What are different propagation methods?

Answer 36

seeds (sexual), clippings (herbaceous), cuttings (woody; i.e. grafting), seedlings/transplants, bulb (clone), tubers (i.e. stolons, rhizomes, clones), tissue culture (i.e. chunk of potato), spores (mushrooms)

Question 37

What are various parts of the plant that can be used?

Answer 37

seed, leaves and stems, roots, flower, fruit, nuts, sap, bark, fungi, herbs (whole plant), sprouts

Question 38

What is involved in field preparation?

Answer 38

plowing, incorporation of cover crops, adding amendments (manure, compost), secondary tillage, removal of rocks, possibly initial herbicide application

Question 39

What are important considerations for timing?

Answer 39

temperature, soil moisture, frost, field conditions adequate for traffic