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SOCR 320 > Exam #1 Study Guide > Flashcards

Exam #1 Study Guide Flashcards

1
Q

What is the definition of cultivated forage?

A

Plants that are seeded and/or grown using agricultural practices such as tillage, irrigation, and fertilization to produce herbage for consumption (can be grazed or packaged and fed as hay or silage) by domestic animals

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2
Q

Why are cultivated forages important?

A
  • Comprise the majority of nutrients fed to domestic livestock including cattle, sheep, and horses
  • Reclamation/revegetation of disturbed lands - Grasses used for soil conservation
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3
Q

What is considered herbage?

A
  • Leaves
  • Stems
  • Roots
  • Seeds of non-woody species
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4
Q

What is pasture?

A

Forage grazed by livestock. More commonly refers to an area of land (generally enclosed and separated from other areas by fencing or other barriers) which is used to grow forage for grazing by livestock.

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5
Q

What is hay?

A

Dry form of forage produced by harvesting fresh herbage, field drying it to moisture levels low enough to prevent microbial growth (spoilage), and packaging it in the form of loose stacks or bales of various sizes and shapes.

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6
Q

What is silage?

A

Wet form of forage produced by harvesting fresh herbage and placing it in an anaerobic environment (generally a silo) where it is allowed to ferment. Fermentation of sugars produces organic acids (lactic) that lower the pH, essentially “pickling” the forage. Commonly made from annual forages such as corn and forage sorghums.

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7
Q

What is haylage?

A

Drier form of silage used to preserve forage plants such as alfalfa and perennial grasses that are often difficult to ensile using conventional (direct-cut), high-moisture techniques. Forage is generally swathed, allowed to wilt to about 45% moisture, and then chopped and packed in silos.

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8
Q

What is greenchop?

A

Forage that is harvested, chopped, and fed directly to livestock on a daily basis.

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9
Q

What is the general classification for grasses and grasslike plants?

A

Monocots

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10
Q

What is the main distinguishing characteristic of monocots?

A
  • All are herbaceous
  • Narrow leaves with parallel veins, generally have inconspicuous flowers
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11
Q

What is the general classification of broadleaf plants such as legumes?

A

Dicots

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12
Q

What is the main distinguishing characteristic of dicots?

A

Broadleaf plants, leaves have net veins, showy flowers

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13
Q

What is the unique ability associated with legumes?

A

Plants capable of fixing atmospheric nitrogen

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14
Q

What is an annual, perennial, and biennial plant?

A
  • Annual: Plants that grow from seed and complete their life cycle within a single year or growing season
  • Perennial: Plants that survive from year to year without reseeding
  • Biennial: Plants that complete their life cycle in 2 years.
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15
Q

What is a C3 plant?

A

A C3 plant is a cool-season plant
- Optimum growth occurs at lower temperatures: near 70 degrees F
- Growth temperature range: 60 to 85 degrees F
- Can still grow slowly at 35 degrees F
- Growth can be maximized at moderate light levels, can become light saturated
- Water use efficiency tends is lower
- Tends to be less drought tolerant

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16
Q

What is a C4 plant?

A

A C4 plant is a warm-season plant
- Optimum growth occurs at higher temperatures: near 90 degrees F
- Growth temperature range: 85 to 104 degrees F
- Little growth occurs below 60 degrees F
- Require higher light levels for optimum growth, do not become light saturated
- Water use efficiency is higher
-Tend to be more drought tolerant

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17
Q

What is a short-lived, moderately long-lived, and long-lived perennial?

A

Short-lived: 3-5 years
Moderately long-lived: 5-10 years
Long-lived: More than 10 years

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18
Q

What is a winter annual?

A

Planted in the late summer or early fall, overwinter in a vegetative state, and complete life cycle by early summer.

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19
Q

What is a summer annual?

A

Cool-season species planted in the early spring and complete life cycle by mid summer or warm-season species planted in late spring or early summer and complete life cycle by late summer/early fall.

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20
Q

What makes an ideal soil?

A

50% solid matter (~45% mineral, ~5% organic matter)
50% pores (~25% air, ~25% water)

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21
Q

What is sand?

Characteristics?

A

2.0-0.05 mm
- Least amount of surface area
- Low water holding capacity/drought prone
- High infiltration rates/good drainage
- Little chemical reactivity

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22
Q

What is silt?

Characteristics?

A

0.05-0.002 mm
- Greater surface area and water holding capacity than sand
- Little chemical reactivity
- Highly erodible

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23
Q

What is clay?

Characteristics?

A

< 0.002 mm
- Chemically active (neg. charge) –> affects pH (acidity)
- Greatest nutrient holding capacity
- Greatest water holding capacity, not all available to plants

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24
Q

What is pH a measure of and why is it important?

A

pH is the measure of the acidity or alkalinity of a soil
- Proper plant root function & microbial activity
- Availability of soil nutrients

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25
Q

What is the optimum pH range for plant growth?

A

pH 6 to 7.5

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26
Q

What are the characteristics of calcareous soils?

A

– Derived from CaCO3 (limestone)
– Low in sodium, very productive soils

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27
Q

What are the characteristics of saline soils?

A
  • High in salts (Chlorides and sulfates)
    – Low in sodium (Na)
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28
Q

Where does most soil organic matter come from?

A

Most OM comes from vegetation in varying
stages of decomposition

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29
Q

What are 2 important characteristics of soil organic matter?

A
  • Increases a soil’s nutrient holding capacity
  • Increases a soil’s water holding capacity
30
Q

What is humus?

A

Fairly stable end product of organic matter decomposition

31
Q

What is the easiest way to increase soil organic matter?

A

Permanent pasture and hay

32
Q

What are the important factors to look for on a soil test report?

A
  • pH
  • Organic matter content
  • Nitrate, phosphorus, potassium
  • Soluble salts
  • Micronutrients (boron, zinc, iron)
  • Soil texture
33
Q

What makes an ideal agricultural soil?

A
  • High in organic matter
  • pH 6.0 to 7.5
  • Loams: Good mix of sand, silt, and clay
34
Q

What are the characteristics of Western soils?

A
  • Not highly weathered (low rainfall)
  • At least mildly alkaline – higher in calcium
  • West of 100th meridian, high levels of potassium
  • Relatively low in OM, 0.5 to 2.0%
35
Q

Grass plants are made up of a series of units called what?

A

Tillers

36
Q

What are plant parts make up tillers?

A
  • Stems (culms)
  • Leaves
  • Roots
37
Q

What are the 2 types of grass tillers?

A
  • Vegetative
  • Reproductive

Reproductive tillers have seed heads (inflorescence)

38
Q

A grass stem or culm is comprised of what 2 main parts?

Which part accounts for growth (height)?

A

Nodes and internodes

The internode accounts for growth.

39
Q

Describe where crowns are found on grass and legume plants and why they are important?

A
  • Crowns are found at the base of perennials and have compacted nodes and internodes with numerous buds on the lower nodes to help with growth in the spring.
  • Site of carb and protein storage
40
Q

What are the characteristics and importance of stolons and rhizomes?

A

Contain nodes, internodes, and buds - capable of forming new roots and tillers at the nodes - means of vegetative reproduction.
* Stolons - aboveground stems
* Rhizomes - belowground stems

41
Q

What is the difference between a bunchgrass and sod-forming grass?

A

Growth pattern, sod grass is more even in growth whereas bunch is in bunches

42
Q

Legume plants are made up of a series of units called what?

What do these units consist of?

A

Shoots

Leaves & Stems

43
Q

How do nodes on legume plants differ from nodes on grass plants?

A
  • Source of axillary buds from which new leaves, stems, and flowers can initiate.
  • Buds are functional
44
Q

How do the roots of grasses and legumes differ?

A
  • Has taproots and feeder roots
  • Easily extend 4-6 feet
  • Also the site of nodulation by nitrogen fixing bacteria
45
Q

What is the importance of buds and where are they found?

A
  • Buds initiate new growth
  • They are found on the crown
46
Q

What are the 2 main phases of legume development?

How much time is spent in each?

A
  • Vegetative phase: Plants spend ~50% of time in this phase
  • Reproductive phase: Plants spend other 50% of time in this phase
47
Q

What is the historic stage of growth to harvest alfalfa?

At what stage is a lot of alfalfa harvested at today and why?

A
  • Historic: 1/10 bloom stage –> flowers present on ~10% of stems
  • Today: Alfalfa harvested at mid and late bud stages for optimum quality
48
Q

As the leaf to stem ratio continues to decline over time, what happens to forage quality?

A

Forage quality decreases

49
Q

Where is the growing point found on a legume plant?

When removed, where does new growth originate from?

A
  • Growing point is always at the top of the developing stem (or shoot)
  • When removed by harvest or grazing, plants must regrow from axillary buds at lower nodes, especially those buds at nodes near the soil surface
50
Q

What are the 3 phases of grass development?

What happens during the transition phase?

A
  • Vegetative
  • Transition (jointing/elongation) –>Growth consists of continued leaf expansion, stem elongation, and expansion of the developing inflorescence (immature seed head)
  • Seed filling
51
Q

How many reproductive cycles do most perennial grasses undergo in a year?

A

One

52
Q

What is a culmless and culmed vegetative tiller?

A
  • Culmless vegetative tiller: No stem elongation (orchardgrass)
  • Culmed vegetative tillers: two phases of growth occur (smooth brome)
53
Q

At what 2 times of the year are tillers of C3 plants initiated?

What can stimulate initiation in some grasses?

A
  • Late fall or early spring
  • A small application of N fertilizer in the fall can stimulate bud initiation which influences the number of reproductive tillers the next growing season.
54
Q

What 2 factors can initiate floral induction in C3 grasses?

Main factor in C4 grasses?

A
  1. Vernalization (cold requirement near freezing)
  2. Critical daylength

Shorter day lengths

55
Q

Where is the growing point found on grass plants?

A

Terminal meristem

56
Q

At what stage of growth does the growing point begin to elevate?

A

Jointing

57
Q

What happens when the growing point is removed or damaged?

A

A new tiller must
initiate from an axillary or basal bud

58
Q

What is the range in moisture content for most fresh herbage?

A

65 to 85%

59
Q

What is the range in moisture content of preserved hay?

A

Hay: 10 to 20% (conventional hays); 20 to 30%
(when preservatives used)

60
Q

What is the main difference between cell contents and cell wall constituents?

A
  • Cell contents - nonstructural chemical components
  • Cell wall constituents - structural chemical components
61
Q

What is the importance of simple carbohydrates?

Give an example of a monosaccharide and a disaccharide

A

They are the basic building blocks for other more complex carbohydrates

Monosaccharide: Glucose
Disaccharide: Sucrose

62
Q

Why are polysaccharides important?

A

Serve as energy reserves

Ex. Starch, Fructans

63
Q

Where are they stored in the plant?

A

Crowns, roots, rhizomes, stolons, and seeds

64
Q

What are the 2 main nitrogenous constituents found in the cell contents?

A
  • Amino acids
  • Proteins
65
Q

What is the conversion factor to convert % nitrogen to crude protein?

Why is this value used?

A
  • 6.25
  • Vegetative protein is consistent in amino acid
    composition
66
Q

What are the 2 types of structural carbohydrates?

A
  • Cellulose
  • Hemicellulose
67
Q

Cellulose is made up of polymers of what?

A

Glucose that are
cross-linked together

68
Q

What areas of cellulose are partially digestible?

A

Amorphous areas (50-90% digestible)

69
Q

Rate the relative digestibility of hemicellulose, cellulose, and lignin

A
  • Cellulose
  • Hemicellulose: Partially digestible (20 to 80%)
  • Lignin: Indigestible
  • Hemicellulose > Cellulose > Lignin
70
Q

How does lignin differ from cellulose and hemicellulose?

A

Not a carbohydrate

SOCR 320 (9 decks)

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