Midterm Study Guides Flashcards
How many GDD would accumulate during a 24-hour period where the low temperature was 60 and the high was 74 for a corn crop? (60 as base temperature)
17
What is the formula used to calculate Growing Degree Days (GDD)?
(Maximum Temperature + Minimum Temperature)/2 - Base Temperature (usually 60)
Nutrient Deficiency symptom: yellowing along tip and edges, lower leaves
Potassium
Nutrient Deficiency Symptom: yellowing starts at tip and moves along midrib
Nitrogen
Nutrient Deficiency Symptom: reddish-purple in young leaves
Phosphorous
Drought symptoms:
rolled leaves: grayish green
Corn Hybrid Improvements
- withstand higher populations
- more vertical leave angle
- reduced tassel size
- close timing silking and pollen shed
- increased stay green
- more starch
- altered root architecture
- water use efficiency
Current record for bu/a
350-355 bu/a
Kinds of corn: starch shrinks and dries, forming dents
Dent corn
Kinds of corn: hard starch/kernals that form ornamental ears
Flint corn
Kinds of corn: soft starch which makes flour and corn shells
Flour corn
Kinds of corn: very hard, resists steam, smaller kernal
Popcorn
Kinds of corn: dry and wrinkled, high in sugar
Sweet corn
Kinds of corn: dull, starch quality
Waxy corn
Kinds of corn: primitive features
Pod corn
Types of corn growth stages
Vegetative and Reproductive
VE
Emergance
V1
1st Leaf Collar
Growing point below soil
Tassel and ear shoots initiated
Seed rows set
V3
three leaf collars are very obvious
V12-16
kernals/ear (size of ear)
VT
Tassel (2-3 days before silking)
(pollen lives 24 hrs)
(pollen shed 1-2 wks)
R1
Silking (coming out of ear - every kernel develops a silk)
R2
Blister (10-14 dy) white on outside
R3
Milk (18-22 dy) inner fluid now milky (starch building)
R4
Dough (24-28 dy) inner fluid now thick/pasty
R5
Dent (35-42 dy) dented kernels
R6
Black layer (55-65 dy) dark layer on corn kernel indicates maturity for harvest
What can delay seed emergence?
soil compaction
cold soil
herbicide injury
fertilizer injury
Corn insect: small, bluegreen, pear shape with black tail pipes. Known for sucking sap and speckling on leaves/stems
Leaf aphid
Corn insect: yellow with black stripes. Known for chewing, plants lodge, destroy silks, poor pollination (attacks roots and silks)
Corn rootworm
Corn insect: chews edges, ragged leaves
Grasshopper
Corn insect: off white with grey line down back and two brown spots. Known for tunnels, shot holes in leaves (attacks stem)
European corn borer
Which growth stage represents the grain filling period in corn?
R 1-2
Durum Wheat
Used for pasta, low gluten
White Wheat
Used for rolls, tortillas
Hard white winter
Soft white winter
Soft Red Wheat
Used for pastries, cakes, crackers
Soft Red Winter (light brown with red tints)
Hard Red Wheat
Used for bread
Hard Red Winter
Hard Red Spring
The primary function claimed for bacterial non-protein inoculants used as silage additive is to:
increase fermentation rate and efficiency
Autotoxicity in alfalfa production is the result of toxins from
the alfalfa plant itself
Which harvest method for alfalfa has the highest field loss associated with harvesting?
field cured hay
Aflatoxins in corn can affect livestock by causing
liver damage
The odorless, colorless, heavy poisonous gas that can develop as a layer on the surface during filling of upright silos and causes lung damage is
Nitrogen dioxide
An indeterminate growth habit soybean ________.
continues to flower and grow vegetatively simultaneously
A higher number for the ADF and NDF forage test scores result in a ___________ RFV score and _________ quality.
lower, lower
Which statement represents the best quality corn silage?
- silage “cut” should be 1 to 1 1/2 inches
- harvest silage at the milk stage of corn kernels so yield is highest
- corn grain content contributes at least 50% of the energy
- silage in a bunker will pack best at 40-45% moisture
- corn grain content contributes at least 50% of the energy
What percentage of the flowers that develop on soybean plants can be expected to abort or fail to form pods?
60-75%
Which factor has the greatest influence on flower initiation in soybean?
temperature
Which fatty acid is considered the most desirable by the foot industry for cooking foods?
oleic (unsaturated)
List all oilseed crops:
flax
safflower
canola
sunflower
List all pulse crops:
dry pea
lentil
chickpea
Corn growth peaks at _____.
86 degrees Fahrenheit
