Agro 240 Exam 2
How much forage production and in what month would the production be expected with cool-season annuals seeded on April 1?
3 tons in mid-June
What soil pH would give alfalfa its best growth?
6.8
What nitrogen fertilizer rate in pounds per acre is recommended on annual warm-season forage grasses?
60
At what moisture percentage should corn be harvested for best preservation as silage?
65%
How much nitrogen fertilizer in pounds per acre is recommended on cool-season annuals to be used as spring forage?
70
How much stubble height after grazing should remain on perennial warm-season grasses before they go dormant for winter to ensure continued stand persistence?
8 inches
How much moisture is common in fresh forage?
80%
What is the most reliable method to preventing nutrient deficiencies in alfalfa?
A combination of soil and plant tissue analyses
Which is not true about managing alfalfa for both forage yield and quality?
A late September harvest is recommended with this strategy
What is the order of phases in silage preservation?
Aerobic phase, lactic acid produced, pH drops to 4.0, and stable phase
Which forage legume has poor tolerance to low soil fertility and is sensitive to acidic soil?
Alfalfa
Which is answer does not accurately describe autotoxicity?
Alfalfa seedlings affected by autotoxicity have more robust root growth and nutrient and water uptake.
Which is not true about phosphate and potash applications to alfalfa?
All of the Answers are true
Which of these sequential plantings and utilization strategies would provide a double forage crop on the same ground across one calendar year?
All of these
Which describes either coumarin or dicoumarol?
All of these answers are correct.
Why does alfalfa require well-drained soil?
All of these answers are correct.
Which is not a mode by which forage legume stands persist?
All of these are modes by which forage legume stands persist.
How can burning in early spring improve warm-season grass pastures?
All three of the other answers are correct.
Which statement is least true about nutrient needs during alfalfa establishment?
Application of nitrogen fertilizer at 125 lb/acre will enhance alfalfa establishment and nitrogen fixation.
Which answer accurately describes alfalfa autotoxicity?
Autotoxic compounds will be least if alfalfa is reseeded after a corn crop.
Which forage legume best tolerates soils with low fertility, low pH, and poor drainage?
Birdsfoot trefoil
Which forage legume does not have bloat potential?
Birdsfoot trefoil
Which forage legume stores only small amounts of reserves during summer and thus is dependent on residual leaf area and active axillary buds on stems for new growth after grazing?
Birdsfoot trefoil
Where do most dry matter losses during storage of large, round bales occur?
Bottom of bale
What is the name of the process that describes the crushing or crimping of stems to speed up moisture loss during production of hay?
Conditioning
Why is it recommended that warm-season grasses be established and managed in separate pastures than cool-season grasses?
Cool-season grasses initiate growth earlier in spring and are quite competitive with warm-season grasses
Which does not describe crownvetch?
Crownvetch grows rapidly and tolerates frequent grazing or cutting.
Which practice would not reduce milk fever in early-lactation cows fed alfalfa with high potassium concentrations?
Cut alfalfa as high as possible since potassium is concentrated in lower stems.
For which class of animals are nutrient needs greatest?
Dairy cows in their 1st trimester on
Which answer best describes alfalfa as opposed those of red clover?
Deep rooting perennial that undergoes contractile growth which places the crown 0.50 to 0.75 inch below soil.
When is evapotranspiration (water loss through transpiration and evaporation) greatest in alfalfa?
During summer growth before harvest
In which is dry matter density greatest?
large, rectangular bales
What is the recommended seeding date of annuals to be used for fall and early winter forage?
mid-July through August
What is the ideal time of seeding cool-season annuals to produce spring forage?
mid-March to mid-April
What is the recommended planting date for annual warm-season forage grasses?
mid-May to August
In which is long distance transport most efficient?
Large, rectangular bales
Which is least true about liming fields before seeding alfalfa?
Lime is more effective if it is applied to fields immediately before reseeding.
Which alfalfa nutrient deficiency does application of dolomitic limestone most alleviate?
Magnesium
Removal of which nutrient, and therefore, replacement through annual fertilization, should be of least concern with regard to alfalfa harvests?
Nitrogen
If the goal is to seed in the fall for early spring forage, which of these species should not be used?
Oat
What environmental factor decreases resistance of alfalfa to freezing stress the most?
Occurrence of warm fall weather and midwinter thaws.
Which nutrient when applied and incorporated into soil before planting improves alfalfa establishment and root development?
Phosphorus
Which nutrient does alfalfa generally need the most of in annual fertilization programs?
Potassium
Which nutrient maintains alfalfa yields, reduces susceptibility to certain diseases, and increases winter hardiness and stand survival?
Potassium
Which statement is not true about animal nutrient needs?
Protein and energy supplementation is required more often to meet needs of animals fed alfalfa.
Which forage legume does not spreads by either stolons or rhizomes?
Red clover
Which is not true about managing alfalfa for high forage quality?
Root carbohydrate levels will be maximized with this strategy of alfalfa management.
Which does not describe sainfoin?
Sainfoin tolerates close and continuous defoliation, but it may cause bloat.
Which describes forage preserved at a low pH due to production of organic acids by partial anaerobic fermentation of sugars?
Silage
Which form of silage storage minimizes loss of dry matter but is not well suited long-term?
Silage bag
Which form of silage storage results in the greatest loss of dry matter but has minimal construction cost?
Silage piles
Which cool-season grass species is not considered a bunchgrass?
Smooth Bromegrass
Which of these perennial grasses that may be used for summer pasture is not a warm-season grass?
Smooth Bromegrass
What is the benefit of conditioning during hay production?
Speeds up moisture loss
Which trait is least characteristic of orchardgrass?
Spreads in pastures with rhizomes
At what time of the year would application of nitrogen fertilizer have the greatest effect on rates of dry matter accumulation in cool-season grasses?
Spring
When does peak growth or dry matter accumulation occur in cool-season grasses in temperate regions?
Spring
Which part of a corn plant is least digestible to beef cows grazing residues during winter?
Stalk
Which of these annual warm-season grasses produce the most forage in the north central US?
Sudangrass
Which forage legume is a true biennial?
Sweetclover
What process disperses a hay crop across the entire field before baling?
Tedding
Which is not true about managing alfalfa for maximum stand persistence?
The last harvest date typically occurs within a window 6 weeks before a killing frost.
Which statement is not true about lime?
The more course the particle size, the more effective the lime.
Which is not true about alfalfa stands in rotation with corn?
The older the alfalfa stands get before rotation, the more nitrogen that would be credited upon plowdown.
Which is not a reason why legumes are important in pastures?
Their extensive, fibrous root system holds soil in place.
Which does not describe annual lespedezas?
They grow rapidly, flower, and produce seed in spring.
Which does not describe either white or yellow sweetclover?
They have a shallow root system that spreads along the soil surface and helps stands persist through time.
Which trait explains why warm-season grasses, when examined at similar stages of maturity, have less nutritive value (i.e., forage quality) than cool-season grasses?
They have more structural tissue (i.e., bundle sheath cells) in their leaves which reduces digestibility.
Which is not true about nitrogen needs of alfalfa?
Top-dressed nitrogen fertilizer applications will improve yields, quality, and vigor of alfalfa stands
Which cool-season crop works particularly well for making silage?
Triticale
At what developmental stage is forage quality maximum in alfalfa?
Vegetative
Which of these annual grasses should not be planted in late spring if the objective is to produce pasture, hay, or a silage crop during summer?
Wheat
Which situation constitutes the greatest alfalfa autotoxicity risk?
When there has been more than 1 ton of topgrowth incorporated or left on the soil surface
Which forage legume produces adventitious roots at nodes along its stolons?
White Clover
Which legume does not rely on crown formation as a persistence strategy?
White Clover
What trait least explains why smooth bromegrass is well-adapted in northern areas?
It tolerates frequent defoliation
At what developmental stage are perennial grasses such as smooth bromegrass most vulnerable to defoliation?
Elongation
Which of these cereals is not considered an annual cool-season forage?
Foxtail Millet
When are carbohydrates maximum in alfalfa crowns and roots?
Full Bloom
At what developmental stage is forage yield (mass) maximum in alfalfa?
Full flower
Which situation should a manager be most concerned about with regard to prussic acid poisoning of animals?
Grazing of young forage sorghum leaves and stems that were recently frosted.
What management factor would decrease resistance of alfalfa to freezing stress the most?
Harvesting the last cut of alfalfa within 6 weeks of a killing frost.
What is forage preserved by field drying to moisture levels low enough to prevent microbial activity and spoilage?
Hay
Which does not describe nitrogen fixation in forage legumes?
High rates of nitrogen fertilizer will enhance nitrogen fixation by legumes.
Which does not describe kura clover?
It is a short-lived perennial that does not tolerate close and frequent defoliation.
How is fall dormancy determined on alfalfa varieties?
It is measured by determining how tall alfalfa grows following a September 1st cutting.
Which trait is not characteristic of tall fescue?
It is the most winter hardy cool-season grass.
What advantage does big bluestem have on switchgrass for pasture?
It matures later than switchgrass and better fits complimentary systems with cool-season grass pastures.
Which does not describe cicer milkvetch?
It tolerates close and repeated defoliation.
