Grass & Forage Production MCQ1 Samples Flashcards
Sample Questions
What is the % N in the atmosphere?
78%
What type of plant has the ability to fix atmospheric N?
Legumes
What is N gas converted to in the root nodules of the plant?
Ammonia (NHa)
What form of nitrogen do the bacteria provide for the legume plant?
Ammonium
What is the benefit of the symbiotic relationship for the bacteria?
The legume plant provides the bacteria with CHO for energy
What is plant growth in legumes directly related to?
Rate of Na fixation
Which of the following will have an effect on the rate of N2 fixation?
- Drought
- Low temperature
- Nutrient availability
- Disease/weed infestation
What is the fixation rate of red clover?
200kgN/ha/yr
What are characteristics of red clover plants?
- short life span
- Erect growth habit
- Good winter hardiness
What is the function of PPO (polyphenol oxidase) ?
Inhibition of post harvest proteolysis by inhibiting activity of the plants proteases in the silo.
What are some of the disadvantages of red clover?
- unsuitable to intensive grazing
- Yield declines markedly over time
- Can lead to bloat in ruminants
When sowing a red clover, PRG mix, what should the ratio in the seed mix be?
3:1
Why is it important to encourage stolon growth throughout the year?
To ensure high survival rates over the winter
How much white clover should be included per hectare?
4.63kg/ha
How much grass is grown per ha?
- 14kg/ha for a Diploid
- 16kg/ha for a tetraploid
If a plant has caespitose growth habit, what does this mean?
Grows in tufts
What type of a growth habit does white clover have?
Stoloniferous
What is the usual inclusion of white clover in a seed mixture?
1kg/ha
How much red clover would you usually find in a permanent pasture in Ireland?
Rarely 5%
For high clover establishment, how much will need to be incorporated in the seed mix?
3-4kg/ha
In relation to white clover cultivars, what are characteristics of varieties with medium sized leaves?
- moderate stolon density
- suitable for frequent, close grazing
What are characteristics of white clover varieties with large leaves?
- longer petioles & fewer stolons
- suitable for lax, rotational grazing
When does white clover have a lower leaf photosynthesis rate than grasses?
Spring
When does white clover have a higher photosynthesis rate than grasses?
Summer
When does white clover rebuild its stolon/root reserves?
Autumn
Over the summer period, which animals should be grazed on white clover ground?
Priority stock
What is the standard length of recovery period over the winter for white clover swards?
100-150 days
What grazing technique should be employed on white clover ground in spring to ensure grazing quality for later in the season?
Frequent rotational or continuous grazing
What would the crude protein content of a white clover/PRG sward be?
21%
What are some of the advantages of white clover in the sward?
- Intakes are increased
- Mineral contents are increased
What are some of the disadvantages of using clover?
- Issues with persistence
- Can lead to increased bloat incidence
- Dock control becomes more difficult
What are the 3 methods of increasing white clover content of the sward?
- direct reseeding
- oversowing
- promoting the existing sward
Clover is introduced to an existing sward & conditions are then optimised for the establishment of clover in the sward. This is known as:
- oversowing
When should oversowing occur?
After silage or a tight grazing in late May/ early June.
What fertiliser should be applied when oversowing white clover?
0:7:30
What is the best stage to kill docks?
100 days
How many seeds does an adult dock produce per year?
60,000
What are some of the characteristics of soils that are favourable to clover production?
- Fertile
- High moisture in summer
- Warm
- High lime status
- Med-free draining
What is the normal freshweight intake level of a 600kg lactating dairy cow?
100-125 kg/day
Utilisation of 1 tonne extra of grass can result in an increase in profitability by how much on a dairy and dry stock farms respectively?
€181/ha - dairy
€105/ha - dry stock
In a high sward density, how many tillers will be present?
30,000/m^2
Undergrazing will:
- Improve individual animal performance
- Reduce the output per unit area
- Reduce sward quality
Overgrazing will:
- Reduce the persistency of the sward
- Reduce yield
- Reduce individual animal performance
How much time should animals spend in each paddock in a rotational grazing system?
4-5 days at most
What height should grass be cut to when measuring using a quadrat & shears?
4cm
During periods of continous rain you should estimate the grass DM as?
12-15%
During the first rotation in the spring or in periods of drier weather, what should you estimate grass DM as?
18-19%
During drought conditions, what should you estimate grass DM as?
22-23%
Post grazing sward height can be an indication of:
- Residual grass yield
- Pasture quality
- Allocation/day
A post-sward grazing height of less than 3.5cm would indicate what?
overgrazing
A post grazing sward height of 3.5-4cm represents a post grazing residual of?
0-50kg DM/ha
What is organic matter digestibility used to calculate?
Energy content/ UFL / UFV value
What is the crude protein content of grazed grass?
180-250 g/kg DM
What is the neutral detergent fibre (NDF) content of grazed grass?
350-400g/kg DM
ADF = 180-250 g/kg DM
What is the acid detergent fibre (ADF) content of grazed grass?
180-250 g/kg DM
NDF= 350-400g/kg DM
What is the expected DMD, UFL content & crude protein content of Autumn grass?
- 80% + DMD
- 0.85-0.90 UFL/kg DM
- 21-23% Crude protein
Grazing swards with medium pre-grazing yields instead of high pre-grazing yields should result in:
- Higher grass utilisation
- Better sward quality
- Higher leaf content
In the perennial ryegrass plant, what is the standard length of the true stem?
3cm
