Lecture 3 Flashcards
Nationally what % of land is reseeded per annum?
2-3%
Regular reseeding tool place on a **% of participants farms, **% reseed in frequently, **% never reseed
(Dairy)
-50%
-25%
-25%
Of those that reseed
-50% of participants reseed **ha/year
-20% reseed **ha/year
-2-4 ha/year
-<2ha/year
**% of participants prioritise reseeding the grazing area
75%
Whats the benefits of reseeding? (2)
-Increased spring/autumn DM production
-Improved sward quality
Whats the preferred time to reseed?
-What % in preferred time?
-What % in other time?
-What % in combination?
Autumn - 66% of survey participants
-13% in spring
-21% combination
On dairy platforms what % of participants soil test area before being reseeded?
-50%
-what % use plough
-what % use minimum cultivation
-what % use a combination of both
-50% plough
-20% use minimum cultivation
-30% use combination of both
When seeding:
-what % use fertiliser spreader
-what % use seed barrow/drill?
-40%
-35%
What % of farms used post emergence spray?
-50%
What % of participants have swards affected by docks?
-85%
Whats docks directly linked to?
Directly linked to low usage of post emergence spray and timing of reseeding
Why do we reseed?
-Because Permanent Grassland is composed to grass inferior to PRG
-Its important to have vigour’s sward as we need grass in early spring and late autumn
Definition: Vigorous Sward:
a sward that can grow out of season, have a high tiller density and provide adequate grass production when required
* Medium term investment = management objectives of the farm
If there is a lot of sward patchy and bare soil on your farm what happens? (2)
1-Productivity decreases due to extra weed grasses
2- Decreased root structure - soil is more easily damages
What is the aim for grass area on your farm?
Thick , leafy sward with plenty of young shoots
– A thin open sward will have a low yield of grass (low DM/h)
– A small % can be tolerated for tetraploid varieties
A thin open sward will have :
Low yield of grass (low DM/ha)
How long does it take silage swards to deteriorate ?
any why?
-Relatively short time
-Because it becomes more open
-Unsown species creep in ( creeping bentgrass/ Yorkshire fog)
What % ryegrass do you aim for?
-How much tonne/DM /Ha/Year vs PP
-How much more responsive is it to available nutrients?
-Losses of us to how much/ha in grass production?
-When is ryegrass less persistent ?
-60%
-+3 tonne DM/Ha/year vs PP
-25% more responsive to available nutrients
-Losses of up to €300/ha grass production
-Less persistent under silage harvesting (5-6 years)
What is detrimental to ryegrass?
-Late harvesting
-Low cutting heights
-Poor soil fertility
Where are grass weeds abundant?
Long term pastures
Are unknown species productive?
Alot less productive than PRG
-Creeping bent has only a **% production potential of PRG
-Whats the DMD ?
-75% Production Potential of PRG
-Lower DMD by 8 units
What is used to control weeds ?
Herbicides- but under certain conditions it may be necessary to reseed a sward
Grass production per month in a sward containing 15% PRG and 100% PRG - what does it show?
-100% PRG has higher tonnes DM/ha
-There is an extra +2.7 tonnes DM/ha
Where do you see benefits of increased % of PRG?
-What happens if pastures have less than 60% PRG?
In February:
-Pastures with less than 60% PRG will not support early or late grazing systems as insufficient grass is being produced.
6 advantages of reseeding :
1- Increased the productivity of swards- with better out of season production
2- Allow a higher level of mid - season regrowth
3-Provide swards which respond better to applied N (25%)***
4-Imporved grass quality
5-Reduce silage requirements
6-Increase carrying capacity
What is the benefits of Grazing newly reseeded sward: (4)
-More grass grown (10-20%) > productive tillers in the seed mix
-Longer growing season
-Rapid re-growth - more productive cultivars
-Higher palatability/digestibility , increased sugar/WSC
What are the benefits of newly reseed sward for silage ? (4)
-Higher quality (6+ units DMD)
-Easier to preserve (higher sugar content)
-Faster recovery
-Consistently higher yields
When and why to reseed?
Early Spring-Autumn
* Low production, regrowth, response to nutrients
* High percentage of open ground
* Low percentage of PRG
* High percentage of undesirable grasses/weeds
* Low percentage of clover
* Change of pasture species (+ other grasses/ legumes/ herbs)
* Part of rotation/ winter forage crops
What are the objectives of reseeding ? (4)
1-Increase the overall productivity of the farm
➢ Increase the carrying capacity (stocking rate)
➢ Allow higher animal output – 8% higher milk output per hectare relative to permanent pasture
➢ Increase grass quality
2-Are more responsive to fertiliser
3-Increase grass utilisation
4-Allow white clover/perennial ryegrass pastures to establish
Whats the target turnout time to get reseed back into production?
Should be 60 days (8-9 weeks)
How long does it take a sward to fully establish?
11 months
Autumn reseeding:
1-What sort of establishment can you get?
2-Degrees for grass seedlings and clover seedlings?
3-What is required for tillering during winter?
4-What can be an issue for Autumn reseeding (2 anwsers)?
1- you can get poor establishment
2- 6 degrees for grass, 8 degrees for clover
3- Early sowing is required for tillering during winter
4-Frit-fly attack
4- There is little-to-no time to apply post emergence herbicides**
1-For Autumn reseeding when is the most suitable month for reseeding?
2-What does reseeding early allow?
3-If clover is included what needs to be done?
4-What is the establishment like?
5-What is the soil temperature threshold like?
1- August
2- Allows seedlings to commence tillering before the onset of winter
3-Reseeding dates needs to be earlier
4-Longer establishment (8-10 vs 4-6 weeks)
5-Higher threshold soil temperature (8 degrees vs 6 degrees)
Whats the advantages of reseeding in spring: (4)
1- Reduced risk of low temps and frost damage
2- Risk of drought and SMD is not a factor
3- Opportunity to graze the sward that helps to promote tillering
4- Application of post emergence spray
Whats the disadvantages to reseeding in spring (3)
1- Increased damaged as cows are reaching peak lactation
2- Large areas of grassland are closed off for silage production
3- Labour
Why do you soil test before reseeding? (5)
1- Shows fertility and pH of soil
2- Correct fertiliser and lime levels
3- Work fertiliser into the seedbed
4- Lime application when not ploughing
5- Developing seedlings are very sensitive to pH
Definition: Soil Fertility
The quality of a soil that enables it to provide nutrients in adequate amounts and in proper balance for the growth of specific plants or crops
List 3 Essential Nutrients in Soil :
1-Phosphorus
2-Potassium
3-Lime
Why is Phosphorus essential ?(2)
1- Essential for root development and sward establishment
2- P is immobile in the soil
Why is Potassium essential? (3)
1- Controls the loss of water by transpiration through the leaf pores
2-Sugar formulation and root development
3-Transport of metabolites and nutrients within the plant
Why is lime essential? (3)
-Optimum pH of 6.3 for grassland
-If pH is low there will be poor establishment
-Trash can release organic acids (OA’s) as it breaks down - inhibit germination
Reseeding methods/ systems:
1- Plough , till, sow
2-Alternatives to conventional: Disking, one-pass, direct drilling
3- Shallow cultivation (Disking) (Disk Harrow)
4- Minimum Cultivation (One-pass)
5- Direct drilling/stitching in /overshowing
What does the Plough , Till, Sow system include:
(Steps)
What is a con of doing this?
- Expensive
- Bury trash, competitors and pests
- Provides the basis for a level sound
seedbed - fine, firm, level - Ploughing may not always be possible
- Shallow ploughing (c.15cm)
- Steps: Spray off old
sward/Plough/Spread Lime/Land
Level/ Spread Fertiliser/One pass
with Seed/Roll
If you are using the conventional Plough, till, sow what steps are involved? (9)
-Involves ploughing
* Old sward is sprayed off – glyphosate
* Can be burnt off before harvesting (10 days)/ grazing (5-7 days)
* Plough <15cm
* Apply lime
* Land level
* Apply fertilizer
* Sow the seed
* Roll > important not to bury seeds***
Whats important about your seedbed?
Needs to be a firm , fine, level seedbed
What are the alternative methods to conventional ? (3)
- Discing
- One pass
- Direct drilling
➢Stitching in
➢Undersowing
➢Oversowing
What can deep cultivation do?
-Bury Nutrients
What is the benefits of shallow cultivation?
keeps nutrients close to the surface <where the developing roots will be
What is the one pass system? for shallow cultivation ?
Whats the Aim?
-2-3 passes of disc harrow in angled directions, land level, lime & fertiliser, one pass with seed, roll
* Aim: produce a fine, firm, level seedbed
What does a firm seedbed do?
Conserves moisture
What does a loose seedbed allow?
Moisture to evaporate easily inhibiting germination
Benefits of minimum cultivation:
-Introduction of PRG without ploughing (reduced cost)
-Some areas are too stony to plough, topography
-One – pass: lime & fertiliser, one pass with rotary power harrow
with seed, roll
* Spray off as trash will not be buried by ploughing
* Sward is then grazed / cut to a low level
* Apply 2.5 t lime/ha to neutralize the OAs produced by the trash
before sowing**
* More weeds may occur**
Whats the benefits of minimum cultivation ?
Soil disturbance is at a minimum- support traffic post establishment
Young seedlings can make use of the fertile soil at ground level, as cultivation is shallow
Machine , accuracy, setting, speed- is very important
If the existing sward is sprayed off then you can :
Direct drill
Existing sward is sprayed off (round - up)
If the existing sward remains then you can:
Stich in/ Oversow
Sward is supressed in some cases (Reglone) to reduce competition.
Important to keep the existing sward supressed to allow the new seedlings develop
What can direct drilling graze with?
What do you deposit the grass slots in?
When is it most successful to direct drill?
- Can graze with weanlings or sheep
- Deposit the grass in slots 2
to 5apart - Most successful after a heavy cut of silage – as the
old sward will be much more open
List Cultivation Techniques: (4)
-Ploughing
-Disking
-One-pass
-Direct Drill
What is a dont with ploughing:
dont plough too deep (>15cm) cloddy , loose seedbed
What is a do with ploughing?
Shallow plough- develop a fine firm level seedbed
Whats a dont with dicsing?
Drive with fast forward speed- rough, uneven seedbed
Whats a do with disking ?
graze tight 2-3 passes in angles directions - apply lime
Whats a dont with one-pass system?
Drive with fast forward speed- rough, patchy, seedbed
Whats a do with one-pass system?
Graze tight , apply lime, slow forward speed at cultivation
Whats a dont with direct drill?
Trashy seedbed- no seed/soil contact. Use when ground it hard and dry
Whats a do with direct drill?
Graze tight apply lime and slug pellets , wait for moist ground conditions (slight cut in ground)
What is the only thing that isn’t sprayed off with glyphosate before reseeding?
Chemical application of diquat to suppress existing sward (DIQ)
If reseeding is carried out correctly is there a difference in reseeding methods?
No there’s no difference
When choosing a seed mixture for reseeding what are the seed mixture questions you need to ask yourself?
- Why are you reseeding?
Open ground/ old grasses/ return from tillage etc. - What sort of sward do you want?
Silage sward/ early grazing/ low N etc. - Are you going to include clover in the mix?
If yes, then what varieties.
Whats the objective of choosing a seed mixture?
to combine grasses of differing traits to obtain good overall DM production especially in the Spring/ Autumn periods
When choosing a seed mixture what do you need to ensure : (9)
- Good overall DM production (spring/autumn)
- High sward density
- Suitable to a range of enterprises
- Heading date
- WSC/DMD
- Persistency
- Combination of grasses of different traits
- 3 to 4 varieties (min 3kg each)
- 35 kg/ha (14kg/ac)
What sort of leaves are you looking for for dairy / beef animals and sheep?
- DAFM NRL simulated grazing – PPI value €€€
- Seasonal growth
- High DMD
- Medium leaf WC for dairy/beef and small leaf
WC for sheep
When choosing a silage mix what are you looking for?(5)
- DAFM NRL high yield varieties especially 1st cut
- Heading date will have a big impact – small range
- Intermediate varieties for 2-cut system (40%)
- Reduced intermediates for 1-cut
- Max 40% tetraploids – need to be persistent
If you are choosing a mix for wetlands, what are you looking for?
- Late heading varieties preferably diploid
varieties should dominate - 15-20% highly persistent tetraploid
- Low growth habit
- High tiller density
- Good mid season grass quality
If you are choosing a mix for drylands what are you looking for?
- Late heading varieties play a major role
- Some excellent late tetraploids with high
spring grass growth - Combined with high density high digestibility
diploids - Tetraploids > 35 - 50%
List the 4 important stages of sward establishment:
- Germination
- Emergence
- Root development
- Tillering
Definition: Germination
➢ Re-growth of a seed (embryo) after a period of dormancy if environmental
conditions are suitable
➢ Growth of the seed into a new plant is fueled by using the food stored
inside the seed
Definition : Emergence
➢ Shoots to emerge above ground
Definition: Root emergence
➢ Access own feed supply from the soil
Definition: Tillering
➢ Development of a plant that is similar to the parent plant from a bud that
is formed as each new leaf appears in the leaf axial or where the leaf joins
the stem
What sort of germination rate does PRG seeds have ?
PRG seeds have a very quick germination rate, so once the temperatures are right, there is water, oxygen and seed-soil contact,
the seeds should germinate within 5 to 10 days
Seed tissues (7)
- Embryo – contains the tissues that develop into the new
seedling plant - Endosperm – energy reserve
- Cotyledon – barrier between the embryo and endosperm
- Plumule – primary shoot
- Radicle – primary root***
- Coleorhiza – protective sheath for the radicle
- Coleoptile – protective sheath for the plumule
Whats germination dependent on?
What does the 1st stage involve ?
– Viable seed
– Correct environment
– Decay of seed coat
- First stage involves the passive uptake of water - 12 to 24 hrs **
- Cells surrounding the endosperm release enzymes that break down the starch to sugars
What happens to the sugars when seed is germinating?
- Sugars absorbed by the cotyledon and pass to the embryo
- These supply the energy and raw materials
necessary for the growth of the plumule and
radicle
in germination what appears?
Coleorhiza and Radicle Appear
What is the Coleorhiza?
Protective covering for the primary root and emerges first
-Radicle follows soon after
-2 pairs of lateral roots follow (rootlets)
What does the seed provide foe the shoots to emerge above ground?
Sufficient energy
If seeds are buried too deep what happens ?
Whats a sufficient level to bury seeds?
- If buried too deeply, seeds will not have
sufficient energy to emerge – seedlings die - 1-2cm is sufficient
Germination rate % of PRG and White clover when sown at 2cm depth:
PRG- 94%
White Clover- 63%
What do seedlings depend on for energy until the roots gain their own feed supply from the soil?
-There own energy reserves
What is essential for good root development?
Rapid and good seed soil contact =FIRM, FINE, LEVEL SEEDBED
When is the vegetative stage for seeds?
Germination- Tillering
What is tillering of a plant similar to?
Similar to the parent plant from a bud that is formed as each new leaf appears in the leaf axel or where the leaf joins the stem
Definition: Tillering
development of a plant that is similar to the parent plant from a bud that is formed as each new leaf appears in the leaf axial or where the leaf joins the stem
Stages of tillering:
How many tillers/plant :
-Parent plant - Primary tillers- Secondary tillers
-4-5 tillers/plant
Whats PRG’s 2nd advantage when it comes to tillering ?
-When do tillers normally develop?
-Whats the seeding rate ?
-What influences tillering?
-What should you use on PRG after sowing?
-What do you need to make sure in terms of grazing?
-What does too soon silage cut lead to?
- Main shoot appears above ground level – leaf
formation should proceed rapidly - At 3-4 leaf stage, a tiller normally develops in
the axial of the first leaf - Seeding rate of 1000 seeds/m2 > 10,000 to
15,000 tillers/m2 - Influenced by light and nitrogen
- Nitrogeous fertiliser at sowing and after grazing
- Must be grazed before closed off for silage
- Too soon silage cut > leads to open swards/
weeds
What happens in the 3-4 leaf stage?
A tiller develops in the axial of the first leaf
What does tillering allow the PRG plant to do?
Fill a paddock , increase its density and regenerate itself
List 3 factors that affect litter production:
- Defoliation
- Nitrogen level
- Shading
What is the number of tillers dependent on?
When is production of new tillers peaks?
When are there tiller deaths?
When is there the greatest number of tillers?
Management inputs- difficult to predict the number of tillers
Generally :
* Production of new tillers peaks in March/ April and again June/ July
* Tiller deaths greatest in May/ June
* Tiller no.s greatest in March-May and July- August
What does tillering help reduce?
To encourage tillering what should you do?(4)
Tillering helps reduce the space available for
weeds
* To encourage tillering:
➢ Apply nitrogen 3-4 weeks after sowing
➢ Graze the reseed when it is about 6-7 cm high
➢ Continue to graze the reseed in the first year of
production
➢ Avoid cutting the new reseed for silage in the first
year (if possible)
What is PRG vegetative structure like?
How long?
What sort of stem?
What sort of growth habit?
- Growing tip is just above ground level throughout the vegetative phase
- Very short true stem - 3cm
- Pseudo stem that consists of leaf sheaths
- Good grazing management does not damage the growing point
- Tufted growth habit
How often does a new leaf appear for PRG?
Every 11 days (April-September)
How many live leaves of PRG is there at any 1 time ?
3 live leaves
Whats the average leaf longevity of PRG?
33 days
Whats the most important variable affecting leaf growth?
Light and temperature
Whats the story with PRG tillering?
Freely tillering***
Tiller density is high in grazing and lower in a cutting regime
3 leaf per tiller - 3 leaf grazing
In spring 1st leaf relatively small increase in size until the maximum reached
in autumn the opposite evolution is observed
What sort of root system foes PRG have?
What dept does it reach?
Fibrous root system
– Reach 1 - 1.5 m deep
– Majority in the first 15 cm
– Highly branched
– Root hairs absorb water from the soil
When does root growth start in PRG?
When does growth slow?
How long is the root lifetime?
1-2 months before leaves
Slows in summer and starts back in autumn
Root lifetime 2-3 months during growing season
Whats the primary organ for photosynthesis and transpiration in PRG leaves?
Leaves
How does Photosynthesis work?
Light energy > chlorophyll of the leaf mesophyll cells
What does leaves have for vascular system?
Veins
What is in the Cell wall of grass?
NDF
What is in the cell content of grass?
-Sugars
-Oil
-Protein
-Minerals
-Other
What are essential metabolic processes that occur within the plant ? (4)
-Photosynthesis(Chloroplast)
2-Respiration(Cytoplasm and mitochondria)
3-Biological Nitrogen Fixation(Legumes)
4-Transpiration (Stomata)
- Use this energy for ALL other metabolic processes
- Directly relates to yield
-What is this process called?
Photosynthesis (Chloroplasts )
Post establish management :
For the first 8 weeks what’s the DONTS
Graze at high cover >1200kg DM/Ha
Don’t Harvest for silage
Post establish management :
For the first 8 weeks what’s the DO’s
Spray weeds before grazing
Graze when grass is at stage 2 leaf stage
N and P and K
Slug Pellets if required
Post establish management :
Second grazing onwards what’s the DONTS
Allow high covers to develop
Graze in really dry or wet conditions
Post establish management :
Second grazing onwards what’s the DO’s
Graze at 1000-1400 kg DM/Ha (6-7cm)
Respray weeds if necessary
Post establish management :
Autumn what’s the DONTS
Overgraze or poach
Apply excessive slurry
Post establish management :
Second grazing onwards what’s the DO’s
Keep grazing at 1200kg DM/ha
Graze off well before first winter (<4cm)
Light slurry application
Post establish management :
Second year what’s the DONTS
Overgraze or poach
Post establish management :
Second year what’s the DO’s
Ensure the new sward receives adequate nitrogen
Monitor soil P and K status
All the benefits of reseeding can be lost after sowing due to :
- Poor soil fertility - poor establishment and tillering
- Grazing at high grass covers or cutting for silage – tiller/plant death
- Weed infestation (especially docks) – loss of ground cover
- Pest attack (frit fly, leatherjackets and slugs) – tiller/plant death
- Poaching – don’t damage new reseeds
For weed control when is the best time to spray?
What are the most popular weeds?
When is it essential to control certain weeds?
What dictates choice of herbicide?
-Best control 2-3 leaf stage
* Docks, thistles & chickweed most prevalent
* Essential to control docks and chickweed @ seedling
stage
* White clover inclusion will dictate choice of herbicide
What are the 3 pests
What so you need to comply with?
- Frit fly
- Leatherjackets
- Slugs
➢ Compliance with Sustainable Use Directive (SUD)required
When is fruit fly most common?
What happens?
What is the control:
- Most common in autumn after a dry summer
- Larvae are born in the centre shoot which will
turn yellow and die - Control: ➢ Leaving ground unsown after ploughing (6weeks +)
➢ Suitable insecticide
Where is Leather jackets most commonly found:
What does it result in?
What is important to do after sowing?
When are you at highest risk for these?
- Most common in wetter or heavier soils
- Results in dead plants on soil surface
- Rolling important after sowing (firm seedbed)
- Up to the time of tillering is the highest risk
time
Where are slugs most commonly found?
What attracts them?
What do they do?
- Common in wet weather/ damp fields
- High levels of trash on the seedbed
➢ Direct drilling – slit in ground - Shred leaves
What do you watch out for to ensure pests arent in your ground?
- Patchy establishment
- Mild damp autumns
- Must roll the reseed
- Weed infestation
Whats the cost of reseeding in 2023? per ac?
€40/ac
