Grass Questions MCQ1 Flashcards
1
Q
Grass growth curve in 2018
A
- In Spring time it was well below average due to snow storms
- Above average increase in May
- Summer months there was a drought where grass growth dropped to single figures for 6 weeks
- Resulted in a deficit of 1.5 t DM/ha grown
2
Q
Grass land accounts for what percentage of the total land area globally?
A
25%
3
Q
Grass land accounts for what percentage of the total land area globally without permenant ice cover?
A
40%
4
Q
What percentage does Europe have in the worlds total grassland area?
A
13%
5
Q
What continent does grassland not exist?
A
Antartica
6
Q
Different grasslands around the world that all have grasses as their naturally dominant vegetation?
A
- The Praries in north America
- Stepps in Asia
- Pampas in South America
- Savannas in South Africa
7
Q
What percentage of the total ice free land surface is managed intensely?
A
Around 10%
8
Q
How much does Intensive and semi-intensive grasslands represent in the total land use?
A
- 2%
-16% used in Savannahs and Shrublands - 29% used in extensive pasture
9
Q
Grassland definition
A
Refers to a plant community in which grasses (graminaea) are usually the dominant species, with forbs (herbaceous dicotyledonous species including legumes) present in variable amounts, but trees and shrubs are absent or only present in minor constituents
10
Q
Role of Grasslands
A
- Forage Production
- Ecosystem Production: Biodiversity preservation, carbon storage, erosion control, and water and nutrient cycling regulation
- Landscape and amenity value
- Converting human inedible feed to high quality nutrients
- Significant contribution to global food supplies
11
Q
When was ice age?
A
- 20,000 years ago
- No vegetation of animal life
12
Q
What happened 15-13,000 years ago?
A
- Ireland had a species rich grassland
- The plants and grasses began to grow after the ice melted
13
Q
What was Ireland mainly consisting of 5500 years ago
A
Forest
14
Q
What was Ireland mainly consisting of 4000 years ago?
A
Grasslands
15
Q
How old is treeless pasture?
A
- About 300 years old
- 1700’s
16
Q
Grassland Development
A
- Grazing
- Topography
- Soil
- Climate
17
Q
How many hectares were grassland in Ireland in 2010?
A
- 4,215,000 hectares
18
Q
Clifton Park Mixture for uplands Ulster in the early 1990’s?
A
- Grass, herbs and legumes
- 13 plant species
19
Q
What percentage of the total land use in Ireland in 2021 accounts for grassland?
A
59%
20
Q
Improved Grassland in Ireland
A
Intensively managed or highly modified agricultural grassland that has been reseeded and/or regularly fertilised with chemical fertilisers
21
Q
What is the largest land use category?
A
Grassland
22
Q
Landuse Catagories
A
- Grassland
- Wetlands
- Cropland
- Forest
- Settlement
- Other land
23
Q
What is the total land area of Ireland?
A
6.9 million hectares
24
Q
How much Agricultural Area Used in Ireland in 2016?
A
- 4.9 million hectares
- Includes 427,800 hectares of commonage
25
What percentage of Irish Agricultural Land area is used for grassland?
92%
26
What percentage of the global land areas does grassland account for without permenanat ice cover?
40%
27
What percentage of the worlds total grassland area is in Europe?
13%
28
How much does grassland account for of the total land use in Ireland?
59%
29
What percentage of the Irish agricultural land area is grassland?
92%
30
Who has a higher proportion of land under grassland? Ireland, the UK, or European Countries?
- Ireland
- This attribute is a competitive advantage to Irish ruminant production systems
31
What percentage of farms were dairying in 2020?
-57.5%
32
What percentage of farms were mixed crops and livestock in 2020?
48.9%
33
What percentage of farms were tillage in 2020?
2.9%
34
What percentage of farms were over 50 hectares in 2020?
More than 40%
35
What percentage of farms were beef in 2020?
47.1%
36
What percentage of farms were sheep farms in 2020?
57%
37
What percentage of farms were lass than 20 hectares in 2020?
45%
38
What percentage of farmers were female in 2010?
12.4%
39
What percentage of farmers were female in 2020?
13.4%
40
Is there more farmers under 45 or over 65?
- Over 65
- In 2020, almost one third of all farm holders were aged 65
41
Factors affecting land use?
- Soil
- Topography
- Climate
- Agro-ecological zones
42
What are the main soil types?
- Brown Earth, brown Podzolics and Luvisols
- Lighter sandier well drained soils
- Alluvials, surface water and groundwater gleys
43
Brown Earths, Brown Podzolics and Luvisols
- More intensive and productive soils
- Moderately to well drained
- Good nutrient retention capacity
44
Lighter sandier well drained soils
- Responsive to nitrogen (N) fertiliser inputs
- Greater risk for N-leaching in wetter periods
45
Alluvials, surface water and groundwater gleys
- Less productive
- Can release N from Organic Matter
- Production of Nitrous Oxide (N2O) due to denitrification under anaerobic conditions
46
What is the basis of a resilient grassland system?
The maintenance of proper soil physical, chemical and biological properties
47
What are the 11 great soil groups?
Sandstone:
- Alluvium
- Groundwater Gley
- Lithosol
- Blanket Peat
- Podzol
- Brown Podzolic
- Brown Earth
Limestone:
- Surface Water Gley
- Basin Peat
- Luvisol
- Rendzina
48
Why does Ireland have so much land dedicated to growing grass?
- Temperature
- Sunshine/Radiation
- Sunshine hours
- Rainfall
- Frost
- Topography
49
Average temperature in Ireland
- 9 degrees in the north east and 10.5 degrees in the southwest
- Gulf stream has a warming effect in the winter and a cooling effect in the summer
50
How much longer are soil temperatures more favorable for grass growth in the south and southwest compared to the midlands?
11 weeks longer per year
51
Why is knowing the soil temperature important?
To know when the plant is growing so that N fertilisers can be applied to promote growth at the opportune time
52
Where is the sunniest place in the world and how many hours of sunshine do they get per year?
- Sahara Desert
- 4300 hours per year
53
How many hours of sunshine does Ireland normally get each year?
- Between 1400 and 1700 hours
- 36% of the Sahara Desert
54
How much are the Irish skies completely covered by clouds for?
More than 50% of the time
55
Photosynthesis Equation
CO2 + H20 -> C6H12O6 + O2
56
Where is the rainfall highest in Ireland?
- Western Hills
- > 3000 mm
57
Where is rainfall the lowest in Ireland?
- The east coast
- <1000mm of rain
58
What has an effect on soil development?
The intensity and varability in rainfall
59
How many days is it raining in the south east of Ireland?
less than 200 days
60
How many days is it raining in the west of Ireland?
270 days
61
How many days a year does frost occur in the west?
< 25 days
62
How many days a year does frost occur in the interior of the country?
More than 50 days
63
What is topography?
- It governs the position of a soil on the landscape = water runoff and drainage
- The amount of water that moves through a soil is less on the steep than on gentle slopes and low-lying and flat areas generally receive more water
- Soils of poor drainage, however, may be found on good slopes where the lower soil horizons or parent material are of poor permeability, leading to reduced water movement
64
What is permeability?
The ability of a soil to allow water to pass through
65
Factors affecting land use and grass growth?
1. Soil Type
2. Global Location
3. Temperature
4. Rainfall
5. Topography
66
What is the variation in annual profitability between free draining and badly draining soils?
Up to 28,000 euros
67
What soil is good for dairy cows?
- Dry loamy soil
- Mainly found in the South of Ireland
- 2/3 of dairy cows are in Munster
68
What is the average annual grass production in t DM/ha in Ireland?
12.3 tonne/ha
69
What target should dairy farmers set to increase the grass utilisation?
10 tonnes/ha
70
When is the aim for Ireland to be carbon neutral for?
2050
71
What percentage is Irish agriculture accounted for as part of the national GHG emissions in 2021?
37.5%
72
What is the aim for the reduction of green house gases in Ireland for 2030?
25%
73
What is the aim to improve water quality in Ireland?
- 50% reduction in nutrient losses
- 20% reduction in the use of fertilisers
74
What percentage of the total farmed area is for grassland?
Over 90%
75
How many days of the year are livestock entirely dependent on grass?
200-235 days of the year
76
What were Irish dairy exports worth in 2021?
Over 5 billion euros
77
What is Ireland GHG footprint in cow milk production?
1 kg CO2 eq/kg FPCM
78
Approximately what percentage of our emissions from agriculture are associated with the dairy sector?
40%
79
What percentage does the dairy sector use of all chemical nitrogen?
50%
80
What latitude is Ireland on?
Between 51 and 55 degrees north
81
What climate does Ireland have?
Temperate climate
82
What is the prevailing wind in Ireland?
Westerly winds
Ocean and gulf stream
83
What is Irelands annual rainfall?
Between 750-1450mm
84
What is Irelands water stress index?
0
84
When is there a surplus of grass?
April to August
84
How much grass is produced on the shoulders of the year?
- 40 kg DM/ha/day
- April and September
84
When does grass start growing?
February/March
84
When does grass growth fall off?
June
85
86
When does grass growth peak for the second time?
August
86
When does grass growth stop?
November
87
What is the annual DM yield?
11 to 15 t/ha
88
How long is the growing season for?
8-11 months
89
When does the grazing season star?
11th of February to the 20th April
90
What is the cost of production of grazed grass?
47 euros
90
How long does the grazing season last?
200-300+ days
91
Pasture Definition
An area of land in which grass or other plants are grown for the feeding of grazing animals
92
Forage Definition
Edible parts of plants other then separated grain, that provide feed for animals or can be harvested for feeding
93
Herbage definition
The biomass of herbaceous plants. The term generally refers to edible plant parts other than grain
94
What are the three types of grassland?
1. Leys
2. Permanent Pasture
3. Rough grazing
95
What are short term leys?
- 1-2 year leys
- Silage Production
- Containing variteties suitable to this type of production (IRG/HR/RC)
96
Medium Term Lays
- 3+ years
- Grazing rotation
- Containing PRG/WC/Timothy/Cocksfoot
97
What is permanet pasture?
- Land that has been under grass for at least five years and has not been ploughed for other crops in that time
- Semi natural
- Improved grassland
98
What is rough grazing?
- Including commonage, area that is unfenced, has low levels of inputs and management
- Usually is hilly/upland area and is often grazed by sheep
99
What is a Ley?
- A grass-legume sward
- Specifically sown as part of a pre-designed rotation of crops
-The intention to be ploughed up after a predetermined number of years
100
How long does a ley remain a ley?
- As long as the species of grasses and clovers which it contains are directly attributable to the seeds that were initally sown
101
What benefit does ley farming have?
- Managerial and technical advantages
- Soil fertility, wee, pest and disease control
- Orgnaic matter
- Soil structure- compaction/earthworms
102
Why is there a decline in ley farming?
- Intensified cropping systems
- Cheap sources of fertiliser- rediced the need for crop rotation
- Herbicide and pesticides become readily avaliable
- Still has an important role to play in orgnaic farmin- atmospheric N
- Decline in ley farming has lead to an increase in specialisation (continuous cropping or permanent grassland)
103
What is permanent grassland?
Land that has not been included in the crop rotation of a holding for 5 years or more
104
Why must Ireland ensure that the permanent grassland not be reduced?
The total agricultural land area shall be maintained and that this ration shall not decrease by >5% versus 2012 (Green Direct Payment)
105
What are the three greening measures?
1. Crop diversification
2. Protection of permanent grassland
3. Protection of environmentally sensitive areas
- Holdings where >75% of the eligible agricultural area is permanent grassland or is used for the production of grasses or other herbaceous forage have no further obligation to implement the 3 greening measures
106
Semi Natural Grasslands
They have been altered by human agricultural or pastoral activity, generally grazing or mowing, but without the input of fertilisers or reseeding with high yielding species such as Lolium perenne and trifolium repens
107
Whats important to consider for permanent grassland?
1. Types of grasses
2. Perennial Rygreass
3. Categories of ryegrass
4. Variety testing
5. Pasture Profit Index
6. National Recommended List
108
What are the most common sown grasses?
- Perennial Ryegrass
- Italian Ryegrass
- Cocksfoot
- Timothy
- Meadow fescue
109
What charactreistics does PRG have?
- Dark green tufted plant
- Leaves are flat, smooth, glossy
- Fibrous roots
- Infloresence, narrow spike with flattened spikelets containing 8-12 florets
- Yellow/violet anthers
- Rapid early growth
110
Why is PRG good?
- High yield of quality forage
- Productive on well drained soils
- Suited to rotational grazing
- Palatable
- Nutrient hungry grass
- Not tolerant of drought, heat stress or low fertility
- Tolerates trampling
- Target 60% sward PRG
111
What are the characteristics of Italian ryegrass?
- Tufted plat
- Taller than PRG
- Leaves x2 that PRG
- Fibrous roots
- Upright stems
- Long narrow larger spike
- Infloresence with awned spikelets
- Yellow/grey violet anthers
112
Advantages and disadvantages of IRG?
- Not winter hardy
- Will tolerte low fertility and poor drainage but not drought
- Similar nutritive value
- Higher yield
- Only lasts around 3 years
113
Cocksfoot characteristics
- Dense tussocks up to 1 meter high
- Broad flat leaf with smooth surface
- Duller green than PRG
- Deep root system
- Drought tolerant
- Inflorescnse is a panicle
114
Advantages and disadvantages of cocksfoot?
- Lower nutrient value
- Palatable
- High yielding
- Responds well to fertilise
- Intolerant of wet conditions and tight grazings
115
Characteristics of Timothy
- Found in seed mixtures for heavier and more challeneging soils eg peat
- In horse mixtures
- Smooth stemmed grass
- Short broad greyish-green leaves
- Infloresnces true spike
- Low tiller density
- Deep root system
- Tolerates lower pH and extremes of heat and cold
- Short lived perennial
116
Advanatgaes and disadvantages of timothy
- Lower digestibility (low WSC) than PRG
- 75% the prod of other grasses
- Winter hardy
- Early season growth
- High yield
- Less palatable
117
Characterisitcs of Meadow Fescue
- Persistent grass
- Slowe to establish than PRG
- Suited to poorer fertility soil
- Winter hardy
118
Advantages and disadvantages of Meadow fescue
- Does not respond well to chemical N
- Wide leaves produce high quality hay
119
How many species of volunteer grasses are in Ireland?
- 100
- About 60 are common or locally adundant
- Present in grasslands, amenity areas, headgrows, woodlands etc
- Meadow grasses
- Bent grasses
- Yorkshire fog
120
What is the issue with volunteer grasses?
Lower growth rate, lower feeding value and they dont respond as well to chemical or organis fertilisers
121
Yorkshire Fog Meadow Grass
- High production potential
- Less palatable
- Leafy stage it has good digestibility and mineral concentrations
- Prone to winter damage
122
Creeping Bentgrass
- Adapted to environments of low production potential
- Low digestibility
- High CP
- Drought resistance
123
Advantages of PRG
- Rapid establishment
- Good tillering
- Dense sward
- Excellent production response to fertile conditions and fertiliser N
- Highly acceptable to stock
- High DM yields and good digestability
- Tolerant to intensive grazing/cutting and regrows quickly after defoliation
- Growing point at ground level
- Does not grow well under dounght conditions, hot weather or inferitle soils
124
PRG characteristics
- Sensitive to intense frost and high temperatures
- Quite sensitive to shade
- Sensitive to drought and winter flooding
- Optimum on nutrient- rich soils and slightly acid to neutral
- Dry or wet soils are not suitable
- Sands can be suitable if the water supply and the nutrient availability are sufficient
125
Two types of IRG
- Westerwolds- annual and plants die after seed formation
- Multiflorum- short lived perennial, lastas about 2-3 years, is winter active, has an early season growth and is difficult to manage mid season
126
Hybrid Ryegrass
- Italian x Perennial ryegrass
- Apperance reflect one parental type
- Out of season growth IRG
- Sward density PRG
- More persistent than IRG
127
Grass seed sales
- Over 95% PRG
- PRG, IRG, WC account foe nearly all of the agriculturals grass/clover seed sold in Ireland
128
What are the three main categories of PRG
- Vary according to their heading date
- Early
- Intermediate
- Late
- Diploid and tetraploid
129
Heading date definition
Approx date around which 50% of reproductive tillers will produce seed heads
130
Early heading date for PRG
- Heads in the first half of May
- Early spring grazing in March and April
- Boosts first cut silage
- harvested by the 3rd week of May
- Stemmy regrowth in early summer can be a problem
- Use of this group has declined
131
Intermediate heading date for PRG
- 16%
- Head in the second half of May
- Produce high quality silage cuts
- Cut Late may and mid July
- Do not bulk up as soon as earlies but overall silage yields are good
- Suited to a broad range of management systems
- Spring growth has improved as has ground cover (sward density)
132
Late heading PRG
- 84%
- Head in the first half of June
- High tiller density/good ground cover
- Well suited to long term grazing pastures
- Good quality silage cuts in early June and late July
- Leafy mid summer and have good autumn growth
- Spring growth not as good as intermediates
- Very persistent
133
Grass Ploidy
Refers to the number of chromosomes in the nucleus of the cell
134
What are the two types of grass ploidy?
- Diploid
- Tetraploid
135
Diploid
- High tiller density
- Prostrate growth habit
- Smaller leaves
- 2 sets of chromosomes
- Lower yielding
- Slightly lower DMD
- Higher DM content
136
Tetraploid
- Low tiller denisty
- Erect growth habit
- Large dark leaves
- Greater leaf area
- 4 sets of chromosmes
- Higher yielding
- High DMD- more palatable
- Lowe DM percentage
- More open- more suscpetible to poaching
137
Benefits of tetraploid only mixtures
- Increased palatability driving higher intakes
- Higher quality grasses giving animal performance
- Excellent sward utilisation
- Suited to overseeding to repaid damaged swards
- Rapid establishment
138
White clover
- Sown in mixture with an late perennial ryegrass in May/June
- Following an establishment year they are assessed over two years
- 6/7 cut system
- 50kg of N/ha applied in Spring
139
What percentage of land is reseeded nationally per annum?
2-3% of land
140
Why are docks present in some reseeded land?
Due to the low usage of post emergence spray and time of reseeding
141
Questions to be answered when reseeding
1. Why
2. When
3. Soil fertility
4. System
5. Seed mixture
142
What is a vigorous sward?
- A sward that can grow out of season, has high tiller density and provide adequate grass production when required
- Medium term investment = management objectives of the farm
143
What percentages of ryegrass should you aim for?
- 60% +
- + 3 T DM/ha/year vs
- 25% more responsive to avaliable nutrients
- Losses of up to 300 euros per ha
- Ryegrass is less peristent under silage harvesting (5-6 years)
144
What is detrimental to reseeding?
- Late harvesting
- Low cutting heights
- Poor soil fertility
145
Percentage of other grasses/weeds
- Many unsown species are abundant in swards especially long term pastures
- Unknown species are much less productive than PRG
- Creeping Bent has only 75% production potential of PRG (lowers the DMD by 8 units)
- Herbicides can be used to control weeds- under certain conditions it may be necessary to reseed a sward
146
What pastures will not support early or late grazing systems?
Pastures with less than 60% PRG as insufficient grass is being produced
147
Advantages of reseeding
- Increase the productivity of swards- with better out of season production
- Allow a higher level of mid-season regrowth
- Provide swards which respond better to applied N (25%)
- Improve grass quality
- Reduce silage requirements
- Increase carrying capacity
148
Benefits of a newly reseeded sward (grazing)
- More grass grown (10-20%)
- More productive tillers in the seed mix
- Longer growing season
- Rapid re-growth- more productive cultivars
- Higher palatability/digestibility (higher sugar and WSC)
149
Benefits of a newly reseeded sward (silage)
- Higher grass quality (6+ units DMD)
- Easier to preserve (higher sugar content)
- Faster recovery
- Consistently higher yield
150
Why do we reseed?
- Low production, regrowth, response to nutrients
- High percentage of open ground
- Low pecentage of PRG
- High percentage of underisrbale grasses/weeds
- Lower percentage of clover
- Chnage of pasture species (+other grasses/legumes/herbs)
- Part of rotation/ winter forage crops
- Field inspection in March/April
151
Objectives of reseeding?
- Increase the overall productivity of the farm
- Increase the carrying capacity (stocking rate)
- Allow higher animal output- around 8% higher milk output per hectare relative to permanent pasture
- Increase grass quality
- Are more responsive to fertiliser
- Increase grass utilisation
- Allow white clover/ perennial ryegrass pastures to establish
152
Timing of reseeding
- Target turnaround time in which to get a reseed back into production should be 60 days (8-9 weeks)
- The objective is to minimised the non-productive period
- Takes a swards 11 months to fully establish
153
Autumn Reseeding
- Can get poor establishment
- 6 degrees for grass seedlings/ 8 degrees for clover seedlings
- Very dry autumn
- Early sowing is required for tillering during winter
- Fruit fly attack can be an issue
- Little or no time to apply post emergence herbicide
- August is the most suitable autumn month for reseeding
- Reseeding early allows the seedlings to commence tillering before the onset of winter
- If clover is included, reseeding date needs to be earlier
- Longer establishment (8-10 weeks vs 4-6 weeks)
- Higher threshold soil temperature (8 degrees vs 6)
154
Disadvantages to reseeding in spring?
- Higher demand for land on dairy farms
- Increased demand as cows are reaching peak lactation
- Large areas of grassland are closed off for silage production
- Labour
155
Advantages of reseeding in spring
- April sowing should produce good results
- Reduced risk of low temps and frost damage
- Risk of drought and SMD is not a factor
- Opportunity to graze the sward that helps to promote tillering
- Application of post emergence spray
156
Soil test/fertility assessment
- Shows the fertility and pH of the soil
- Correct fertiliser and lime levels
- Work fertiliser into the seedbed
- Lime application when not ploughing
- Developing seedlings are very sensitive to pH
157
What are the essential nutrients for soil?
- Phosphorus (P)
- Potassium (K)
- Lime
158
What is phosphorus needed for?
- For root development and therfore sward eatablishment
- P is immobile in the soil
159
What is potassium important for?
- Controls the loss of water by teanspiration through the leaf pores
- Sugar formation and root development
- Transport of metabolities and nutrient within the plant
160
What is lime important for?
- Optimum pH of 6.3 for grassland
- If pH is low, there will be poor establishment
- Trash can be release organic acids as it breaks down, inhibits germination
161
Plough, till, sow
- 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 (15cm)
162
Steps to Plough, till, sow
- Spray off old sward
- Plough
- Spread lime
- Land level
- Spread fertilieser
- One pass with seed
- Roll
163
Conventional setting
- Plough, till, sow
- Involves ploughing
- Old sward is prayed off- glyphosate
- Can be burnt off before harvesting (10 days)/ grazing (5-7 days)
- Ploughing (<15cm)
- Apply lime
- Land Level
- Apply fertiliser
- Sow the seed
- Roll
164
Alternatives to conventional
- Discing
- One pass
- Direct drilling (stitching in, undersowing, oversowing)
165
Shallow cultivation/discing
- Deep cultivations can bury nutrients
- Shallow cultivation keeps the nutrients close to the surface where the developing roots will be
- 2-3 passes of disc harrow in angles directions, land level, lime and fertiliser, one pass with seed and then roll
- The aim is to produce a dine, firm, level seedbed
- Firm seedbed conserves moisture
- Loose seedbed allows mositure to evaporate inhibiting germination
166
Minimum cultivation (one-pass)
- The introduction of mini cult allows the intoduction of PRG without ploughing >reducing cost
- Some sites are not suitable for ploughing- stony topography
- One pass: Lime and fertiliser, one pass with rotary power harrow with seed, roll
- Spray off trash will not be buried by ploughing
- Sward is them grazed/ cut to a low level
- Apply 2.5 tonnes lime/ha to neutralise the OAs produced by the trash before sowing
- More weeds may occur
167
Benefits of minimum cultivation
- Soil disturbacne is minimum- support for traffic post establishment
- Young seedlings can make use of the fertile soil at ground level, as cultivation is shallow
- Machine, accuracy, setting, speed are all important
168
Direct drilling/stitiching in/ oversowing
- If existing sward is sprayed off- direct drilling
- If the exisitng sward remains- stitching in/over sowing
- Fast and simple method of reseeding
- Seed is being placed in a hostile enrironment
- Exisiting sward sprayed off (round-up_
- Suppressed in some cases (Reglone) to reduce competition
- Important to keep the exisiting sward suppressed to allow the new seedlings to develop
169
Direct drilling
- Can graze with weanlings or sheep
- A number of machines are used for direct drill
- Deposit the grass in slots 2 to 5 inches apart
- Most successful after a heavy cut of silage- as the old swards will be much more open
170
What is the main objective when choosing a seed mixture?
To combine grasses of differing tratis to obtain good overall DM production especially in the Spring/Autumn periods
171
Factors that influence choosing a seed mixture?
- Good overall DM production (spring/autumn)
- High sward density
- Suitable to a range of enterprises
- Heading date
- WSC/DMD
- Persistency
- Combination of grasses of differnt traits
- 3-4 varieties (min 3kg each)
- 35 kg/ha (14kg/ac)
172
What are grazing specific mixtures
- Seasonal growth
- High DMD
- Medium leaf WC for dairy/beef and small leaf WC for sheep
173
Silage Seed Mixture
- High yield varieties for 1st cut
- Heading date will have a big impact (small range)
- Intermediate varitiees for 2- cu system (40%)
- Reduced intermediated for 1-cut
- Max 40% tetraploids- need to be persistent
174
Wetland Seed Mixture
- Late heading varitieies preferably diploid varities should be dominate
- 15-20% highly persistent tetraploid
- Low growth habit
- High tiller density
- Good mid season grass quality
175
Dry land seed mixture
- Late heading varieitesi play major role
- Some excellent late tetraploids with high spring grass growth
- Combined with high density high digestibilty diploids
- Tetraploids > 35-50%
176
Important stages of sward establishment
1. Germination
2. Emergence
3. Root development
4. Tillering
177
Germination
- Regrowth of a seed after a period of dormancy if environmental conditions are suitab;e
- Growth of the seed into a new plant is fueled by using the food sotred inside the seed
178
Emergence
Shoots to emerge above ground
179
Root development
Access own feed supply for the soil
180
Tillering
Developmetn of a plant that is similar to the parent plant from a dud that is formed as each new leaf appears in the leaf axial or where the leaf joins the stem
181
When should PRG seeds germinate?
Once the tempeature is right and there is enough water, oxygen and seed soil cantact, the seeds should germinate within 5 to 10 days
182
Seed Tissues
- Embryo- contains the tissues that develop into the new seedling plant
- Endosperm- energy reserve
- Cotyledon- barrier between the embryo adn endosperm
- Plumule- primary shoot
- Radicle- primary root
- Coleorhiza- protective sheath for the radicle
- Coleoptile- protective sheath for the plumule
183
Germination
- Dependent on the viable seed, correct environment, decay of seed coat
- First stage involves the passive uptake of water- 12 to 24 hours
- Cells surrounding the endosperm release enzymes that break down the starch to sugars
- 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
- Coleorhiza and radicle appear
- Coleorhiza is a protective covering for the primary root and emerges first
- Radicle follows soon after
- Two pairs of lateral roots follow
184
Emergence
- Seeds provide sufficient energy for shoots to emerge above ground
- If buried too deeeply, seeds will not have suffiecient energy to emerge- seedlings die
- 1-2cm is sufficient
185
Root Development
- Seedlings depend on their own energy reserves until the roots gain their own feed supply from the soil
- Rapid and good seed-soil contact is essential
- Firm, fine, level seedbed
186
What is tillering?
The 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
- Parent plant -> Primary tillers-> Secondary tillars
- Generally 4-5 tillers per plant
187
Tillering: PRG's 2nd advantage
- Main shoot appears above ground level- leaf formation should proceed rapidly
- At 2-4 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
188
Factors affecting tiller production
1. Defoliation
2. Nitrogen level
3. Shading
189
Number of tillers
- Difficult to predict- dependent on management inputs
- Generally, production of new tillers peaks in March/April and again in June/July
- Tillers deaths greatest in May/June
- Tiller nos greatest in March- May and July-August
190
Promoting Tillering
- Tillering helps to reduce the space avalibale for weeds
- To encourage tillering, apply nitrogen 3-4 weeks after sowing
- Graze the reseed to about 6-7cm high
- Continue to graze the reseed in the first year of production
- Avoid cutting the new reseed for silage in the first year
191
PRG vegetative structure
- Grwoing tip is just above ground level throuhgout vegetative phase
- Very short ture stem- 3cm
- Pseudo stem that consists of leaf sheaths
- Good grazing management does not damage the growing point
- Tufted growth habit
192
PRG tillers
- New leaf appears every 11 days (April to September)
- 3 live leaves per tiller at any one time
- Average leaf longevity is 33 days
- Light and temperature are the most important variable affecting leaf growth
- Free tillering
- Tiller denisty is very high in grazing, lowing in cutting regime
- 3 leaves per tiller - 3 leaf grazing
- In spring, first leaves are relatively small but increase in size until the maximum rached
- In autumn, the opposite evolution is observed
193
PRG roots
- Fibrous root system
- Reach 1-1.5 m deep
- Majority in the first 15cm
- Highly branched
- Root hairs absorb water from the soil
- Root growth starts 1-2 months before leaves
- Slows down in summer and restarts in autumn
- Root lifetime of 2 to 3 months during grwoing season
194
PRG Leaves
- Primary organ for photosynthesis and transpiration
- Light energy >chlorophyll of the leaf mesophyll cells
- CO2, O2 and H20> exchanged> stromata on leaf
- Leaves have veins > vascular system
195
How can the benefits of reseeding be lost after sowing?
- Poor soil fertility (poor establishment and tillering)
- Grazing at high grass covers or cutting for silage (tiller/plant death)
- Weed infestation (docks/loss of ground cover)
- Pest attack (fruit fly, leatherjackets and slugs- tiller/plant death)
- Poaching- dont damage new reseeds
196
Weed Control
- Best control at 2-3 leaf stage
- Docks, thistles and chickweed most prevalent
- Essential to control docks and chickweed at seedling stage
- White clover inclusion will dictate choice of herbicide
197
Common weeds
- Docks
- Chickweed
- Thistle
198
Pests
- Frit fly
- Leather jackets
- Slugs
Compliance with Sustainable Use Directive required
199
Fruit Fly
- 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 flowing for 6 weeks+ and suitable insecticide
200
Leather jackets
- Most common in wetter or heavier soilds
- Results in dead plants on soil surface
- Rolling important after sowing (firm seedbed)
- Up to the time of tillering is the highest risk time
201
Slugs
- Common in wet weather/damp field
- High levels of trash on the seedbed(direct drilling- slit in ground)
- Shred leaves
202
How much is it to reseed per hectare?
540 euros using a conventional method
203
What is the purpose of fertiliser
The purpose of fertiliser application to grassland is to produce an appropriote level of soil fertility to support adequate crop growth (and animal performane) and to maintain an adequate level of soil fertility by replacing all nutrient off-takes, be they in the forms of milk, meat or crops
204
What are the three main elements that need to be returned to the soil following grazing/silage harvesting
- Nitrogen (drives plant growth and element of AA)(20-50 g/kg DM)
- Phosphorus (root development, energy utilisation, cell division)(2-4 g/kg DM)
- Potassium (Maximise N use, sugar formation)(25-40 g/kg DM)
205
What is the most abundant element in th atmosphere?
Gaseous Nirtogen
78%
206
What ions does grass require for growth?
Nitrate or ammonia ions
Greatest requirment by grass for DM production
207
How much nitrogen is removed under a 2 cut system?
400 kg N
208
How much nitrogen does 15t DM/ha/year require?
450 kg N/ha
15,000 kg DM @ avg. 18.75% CP (3% N) = 450 kg N/ha
209
What is the minimum required amount of N for optimum photosynthesis?
30 g N/kg DM
210
N2
Di-nitrogen gas
211
NO2
Nitrite
212
NO3-
Nitrate (nitrate leaching:soil colloids negatively charged)
213
N2O
Nitrous oxide (potent GHG)
214
NH3
Ammonia (ammonia volatizisation)
215
NH4+
Ammonium
216
How is nitrate poisining caused?
- By high nitrate levels
- Usually occurs in late autumn or winter, particularly during a flush of growth after a dry period
- Nitrate levels build up in herbage when nitrate is taken up by the plant faster than it can be converted into protein
217
What is released by the plant root when nitrate is taken up?
OH-
218
What is released by the plant root when ammonium is taken up?
H+
219
Nitrogen Fixation
Fixation is the process of converting dinitrogen gas (n2) to chemically reactive forms
220
Nitrogen mineralisation
Microorganisms decomposed OM into easily available N forms to plants
221
Nitrification
Microbial process by which ammonia is converted to nitrite and nitrate
222
Leaching
The nitrate is soluable and is leached easily when excess water percolates through the soil
223
Plant asssimilation
Plant roots take up nitrogen in primarily the nitrate or ammonium forms
224
Denitrification
The process which microbes convert nitrate to nitrogen gas
225
Volatilisation
Ammonium in the soil is converted to ammonia, which is lost as a gas
226
Immobilisation
Nitrate and ammonium are taken up by the soil organisms and therefore become unavailable to crops
227
What is the response to nitrogen for up to 250-350 kg/ha
15-25 kg DM/ kg N
228
What is the response to nitrogen for up to 350-450 kg/ha
5-15 kg DM/kg N
229
When is the Nitrogen response reduced?
As the N rate is increased
230
N uptake
- Nitrate or ammonium
- In the plant, the nitrate is converted to ammonium ions
- NH3 combined with CHO to synthesise amino acids
- Amino acids change to proteins
- N take up that surplus to requirements remains in the plant tissue as non-protein N (NPN)
231
N deficiency
- Lighter green colour
- Reduced growth and sparse ground cover
232
Sources of Nitrogen
- Atmospheric decomposition (12 kg/ha/year)
- Background release (soil organic N)
- Clover (100-150 kg/ha/year)
- Animal excreta
- FYM/slurry
- Fertiliser
- Must account for all sources in a nutrient management plan (NMP)
233
Background N
- Soil contains OM (5-20%) that contains large stores of organic N (5000+ kg/ha)
- Only a small proportion is available to the grass plant in any one year (98% unavailable)
- Average background N release 124 kg N/ha (40-330kg)
- Constant turnover renders some N available
- Mineralisation is increased following ploughing
234
Where are lower quantities of N found?
Deeper topsoil with heavier soils eg long term grassland
235
Where are higher quantities of N found?
Deeper topsoils with heavier soils eg long term grassland
Soil OM and drainage are also importnat
236
When is the highest N release from soil?
Late sping and early autumn when temperature and soil moisture levels are favourable
237
Background N in Winter
200-250 g/ha/day which would be sufficient to produce 6.5 to 7.5 kg/DM/ha/day
238
Animal excreta
- 75-90% of N consumed in herbage is excreted depending on the type and class of animal and diet offered?
- Before store cattle utilized the least and dairy cows the most
- While dairy cows utilise the most of N consumed, they are still very inefficient users of N
- Approx 1/4 of N is in the dung (not immediately available) and 3/4 in the urine (available)
239
What is the aim of the EU Nitrates Directive?
To prevent pollution of surface waters and groundwater from agricultrual sources and to protect and improve water quality
240
How many nirtogen bands are there
- 3
- <4,500 kg milk yield per annum
- 4501-6500 kg milk yield per annum
->6,500 kg milk yield per annum
241
Fertiliser N
- Increase DM yield
- Reduce seasonality of growth
- Extend the grazing season
- Supply both nitrate and ammonium
- CAN (calcium ammonium nitrate) supplies nitrate and ammonium (27% N)
- Urea following application is converted to ammonium (46% N)
- Ammonium not taken up by the roots is converted to nitrate- losses via ammonia gas also
242
What is the average DM% in cattle slurry on irish farms?
6.3%
243
Which pastures to fertilise?
- Give priority to pastures with the greatest production potential
- This is often ryegrass dominant pastures, pasture height of 5-8 cm (cattle) and 3-6cm (sheep), and have high fertility (P-K-S) and well drained soils
244
What is the minimum soil temp for grass growth?
5 degrees
245
How much urea to spread?
28.8 kg N/ha (about 0.5 bags/ac) at grange but response depends on soil, pasture and management
246
When to apply nitrogen?
When 5 cm soil temp is above 5 degrees and is increasing ie when most pastures are starting to grow
247
What is the Spring N recommendation?
- 60 kg N/ha split 33:66 between February and March
- N response reduced as N rate is increased
248
General N fertiliser advice for grassland
1. Determine avaliable N rates and timing for grazed swards
2. Determine available N rates for cut swards
3. Take account of available N in slurry and FYM
4. Calculate chemical fertiliser N
5. Determine maximum N allowance and confirm that N advice for the holding is compliant with NAP regulations
249
What is the EU Nitrates Directive?
- Livestock manure loading shall not exceed 170 kg organic N/ha/year
- Can apply for derogration to farm up to 220 kg organic N/ha/year
250
Losses of N
- N supplied to the soil from any source is susceptible to loss
- Leaching
- Denitrififcation
- Volatilisation
251
Nitrogen Leaching
- The nitrate is soluable and is leached easily when excess water percolates through the soil
- Washing of nitrates from the soil
- Soil mobility is a disadvantage with high rainfall, where the level of rain exceeds the ability of evapotranspiration to remove water from the soil
- Water and nitrates pass down through the soil, away from plant roots and lost to water course
252
Denitrification
-The process that microbes convert nitrate to nitrogen gas
- Heavy waterlogged soils (SMD - 10)
- Soil becomes depleted of oxygen
- Bacteria detach O2 from nitrate (NO3)
- Release N2O and N2 gases
253
Volatilisation of ammonia
- The loss of nitrogen to the atmosphere as ammonia gas (NH3) from soils or from fertiliser applied to soil surface (N2O)
- 99% of ammonia emissions come from agriculture
- Associated with the application of urea or slurry
- This dissolves in soil water and hopefully moves down to the roots
- Under good drying conditions this water and ammonium is evaporated as ammonia
- Therefore, advice is not to use urea after May
254
When must LESS be used?
On holdings with grassland stocking rates of 170kg N/ha from grazing livestock manure or above prior to export of livestock manure from the holding
255
Methods to reduce volatilisation?
- Band spreading
- Trailing hose
- Trailing shoe
- Shallow injection
256
Why is Phosphorous required?
- Chemical reactions within the plant
- Plant metabolism/new growth
- Root and seedling development
- Plant maturity process and tillering
- Seed production/flowering
- Present in herbage at 2-4 g/kg DM
257
Phosphorus
- Has poor mobility in the soil
- P tends to remain near the surface
- Reseeding is a good opportunity to incorporate it through the soil
- Poor uptake in cold spring
Phosphates are not taken up by plants in excess of requirements
- Soils have a high affinity for phosphorus ions
- Phosphates bind to mineral soils so there is a low risk of leaching
- Except in peat soils and when you have P saturation- leaching as phosphate
258
General P fertiliser advice for grazing
1. Determine P required for soil P build up
2. Determine P required for soil P maintenance
3. Take account of available P in slurry and FYM
4. Calculate chemical fertiliser P
5. Determine maximum P allowance and confirm that P fertiliser requirement of the holding is compliant with the NAP regulations
259
P deficiency
- Can be difficult to recognise
- Weak growth during establishment
- Subsequent reduced leaf size
- Lowered grass production
- Symptoms include stunted, thin stemmed and spindly plants with bluish-green leaves particularly older leaves
260
P losses
- Over application of P
- Adds unnecessary costs
- Some soils (peats) are vulnerable to P loss
- Loss to waterways and has negative effects on water quality through Eutrophication
261
Potassium
- Essential element
- Needed to compliment N if high production is to be attained
- Regular soil analysis important as K status can drop rapidly in some soils
- K content in grass of 25-40 g/kg DM- concentrated in cell sap
- Requirements depend on utilisation
- A large amount of K is recovered in silage
- K is highly mobile and is readily taken up
- K suppiled by the soil depends on the soil type
262
Functions of Potassium
- Regulates cell water content > controls the loss of water by transpiration through the leaf pores
- Maintaining cell turgor and strengthening the structure of the foliage
- Sugar formation
- Root development
- Transport of metabolites and nutrients within the plant
263
K deficiency
- Grass growth lacks vigour even where N is sufficient
- Older leaves turn light green as K moves to younger leaves
- Some scorching of leaf tips may occur
- Root development is restricted
- Wilting during drought
- Clover are poor competitors of both P and K
- Clover will be affected first
- Dissapperance from the sward before negative effects are evident in the grass
264
pH and lime for grassland
- Optimum pH at/above 6.3 (Teagasc target 6.5)
- Ca is leached and removed in harvested herbage
- Surface aciditity often occurs in the top 50mm of grassland due to high rainfall and heavy use of chemical N
- No best application time- evenly distributed
- Grazing rotation as soon as lime is washed off leaves
- If advice is greater than 7.5 t/ha, apply 75 initally and the remainder after 2 years
265
Benefits of Lime
- Improves physical structure of the soil and improve the chemical and biological condtions for uptake of soil nutrients
- Mineralisation of nutrients from soil OM is stimulated
- Supplies Ca for plant growth (concentration of Ca in grass 4-12 g Ca/kg DM)
266
Soil acidity
- Reduces earthworm and microbial activity
- Build up of dead material
- Forms a mat that prevents light penetration to the base of the ward
- Tiller production is reduced
- Nutrients are locked up
