Ultimate Guide to Grassland
In the UK, grass occupies 50% of the total agricultural area (this includes temporary, permanent, and rough grazing) (DEFRA, 2019). This is a significant proportion of land that still requires the same time and inputs as other agricultural crops. Looking a bit closer at the south west, permanent pasture takes up 48% of the total farmed area (DEFRA, 2020). In the south east permanent pasture takes up 30% of the farmed area (DEFRA, 2020). Grass offers the cheapest form of feed to livestock and, is often a popular option due to its flexibility in its ability to grow for the majority of the year. Value of grass Clamped silage – 11.2 Metabolize energy (ME), 15% Crude Protein (CP) Grazing Spring grass – 11.5 ME, 17% Protein Old grass ley – 10.5 ME, 15% Protein (AHDB 2020) However, with good or poor management, these figures can be significantly changed. Permanent pasture has been recorded to have values as low as 9ME and 10.5%CP. Similarly, a standard 2 year ley has recorded 10.4ME and 12.7%CP. One ley fed N:S after every grazing rotation, recorded values of 12ME and protein up to 25%. Looking at these results, it shows how much management has a massive effect on nutritional value. Like most species in the natural kingdom grass has one life objective; to reproduce. To achieve this the grass plant needs to produce viable seed which can be redistributed back into the soil and establish the next generation. An understanding of how a grass plant endeavours to achieve this life ambition can help livestock farmers gain maximum nutritional value from grass when feeding it to their animals.
After a period of winter dormancy, a grass plant needs to rebuild its energy stores. With the emergence of longer, warmer days in Spring, grass can begin converting sunlight energy into sugars via photosynthesis. Photosynthesis occurs within the chloroplasts found in the leaves of grass plants, therefore during the spring months of April – May grass offers livestock an energy dense feed which can be either grazed directly, or cut and ensiled. If left to its own devices, grass will utilise this store of energy to build its stem and ensuing seed. To insure against damage, as the stem elongates the plant protects it with an indigestible sheath called lignin. This focus on stem production causes the proportion of leaf material to diminish and be replaced by the lignified stem, causing a dramatic decline in nutritional value to the grazing ruminant. Ruminant farmers can benefit from the grass plants mechanics of growth by encouraging photosynthesis and impede stem production. Regular defoliation after the 3 leaf stage will achieve this by manipulating the grass plant to consistently re-build energy reserves. Protein is also a key nutrient required for growth, therefore nutritionally a ruminant farmer will benefit from both photosynthetic sugars and proteins as the grass plant re-builds itself after defoliation. As grass managers, farmers must also assist grass in its effort to reconstruct itself. When defoliating the plant, it is important to leave a proportion of reserves behind to aid instant regrowth, this is achieved by managing grazing covers and stubble heights. Furthermore, similarly to our animals, the grass plant requires tailored nutrition. Nutrients available in the soil can be complimented with organic and inorganic fertilisers to sustain growth. Allowing an adequate recovery period will also benefit grass re-establishment.
It is important to note however that in times of stress, i.e. drought, over-defoliation, season extension and nutrient deficiency; the grass plant becomes pressurised to develop its seed. Management of the grass plant is thereby crucial to allow us to reap the harvest of the energy and protein it builds. By understanding the production ambitions of grass and the steps it takes to achieve this, ruminant farmers can manipulate its growth characteristics to provide a highly nutritious, cost effective feed. Types of Grass & Clover Italian Ryegrass (IRG) The highest yielding type of grass and will produce heavy crops. IRG is less persistent than a perennial ryegrass, making them very useful for short term leys. Mainly used for cutting and producing silage or intensive spring grazing. Typically, Italian ryegrass has an upright growth habit with wide leaves. Mid-season growth can become stemmy but maintains good palatability and digestibility. Hybrid (HRG) Offering better persistency than IRG, it will also produce a high D value cut of silage. Perennial Ryegrass (PRG) This is by far the most commonly used grass seed in the UK, it is used in most types of seed mixtures. Far more persistent than Italian or hybrid, it is suitable for the longer term leys. It is very palatable, high yielding and does respond well to nitrogen applications. There are three categories of PRG, depending on heading date and growth habit. Early • Erect type • Mainly used for cutting leys • High yields for conservation • Early spring growth
Intermediate •
Semi-prostrate
• •
Dual purpose, suitable for both cutting and grazing
Often used in long term leys
Late •
Prostrate type Mainly used for grazing Gives good ground cover
• • •
Can be useful in conservation with its high yields
Diploid or Tetraploid Ryegrass Tetraploids have twice the number of chromosomes, so are a slightly larger seed compared to diploid types and require a more robust sowing rate. A bigger plant with deeper roots makes it more drought tolerant but offers similar DM yields to diploids. They are quick to establish and more competitive, making them ideal for overseeding situations. Tetraploids are more palatable than diploids, with an increased amount of sugars, leading to higher voluntary intakes. This makes tetraploids more suited to cutting leys where the contribute to yield. Diploid plants tend to tiller more, giving more ground cover and persistency, and more suited to grazing. Timothy Slower to establish than ryegrasses, but a valuable species to include in mixes. A highly palatable species, Timothy also provides mid-season growth when the ryegrasses are slow. It is also cold tolerant and will do well in wet conditions. It can also do well on the lighter soils, with less chance of burning up in the dry conditions.
Cocksfoot A deep rooting grass that is slightly drought tolerant. Newer breeding has increased palatability, but management is key to maintain it, otherwise it can form tufts/tussocks that are less favoured in grazing but can be useful in creating habitats for wildlife. Cocksfoot will grow early in the spring to produce an ‘early bite’ and has a quick recovery time once grazed. Smooth Stalked Meadow Grass A slightly lower yielding species but is very palatable and useful in some situations. Deeper rooting, it copes well in drier soils and can tolerate some heat stress. Its creeping rhizomes make it tolerant to grazing and trampling as well as creating a dense sward. Red Fescue A fine leaved species that is slower growing but long lived, growing for a longer period of time. More suited to free draining soils, it can also withstand some nutrient and drought stress. Whilst being palatable to livestock, it can tolerate the trampling and wear from grazing. White Clover Mainly used in grazing mixtures, clover adds a good source of protein and nitrogen. It helps to fill out the bottom of the sward but can be sensitive to a lack of moisture and can be easily outcompeted by more dominant grass species. Small Ideally used of grazing mixtures, it is quite persistent. Suitable for sheep systems, it is tolerant of close/hard grazing. Medium The most widely used type, as it is most versatile. It is more productive, will tolerate frequent cutting and rotational grazing. It is adaptable for short and long terms leys.
Large These tend to be higher yielding but shorter lived. Most suited to cutting mixtures. Red Clover Most often seed in cutting mixtures, they are shorter lived. Will produce protein rich hay/silage. Chicory A perennial herb with a deep tap root, making it useful in situations where the soil is light or prone to drought, and will maintain production throughout the season. Chicory is also very palatable, with high protein and mineral content too. Fairly persistent in leys, lasting up to 5 years, it will also regrow rapidly after grazing. Chicory has been known to have anthelmintic properties too. Plantain Another deep rooting herb, that is very palatable to grazing livestock. Similar to Chicory, Plantain has also been shown to reduce anthelmintic use in sheep. Reseeding Before reseeding, you must first determine the current state of the grassland areas: • Check for compaction, weed problems or patches. • How much of the original sown species are still there? This will determine if an overseed could work, or if its best to do a complete reseed. • Have weeds or other grass species taken over? When the sward gets to below 50% of sown species it might be time to look at sward rejuvenation. Overseed Reseed If the existing ley still has a good proportion of original sown species Best method of establishing a new ley Offers a short term boost Sown species are less than 50% of the sward Ideal if reseeding is not possible due to conditions Improves yield, quality, and productivity Repairs damaged swards Introduces new varieties and genetics Improves productivity Opportunity to tackle weed and/or compaction issues Can introduce clover There is less competition from existing grass species
Causes little damage to the existing ley Less interruption to the use of the field Requires use of varieties and species with more competitive habits
What to overseed with? Look at species, ploidy, and variety...
Even though there is existing grass there, the new seed needs to get the best seed to soil contact possible. This requires sufficient open spaces for the seed to establish. Larger seeds, such as Tetraploids, tend to work best. Adding Clover to the mix, or on its own, is a good way to introduce it without a full reseed. This can be added in after a previous reseed if weed control has been a problem or waiting for the warmer soil temperatures in the spring. Herbs can be stitched into an existing ley to increase diversity, add drought tolerance, or even add in anthelmintic properties. Improves sward production and quality Equally as effective as autumn reseeding Allows time for the crop to establish before winter No heading in first season Grass can be more competitive with weeds Offers more flexibility as conditions improve and soils warm Establishing clover is more reliable with more favourable conditions Things to consider: The grass reseed might not have time to fully establish before needing to turn livestock out onto it. This risk can be reduced with overseeding the existing ley to boost production. As conditions improve in the spring, if the grass reseed has not taken, there is more chance of weeds taking over. However, there is always the second chance of an autumn sowing if things have not gone to plan! Spring seeding Advantages
Things to consider: Weed competitions can be significant with autumn reseeds, watch out for slugs and frit flies. There is a narrow window of establishment, consideration other crops in the rotations. Where conditions allow, establish the ley as soon as possible to allow strong vigorous plants to establish before winter. This will also avoid frosts on seedlings when they emerge. * Timing is important! Wait until the soil is warm enough for grass growth – at 5 degrees (8 for clover). Avoid overseeding at times of peak growth for existing grass. * Make sure soil conditions are good before proceeding. * Choose varieties suited to the chosen option – use species that will establish rapidly and will not be out competed by the existing ley if overseeding, i.e. IRG, Hybrid or Tetraploid PRG. Species such as Timothy will be slower to establish and less competitive but are beneficial late on in the season when other species growth slows, making them more suitable for a reseed. Autumn seeding Advantages Minimum impact to yield loss Seedbed has time to settle over winter allowing good struc- ture to form Less impact on grazing stock Good weed control if early enough Higher soil temperatures, with little risk of drought Provides early spring growth Usually the choice for short term leys
Adding in Clover Adding clover into an existing ley or as part of a complete reseed has may benefits. From a forage perspective, clover is a good source of protein to the feed, while also boosting palatability. As well as this, clover has the ability to fix Nitrogen. This is useful in increasing yield in low input systems and increasing N uptake of the companion grasses. Due to the nature of the clover it does also offer some drought resistance in hot years, with its extensive root network. Clovers are best sown in early spring or post first cut of silage, as there will be less competition from the more dominant grass species. Or choose a mix with clover in for a complete reseed. Adding in herbs The inclusion of herbs in a mix can have several benefits. These can include species such as chicory, plantain, yarrow, burnet, sheep’s parsley, birdsfoot trefoil and black medic. Each individual species has its own benefits, and put together, they can increase the performance of the ley. Adding in herbs to the mix increases the diversity, and in turn the resilience of the mix increases. Common grassland weeds Creeping Buttercup A perennial plant that flowers from May to September, it is propagated from creeping root stolons. Buttercups are generally avoided by livestock due to their bitter taste but can cause stomach irritation if digested. Controlling buttercups improves pasture palatability and productivity and can be done through pH of the soil or soil structure and drainage. Common Chickweed An annual broadleaved weed that propagates by seed in the soil, it is commonly seen in autumn reseeds after a cereal crop. Chickweeds needs to be controlled as it will compete aggressively with the grass, affecting yield, particularly in new leys. It can also cause problems in the conservation of grass, affecting wilting, fermentation of silage and drying of hay. Heavy grazing of young stock can graze it out. Can cause digestive issues on older livestock.
Dandelion A deep tap rooting perennial plant, flowering from May to October. It propagates with seeds via wind dispersal, with one flower head producing approx. 400 seeds. Dandelions will compete with grass, which reduces palatability and yield. Improving soil fertility and avoid overgrazing to reduce risk. Docks Deep rooting plants which will compete aggressively with grass, they can also regenerate shoots from their tap roots. Their seeds can remain viable for up to 80 years. Docks thrive on intensively used and highly fertilised areas and should not be allowed to set seed. Neither intensive grazing, ensiling, or topping are ideal methods of control, as the seeds can survive both digestion and ensiling and the tap roots can allow the plant to recover after topping. Common Nettle Growing to one meter high, they propagate through extensive creeping stolons and can easily germinate from soil disturbance. Nettles are unpalatable, and with their ability to spread across a field they also reduce grazing area. They are best controlled when they are young, with cutting three times a year before flowering. Ragwort A biennial plant, that flowers in its second year. Ragwort is poisonous, but unpalatable in its living state. Once the plant has been damaged, wilted, or dead, it becomes more palatable and still as poisonous. Horses are particularly susceptible, and it is a danger in hay or silage. Grazing with sheep in the early spring or winter can help reduce light infestations, or uprooting will help prevent spread of seed. Cutting is not a recommended option. Thistles Spreading through vegetative growth of roots, seeds are also dispersed by the wind. Thistles have extensive underground roots so can be difficult to control or remove. Topping can be useful to ensure that all the plants are at the same height. For control options, please speak to your BASIS qualified advisor.
Method of sowing There are two main ways to establish a grass ley: • Broadcasting • Spread seed on to a level surface, followed by a light harrow and/or ring roll. • Take care on soils that are liable to cap – in this situation is it best to roll after emergence when seedlings are sufficiently established • Drilling • Avoid drilling too deeply, and then lightly roll. • In some cases, it is best to halve seed rate and drill in two directions, the second at a different angle to get a better cover. • Direct drilling into stubble or existing pasture can be more prone to slug or other pest attacks Seeding rate Seed rates for mixtures can vary depending on end use, method of sowing and individual circumstances. Higher rates are often used as an insurance policy to reduce weeds or to counter poor emergence rates. Most standard mixtures will be between 12 and 15kg per acre. (approx. 29 - 37kg/ha) Seed Mixture Grass is a versatile forage, for both grazing and conserving. Creating a mixture offers more flexibility with end use and the ability to fit in most situations. Italian Ryegrass offers a short-term mix that will produce the bulk, ideal for silage. Comparatively, a longer-term mix, with Perennial Ryegrass can be used for either cutting or grazing, with persistently good yields.
Grazing
Cutting
• High diploid content • Small or medium white clover • Can use a wide range of heading dates • Take notice of disease rating
• Good tetraploid content • Use a narrow window of heading dates, no more than 10 days difference • Large white clover or red clover • IRG for short term
By using a range of species and indeed varieties will make the mix more versatile. For example, adding timothy in for palatability and the ability to grow in colder wetter conditions; adding clover in for its nutritional value and benefits the soil; adding cocksfoot will be beneficial for more slightly drought tolerance. The balance of Tetraploid to Diploid grasses will also need to be considered. Tetraploids offer increased palatability with increased sugars and more upright growth, perfect for cutting and grazing. Diploids are more persistent with higher dry matter. Dual purpose mixtures • Needs to be able to cope with a cut (or multiple) of silage whilst offering good quality grazing afterwards • Using a blend of white clover sizes will work best • Using tetraploids will increase palatability • Mid-summer production is important for grazing - a blend of early and late perennials will help with this • Timothy can be included with its long growth season
Sheep grazing • Due to the nature of how sheep graze, the mix must be able to tolerate hard, close, and persistent grazing • Often will be in a low management system • Use mostly late PRG which will tolerate the close grazing • Perennials with prostrate growth habits are better suited to the close grazing • White clover adds nutrition while also coping with the persistent grazing Dairy grazing • Needs to provide maximum production throughout the season • High voluntary intake • Responsive to N if used intensively • White clover to increase nutritional value • Late PRG should make up the majority of the mix • Early and intermediate varieties of PRG will also be useful to create a succession of growth • Timothy can be used to increase palatability Silage production • Requiring highest yields with minimal cuts, the mix needs to be highly productive • Chose high yielding varieties and species such as IRG • Add in Hybrids or perennials to increase persistence • Choose varieties with close heading dates to offer maximum quality • Tetraploids can be used to increase sugars
Grassland nutrition Correct crop nutrition is fundamental to growing any crop successfully and grass is no exception. To grow a good crop of grass in any situation; whether it be for low or high intensity grazing, hay, or silage the nutrition must be tailored to what is already in the soil. P, K, Mg, and pH Soil testing Soil analysis is required to ascertain the fertility and acidity of your grassland fields. At Bartholomews we recommend that each field should be soil tested once every three years to get the best crop. The results from the soil test will be displayed as an index, aiding decision-making regarding fertiliser requirements. Soil analysis will also reveal the pH of your soil, a measure of the acidity which affects soil fertility. Soils which are too acidic can decrease the availability of nutrients such as phosphate.
Nutrient / pH
Optimum index / pH
Phosphate (P)
2
Potassium (K)
2-
Magnesium (Mg)
2
pH
6
Soil test results When an index is given, fertiliser decisions can be made in confidence knowing that you will be supplying the correct nutrition that is needed. This fertiliser requirement would depend on the grassland situation/use. Tissue sampling Tissue sampling can be a useful indicator of nutrient deficiencies, both macronutrients and micronutrients at a particular growth stage in a crop of grass. These tests allow rectification of any deficiencies in both the current crop and any further crops of grass. Samples should be taken in a ‘W’ shaped pattern in the field at the first fully-expanded leaves from the growing point and should not be contaminated by roots or stems. Establishment P, K, or Mg Index 0 1 2 3 4 and higher Kg/ha Phosphate 120 80 50 30 0 Potassium 120 80 60(2-) 40(2+) 0 0 Magnesium 100 50 0 0 0
Correct nutrition is essential to get a crop of grass established well. Phosphate is particularly important as it helps with root development. Establishment fertiliser is best incorporated in the seedbed.
Silage P, K or Mg Index
0
1
2
3
4 and higher
Kg/ha First cut (23t FW/ha)
Phosphate
100
70
40
20
0
Potash*
Previous autumn
60
30
0
0
0
Spring
80
80
80 (2-) 60 (2+)
30
0
Second cut (15t FW/ha)
Phosphate
25
25
25
0
0
Potassium
120
100
90 (2-) 60 (2+)
0
0
Third cut (9t FW/ha)
Phosphate
15
15
15
0
0
Potassium
80
80
80 (2-) 40 (2+)
0
0
Fourth cut (7t FW/ha)
Phosphate
10
10
10
0
0
Potassium
70
70
70( 2-) 40 (2+)
0
0
*No more than 80 kg of potash should be applied in spring for first cut.
Grazing
P, K or Mg Index
0
1
2
3
4 and higher
Kg/ha
Phosphate Potassium
80 60
50 30 50
20
0 0 0
0 0 0
0 0
Magnesium 100
Applications of Potash to grazing leys should be avoided during the grazing season. If in doubt, consult with one of our FACTS qualified advisors.
Nitrogen Nitrogen is the most important nutrient for yield and must be applied according to levels already present in the soil. Standard soil testing does not measure soil nitrogen, a more complex test is required for assessing nitrogen present in soil. This may be discussed with a member of our fertiliser team. Alternatively, soil nitrogen may be estimated from the AHDB RB209 based on previous management and nitrogen usage. Results from either the soil tests or using the RB209 gives an index similar to Phosphorous and Potassium which can be used to ascertain nitrogen rates. Establishment A small amount of nitrogen is required to boost growth during establishment. Pay particular care to NVZ guidance for autumn sowing. Soil Nitrogen supply Low Moderate High Kg N/ha Spring sown 60 0 0
Summer or autumn Grass and clover swards
30-50
0-30
0
0
0
0
Sulphur Often overlooked in grassland nutrition, sulphur deficiencies are becoming more common as environmental regulation has had an impact on cleaning our air. Sulphur is important in nitrogen utilisation and should be supplied in adequate amounts with nitrogen to ensure maximum yield. Silage - ensure 40kg SO3 before each cut Grazing - 20-30kg SO3 with up to 100 kg/N ha applied and an additional 20-30 kg SO3 for each additional 100 kg N.
Magnesium, Sodium, and other micronutrients
Important for growth and development of grass as it is an essential ion that forms the structure of chlorophyll. Chlorophyll is a component of the leaf where photosynthesis takes place. Photosynthesis is the process in which the plant uses energy from the sun to convert carbon dioxide and water into glucose sugars and oxygen. Encouraging photosynthesis is key to building sugar reserves within the plant, these sugars improve the nutritional value of grass to grazing ruminants and/or offer a feed source to fermenting bacteria to help produce stable silages.
Although nutritionally Sodium does not offer much to the plant, applying sodium is the equivalent to putting salt on your chips, it improves palatability. A critical factor of ruminant nutrition is ensuring the animal is eating sufficient to support production, known as the dry matter intake (DMI). Encouraging DMI enhances digestion of nutrients which will support the animal’s maintenance and production requirements allowing for sustained performance. Whilst applying all other nutrients will support the growth of the plant and defoliating at the correct time will capture maximum nutritional quality, applying sodium to grassland will encourage the animal to eat greater amounts of it. Calcium is also an essential element to consider as part of a nutrition program as it supports the re-growth of grass after defoliation from grazing and/or cutting. As described previosuly, to gain maximum nutritional quality from grass it is recommended to regularly defoliate the plant with appropriate periods of recovery. Calcium assists re-growth as it offers structural support and strength to the developing cell walls and membranes. A strong plant will therefore recover quicker allowing for another opportunity to defoliate. Please contact one of our FACTS qualified advisors for any further advise or information. Call 01243 784171.
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