In the first of a series of webinars organised by GrassCheck GB, the methods and mixtures required for a successful grass reseed were discussed.
The amount of grass grown, and utilised, on livestock farms is widely acknowledged as being a key
driver for profitability.
With this in mind Helen Mathieu, of Germinal GB, said it was a ‘false economy’ not to reseed. She said: “One of the best returns on investment available to livestock farmers is reseeding.
“A higher percentage of perennial ryegrass will give greater yields and quality, increasing output and
reducing bought-in feed costs.”
She added a reseed was a good time to tackle weed and compaction issues, and was also an opportunity to introduce modern varieties and improve pasture response to nutrients.
She said a full reseed would cost about £178/acre (£440/hectare), which included all field operations, fertiliser and seed.
“However, to counter this cost a new ley, containing about 95 per cent perennial ryegrass has the potential to yield about 13 tonnes dry matter (DM) per hectare at 12 metabolisable energy (ME).
“This is in contrast to a three or four-year-old ley containing 70 per cent perennial ryegrass, which typically yields about 9.5t DM/ha at 11.3 ME.
“A permanent pasture containing 50 per cent perennial ryegrass would yield about 7t DM/ha at 10.5 ME.”
When it came to selecting fields for a reseed, Ms Mathieu said it was important to identify under-performing fields by regularly walking swards and using any grass growth data available.
“Then it is important to check the reasons why a particular field is under-performing,” she said.
“Make sure you have an up to date soil test, walk the field and make surface assessments and check for any underlying issues, such as compaction.
“Check sward composition to see what is left of what was sown, and assess ground cover to see how dense the ley is.”
She added this was a good time to carry out any drainage work that needed doing.
However, she advised growers against basing reseeding decisions on how grass currently looked given the recent dry conditions.
“All grass looks stressed now, so do not base opinions on what it is like now,” she said. “We will need to see how it looks once it has had chance to recover.”
Ms Mathieu said timing of reseeding was to a large extent down to a farm’s particular system, soil type and rotation preferences.
“Spring reseeding is influenced by the weather, but it can offer greater opportunities,” she said.
“Unless you are using an annual species, there is no seed heading in the first year and it is easier to control weeds if necessary.”
She added by reseeding in spring there was also an opportunity for a break crop to be put in. However, she said a spring reseed could offer lesser yield potential, and depending on the method used, the soil might be too tender to travel or graze early on.
In contrast an autumn reseed offered the opportunity to get the maximum yield off a field before reseeding, and then get a full yield the following year as the soil has chance to settle prior to grazing or travel.
However, Ms Mathieu said depending on the season and the previous crop there could be a narrower window of opportunity compared to spring sowing.
Ms Mathieu added the method of reseeding depended on a farm’s particular conditions. “Ploughing will produce a fine, firm and level seed bed, but it can bring potentially less fertile soil to the surface as well as disturbing banks of weeds,” she said.
She added there were many different min-till methods, which all had their place and could work well in the right circumstances.
When it came to selecting a mixture, Ms Mathieu said it was important to think what was needed from the grass ley.
“When looking at different species, think about what you want in terms of longevity, yield and season growth,” she said.
“And then when looking at varieties you will want to focus on quality, yield, heading date, seasonal growth, persistence and disease.
“If you are going to silage the ley, you need to consider when and how often you want to be mowing it, and if it is going to be a grazing ley then think about what the grazing priority will be and what species is going to be grazing it.”