Hybrid rye is an increasingly popular option among farmers supplying feedstocks to biogas plants, offering many agronomic and rotational
benefits, says Elsoms.
Hybrid rye is a crop with a reputation for being hardy and ‘cheap’ to grow and while input costs may be lower than other cereals, careful management is essential to maximise returns, says Elsoms energy and forage manager Heather Oldfield.
“Hybrid rye often performs best on lighter soils, but it can do equally well on heavy land. It is grown widely across Europe in much harsher conditions than the UK, but you must look after it for best results.”
Treat the crop as well as a decent second wheat and the margins can be just as good, adds south Yorkshire farmer Willie Mackintosh, who grows a commercial crop of SU PERFORMER and a range of conventional and hybrid rye in a variety trial.
The total 40-hectare (99 acres) area goes alongside 200ha (494 acres) of maize to supply an on-site AD plant built and operated by Future Biogas. “Hybrid rye is a good crop to grow and responds well if you treat it properly.”
Selecting the most suitable varieties for your farm is the first step in maximising returns, says Mrs Oldfield. With 53% market share, breeder Saaten Union is the hybrid rye market leader in Germany and through Elsoms it offers a range of varieties suited to UK conditions, including:
Hybrid rye is best sown around mid-September at a seed rate of 2.5 units/ha, equivalent to 90-100kg/ha depending on thousand grain weight. Mrs Oldfield recommends increasing rates by about 10% for every 10-14 days after mid-September as establishment conditions normally worsen.
While rye has been successfully sown on light land into November and December, she says winter triticale is usually a better option for sowing beyond mid-October, as cold, wet soils can restrict rye establishment. “Hybrid rye’s prostrate growth habit covers the ground well, it begins growing earlier than any other cereal in the spring,” she says.
Drilling depth must not exceed 2cm as rye has a weaker coleoptile than wheat and barley, she adds.
Support early growth
A key feature of hybrid rye is its ability to start growing at lower temperatures than barley in spring. This early growth must be supported with a prompt nitrogen application as soon as field conditions allow in February, Mrs Oldfield says.
The optimum is about 150kg N/ha and should be split equally between February and late March/early April applications. It is an approach favoured by Mr Mackintosh, who typically applies 150-170kg N/ha in two splits, and also by Lincolnshire farmer and agronomist Harvey Smith who opts for two equal doses of about 90kg N/ha on his 75ha of SU COSSANI grown for a local AD plant.
Yield plateaus occur around 180kg N/ha (with slight variations depending on variety), while applying less than 150kg N/ha risks sub-optimal yields, Mrs Oldfield notes. Although hybrid rye is a ‘fantastic scavenger’ for water and nutrients, it can be quite potash hungry and growers must ensure other macro and micro nutrients are not deficient.
Modern hybrid rye varieties require one to two fungicides each season, with late-season brown rust and mildew being the main issues to watch out for. Brown rust has no significant wholecrop yield impact if infection occurs after flowering, but outbreaks prior to this should be controlled quickly, Mrs Oldfield says.
For Mr Smith, this typically involves a single tebuconazolebased fungicide, such as Folicur, around late April to protect crops against brown rust well into May. In higher-risk seasons he says there may be a need for an earlier fungicide to tackle early rusts and mildew, which is typically applied with the first PGR at GS 30-31. “A lot of cereal fungicides are approved for use in rye, but always check the label first.”
He acknowledges lodging has been an issue with conventional rye in the past, but insists there have been no issues with his hybrid varieties. “It grows to around 5ft tall and stands very nicely.” Crops receive two trinexapac-ethyl-based PGRs at the traditional cereal timings around GS 30-31 (Moddus/ Tempo) and GS 32-33 (Medax Max).
Mr Mackintosh also highlights the importance of PGRs in minimising lodging risk and associated harvesting difficulties. He opts for one to two growth regulators according to field conditions.
Foraging of Hybrid rye should ideally begin at 32-33% dry matter, this usually occurs around the end of June / early July. Crops should be cut before reaching 38%-40% DM, says Mrs Oldfield.
Yields are typically 45-53t/ha freshweight, which equates to 15-18t/ha DM. Clearing fields early spreads workloads and provides a good opportunity to apply digestate and to establish early-sown following crops such as cover crops or oilseed rape.
Mrs Oldfield says it is possible to use the early-maturing conventional rye variety GENERATOR for double cropping. GENERATOR matures in mid-May/ early June, which gives just enough time to sow a following maize crop. “There is a 15-20% yield penalty from the early maturity, but at the same time, you are getting more crop off that land.”
While ergot can be a concern when growing rye for seed, Mrs Oldfield says modern varieties minimise this risk.
SU’s ‘turbo technology’ mixes a small amount of conventional rye seed (Dukato) with every batch of hybrid rye to act as a supply of pollen within the flowering crop and prevent ergot forming, she explains.
Black-grass control is a key attraction of hybrid rye, as the crop’s prostrate autumn growth and height later in the season competes with the weed, while whole-crop harvesting for forage in June/ early July minimises seed return. “It’s by no means a silver bullet, but can be a useful part of any control strategy,” says Mrs Oldfield.
It is a key benefit of the crop for Mr Smith, who manages 1,011ha (2,500 acres) of combinable crops on heavy silt and silty clay loams near Spalding. “We are plagued with black-grass, but have found rye does a very good job at cleaning the land. Some of the worst fields may have two consecutive rye crops.” Although black-grass has set seed by the time crops are foraged in June, little has been shed and much of the seed is unviable, he notes.