Giving grass a helping hand with an arable approach
30 May 2019
As farmers strive for more milk from forage, are there any lessons from our cereal-growing cousins to help get more from our raw material: grass?
For a more sustainable dairy business, there’s little doubting the value of maximising milk from forage – both grazing and silage.
Key to this is getting the most from every hectare or tonne of crop.
Arable farmers focus on this consistently. But is there scope for dairy farmers to bring an arable level of precision to producing grass?
Bryn Thomas, general manager of Shropshire and Welsh borders agricultural merchant, Spunhill, who advises on both arable and livestock farms, believes in some cases there is.
“While a percentage of grass farmers are certainly doing a lot of things right, it’s always worth keeping an open mind to see what can be learned,” says Mr Thomas.
Arable farmers are focused solely on crop output. The yield and value of the crop can be measured directly at harvest. With dairy farms, the focus is on milk production and the crop is one step removed from this. But when steps are taken to improve grass and silage, it’s not unusual to see significant gains.
Arguably the focus should be on milk production per hectare. Pushing ME from 10.5 to 11.5 can make a big difference,” he says.
As an example, Mr Thomas says wheat growers will spend a lot of time choosing the right varieties to meet their needs for yield and quality, as well as the agronomic needs of the farm.
Livestock farmers do this also, he stresses, but with grass crops in the ground for much longer, choosing the right variety mixtures is even more important – particularly with so many grass types to choose from: such as Italian and perennial ryegrasses, hybrids, and different heading dates. Between varieties of grass, there is also a great range of agronomic and nutrient characteristics, he notes.
“Wheat is an annual crop, so the wrong variety choice one year can easily be rectified with a different variety the year after,” says Mr Thomas. “With grass the ley is down for much longer. So correct variety choice has a longer term impact on the bottom line.
The other question to ask is: are you reseeding often enough? You should be looking to reseed every 4-5 years. After that, swards start to lose quality. AHDB figures show even in a 5-year old ley, the sown rye-grass content of the sward can fall below 80%. This results in a yield and ME reduction and the cost of concentrate to replace lost yield and feed value will approach £500/ha.
Attention to detail with timings of key field operations could be another area where grass production benefits from an arable type mindset, believes Mr Thomas, most notably the timing of cutting for silage.
As an example, he says when applying fungicides cereal growers and agronomists will carefully inspect crops to ensure treatments are applied at the precisely the right growth stage, even dissecting plants to identify which leaves have emerged.
Although fungicides are rarely used in grassland, he believes a similar level of crop scrutiny is beneficial with grass to predict heading dates, so that cutting can be timed before quality starts to decline.
Indeed, there is less leeway with growth stage for cutting grass than there is with harvest date for cereals, he maintains.
“With cereals, once the crop has reached maturity it can sit there for a reasonable time period,” says Mr Thomas. “But grass is cut while it’s still growing, so will keep progressing through growth stages and can soon be past its prime.”
Volac silage expert, Darran Ward, agrees.
After heading, the digestibility of grass falls by 0.5% per day,” Mr Ward stresses. “So even a week’s cutting delay loses 3.5 D units. To get the best quality you have to be able to anticipate heading so that you cut before this,” he says.
Wilting wish list
Although cereal growers have more control over grain drying than livestock farmers do when wilting grass – with any final grain drying controlled carefully in store rather than being at the mercy of the weather in the field – Mr Thomas believes silage production can still learn lessons from the precise targeting of dry matter percentage that cereal growers use.
“Arable farmers pay a lot of attention to drying grain to precisely 14.5% moisture (85.5% dry matter) for optimum storage. Similar attention should be put into wilting grass accurately to 30% dry matter.
“Achieving this not only helps reduce effluent losses from making silage too wet or heating losses from being made too dry, it also helps the crop ferment better in the clamp. Also, the shorter you make the wilting period to 30% dry matter, the better the quality,” he says.
Darran Ward agrees. He says:
Grass wilts most rapidly the first two hours after cutting, so ted as soon as you can. You should be aiming to get to 30% dry matter within 24 hours.
Another area where there can be key lessons is in preparing the crop for storage, Mr Thomas believes.
Grain farmers are fastidious when it comes to store hygiene, he points out, for example disinfecting before harvest and using an insecticide to control unwanted pests that would cause grain to heat up in-store.
And there are similar opportunities to be thorough when ensiling grass for a better preservation, he highlights, in particular: thorough clamp cleaning to minimise mould spores carrying over from last season’s silage; use of a proven additive such as Ecosyl to put you in better control of the fermentation; and ensuring thorough clamp consolidation, sheeting and weighting to keep out air.
“Grain can still be managed when it’s in store, for example by blowing air through it to cool it down. But once grass is in the clamp you can’t do anything about it. So you’ve got to get everything right at the time of ensiling,” he explains.
A quality additive is effectively controlling the ‘bugs’ of bad bacteria and moulds that reduce silage dry matter and nutrient quality in a similar way to an insecticide controlling insect ‘bugs’ that cause grain problems. By better managing the fermentation you are better managing your grass in store.
When it comes to crop productivity, Mr Thomas says arable farmers also know that irrespective of grain price they have to control weeds problems if crop output is to be maintained.
Most livestock farmers are also good at weed control, he says, especially annual weeds when establishing new leys. But decisions over perennial weed control can often be driven by milk price, he has noticed, when in fact the weed threshold for treatment doesn’t change.
“There is scope for greater awareness of the thresholds for controlling weeds in grassland. With docks, for instance, 1% ground cover equates to 1% yield loss. Arguably, a low milk price makes it even more important to maximise productivity from grass.
“Another area to pay attention to is the timing for spraying off perennial weed species. The best time is spring when they are actively growing. This can clash with harvesting or grazing, but it is important to prioritise,” he says.
“Fertiliser applications are also finely-tuned in cereals. With grassland, a lot of nutrients come from slurry. But it’s very important to accurately account for the level of nutrients this provides when applying bagged fertiliser. Getting this wrong can waste fertiliser or damage yield.
“Soil sampling on a regular 3-4 year basis is also vital to maintain soil pH and nutrient levels,” he concludes.