Despite recent rainfall, the hottest June on record will have affected pasture biomass, warns Janet Montgomery of Barenbrug, a leading grass breeder.
“Although pastures are in a better position than this time last year, it’s important to remember that while the dryness won’t affect the growth stage of grass, it will have an impact on the amount of biomass produced per unit area of pasture,” she says.
“What’s concerning is that the dry spell came at a time when grass growth is at its highest, because of the long hours of sunlight and high temperatures.
“Both on grazing and forage amounts, this could really catch people out,” she warns, “because pastures haven’t been pumping out the amounts of grass that we’d normally expect.”
Advice on stocking levels
To increase pasture resilience Janet offers the following advice.
“On a set-stocking system, reduction in biomass will necessitate a decrease in the stocking rate, while rotational grazers will need to go for a bigger allocation each time.
“That’s especially important for dairy farmers to observe, because both milk quality and output will be affected if steps aren’t taken to manage that drop-off in biomass.”
Sheep and beef farmers, meanwhile, will likely see slower growth rates and a longer time to finishing, Janet suggests.
Pasture preservation during dry conditions
Janet also highlights the importance of pasture preservation during dry conditions to prevent lasting damage: “we need to manage ‘the dry’” she says. Janet gave a number of suggestions to achieve this:
1. Avoid grazing too short: allow sufficient time between grazing and re-grazing to prevent too much damage to the sward.
2. Remove seed heads: while topping might seem counterintuitive in the face of less biomass, taking off seed heads removes stemmy material which makes the pastures more palatable and also encourages the plant to divert energy into vegetative growth.
3. Monitor moisture levels: with consistent periods of dry, a decision-support process will help you to identify the right time to introduce supplementary feeds.
4. Consider changing species: to make pastures and swards more resilient in the face of a drier climate, consider changing species of grass. An autumn overseeding can prove a cost-effective route to help mitigate the effects of future dry periods wher fields are not of an age when they would benefit from a full reseed.
Change grass species to increase pasture resilience
Janet continues: “Consider species that are a little higher in root biomass, such as tall fescue, which will help preserve pastures during dry periods.
“And although cocksfoot and tall fescue have a reputation for being clumpy, coarse and unpalatable, modern varieties make that a largely undeserved reputation. These species are deep-rooting, giving better access to moisture lower down in the soil profile.”
Finally, Janet adds a word of reassurance for farmers concerned about balancing pasture health with livestock welfare. “While pasture health is at greater risk the longer the dry period continues (as grass isn’t able to refill its carbohydrate reserves in time to prevent damage) with time and correct management, it will come back.
“It’s easier to allow plants to recover than to put animals’ welfare at risk.”
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