Good soil management is the key to securing optimal grassland yields, according to Welsh agronomist Gareth Davies.
Soil is made up of 25% air, 28% water, 42% mineral content and 5% organic matter, he said.
“If these ratios are put out of kilter, problems will arise.”
Davies spoke at the recent YFCU agri conference in Co. Tyrone. He pointed out that soil organic matter contains 500kg of nitrogen per hectare.
Of this 150kg can be made available for plant growth, assuming the conditions prevail to allow soil microbes do their job. In essence, this is free nitrogen.
Davies believes that Irish livestock farmers can significantly improve the output they achieve from grazed grass.
“Set stocking is inherently inefficient: rotational grazing systems are not. Rotational grazing is practised, up to a point within the Irish dairy sector.
"But it is an equally valuable tool for beef and sheep farmers. In my opinion, a paddock-based grazing system should be the first priority established for all classes of ruminant livestock."
Davies said that set stocking does not work because the system doesn’t allow for optimal grass re-growth.
“Stock will preferentially select out the most nutritious grasses at all times."
As a result, these plants will not get the chance to recover properly, once they have been grazed off for the first time.
Turning to the management of grazing paddocks, Davies said that “one is the all-important number.”
“The first paddock grazed will always be the indicator of how well grass is growing. As soon as it is ready to be grazed again, once a rotation is underway, stock should be put back into it.
"The other paddocks in the system that had previously been ahead of the stock should be cut for silage.
“By taking this approach farmers will ensure that the grass quality available to their cattle and sheep is always optimal.”
Davies pointed out that rotation periods can range for 21 days to 35 days.
“The absolute priority is that of matching grass availability with the nutritional needs of stock.
“Achieving the highest standards of grassland management is crucially important for the Irish livestock sector.”
