Early findings from Dairy UP research have shown there are times when the pasture on offer is too high, leaving greater than desired residuals of more than 1700kg DM/ha leading to a potential loss in regrowth.
And in the autumn when growth is slow, residuals can be far lower than the recommended 1700kg DM/ha.
The Dairy UP team has been monitoring 15 farms at Bega, Tocal, Taree and Lismore in NSW, using rising plate meters at five locations on each farm, with results compared to satellite-derived data.
The findings are consistent with previous research which showed a potential loss in regrowth rate of 25 per cent for the following grazing where residual dropped to less than 1300kg DM/ha.
Project lead Professor Yani Garcia said the results highlight the hidden cost of less-than-ideal grazing residuals.
“The challenges that occur when growth rates change rapidly with seasonal conditions,” he said.
“At key times it can be hard to stay with a set rotation length and/or stocking pressure — we need to recognise conditions that slow or speed growth rates and respond quickly.”
Dairy UP is exploring new management options to grow and utilise more kikuyu over summer but moving pasture research forward is not without challenges.
“Satellite imagery is helpful but it needs more refinement and more research,” Prof Garcia said.
“For example, as the regrowth of ryegrass or kikuyu reached canopy cover, the satellite measurements of greenness — and so growth — were less accurate because the reflection of light waves didn’t change, but biomass continued to increase.”
The results were encouraging, but Prof Garcia said that without adding the rising plate meter data, the variations were too high to confidently adjust supplements and grazing.
However, the team believes there is potential in pursuing the use of satellite imagery.
The number of satellites in orbit has increased, providing greater accuracy and the ability to miss cloudy days.
“There’s now a real opportunity to automatically measure and monitor pasture growth,” Prof Garcia said.
The use of advanced sensing technologies is part of a suite of Dairy UP projects that aim to unlock the potential of kikuyu pastures used by NSW dairy farmers.
Other projects are investigating kikuyu varieties, kikuyu poisoning (toxicity) and carbon from kikuyu pastures.
For more information, go to: www.dairyup.com.au
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