Across Australia, rainfall and temperature conditions have combined to have a significant impact on pasture biomass in all states and territories. The Bureau of Meteorology reports the National Rainfall was 49.5% below the 1961-1990 average, making this year the 10th driest on record. Temperatures were 2.28C above average, making this August the second warmest on average.
The impact of these events, combined with above average temperatures have strongly influenced the national pasture biomass.
For the week ending 1 September 2023, there are noticeable changes in Total Standing Dry Matter in the two weeks since the 18th of August summary.
In particular the western Darling Downs in Qld, Western and Central Western regions of NSW and the eastern portions of Western Australia have recorded significant declines in Total Standing Dry matter, (evidenced by the increase in shading of red and amber).
While TSDM in northern Australia remains high, the areas above 2000kg TSDM/Ha are retracting to areas closer to the coast in both the Gulf of Carpentaria and the northern portions of the NT and WA Kimberley.
These changes are also noticeable in the National TSDM Seasonal Ranking. The Western Kimberley areas that are below 40% of the seasonal ranking have expanded, as have the Queensland & SA Channel Country.
The Barkley Tablelands remains the only major region exceeding 90% of the seasonal rankings in the past two weeks, reflecting the high TSDM accumulated this year.
Pasture Biomass Growth events (as indicated by Fractional Cover) reflect the increase in winter crop growth through central NSW, Victoria, and Southwest WA. The area of active growth (green shading) has increased noticeably in these areas in the past two weeks.
Tasmania and the Eyre Peninsula and south-eastern SA also show strong signs of spring pasture and crop growth.
The Green Portion of Total Standing Dry Matter has started to decline in northern Australia, reflecting the final stages of the annual dry season. High levels of green material are now retracting to waterways and areas of stored moisture.
In southern Australia despite growth from crops and some spring growth, the amount of green Dry matter in pastures is largely between 500 – 1250kg/ DM / Ha.
This suggests livestock producers will still need to manage for low levels of green in feed intake and manage according to high levels of dead and low-quality feed in diets.
As to be expected the Dead Component of Dry Matter continues to be the major contributor to the overall totals of TSDM across the country.
The dryer and hotter conditions have seen an increase in pasture senesce in central and north-western Queensland. Areas north of Roma still have large amounts of dead standing matter, posing a risk from both livestock production and contributing to the potential fuel levels for fire.