Country News

Dookie trials reveal impact of dry season

By Geoff Adams

By Professor Tim Reeves

University of Melbourne

It’s now official that the 2019 annual and growing season rainfalls for Dookie and many other regional locations, were both in decile one — that is in the bottom 10 per cent of all years recorded.

Unsurprisingly, this had an impact on productivity and profitability for both cropping and livestock farms.

Here on the University of Melbourne's Dookie Campus farm we did, however, have a couple of pleasant surprises, with one RR canola crop on wheat stubble yielding 2 tonne/ha and also some reasonable yields from the cereal variety comparison blocks that we established with the collaboration of Baker Seeds, Rutherglen.

These blocks (about 2 ha each) were planted into a wheat stubble (cut for hay in 2018), on May 15, 2019.

Pre-sowing soil cores showed that there was little or no moisture in the top 90 cm of the profile at seeding and the growing season rainfall received was 221 mm. The yields were as follows:

● Trojan wheat 2.9 tonne/ha.
● Vixen wheat 3.0 tonne/ha.
● LPB 14-0392 wheat 2.1 tonne/ha.
● Scepter wheat 2.7 tonne/ha.
● Planet barley 2.5 tonne/ha.
● Spartacus barley 3.5 tonne/ha.

These yields are near the potential for the growing season rainfall and clearly Spartacus barley was the best performer in the tough conditions.

The comparisons attracted plenty of attention and were used by more than 200 students and viewed by a number of growers.

It’s also good to report that many of the local district yields were surprisingly good, with some growers achieving average wheat yields of 3-4 tonne/ha and canola yields from 2-3 tonne/ha — and a significant proportion of the best crops were planted into faba bean stubbles.

I am convinced that legumes should be a significant component of regional farming systems if those systems are to be more sustainable, and it is critical that pulses are persisted with, as all of the research shows that the benefits arising from their use are usually gained over a six or seven year period.

A very experienced colleague who works with leading farmers in southern NSW has been a proponent of using legumes (mainly vetch) as a ‘double break’ in ‘brown manure’ systems and he concluded: "A crop production system involving brown manure legumes, can be as profitable as continuous cropping, but even if slightly less profitable, has considerably less production and financial risk due to lower input and operating costs".

There have been outstanding results from these ‘brown manure’ systems.

Our modern farming systems and technologies have enabled growers to achieve yields that were generally much higher than would have been possible in the past, when similar seasonal conditions were experienced.

I can well recall decile one rainfall years in 1967, 1972, 1982 and a number during the millennium drought period, when successive dry years resulted in average crop yields of around 1 tonne/ha.

We have come a long way because of the successful partnerships between scientists and farmers, but more is needed as long experience has clearly shown that sustainability is a ‘moving target’ and we must keep moving towards more diverse and resilient farming systems.