By Dr Peter Hayman, South Australian Research and Development Institute
It is a cliche that farmers are always talking about the weather. However,
it is a cliche for a good reason, as farmers know the impact seasons have
not only on their crops but their livelihood, families and rural communities.
Rebbeck, senior research officer at the South Australian Research and
Development Institute (SARDI), has been working with colleagues from CSIRO
Marine and Atmospheric Research in a project "Oceans to Grains", part-funded
by the GRDC through the Managing Climate Variability Program. Ms Rebbeck"s
role is to help the project engage with graingrowers to ensure there is
a flow of information from grain farms back to oceanographers.
Photo: Melissa Rebbeck (left) at a workshop with farmers.
In a series of workshops at Campbell Town in northern Tasmania, Karoonda
in the Murray Mallee of SA and Birchip in the Wimmera Mallee, the project
team worked with growers to find out more about their management decisions.
Growers were asked to describe what they saw as an exceptionally good
season. At all three locations, growers wanted an early break to the season.
Although definitions of a break differ from region to region and farm
to farm, it is well recognised that the earlier the break, the better
the outcome for that season. In the Murray Mallee and Birchip regions,
the importance of stored soil water from summer and early autumn was also
Following an early break, graingrowers focused on a mild spring, with
rain at the right time and no late frost, and then a dry harvest with
no strong winds. Tasmanian farmers" main interest in winter was that it
was not too wet or cold, while drier winters were seldom requested in
Birchip or the Murray Mallee.
This description of good seasons provides a useful catalogue of the climate
risks of farming. The exact combination of everything going right is a
rare, almost impossible event. These discussions also provide an indicator
of some of the management options to minimise these risks. For example,
with no till and larger machinery, farmers are able to take advantage
of an early break but, more importantly, are able to manage the risks
of a late break. The widespread use of dry sowing this year is another
example of managing late breaks.
The difficult trade-offs of aiming for grain crops to flower after the
last frost but before the hot dry spring is well known to most growers.
A suite of varieties, a good understanding of frost risk in the region
and across the farm and some interesting agronomic techniques to minimise
frost risk can be added to the old risk-management strategy of diversification.
In addition to the tried and true methods of managing climate risks,
there is the increasing question of whether the season ahead can be forecast.
In a large national survey, about 40 per cent of farmers in Australia
said that they took seasonal forecasts into account when making farm management
Ms Rebbeck has spent eight years asking graingrowers what their climate
risks are and what they would adjust with information on the coming season.
She points out that in general, low rainfall farmers speak of adjusting
crop area, then crop type, then inputs. In contrast, higher-rainfall regions
seldom adjust crop area, but will adjust crop type and crop inputs, especially
Ms Rebbeck notes that the strength of risk management in low-rainfall
regions is the ability to set a series of trigger points (say a date for
the break of season) and develop appropriate management responses on crop
area and type. In contrast, the higher rainfall regions often manage risk
through complex diversity of crops and enterprises.
A challenge is to ensure that seasonal climate forecasts work with these
risk-management strategies rather than against them. An over-reliance
on seasonal forecasts could cause a low-rainfall farmer to ignore their
trigger points and bet too heavily on a good season. Likewise, over-reliance
on a seasonal forecast could cause a high rainfall farmer to lean too
heavily one way and go for a single optimum crop, and in doing so miss
the benefits of diversity.
A perfect seasonal climate forecast would replace risk management. We
are likely to see improvements in the timing, accuracy and usefulness
of seasonal forecasting. However, it will still be the case that seasonal
climate forecasts have enough information for graingrowers to adjust their
risk-management strategies, but are not accurate enough for them to ignore
sound risk management.
GRDC Research Code LWR25
For more information: Dr Peter Hayman, 08 8303 9729
National, North, South, West