Listening to graingrowers talk about the weather

Melissa Rebbeck (left) at a workshop with farmers

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.

Melissa 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 recognised.

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 decisions.

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 nitrogen.

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

Region National, North, South, West