Chris and Sarah Roche
'Reedsdale'
Gulargambone NSW

Joining a local climate study group prompted Chris and Sarah Roche to align their cropping rotations closely with the seasonal outlook each year, allowing them to better profit from their sub soil moisture and actual rainfall during the year. 'Reedsdale' is a 1591 hectare mixed cereal farm growing wheat, lupins and canola, plus running merino sheep and fat lambs. Chris and Sarah have farmed the property since 1992. The climate study group was started by the local office of Agriculture NSW as part of a Grains Research and Development Corporation-funded trial to aid producers in using climate information. Applied climatologists Roger Stone from the Queensland Centre for Climate Applications, Peter Hayman and Kirrily Pollock from Agriculture NSW visited the group and gave instruction on several occasions.

'At the beginning we would report back to Kirrily every week about our decision making and how the weather and climate information affected it' said Chris.

'One of the main things we came to understand was how probabilities worked in relation to climate.'

The group used the 'chocolate wheel' model developed by Peter Hayman as a way of understanding probabilities. This method shows the seasonal probabilities in relation to the Southern Oscillation Index on a pie chart. For example, a falling SOI in April/May results in pie chart showing a 38% change of normal rainfall, a 29% chance of lower than average rainfall and a 33% chance of higher than average rainfall for the district.

'You have to spin the wheel like a chocolate wheel and the needle can still be anywhere when the wheel stops spinning, but the chances of it being in the normal range are higher' said Chris.

'It's a good way of getting farmers to understand the probabilities of climate forecasting. It shows that it's not about exact prediction.

'I use the pie graphs in conjunction with measuring our sub soil moisture to make decisions about our rotations.

'If the SOI is falling or negative and I've got low sub soil moisture, I would long fallow to take advantage of any extra moisture. Under that rotation I would be looking at three wheat crops in five years.

'I used to always crop long fallow like this, but in an above average rainfall year a lot of moisture would be wasted. After studying climate in more detail, I saw that in certain years I could crop back-to-back instead.

'This year we have a full profile of moisture and a rising SOI, so I will grow pulse crops instead of fallowing.

'Combined with zero-till and no grazing on our cropping country, we are getting better moisture retention and we are better able to make use of high rainfall years.'

Chris and Sarah use seasonal outlooks to make decisions about the application of nitrogen fertiliser.

'It's better to put the nitrogen out early - the plant will grow better and you can use a cheaper form of fertiliser' said Chris. 'Knowing what rainfall is most probable gives me more confidence to pre-drill the crop with nitrogen.'

Chris and Sarah look at three key issues when deciding their crop rotations: sub soil moisture, gross margins and disease problems. The SOI is the next factor that comes into account because it is a probability.

'It's not definite, but it's a big tool when we decide what to grow next time' said Chris.

'Improving our rotations and getting some extra crops have put more safety into the farming operation and improved risk management' said Chris. 'This year we hope to see a big improvement in profit.'

The farm is also becoming more environmentally sustainable with the use of an extra decision-making tool.

'In 1998 the indications were that the season would be very wet and we decided not to put stock in with the stubble to avoid compaction' said Chris.

'We didn't rip up any country at all and consequently when other farmers lost tonnes of soil, we didn't lose any. Instead, we were able to burn off very late and sow again.'

'I also decided to top-dress all my roads to make sure the grain could get in and out in a wet season. It wasn't exactly a farming decision, but it paid off!'

Chris has one big item on his wish list: getting an SOI-based indication of winter rainfall one month earlier.

'I could avoid spending a lot of money if I had that information earlier' said Chris.

'I'd also like to know more about the north-west cloud band and how it links up with the SOI. There's not much information on how it operates in New South Wales but I think it's very important for us.

'The main thing to understand is the probabilities side of things - there is nothing exact about the climate but knowing about it is a great tool for decision-making.'