13 February 2002

Canterbury farmer, John Evans, is test driving technology that weighs up the pros, cons and profitability of some key wheat-growing decisions.

He is one of nine volunteers working alongside the Crop & Food Research team of Pete Jamieson, Rob Zyskowski and Tabitha Armour to mould and refine the computer-based Sirius Wheat Calculator program. This aims to help farmers make the best possible individual decisions on wheat irrigation, nitrogen (N) management, choice of cultivar and sowing date.

Once farmers decide where they're aiming on grain tonnage per ha and protein level, the Calculator uses this and other information to prepare a schedule for irrigation and N management. It also predicts the effects of any changes to the schedule on final profit and yield.

Mr Evans, who farms 271 ha at Dorie, says the Calculator will make wheat growing easier. It has already indicated that late application of N has cost him 2 t/ha in yield. So harvest will be of extra interest to him this year - and also because the program has predicted an amazingly high 15.7 t/ha yield for his Claire biscuit wheat. The Calculator is also being used on his wheat silage crop.

Mr Evans says the program helps farmers to use information they may already have, such as on N levels. "The Calculator can tell you how long the N will last and when to put more on."

Farmers are alerted to inspect their crops on certain dates (determined by the crop's growth stage) so they can check whether fungicide may be needed.

Information fed into the Wheat Calculator on paddock soil type and depth, fertiliser applied, rainfall, irrigation and N status also makes it possible to predict the risk of leaching.

Despite being "all for" the system, Mr Evans would like to see a few more refinements. As well as a more user-friendly screen, these include adding predictions based on all soil nutrients (not just N), and crop diseases.

Dr Jamieson is also keen to include disease information so farmers can assess the cost-benefit of applying fungicide sprays. Information on forage quality, on different cereal crops and even peas, beans and potatoes could all be added.

In the shorter term, localised weather information, even weather forecasts, improved estimates of N, and ways of dealing with problem soils are also possible.

The researchers have been working closely with the Foundation for Arable Research (FAR) and further trialling with a larger group of farmers is likely this year. FAR and Ballance Agrinutrients have also assisted with funding.

Dr Jamieson says the Wheat Calculator is a "flagship" system showing how practical and precise decision support programs can be.

Many different systems could be developed from the Sirius base, he says. Some have already been used in scientific roles in France, the UK, and in the USA's Arizona Desert. Dr Jamieson and Mikhail Semenov, of Britain's Long Ashton Research Station, have been developing Sirius since the mid 1980s.