Precison farming: Paddocks work harder

WA graingrower Doug Maitland points to the monitor in his harvester linked to a Global Positioning System.

Space-age technology is being adapted to the needs of Australian graingrowers. Following are two 'you-beaut' ideas — Ed.

Farmers Doug and Noela Maitland, from Wyalkatchem, WA don't have to guess how much money they could save each year by applying fertilisers or sprays to crops only where they are needed — they know.

They have been involved in a trial of a satellite-guided precision farming system which pinpoints crop yield as it varies within each paddock. The system is jointly supported by the CSIRO Division of Soils, Agriculture WA and the Grains Research and Development Corporation.

"It was incredible to see the real yield variation within one paddock using this technology," Mr Maitland said.

"Where we had visually estimated a 2 t/ha yield across one particular paddock, it actually varied from 3.5 t/ha in some spots to 1.5 t/ha in others. This new knowledge means we will be able to maximise our yield potential by varying the phosphate, seeding and chemical rates to better suit the whole paddock's needs."

The Maitlands farm a 2,000 hectare property at Wyalkatchem, about 200 kilometres north-east of Perth. They grow cereals and lupins and, in 1995, sowed 1,200 hectares of wheat, 400 hectares of lupins and 400 hectares of barley.

According to the scientists involved, CSIRO's Simon Cook and AWA's Glen Reithmuller, precision farming is expanding rapidly in the United States and is being trialed on a number of properties in the Wyalkatchem, Esperance, Wannamal and Newdegate areas of the WA wheatbelt.

"Given that yields routinely vary three- or four-fold within a single paddock, the potential for improvement is large," Dr Cook said.

"The idea of precision farming is to use paddock-by-paddock maps of last year's yield to decide how best to manage the crop in the following year," he said.

"The maps are produced by linking a monitor in the harvester to a Global Positioning System or GPS which records yield as it varies over the paddock. These maps can subsequently be used to guide variable rate spreaders or sprayers over the same area."

Dr Cook said the basic challenge for producers was to separate the soil potential, which can't be changed, from the soil status, which can. Precision farming is the first step to achieving this. It answers the question: "Will this part of the paddock respond to more fertiliser or am I merely throwing good money after bad?"

"Further research is needed to combine the yield maps with soil testing and other information to improve the accuracy of the answers even further," he said.

Improved estimations of yield potential would be beneficial not only to the WA wheatbelt, but to grainproducing properties in the temperate zone across Australia.

Subprogram 3.5.03 Contact: Dr Simon Cook 09 387 0138