What is precision farming?

'Enormous' and 'tremendous' are words frequently heard from farmers trying to quantify potential benefits from the use of yield maps and global positioning systems (GPS) — the backbone of precision farming.

Using the new technologies, growers can see clearly which bits of the paddock are earning their keep. Even the poorest readings can have an upside — by showing that some land is not worth the expense of time and fertiliser, or perhaps can be better used to grow a belt of trees.

Precision farming does away with the idea of 'good paddocks' and 'bad paddocks'. Instead, it allows the farmer to identify different areas within a single paddock and give each area special attention.

Farmers will tell you 'most of my paddocks are pretty average.' But those using the systems for the first time report repeated surprise at the range of variation in their 'average' paddocks.

Two farmers in the Wagga Wagga (NSW) district used yield monitors on their 1995 harvest and found that their average 6 t/ha wheat crop in fact varied from 2 t/ha to 9 t/ha. Triticale, canola and lupins showed similarly large variations. Monitors in Victoria and Western Australia gave equally surprising results.

Precision farming can detect and pinpoint disease or insects, drought or waterlogging, lack of fertiliser, differences in soils and their chemistry and structure, soil compaction, acidity and salinity, weeds and differences in growth and emergence.

Which way the future?

US farmers already have access to hardware and software for controlling a range of inputs to their crops. Automatic systems control irrigation flows, regulate application of sprays and fertiliser and measure seeding rates, all in response to previously generated maps of the cropping area. These 'variable rate' systems aim to ensure maximum returns with the least possible inputs.

Not all Australian farmers and researchers are yet convinced that this is the way to maximise benefits from the technology. While they are wildly enthusiastic about the benefits that will flow from better information, they point to differences between Australian and US conditions, especially the wide variations in Australian crop yields.