DEREK TICKNER

Last year, the Grains Research and Development Corporation and CSIRO released the results of a study of six farms that use information technology. The report was entitled, The Economic Benefits of Precision Agriculture: Case Studies From Australian Grain Farms. The project was led by Michael Robertson from CSIRO Sustainable Ecosystems in Western Australia.

The initial capital investment of the participants varied from $55,000 to $189,000. Looked at another way, farmers spent somewhere between $14 and $44 per hectare. The estimated annual benefit varied from $14 to $30 per hectare. On average, the original investment was recovered within three years.

Financial savings come from several areas, according to the report. Guidance systems and auto booms reduce spraying overlap, saving around 10 per cent on costs. 'Other benefits nominated by farmers and estimated by us were: less fuel use, less soil compaction, less hired labour requirement and more timely sowing,' the study reports.

Intangible benefits listed by farmers included the ability to conduct on-farm trials; increased knowledge of the variability in their paddocks; and increased confidence in varying fertiliser rates. They also noted better in-crop weed control due to shielded spraying.

But what exactly is precision agriculture? It relies on GIS and GPS technologies. GIS software is more powerful and easier to use than ever before. Farmers are able to manage and analyse their data much better than they could using pencil and paper – or intuition.

GPS accuracies continue to improve: tractors and harvesters can now auto-steer to within 2 cm. This minimises double spraying or missed strips, improves accuracy when the driver is fatigued and enables precision night driving.

This is important because individual paddocks often deliver a significant variation in crop yield. This is due to factors such as variations in soil type and nutrient levels, slope, drainage, aspect (for sun and wind exposure), salinity and pest activity.

Sowing the same crop variety and blanket spreading equal coverage of fertiliser, pesticide and water across an entire field can result in sub-optimal yield and wasted inputs.

Precision agriculture starts by gathering data from inside the boundaries of the field. GPS-derived points – showing soil sampling locations, drainage or moisture content – can all be used to create layers in the GIS. Topographic maps, aerial photography and the farmer's intrinsic knowledge of the paddock create other layers.

Crop yield is monitored by a sensor connected to a GPS receiver. This monitor continuously records the yield as a function of position. The raw data from the monitor – position, time and pressure – is run through an algorithm to produce a yield map, showing any variation within the paddock.

The GIS manages and graphically displays this data. The operator is then able to search for the factors that influence yield. Advanced analysis involves running predictive models with various combinations of input quantities and composition. The combination of chemical fertilisers – less phosphate, more nitrate – can then be altered in high and low-yield areas in the field. Nutrient, pesticide and water volumes can be optimised.

The implication is that inputs to the field need to be applied with the same resolution as the variations detected by the yield monitor. This can be achieved with variable rate technology. A GPSlinked variable rate sprayer or spreader follows instructions from an on-board computer that has been programmed for that paddock by the GPS. The optimal input/yield ratio is refined in conjunction with yield mapping and/or electromagnetic induction mapping of the soils.

So why is this important? The population of the world has grown drastically over the last 60 years, from 2.5 billion in 1950 to 6.7 billion today. A major factor in this increase is the success of agriculture's Green Revolution.

Between 1950 and 1985, world grain production jumped by 250 per cent, due to four factors. Certainly the massive increase in the application of inorganic fertilisers and pesticides and improved irrigation technologies contributed.

Greater mechanisation – dating from the Industrial Revolution – was also a factor, along with sustained scientific research that has produced betteryielding crop varieties.

Mechanisation has changed the face of the countryside. Small blocks have been amalgamated into broad-acre fields, and native trees and vegetation have been ripped out to provide a wide, efficient, homogenised landscape.

Agriculture is now in the middle of another transformation, as the Green Revolution embraces the analytical potency and data crunching power of the IT Revolution.

Farmers around the world are adopting precision agriculture systems, resulting in further improvements in crop yields. This benefits both the farmer – through fewer input expenses – and the natural environment, due to less pollutant run-off and more efficient use of water.

Another benefit is that farmers get to use and understand GIS software, which has great potential for efficient farm management. Robertson says, 'To my knowledge, these farmers would not have been using GIS before commencing yield mapping.'

It's proving difficult to quantify how many farmers are adopting all or parts of the new technology. 'The survey figures of variable rate adoption – as opposed to controlled traffic and guidance – are low, but from a pretty small survey with a low response rate,' he says.

'To my knowledge, I would guess no more than 30 growers in WA would be using variable rate technology. Many more would use yield mapping – maybe 300 – and many more again employ controlled traffic and steering guidance.'

There are strong reasons for society as a whole to be worried by such low numbers. In the UK, it took around a thousand years for wheat yields to increase from 0.5 to 2 tonnes per hectare. Between 1950 and 1990, yields jumped from 2 to 6 tonnes, thanks to the Green Revolution.

Information technology is poised to increase yields even further. It is also helping to minimise the application of agrichemicals, so that not only do farmer and consumers profit, the natural environment benefits too.

Rising oil and fertiliser prices, increasing demand for food and the impact of climate change are all causes of higher food prices. In some poorer countries, the result is riots and looting. Precision agriculture is an important weapon in the battle to overcome such problems. It can increase food production and decrease production costs, both locally and globally.

CASE STUDY: Precision Agriculture in the Sugar Industry

Economic and environmental factors are pushing the sugar cane industry to implement precision agriculture. In Australia, profit margins from sugar farming are currently very low, due to cheaper production costs in Brazil and sharp increases in fertiliser and diesel prices.

The Herbert Valley sugar region is sandwiched between two environmentally sensitive areas, the Great Barrier Reef Marine Park and the rainforests of the Wet Tropics World Heritage Area. It is hoped that precision agriculture will prove useful in helping to minimise agrichemical runoff, which has been blamed for algal blooming and bleaching of the Reef.

Sugar farms in the Herbert are typically small, family-run holdings. Often, individual farmers lack the knowledge – or the confidence – to implement and run precision agriculture by themselves.

An 'across the region' approach has been adopted, involving groups such as Herbert Cane Productivity Services (HCPSL), CSR Sugar and the Herbert Resource Information Centre. The HRIC collects, administers and analyses the GIS data for the region (see the article 'Success Through Collaboration', Position, Issue 35).

The groundwork for precision agriculture in the Herbert was laid down in the 1990s. The soils were extensively mapped and annual record keeping was commenced for cane yield in tonnes per hectare, and for the sugar content of the cane stalks.

The sugar industry in the Herbert decided to trial precision agriculture as the technology improved and became cheaper. Funding came from the federal government's Sugar Package and from the Regional Community Partnership Program.

Thirteen community GPS base and repeater stations were set up around the Herbert Valley in 2006. In 2007, yield monitoring equipment, GPS receivers and on-board computers were installed in 35 of the region's 80 cane harvesters.

This yield data is currently stored in a flash card memory for downloading and processing at the end of the day. HCPSL is planning to implement wireless data transfer using Telstra's Next G Network so real time yield maps can be generated.

The GPS base stations have also enabled the laser levelling of cane blocks for optimal drainage, and allowed for the provision of auto steer on the tractors and harvesters.

Cane yield is traditionally calculated from tonnage recorded at the weighbridge of the sugar mill divided by the block's area. But that meant that yield could only be shown for the whole block (see Map 1). With on-board GPS-linked yield monitoring, yield data can be recorded inside the block (Map 2).

As I write, the 2008 harvest season is well under way. This year, all the harvesters are fitted with GPS units. They supply data for live tracking, noting which paddock has been cut at what time. Fifty harvesters also carry yield monitors.

Gigabytes of data are being generated. The challenge is to convert this raw data into useful information and develop applications that promote best farm practices. Quickly disseminating this knowledge to interested parties – individual farmers, the sugar mill, other research groups, etc. – is therefore desirable. The HRIC is planning a web-based enterprise GIS, so that maps can be published online.

Ron Kerkwyk, the manager of HCPSL, says, 'We believe that growers will use computers and the websites to look at their maps, harvesting results, etc. But only a very low percentage will use GIS software themselves.'

What will the cost savings be? 'Using yield maps in conjunction with precision agriculture will potentially result in savings of around 15 per cent,' says Kerkwyk. 'Looking at yield variation usually results in a redistribution of inputs such as nutrients, ameliorants and the like.'

This means that the farmer will be able to spread the right mix of inputs more effectively.

The increase in yield and profit will help keep the Australian sugar industry competitive in the global market.

Derek Tickner is a freelance writer/photographer and GIS officer with the Herbert Resource Information Centre.
 
 
Issue 37; October – November 2008