What happened to the adoption of Variable Rate Technology?

Every grain farmer in Australia can benefit from this technology; the message that needs to be heard is that this does not have to be complicated and there are simple ways to start implementing this technology. SST can help you develop a system and procedures that will see you reaping the benefits of the most exciting component of Precision Farming.

Most articles about precision farming technology are totally focussed on some form of steering technology. This individual component of precision farming has developed significantly and most of the technology is simply brilliant; there are some excellent products and the pricing has made some form of the technology affordable for almost every grain farmer in Australia.  So it is no surprise that a product that delivers immediate and tangible benefits like assisted steering attracts a lot of attention.

However, it seems to me that there is a reluctance by many farmers and equipment resellers to pursue Variable Rate Technology (VRT) of crucial inputs. I have seen little advancement in the adoption of this technology in the number of years since I was full time in the precision farming industry. Why is this? I would like to discuss some key points that will hopefully encourage readers to think hard about this opportunity.

Common objections to VRA technology

Most GPS equipment resellers have no knowledge about agronomy or growing crops. So it is no surprise that these individuals would possess some trepidation when it comes to properly understanding VRT. This should not be a strong enough reason for farmers to not pursue the technology. However, it is crucial that the equipment suppliers give farmers concise and accurate information about what their equipment is capable of. And this is completely related to the issue of compatibility.

The next key issue is the use of software and the creation of what the industry calls a “prescription” – the digital instructions that tell a VRT controller what to do and where to put “x” amount of the desired input. Without exception, this can only be properly achieved using a Geographic Information System (GIS) and again the understanding and application of these systems is not the domain of equipment resellers. Lastly, there is the need for the agronomy. There are still limited resources in this profession that have a significant understanding of how to combine machinery, GPS, agronomy and software to benefit the farmer; there is a gradual improvement, however, there is an obvious lack of “literate” precision farming agronomists.

So where does this leave the aspiring precision farmer? I would argue that you are in a very strong position and for a number of reasons.

Most importantly, don’t be nervous! Good farmers are characterised by a willingness to try things.  And I can tell you, it is not a situation where “all the neighbours are doing this and I feel stupid for being left behind, and I will look silly if I make a mistake”.  Most of your neighbours are not attempting this and they would feel encouraged to see their own neighbour enthusiastic enough to try it.  Also, you will probably be teaching your agronomist a few things – they too need clients that are prepared to try things so everybody can learn.

You cannot afford to not pursue this technology.  Currently, we are subject to unprecedented fertiliser prices and staggering fuel bills and we have a very strong dollar (~US$0.85c).  In the short/medium term these issues are partially offset by strong commodity prices but don’t kid yourself, there is a lot of pressure on the bottom line.  Simple research suggests that most farms are spending about 58%-70% of their gross income on variable costs (seed, fertiliser, machinery, pesticides, etc) and of this about 20%-30% is the fertiliser alone.  Any savings that you can achieve against this cost cannot be ignored, and the fact is these savings could be as high as 25%


Full scale farm VRA application

In 2003, SST embarked on a soil testing and VRT program with a client at Jerilderie. The soil testing was targeted using significant on-farm knowledge that had been established through multiple years of yield mapping, as well as studying “cut & fill” maps from laser-levelling and also from crop scouting. This knowledge was used to determine “zones” that were believed to be similar and the soil tests were targeted into these zones and results were referenced against the zones.There were numerous motivating factors on this particular farm and these included:

There were numerous motivating factors on this particular farm and these included:

  • Minimal soil testing had been performed previously.
  • Significant laser-levelling program over previous 10 years.
  • Variable soil structure & colour, sodic subsoils, heavy clays.
  • Very high inputs of P & S for irrigated summer crops.
  • Highly variable winter cereal yields.
  • A desire to save money and better distribute the inputs.
  • Typical crop rotation: tomatoes / wheat / wheat / canola / wheat.

The soil test results collected across 2500 hectares were startling.

  1. pH 5 – 8.8
  2. Sulphur 5 – 130ppm
  3. Phosphorous 13 – 150ppm
  4. CEC 6 – 45meq
  5. Exch. Sodium 2 – 15%
  6. Organic C% 0.6 – 2.8%

The implications of this variability were very significant and it was determined that this provided an opportunity to pursue VRT. The primary focus of this project in terms of crop nutrition was Phosphorous fertiliser; the in- crop Nitrogen requirements are managed later in the growing season when the crops have established. The most important issues are that this project was simple to implement, it was affordable and it would deliver savings.

The project collected 200 soil samples across the 2500 hectares which cost $9000 to analyse ($3.60/Ha); these soil samples are also able to be used for another 2-3 years before re-sampling is required. Of the total area sampled, 1530 hectares was committed to a winter cereal program for sowing in 2004.

This work identified opportunities to pursue VRT on Sulphur, Phosphorous and Gypsum and it resulted in a re-allocation of P-inputs with seeding.  By targeting our soil tests into zones identified by mapping, we had very efficiently exposed the huge variability that existed and now we could start to manage the variability because we know where it exists.

The message is simple; this technology and its application do not need to be over-complicated and in my opinion, there is an obvious opportunity and enough existing knowledge on every grain farm in Australia to justify a VRT program.  The motivation to do this will vary, however the greatest motivation of all is the potential to save money.

Although the project was designed to better manage P-inputs, it was also learned that some fields were not worth managing variably; our soil test data revealed how poor some fields were in other key attributes.  The most pertinent was the huge soil structural deficiencies that laser-levelling had exacerbated in some fields on already poor soils.  It was discovered that some fields would require up to 10 tonnes of gypsum per hectare to begin correcting problems associated with soil sodicity.  And this did not take into account organic carbon, sulphur and micronutrient issues!

Also of importance is the fact that crop variability was not a result of variable moisture.  The farms in question are all irrigable; however data had been collected from yield monitors from multiple years which included higher rainfall years, irrigated seasons and very poor years.  Regardless of the “moisture management”, in crop variability always appeared in consistent patterns within fields.  Clearly the variability is a soil issue.

When the example above was completed in 2004, MAP fertiliser was purchased at $450 per tonne!  The simple application of existing knowledge, a suitably processed yield map (the data was already being collected by the harvest contractor) and a targeted soil-testing program yielded savings of between $17/Ha and $36/ Ha.  This was achieved with the starter fertiliser alone; it was not complicated and does not take into account the Nitrogen topdressing requirements or a gypsum/lime program either.  Also, it does not take into account the cumulative benefits of combining a VRT program with other well publicised precision farming technologies such as controlled traffic and machine control (such as automatic boom shut-off).

How to facilitate an effective VRA program

To facilitate an effective VRT program, extra investment is necessary and it will be in the form of equipping an air-seeder/ spreader to apply fertiliser (or seed) at varying rates.  As with autosteering equipment, there are any amount of brands available and this leads to the most publicised “dilemma” facing would-be participants of VRT farming.  For about 9 years now, the issue of compatibility has been talked about and blamed relentlessly for the lack of uptake of precision farming technology.  This is a weak excuse and the fact is this; there is, and has been for a significant amount of time, excellent equipment available that is very capable of doing VRT and it certainly is compatible with auto-steering, yield mapping, soil testing, and every other aspect of Precision Farming that comes to mind.  However, there is not one single item or brand that will satisfy all the requirements of a precision farming, and more specifically a VRT program completely.

The VRT project in Jerilderie used a combination of machinery and technology working without fault. This included:

  1. JD8410 tractor.
  2. Janke 12.2m (40ft) seeder bar set at 250mm (10”) spacing.
  3. Simplicity 9000L 3-bin trailed castoring air-seeder.

SST supplied and fitted the following precision farming components:

  1. Trimble Auto-Pilot steering system using the AgGPS 170 Field Computer
  2. OmniStar HP GPS correction.
  3. Dickey John Land Manager II VRT controller.

The VRT “prescriptions” for each field, which contain the electronic instructions about fertiliser rates and where they are to be put were created using software called SSToolbox® from SST Software (www.sstsoftware.com).  SST software is the most powerful desktop software available for the PF industry and SST specialise in “open architecture” to alleviate compatibility issues.  The SST software combined the soil test data, cut & fill data from a surveyor, GPS field boundary maps, crop scouting information and yield data from a Case 2388 combine and put all of this data into a common format.

This provided an ability to create prescription maps based on multiple data sets and the result was a set of instructions for each field that was loaded into the Trimble auto-steering system.  The variable rate controller working in conjunction with the auto-steering system controls the Simplicity metering rollers by hydraulic motor. A hydraulic control system was chosen because they are significantly more reliable than electric, they have a much better response time during a rate change (both lead and lag) and if there is a system failure it is very easy to change back to a manually controlled system. Dickey John was chosen because they are the most reliable provider of this technology and have been supplying this equipment in other countries and other Australian cropping areas for many years.

A key consideration in this process was using proven equipment that can perform what is required. A lot of experience had been gained on many projects trying to use software and equipment that was not capable of doing what was required. In many cases, the technical issues of managing and manipulating data for the purposes of creating VRT prescriptions is so difficult and inefficient, that the cost and frustration would deter even the most enthusiastic participants. The single most important piece of technology that facilitated our project was the SST software. SSToolbox® is the only program that can import, store and manipulate various data sets and export the VRT prescriptions to a whole range of controllers. 

VRA Results & Summary

The Jerilderie project resulted in winter cereal fertiliser rates being varied greatly, and often this was a reduction.  Importantly, there was not any area that received no fertiliser, however, there were significant areas that received only maintenance rates of fertiliser and continued to do so for the next two seasons.

The biggest issues that were identified and tackled by this grower are:

  1. in many areas, expensive inputs are in excess
  2. where there is deficiency, it is usually severe
  3. a “one size fits all” fertiliser strategy is completely inappropriate
  4. there is an opportunity to save on fertiliser inputs and redirect spending to repair soil structural issues.

The results obtained from yield mapping the subsequent crops in 2004 were very impressive. SSToolbox® software was used to test the validity of the results and to compare soil fertility, applied fertiliser and yield. Individual fields that had fertiliser applied in zones at 40kg/Ha versus zones of 90kg/Ha showed no significant difference in wheat yield. Other fields with applied fertiliser ranging from 40kg/Ha to greater that 110kg/Ha also showed no significant yield difference. The targeted approach of soil testing in zones, based on significant prior knowledge had paid huge dividends; the fertiliser saving in year one of this project was approximately $35,800 ($23/Ha).

If this same project had been performed this sowing season with MAP currently valued at $750 per tonne (ex-Melbourne) the input saving would be $60,000!

A key point to this project was that variables were chosen that were of significance to the farms in question and they could be tackled and influenced to the farmers advantage. There exists the same opportunities for other farmers in Australia to start benefiting from VRT technologies. It is hard to imagine what more motivation is required before the benefits of this technology will be enthusiastically adopted. And while there may be a lack of expert agronomic advice, there should be no confusion about the compatibility debate and no confusion about requiring more “gadgets”.