Variable-rate application has been available for years, yet adoption remains limited on many arable farms. Interviews with machinery manufacturers, precision farming specialists and crop advisers show that the barriers are rarely technical alone. Farm economics, field characteristics, software complexity and uncertain returns continue to slow the uptake of prescription maps for seeding and fertiliser application.

Fewer than 10% of Dutch arable farmers/growers, contractors and livestock farmers use a task map to vary the fertiliser application rate and/or seed rate. That is the conclusion after a survey among machinery manufacturers, importers and several crop advisers.

Relatively small and homogeneous fields with too little reason to vary, costs that do not outweigh the benefits, and agronomic and technical complexity are most often cited as the reasons for the limited use.

An exception is the use of task maps for the eco-activity precision fertilisation, in order to score extra points under the Common Agricultural Policy (CAP). The condition is that you can also provide as-applied maps. “If spreading fertiliser or applying liquid fertiliser using a task map qualifies you for a gold eco-premium instead of silver, it yields an extra €100 per hectare. That certainly outweighs the additional costs,” says Lars Stapel of Kverneland Group Benelux. André Koskamp of Amazone importer Kamps de Wild and Christiaan Borkus of Kuhn and Rauch importer Reesink Agri confirm that the eco-premium is the main motivator. “I think this could lead to a turning point,” says Borkus. Further reductions in fertiliser application allowances are also seen as a driver.

Exception: residual herbicide and lime

Chris van de Lindeloof of Monosem and Sky Agriculture importer Farmstore asked his audience during a meeting last winter who was already spreading using task maps. “That was 3% of the arable farmers present. The main aim was an even crop and a uniform yield,” he says. “I do see more interest in lime spreading and residual herbicides. The latter is mainly because you have less crop growth inhibition, and that always pays off. Incidentally, it depends very much on whether your crop adviser promotes working with a task map. Some do so actively, others much less.”

Higher percentage

For precisely that reason, Anthon Slootweg of Van Iperen mentions a higher percentage. “My estimate is that 15% of our customers work with task maps. That is more than average because we have been emphasising it for quite some time. Interest increases as arable farms become larger. This year we have 7,000 hectares ‘under task map’, and in terms of area this is more than 15%. Looking at the applications, it is mainly spraying residual herbicides. Although, partly because of the eco-scheme already mentioned, we are seeing an increase in fertiliser spreading. When drilling small-seeded crops, the priority is to get the crop to emerge everywhere, and weather conditions have far more influence than variable output. With potato planters, I notice that they are often far from technically suitable, simply because they are renewed less often.”

Ron Smit of Homburg, importer of Bogballe, Hardi and Väderstad, estimates that 5% of livestock farmers and around 20% of arable farmers occasionally make a task map for fertiliser spreading. “Especially arable farmers with special or high-gross-margin crops such as flower bulbs and bed crops. Although in my view you should not overestimate the effectiveness of a variable rate with a fertiliser spreader either. After all, you always have to deal with overlap.”

When fertiliser is applied variably, the main aim is an even crop and a uniform yield. There is more interest in spreading lime and applying residual herbicides on a task map, and in spot spraying. Photo: Sky Agriculture

Technology still a challenge

Everyone Future Farming spoke to acknowledges that using task maps – despite all the developments such as Isobus and agrirouter and initiatives such as Taakaart.nl and the National Fieldlab for Precision Farming (NPPL) – is still not always technically easy and user-friendly. From contractors to crop advisers and machinery suppliers. Smit: “It remains cumbersome, because you often have to bring in third parties to create the task map. I notice that users run into problems with the technology, and particularly with the software when creating a task map. It also does not help that they have to deal with 3 parties: the tractor manufacturer, the machine manufacturer and the software supplier. It could be so simple, but in practice unfortunately it is not always. A caveat: as an importer, of course, we only hear about it when it really does not work,” says Borkus.

The fact that not every potential user is equally skilled in using task maps is also known within the NPPL project. For that reason, the experts involved from Wageningen University & Research are working on a helpdesk and practical guides for technical support with variable-rate applications using task maps. The expectation is that the first 2 knowledge articles will be available online in July as part of the knowledge bank. In future, it will also be possible to ask questions there via a forum function.

Contractor Harry Koonstra: ‘A lot of experience is no guarantee of success’

Harry Koonstra of the contracting business of the same name in Balkbrug, Overijssel, is an enthusiastic user and promoter of precision farming and the use of task maps. “Interest in spreading fertiliser using a task map in our working area is mainly reinforced by the eco-scheme. 10 to 20% of the customers for whom we spread fertiliser have this done using a task map. We charge an extra €10 per hectare for that. As a basis, we use either data from the soil scans we carried out earlier, or – if those are not available – satellite data on crop condition.

That is relatively simple, but you do have to sit down and take the time to do it. It is an extra step after all. It still happens that the terminal of the fertiliser spreader, for example after a software update, no longer accepts a task map. That is frustrating, because where does it go wrong? With the machine supplier or with the task map maker? That still leads to unanswered questions and technical challenges.”

Business case not always clear

In the United States too, where precision farming and site-specific variable-rate applications were pioneered very early on, growers struggle with the business case. This is shown by a Purdue University study, which has been running for 21 years among 570 farmers in Kansas and is leading in agricultural research.

For 17 precision technologies, the researchers found that the additional costs did not outweigh the benefits in the form of greater efficiency and/or profit. This does apply to auto-steering systems and yield monitoring in combination with soil sampling. Incidentally, more than 20% of the growers surveyed applied fertiliser site-specifically in 2022. For drilling, the figure was 15%. These percentages correspond with national averages.

Future Farming

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