Precision FarmingVari­able N Fertiliser Appli­ca­tion – simple and effi­cient

Georg Stiegler, along with his brother, oper­ates Walden­burger Agrar GmbH, an arable farm covering 1,100ha with a team of five employees. The farm grows cereals, rape­seed, sugar beet, and specialty
crops, with a partic­ular emphasis on seed prop­a­ga­tion for carrots, clover, and grass. Addi­tion­ally, they focus on cleaning, drying, and storing the harvested prod­ucts. Located in western Saxony, Germany, the farm is looked after by the John Deere dealer S & L Connect.

Georg has been imple­menting preci­sion farming prac­tices for years and has utilised Yara’s N-Sensor to opti­mise his nitrogen fertiliser appli­ca­tion, although he hasn’t always used it consis­tently across all fields. Franz Burkhardt-Medicke, who over­sees preci­sion agri­cul­ture at S & L Connect, was aware of this. “When Yara and John Deere approached me looking for a farmer willing to partic­i­pate in a pilot project, Georg was the first person that came to mind,” says Franz.

Collab­o­ra­tion between Yara and John Deere

“The collab­o­ra­tion between John Deere and Yara began about two years ago,” reports Patrick Hofstetter, who is respon­sible for supporting prac­tical demon­stra­tion trials with customers at John Deere. “In arable farming, around one third of costs are attrib­uted to fertiliser.” Beyond just maximising yield, fertiliser plays a crucial role in crop quality, such as protein content. Notably, more than half of agri­cul­tural CO2 emis­sions stem from fertilisers – half of it from their produc­tion and the other half in the field. “There­fore, if we can opti­mise fertiliser use, it not only trans­lates to higher profits for farmers but also bene­fits the envi­ron­ment,” says Marcos Mazzini, B2B digital services director at Yara.

The trial: Advan­tages of vari­able nitrogen fertil­i­sa­tion

In spring 2024, Franz and Georg launched a demon­stra­tion exper­i­ment to assess the prac­ti­cality of combining Atfarm soft­ware with the John Deere Oper­a­tions Centre for vari­able rate nitrogen fertiliser appli­ca­tion. Another goal was to deter­mine whether this provides a finan­cial benefit to the farmer. They received support from the Yara team and Patrick at John Deere, who assisted throughout the demon­stra­tion trials.

For the selected test fields George devel­oped vari­able rate maps, drawing on both recom­men­da­tions by the Yara Atfarm soft­ware and his personal expe­ri­ence with these fields. The objec­tive of the trial was to show­case the agro­nomic and finan­cial bene­fits of the vari­able rate fertiliser strategy by directly comparing it to a flat-rate approach. To facil­i­tate this compar­ison, specific areas within the fields were randomly desig­nated for flat-rate appli­ca­tion.

The results: increased yields, higher gross margins.

Trans­fer­ring the appli­ca­tion maps from the office computer to the tractor display via the Oper­a­tions Centre was completely seam­less. By connecting At-farm to the Oper­a­tions Centre, many processes now operate auto­mat­i­cally. Georg high­lights another advan­tage: He can easily create a work order and send it directly to the Oper­a­tions Centre. “The inte­gra­tion of Atfarm into the Oper­a­tions Centre has made the USB stick unnec­es­sary,” says the farmer.

When the driver arrives at the field with the tractor, they simply need to press a button and follow the desig­nated tracks. The fertiliser spreader applies the pre-planned amounts based solely on the appli­ca­tion map, requiring no special agro­nomic knowl­edge from the driver. Another benefit is that the driver expe­ri­ences less fatigue while working. The compar­ison of yield and revenue is also impres­sive. In total, tests were conducted with four different farmers in the S & L Connect sales area, and six of these fields were eval­u­ated by the end of the trials.

In five of the fields, vari­able rate nitrogen posi­tively impacted yield, with only one instance showing a slight decrease. On average, the yield increase was 120kg/ha. The amount of fertiliser used varied; in some cases, the maps created with Atfarm increased rates, while in others, they reduced them. Overall, approx­i­mately the same amount of fertiliser was applied, indi­cating that it was redis­trib­uted within the area to achieve optimal results.

However, most signif­i­cant for the farmer is the impact on the bottom line. Similar to the yield results, a higher gross margin was observed in five out of six cases. In one instance, the increase was nearly €60/ha (£50), and the average posi­tive differ­ence was around €24/ha (£20). Patrick says: “Our demon­stra­tion tests have shown that vari­able nitrogen appli­ca­tion leads to higher yields and gross margins, although this is not the case in every instance.”

The results from the field trials show an increase in both wheat yield and gross margin in five out of six cases.

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