Master Calibration Matrix and Parameter Tables
The following matrix represents standardized configuration examples for common NPK formulations. These values serve as the initial setup point for the RAUCH AXIS series. Users must understand that these are theoretical starting points; actual flow rates will deviate based on the specific batch of fertilizer.
| Fertilizer Type | Density (kg/l) | Working Width (m) | PTO Speed (RPM) | Disc Speed (RPM) | Drop Point | Slide Setting |
|---|---|---|---|---|---|---|
| NPK 20-5-10 | 1.10 | 18 | 540 | 230 | H | 33 |
| NPK 20-5-10 | 1.10 | 24 | 750 | 325 | I | 33 |
| NPK 20-5-10 | 1.10 | 30 | 1000 | 430 | I | 33 |
| NPK 16-17-15 | 1.01 | 18 | 540 | 230 | L | 33 |
| NPK 16-17-15 | 1.01 | 24 | 750 | 325 | L | 33 |
| NPK 16-17-15 | 1.01 | 30 | 1000 | 430 | I | 33 |
| Urea 46% | 0.75 | 24 | 750 | 325 | G | 28 |
| KAS 27% | 1.00 | 24 | 750 | 325 | H | 31 |
Fertilizer density is the primary variable influencing flow. A change in density of even 0.05 kg/l can shift the application rate by 3 to 5 percent. Always use a calibrated scale to verify the weight of one liter of your specific material before consulting the chart.
Operational Dynamics of the AXIS and MDS Series
The RAUCH AXIS and MDS series utilize centrifugal force to distribute material. The mechanical linkage between the tractor PTO and the spreading discs is fixed by the gear ratio within the spreader housing. When the PTO speed is set to 540 RPM, the discs rotate at a specific velocity designed to achieve a set working width. If the PTO speed fluctuates, the centrifugal force changes, causing the spread pattern to narrow or widen, leading to striping in the field.
The metering slide controls the volume of material entering the disc area. On the AXIS series, this is often controlled by the QUANTRON-A or similar electronic units. The slide position must be calibrated to the specific flow characteristics of the fertilizer. Because fertilizer granules vary in hardness and friction, the slide opening size does not correlate linearly with output across different brands.
Field Calibration Workflow
Calibration is the process of matching the theoretical chart values to the actual physical output of the machine. For MDS models, the calibration test chute is mounted under the left outlet.
- Ensure the hopper contains at least 50 kg of material to maintain consistent pressure on the metering slide.
- Set the metering slide to the value provided by the RAUCH chart.
- Mount the calibration chute and place a container under the outlet.
- Run the PTO at the specified RPM for exactly 60 seconds (or the time indicated by the RAUCH calculator).
- Weigh the collected material and multiply by the factor provided in the manual to reach the kg/ha value.
- Adjust the slide setting if the collected weight deviates from the target application rate.
The drop point adjustment is equally important. By moving the drop point (the position where the fertilizer hits the disc), you change the trajectory of the granules. A drop point set too far forward will cause the material to be thrown too far, while a drop point set too far back will result in a narrow, uneven pattern.
Material Variance and Quality Impacts
Granule size and dust content are the silent killers of precision spreading. Fertilizer that has been stored in high-humidity environments often develops a surface crust or absorbs moisture, increasing its coefficient of friction. This causes the material to flow slower through the metering slide than the chart predicts.
Dust content acts as a lubricant in some cases and a flow-inhibitor in others. If a batch contains a high percentage of fines, the flow rate will be inconsistent. Always screen your fertilizer if it has been stored for an extended period. If the material is visibly degraded, the chart values are essentially void, and you must rely entirely on the physical calibration test to establish a new baseline.
Hardware Setup and Mounting Geometry
Mounting height is defined by the distance from the spreading discs to the top of the crop canopy or the soil surface. For the AXIS series, the standard is typically 50 cm. If the machine is mounted too high, the wind will catch the lighter granules, causing an asymmetrical pattern. If it is too low, the pattern will be truncated.
Spreading disc selection is determined by the working width and the type of fertilizer. The S4 disc is standard for many NPK applications, but specialized discs are required for slug pellets or small seeds. Vane angles on the discs are factory-set but can be adjusted for specific products. Refer to the official AXIS manual for the specific vane angle indices required for your working width.
- Verify PTO shaft is free of debris and the universal joint is properly greased.
- Check that the hopper agitator is rotating freely and not obstructed by clumped fertilizer.
- Ensure the spreading discs are clean and the vanes are free of fertilizer buildup or oxidation.
- Confirm the tractor engine speed is locked at the rated PTO RPM before opening the metering slides.
Operator Consensus and Field Troubleshooting
Operators frequently report that ‘dial drift’ occurs on older MDS models where the slide stop mechanism wears down. It is common practice to use a piece of electrical tape to mark the exact position once calibrated. Another recurring observation is that Urea requires a significantly lower drop point than NPK due to its lower density and tendency to bounce off the vanes. If you notice a ‘heavy’ center, the drop point is likely too far forward; if you notice a ‘heavy’ edge, the drop point is too far back.
Troubleshooting an uneven spread pattern usually begins with the drop point. If the pattern is consistently heavy on one side, check the disc rotation speed and ensure the PTO is not slipping. If the pattern is ‘streaky’, the issue is often a combination of incorrect mounting height and wind speed. Always perform a tray test if you suspect the machine is not distributing material evenly across the entire working width.
Verification & Component Tolerance Notice: The settings provided in the RAUCH Fertilizer Chart are based on standardized laboratory testing and may vary due to local environmental conditions. Users must verify all application rates through physical calibration tests to ensure compliance with local agricultural regulations and machine safety tolerances.
Frequently Asked Questions
Where can I find the official settings for my specific fertilizer?
The official settings are exclusively managed through the RAUCH Fertilizer Chart app or the manufacturer’s online database, which covers over 3,000 product types.
Why is my spreader output different from the chart values?
Fertilizer density, moisture content, and granule size vary by batch, which is why a physical calibration test is mandatory to verify the chart’s baseline settings.
How often should I perform a calibration test?
You must perform a calibration test every time you switch to a new fertilizer type or if the physical quality of your current material changes significantly.
What is the purpose of the drop point adjustment?
The drop point determines where the fertilizer hits the spreading disc, which directly controls the trajectory and the width of the spread pattern.
Can I use settings from a previous season?
No, settings from previous seasons should not be reused because fertilizer formulations and physical characteristics change annually, requiring a fresh lookup in the current RAUCH app.