Findings of a bachelor thesis - Supervised by HORSCH and the HOCHSCHULE WEIHENSTEPHAN-TRIESDORF | Faculty of Agriculture
After the harvest, they can be seen everywhere: stubble fields. Organic matter remains on them, especially straw that does not only serve as a useful by-product, e.g. as raw fibre in animal food or as litter, but also plays an important role directly in the field.
In this respect, the correct incorporation is important. If the organic matter is distributed evenly in the cultivation horizons, it encourages important processes like:
An uneven straw distribution may result in a limited nutrient availability, rot in compacted or wet soil layers as well as uneven growth of the following crop. Moreover, the risk of diseases increases, and the seeding technology can be impaired – e.g. because of clogging or uneven seed placement.
The question is: how can the quality of straw incorporation be visibly and objectively assessed, and are there differences between disc and tine machines?
To examine this precisely, the straw incorporation of two common tillage machines for stubble cultivation was compared in a field test that was set up within the scope of a bachelor thesis:
Shallow cultivator Cruiser
Due to the long, multi-bar design (4- to 6-bar) and the narrow tine spacing of the tines, the cultivator captures the straw on the whole working width and distributes it across the field.
Compact disc harrow Joker
As the discs are arranged in pairs, the compact disc harrow can incorporate large quantities of organic matter.
In the test, the Cruiser 7 XL with 8 cm wide tine points and the Joker 6 RT with serrated discs (52 cm diameter) were used. To ensure the comparability of the work results, the knife roller of the compact disc harrow was lifted.
The field test was carried out on a threshed rye field. Because of the long straw, it was mulched at a height of approx. 5 cm in advance, and the organic matter was crushed to a length of about 10 cm.
The test strips were then cultivated twice with both machines – once shallow with a working width of 7 cm and once deep with 15 cm. All passes were carried out at a speed of 12 km/h.
Traditionally, the straw distribution is assessed according to the so-called Voßhenrich Method: a profile wall is uncovered, a grid is placed over it, and each cell is estimated according to six steps (0 to 100 % coverage). Although his method is established, it strongly depends on the experience of the person carrying out the evaluation – and is very labour-intensive.
The AI-based evaluation is the modern alternative: a camera films the soil profile while ploughing, and a trained neuronal network recognises the straw on the images in a pixel-perfect way. Thus, AI provides quick and objective results directly in the field.
The comparison between visual rating and AI-based evaluation only shows minor differences: both methods provide almost identical courses and clearly visualise the different working methods of the tillage machines.
Joker: Cuts the soil and mixes the straw mainly in the middle soil layer (5-10 cm) where a coverage of about 40 % is measured. In the upper 0-5 cm and the lower 10-15 cm layers, the share amounts to just over 20 % respectively.
Cruiser: Leaves the majority of straw in the upper working horizon of 0-5 cm (over 50 % coverage). Between 5 and 10 cm, the degree of coverage amounts to approx. 30 % and to 20 % in the lower layer.
In stubble cultivation, the cultivator as well as the compact disc harrow have an influence on the straw distribution in the depth. The different working methods of the two machines leave specific “fingerprints” in the soil profile:
While the Cruiser (tine machine) incorporates the straw mainly in the upper 5 cm, the Joker (disc harrow) ensures an intensive mixing of organic matter especially in the medium layer between 5 and 10 cm.
Conclusions for practical use: disc harrows are ideal if the straw is to be mixed in intensively in depth, while tine machines are particularly suitable if the objective is an even distribution of the harvest residues on the surface.
| Cruiser 7 XL | Joker 6 RT |
Design |
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Tools | Points
| Disc
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Working depth | Max. 15 cm | Max. 15 cm |
Mixing effect | Even distribution in the upper 5 cm | Intensive mixing in depth |
Basic applications | Shallow to medium-deep tillage for stubble cultivation and seedbed preparation. | For a shallow and quick incorporation (straw, organic fertiliser, catch crops)
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Additional tools |
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Special features |
| SoftRide system
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