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Disc Harrow - How to Choose the Right One
Discing - Everything You Need to Know About This Agrotechnical Procedure

Why should a disc harrow be included on every farm?
Is a disc harrow a universal machine?
How to choose the type of disc harrow for crops?
Which stubble harrow should you choose for pre-sowing crops?
Are there universal harrows for every type of cultivation?
What is the best plate shape to choose?
Disc diameter: the bigger, the better?
Rubber or spring shock absorber?
Distances between working tools?

A universal and highly valuable machine on the farm

Which machine is essential for contemporary farm operations? Undoubtedly, the disc harrow. However, not every disc harrow performs optimally in all conditions. So, which one should you select for your farm? The disc harrow is among the most popular tillage machines, effectively replacing outdated and inefficient stubble plows on many farms. Beyond post-harvest cultivation, it has a broader range of applications. The benefits of using disc harrows include a relatively low demand for tractor power, minimal susceptibility to clogging even with substantial crop residues, and excellent soil mixing quality. These advantages are compelling reasons to consider purchasing a disc harrow from Rolmako.

What is a disc harrow used for?

A disc harrow consists of a series of discs mounted on an axis that rotate during tractor operation. It is constructed with two beams on which the discs, characterized by their distinctive shape, are mounted. These rotating elements loosen and crush the soil. This implement is particularly effective after plowing to break up soil clods or after sowing to cover seed material with soil. Additionally, disc harrows aid in weed control through shallow plowing and mix scattered mineral fertilizers or manure with the soil. The working depth of a disc harrow ranges from 5-15 cm. The work intensity varies based on the angle of the discs relative to the direction of movement. Smaller angles are used for cutting furrows after plowing or leveling the field, intermediate angles for mixing fertilizers with the soil, and larger angles for stubble cultivation or covering green fertilizers. The disc angle can be adjusted manually or hydraulically.

Is a disc harrow a universal machine?

In theory, a disc harrow appears to be a universal machine, as it is effectively used for shallow post-harvest cultivation, mixing manure, eliminating catch crops, and preparing the soil before sowing. In practice, however, it is essential to define the primary tasks for which the machine will be used during the purchase planning stage, as its configuration depends on these tasks. Factors such as the type of amortization, disc inclination angle, spacing of working tools, diameter, shape, and other parameters will influence the machine's performance in specific field conditions. For instance, the U671 heavy stubble harrow is a different project compared to the U693 disc harrow. There is no definitive answer to which is better; the choice relies on understanding the farmer's expectations, the machine's intended functions, and the conditions in which it will operate.

Why should a disc harrow be found on every farm?

The purchase of a disc harrow is an expense that necessitates evaluating the profitability of the investment. Is it truly worth buying? The use of disc harrow in agriculture provides substantial benefits regardless of the crop type. It aids in weed elimination, enhances soil quality, hydration, oxygenation, and nutrient content. Achieving similar soil conditions using other methods would require significantly more time, effort, and potentially additional labor. By harrowing before sowing and after harvesting, the quality and quantity of crops are significantly improved, leading to tangible profits.

Types of Disc Harrows

Disc harrows generally come in several basic variants, including harrows for shallow pre-sowing cultivation and post-harvest stubble cultivation, such as models U693 and U652 (highly versatile machines), typical stubble harrows like model Rolmako U671, and tillage and sowing harrows model U693 with a seeder coupling. Although an untrained observer may not immediately notice the differences in their construction, these differences are crucial. The primary difference lies in the spacing between the rows of discs. For cultivation and sowing machines, where the harrow is intended to prepare the soil for sowing, the spacing is much smaller compared to stubble cultivation machines. This difference is related to the amount of harvest residues. During stubble cultivation, there is a significant amount of residue, so to ensure the free flow of material through the machine and minimize the risk of clogging, discs should be spaced wider, preferably 90 cm. In contrast, for cultivation and sowing machines, there are few or no crop residues, so a smaller spacing between the discs—around 70 cm—is sufficient. This design also allows the unit’s center of gravity to be closer to the tractor, reducing the load on the lift. These are the basic differences; the machines vary significantly in construction, standard equipment, and configuration possibilities.

What width of disc harrow should I choose? Tractor power required?

The disc harrow must be selected to align with your tractor's power capabilities. Depending on the size and weight of the disc harrow, power requirements can vary from 80 hp to 320 hp. Ground conditions also impact power consumption; heavy and wet soil necessitates a stronger disc harrow, whereas light soils do not require high power. If you aim to cover more field area in one pass, consider that a wider disc harrow demands a more powerful tractor. The angle of the disc influences pulling power, with a more aggressive angle significantly increasing power needs. Disc harrows with widths from 1.25 to 8.0 meters are available. Those opting for a wide disc harrow must ensure that their tractor can operate it. Disc harrows of 8.0 meters are recommended for large farms, while smaller sizes are suitable for other farms.

Which cultivation discs should you choose?

When purchasing a disc harrow, selecting the appropriate discs is crucial, as the disc type significantly impacts work quality and field results. Generally, smooth or less toothed discs with a diameter of approximately 510 mm are more specialized, suitable only for shallow stubble breaking and not ideal for deeper cultivation. These are primarily used for pre-sowing crops or in conjunction with a seeder to create a cultivation and sowing unit. Conversely, more universally toothed discs with a diameter of 560 mm or larger are a more versatile choice. They are effective for both shallow pre-sowing cultivation and deeper tasks, such as mixing manure, destroying catch crops, or cultivating after corn. Discs with a diameter exceeding 600 mm are available in the Rolmako U652 and U671 models. Larger diameters correlate with thicker sheet metal, resulting in a longer service life for the working elements. The disc's angle of inclination also influences work outcomes: an aggressively set disc is better for stubble fields, while a gentle tilt is preferable for pre-sowing work.

Specialized SpeedCutter corrugated discs for ultra-shallow cultivation

The SpeedCutter disc harrow is distinguished by a new type of working element. The traditional disc has been replaced with a wavy shape. The disc arm design has been modified to fully utilize the advantages of a corrugated disc. The length and angle of the arm were developed based on extensive testing in various conditions, including sandy fields, fields with significant crop residues and catch crops, and areas with heavy, wet soil. The corrugated disc is designed for ultra-shallow cultivation of 2-5 cm at a speed of 20 km/h. The refined geometry of the working tool shape enhances cultivation possibilities and improves results in challenging conditions, such as rapeseed stubble, shredding cover crops, cereal stubble, and post-plowing.

Choosing the Right Roller

Roller selection is crucial for disc harrows as it determines the disc's working depth, levels, and compacts the topsoil layer. This aids in moisture retention and creates favorable conditions for the germination of seeds and weeds. The choice of roller varies per farmer and should align with the soil's compactness. Experts recommend lighter rollers with incomplete cores for light soils to ensure effective soil flow without restricting operation speed. Suitable types include string and ring rollers. For compact soils with lumps, heavier rollers with aggressive working surfaces, such as rubber, packer, and sheet metal rollers, are advisable to break clods and even the surface effectively. The double U-ring roller is a versatile option, yielding excellent tillage results when used behind the driving axle, compatible with models like Rolmako U652, U671, and SpeedCutter.

- Disc harrow for vineyards and orchards U 645 -
- Light disc harrow U 622 -
- Compact disc harrow U 693 -
- Disc harrow U 652 -
- Heavy stubble harrow U 671 -

Summary: Which harrow should you choose?

Without agricultural machinery, farm work would be incredibly difficult and labor-intensive. Currently, various tillage tools, notably the disc harrow, assist in these efforts. The combination of two rows of discs and a roller allows for proper soil cultivation, weed control, and soil-fertilizer mixing.

For optimal results with a disc harrow, consider the following before purchase:
- Tractor power
- Disc harrow width
- Disc spacing and size
- Appropriate tillage roller
- Reputable manufacturer.

The disc harrow should match your tractor's power and soil type. In the case of hard and dry soil, agricultural machines that operate with greater force and with significant pressure on each working element, such as Rolmako U652 and U671, will perform better. Consider the type of work, crop species, and field size. Disc size and spacing should align with these factors. Avoid using disc harrows on fertile soils to prevent weed infestation; a tillage cultivator is more suitable in these cases.

The disc diameter, attack angle, and soil pressure impact the disc harrow's versatility. Smaller diameters (about 510 mm) are for shallow cultivation and stubble removal, while larger discs are for deeper cultivation. A 560 mm disc, used in U693 and U652, suits both shallow and deeper work, as well as soil mixing with decomposed manure or lime. The 620 mm disc in U671, with an aggressive attack angle, is ideal for corn cutting.