At a glance

Multi-purpose subsoiler U638 and subsoiler with hitch U632

Key information

Scroll sideways or pick a tab to browse all sections – overview, operating principle, optional equipment, choosing a roller, choosing a configuration, choosing a version, U638 vs. U632 and alternatives.

01 · Overview

Multi-purpose subsoiler U638 and subsoiler with hitch U632

The U638 and U632 subsoilers loosen compacted soil layers and break up the plough pan, and after fitting stubble cutting blades, they can also work on stubble. The U638 is a standalone machine with a roller, while the U632 can be combined with a harrow or another tillage implement.

What are the U638 and U632 subsoilers used for?

The U638 and U632 subsoilers are used to loosen compacted soil layers and break up the plough pan without inverting the soil. This treatment makes it easier for water and air to penetrate deep into the soil profile, creates better conditions for root development, and reduces waterlogging.

The U638 is a multi-purpose machine which, depending on configuration, can be used both for deep loosening and for shallow stubble cultivation with soil cutting and mixing of crop residues. It thus allows various operations to be carried out with a single, independently operating machine.
The U632 is designed primarily to combine deep loosening with the work of another implement in a single pass. It can be paired with, among others, a disc harrow or rotary harrow, to simultaneously loosen the deeper soil layer and perform shallower cultivation, mix residues, or prepare the field surface for subsequent operations.

02 · Operating principle

How do the U638 and U632 subsoilers work?

In both models, the first stage of work is performed by the Atlas tines. The chisel point and skid cut into and loosen the compacted soil layer, while after fitting stubble cutting blades, the tines can work shallower and cut the soil over a wider width. Each tine has independent spring protection: when it hits an obstacle, it deflects and automatically returns to its working position.

In the U638, the following sections work behind the tines:

The optional mulching roller mixes plant residues with the top soil layer and breaks up clods. It works independently of the rear packing roller.
The rear packing roller guides the machine at a set depth, levels the surface, and is responsible for final soil compaction.
The optional spring comb beam spreads residues remaining on the surface behind the roller, reducing the buildup of straw clumps.

The U632 work sequence is shorter:

One row of Atlas tines loosens the compacted layer ahead of the accompanying implement.
The implement mounted on the hitch, e.g. a disc harrow or rotary harrow, performs the next cultivation stage – breaking up and mixing the top soil layer or preparing its surface.
The roller of the accompanying implement is responsible for guiding the entire set at the set depth and for the final finishing of the field. The U632 therefore does not need its own rear roller.

03 · Optional equipment

Additional equipment for the U638 and U632 subsoilers

The U638 can be expanded with elements for mixing, leveling, and compacting the soil. In the U632, additional equipment mainly serves to adapt the tines and hitch for working with the accompanying implement.

Equipment	Model	When is it worth choosing?
Side wing shares 400 mm – cemented carbide	U638 and U632	For shallower stubble cultivation and wider stubble cutting.
Additional mulching roller	U638	Mixes residues with soil and breaks up clods; useful with large amounts of straw
Spring comb beam	U638	Spreads residues behind the roller and reduces the buildup of straw clumps.
APV or Delimbe catch crop seeder	U638	Enables sowing of catch crop during cultivation, so two operations can be performed in one pass.
Hydraulic hitch adjustment	U632	Replaces mechanical adjustment and makes it easier to change the position of the attached implement.
Maintenance-free roller bearing units	U638	Reduce roller servicing requirements; worth choosing for intensive use.

04 · Choosing a roller

How to choose a roller for the U638 subsoiler?

The U638 is standardly equipped with a tube roller. Another variant is worth choosing when soil conditions require stronger crushing, deeper compaction, or a design less prone to clogging.

Expected effect	Suitable roller types
Light leveling and maintaining high throughput	tube, string, tube-ring
More intensive clod crushing and surface finishing	cogged string, tube-and-string tandem, Crosskill, ORION
Strong compaction of medium and heavy soils	Packer, T-ring or V-ring, steel ring
Working in difficult conditions (wet and sticky soils)	U-ring, U-ring tandem, spring; for wet conditions, or steel ring

The additional mulching roller works together with the rear roller, rather than replacing it.

05 · Choosing a configuration

How to choose the right U638 or U632 configuration for the task?

The configuration is chosen based on what the machine should accomplish in a single pass, besides deep loosening.

Purpose of the operation	Recommended configuration
Breaking the plough pan and deep loosening	U638 with standard Atlas tines and a roller matched to the soil type.
Deep loosening and mixing large amounts of crop residues	U638 with an additional mulching roller and rear packing roller. For unevenly distributed straw, the setup can be supplemented with a spring comb beam.
Loosening the subsoil and intensive surface finishing	U632 combined with a disc harrow, rotary harrow, or other tillage implement.
Shallower stubble cultivation and wider stubble cutting	U638 or U632 with 400 mm stubble cutting blades; for U632, additionally a machine matched to the desired surface finish.
Cultivation combined with catch crop sowing	U638 with an APV or Delimbe seeder, and with large amounts of crop residues, also with a mulching roller or spring comb beam.

06 · Choosing a version

How to match the U638 or U632 version to the tractor and working conditions?

The tractor power given in the specification is the starting point. The choice should also take into account working depth, soil compactness, equipment weight, and rear three-point linkage lifting capacity. For U632, the weight and center of gravity of the entire set with the attached machine matter as well.

Version	When to choose it?
U638 2.5 or 3.0 m	For smaller and medium-sized fields. Requires adequate tractor power, linkage lifting capacity, and tractor stability, especially with a heavier roller or mulching section mounted.
U638 H 4.0 or 5.0 m	For efficient work on larger fields. The folding frame requires a powerful tractor with adequate lifting capacity and a hydraulic system.
U638 HP 6.0 m	For large farms and contracting services. The semi-mounted design reduces the load on the linkage, but requires a high pulling force and proper hydraulic and brake connections.
U632 3.0 m	For combining with a tillage implement of the same working width. Check the linkage lifting capacity and tractor stability with the whole set.
U632 4.0 m	For wider sets and more powerful tractors. Besides the weight of the whole combination, its transport width must also be considered.

On clay soil, at greater working depth, or with heavier equipment, it is worth keeping a power reserve and choosing a narrower machine in case of doubt. A wider variant will work well for shallower work or on lighter soil.

Deep loosening should be carried out when the soil is dry enough to crack and lift under the action of the tines. On soil that is too moist, cutting and smearing may occur instead of effectively loosening the compacted layer.

07 · U638 vs. U632

Which model to choose: U638 or U632?

U638 will be the better choice when a complete machine for independent soil loosening and finishing is needed. U632 is worth choosing when deep loosening is to be combined in one pass with the work of another tillage implement already available on the farm.

08 · Alternatives

When to choose U638 or U632, and when another Rolmako machine?

U638 and U632 stand out for their ability to switch the nature of the work from deep loosening to shallower stubble cultivation. Other Rolmako subsoilers are worth considering when the machine is meant to perform a more specialized task.

Universal subsoiler U602 – it will work well when the priority is classic, very deep loosening with straight tines, without a stubble cultivator function.
Subsoiler with hitch U608 – it is an alternative to U632 when the set is primarily meant to loosen the soil deeply without intensively disturbing its surface.
Subsoiler with two rows of tines U619 – worth choosing when the priority is even loosening of the subsoil without intensive mixing of the surface layer. Curved tines gradually penetrate the ground, lift it, and loosen it without inverting it, but they do not allow the machine to be reconfigured for stubble cultivation like the U638.
Chisel plough U624 – it will be better when the goal is intensive, deep non-inversion tillage replacing traditional ploughing, rather than versatile use of the machine for several types of operations.

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Watch the video showcasing the U638 subsoiler from Rolmako

Atlas tine in U638/U632 subsoiler by Rolmako

U638 subsoiler with visible Atlas tines – maximum loosening soil.

Subsoiler and cultivator combined into a single tillage machine

Soil compaction below the plough working depth is a significant issue, exacerbated by increasingly heavier tractors and agricultural machinery. The multi-purpose subsoiler U 638, proposed by Rolmako, addresses this problem. It is a universal cultivation machine suitable for soil cultivation in early autumn and spring, post-harvest plowing, and soil aeration and regeneration. The inclusion of a 400 mm wide side wing shares enhances its efficiency as a post-harvest tool. The machine can be quickly converted from a stubble cultivator to a deep loosening system appropriate for a subsoiler. The U 638 is designed with uncompromising quality, featuring top-class components found only in the most expensive machines on the market. The subsoiler version with a coupling for another tillage machine is designated as U 632.

Versatility unmatched by other tillage machines

The soil structure is severely compromised, with insufficient oxygen levels, leading to decreased cultivation income. The Rolmako multi-purpose subsoiler addresses this issue by facilitating deep soil loosening, allowing oxygen penetration. Weeds are significantly reduced, resulting in increased yield. The Rolmako U 638 and U 632 subsoilers are designed to meet the needs of modern agriculture and assist farmers in soil preparation tasks. The machine comes standard with double spring protection and working elements featuring sintered carbide. Both models share the same components and overload protection. The U 638 is a two-beam subsoiler/cultivator with a tillage roller and an optional mulching roller, while the U 632 is a single-beam subsoiler with a coupling for a tillage machine. The open frame structure enables the attachment of active machines, such as a active harrow or other accompanying machine.

U638 subsoiler – durable frame and working elements.

U638 subsoiler – improved water retention and better soil structure.

Multi-purpose subsoiler for soil loosening and post-harvest work

The multi-purpose subsoiler is characterized by the lowest power requirement per working element. The strongest available spring protection in the Rolmako offering performs optimally during the most challenging cultivation moments. The U 638 and U 632 subsoilers exceed the functionality of standard subsoilers. The Atlas tine is equipped with an overload system featuring two robust springs. An effective mulching roller, combined with an additional tillage roller, prepares the machine for deep loosening and post-harvest cultivation. Depending on the installed working elements, the multi-purpose subsoiler can perform various cultivation tasks. The soil is loosened at depths ranging from 15 cm to 35 cm, depending on the previous crops and soil type, using carbide-tipped cutting skids. The application of a 400 mm undercutter converts the subsoiler into a stubble cultivator for stubble cultivation at depths of up to 15 cm. High-quality working parts allow for reduced soil cultivation costs. The Atlas tine enables faster, more efficient work and minimizes machine maintenance costs. Replacing working elements has never been so easy.

Machine construction

1. Three-point linkage

The massive suspension system serves as a supporting element of the mulching harrow. The solid tower of the three-point suspension system makes the machine durable and resistant to loads.

2. Dual-beam frame construction

The tines mounted on two beams render the subsoiler a versatile machine, also suitable for use as a comprehensive stubble cultivator.

3. ATLAS tine

The standard equipment of the Atlas tine includes a chisel, a skid, and a beam cover. The complete hard-faced plus sintered carbide components are of the highest quality.

4. Side wing shares 400 mm

Equipped with Side wing shares, the device excels in its role during stubble cultivation. This optimizes the use of one machine for multiple cultivation tasks, allowing for money savings that can be allocated to other investments.

5. PREMIUM working elements

The machine employs internationally recognized soil cultivation systems, utilizing readily available high-quality components from specialized suppliers.

6. Cemented carbide in standard

Cemented carbide-equipped working elements are advised for heavy loads on large-area farms or in non-stony soil cultivation services. Carbide plates can extend the operating time of subsoiler working elements by up to seven times.

7. Spring overload protection

Mechanical Non-Stop protection ensures seamless operation by negating the need for part replacements. The rapid upward tilting and return of the tine upon encountering obstacles maintain the preset working depth.

8. Adjusting of the working depth

The working depth is easily and operator-friendly adjusted hydraulically using spacer clips on the cylinders.

9. Additional mulching roller

This roller aggressively mixes soil with straw in deeper earth layers. It crushes clods while maintaining their quality for sowing preparation. The working depth of the tines is adjusted independently of the tillage roller behind it.

10. Tillage roller

To cultivate the soil effectively, selecting the appropriate tillage roller is essential. The choice depends on the soil type and the desired outcome. Each roller variant is designed for specific working conditions.

11. Spring comb beam

The manufacturer optionally installs a beam with a spring comb behind the disc section, ensuring the straw is evenly spread across the field's surface, thereby preventing areas of high straw accumulation that hinder proper cultivation.

12. Automatic arm lock

The transport lock is automatically engaged by a spring-loaded latch, which is released by a single-acting hydraulic cylinder.

13. Solid oversized machine frame

The solid frame construction is the most critical element of the cultivation machine. The substantial amount of steel used in its construction makes these robust tools capable of utilizing the high power of modern agricultural tractors, ensuring many years of operation on the farm.

14. Quality steel

Achieving a high-quality final product necessitates the use of superior metallurgical materials; therefore, in manufacturing the agricultural machine frame, we utilize fine-grained Swedish steels S500MC and S700MC.

Effects of U632 subsoiler – improved water infiltration.

Equipment

standard

Frame built from a square profile 100 x 100 x 8mm, Atlas tine (plough beam 35 x 70mm ended with cemented carbide chisel). The tine is protected from excessive overload by double-spring protection. The basic version of machine equipped with pipe roller Ø 500 mm. Hydraulic folding machine in trailed version is equipped with 520/50-17 wheels and pneumatic brake (with the trailer section in front of the roller).

Equipment

optional

Hydraulic brake
Side wing shares – cemented carbide
Supporting wheels for trailed version
Delimbe aftercrop seeder
APV aftercrop seeder
Front reflective plates (mounted machines)
Front LED lighting beam (trailed machines)
Rear LED lighting beam
Backlit license plate frame with lighting
Maintenance-free roller bearing unit
Spring comb beam
Additional mulching roller

Tillage rollers

optional

String roller with flat bars Ø 460 mm
String roller with cogged bars Ø 460 mm
Packer cogged roller Ø 460/550 mm
Tubular-ring roller Ø 450 mm
Crosskill roller Ø 400/500 mm
Ring roller Ø 500/600 mm
Spring roller Ø 470/550 mm
Rubber roller Ø 500 mm
Tire roller Ø 600 mm
Roller of steel rings 48-52HRC Ø 600 mm
T-ring roller Ø 500/600 mm
U-ring roller Ø 540 mm
Tandem pipe roller Ø 400 mm plus string roller Ø 400 mm
Tandem U-ring roller Ø 540 mm
Prismatic roller ORION Ø 500 mm

Most frequently chosen accessories

Cultivation tools

ATLAS tine
Spring overload protection
Mulching roller

ATLAS tine

The U 638 and U 632 subsoiler tines are distinguished by exceptional wear resistance, achieved through the use of premium materials. The standard equipment for the Atlas tine includes a chisel, skid, and beam cover, with the Side wing shares available as an option. All wear-exposed parts of the Atlas tine are finished with carbide elements, and consumable parts are hardfaced to extend lifespan and minimize machine servicing time. Atlas carbide working elements as standard:
- Higher work culture
- Minimal loss of time related to parts replacement
- Reduced need for mounting screws
- Minimizing additional machine passes
- Operating time extended by 5 to 10 times.

Spring protection in U638 subsoiler – overload protection.

Spring overload protection

The U 638 subsoiler features a mechanical protection system with a double spring. In the event of contact with a stone, the tine and leg swing away, compressing the spring. Once the obstacle is cleared, the working elements automatically return to their working position. Each tine independently responds to obstacles, with the spring minimizing collision forces and ensuring immediate return to the precisely set working position. Spring protection for the tines is part of the standard equipment.

Mulch roller on U638 subsoiler – ideal for mixing soil with crop residues.

Mulching roller

The mulching roller is installed as an option. The working depth of the roller is set independently of the roller behind it. Adjustments are made quickly, accurately, and steplessly using a crank. This roller aggressively mixes the soil behind the straw in deeper layers. It crushes clods while maintaining soil quality as after preparation before sowing. Due to the large number of tines and their spiral arrangement, the mulching roller does not differ in efficiency and quality of work from rollers working in tandem. The mulching roller, in combination with other rear rollers, achieves excellent cultivation results.

Benefits of soil aeration with a subsoiler

Benefits of subsoiling with Rolmako soil loosening implements

The primary properties

Destiny
When should a subsoiler be used?
Advantages of subsoiling
Stubble cultivation
Coupler for accompanying machine

Various configurations available
Oversized agricultural structures
Steel providing an advantage

Purpose of U638 subsoiler – elimination of soil compaction.

Destiny

The subsoiler is engineered to break and loosen the soil to enhance its physical and biological properties. It loosens the layer of soil not reached by plowing, allowing better percolation and aeration, which fosters plant root development. Subsoiling reduces the depth of plowing for several consecutive years, resulting in significant fuel and time savings. It also moves fertilizers to deeper soil layers. This procedure is necessitated by water stagnation in fields during spring. For effective soil crumbling, subsoiling must be done when the soil is relatively dry. Excessive soil moisture leads to smearing rather than crumbling.

When to use subsoiling – key timing in cultivation.

When should a subsoiler be used?

Soil undergoing continuous technological processing (ploughing, machine transport, harvesting) becomes increasingly compacted, preventing water penetration to lower layers. Excessive compaction leading to water stagnation indicates the necessity of a subsoiler to loosen deeper soil layers. Rolmako offers a comprehensive range of machines designed to address excessive water retention on the field surface efficiently. The robust and durable main frames are the hallmark of all Rolmako subsoilers. Utilizing the U 614 subsoiler enhances the soil's microclimate by retaining more moisture and improving ventilation, resulting in better crop yields. The subsoiler's operation ensures water absorption into the soil, promoting healthy and stable crop growth. Rolmako subsoilers are available in multiple varieties, featuring various tine types and overload protection, with distinct supporting frame structures.

Benefits of subsoiling with U638 – improved water management and higher yields.

Advantages of subsoiling:

- Increased yields
- Improved root development
- Enhanced water management through better soil permeation and greater water retention
- Mitigation of fungal disease risks
- Potential for earlier sowing
- Decreased soil pollution
- Reduced pre-winter ploughing costs by shallowing
- Positive impact on future crop cycles

Stubble cultivation

Conducting both shallow and deep soil cultivation with a single device facilitates savings in investment and operating costs. Equipped with shares featuring undercutting wings, the Rolmako cultivator excels in preliminary shallow soil cultivation, providing sufficient space for the flow of significant amounts of post-harvest residues and soil. Optional wing shares (400mm), like all working elements of the U 638 and U 632 systems, are equipped with cemented carbide. The machine stands out not only in terms of durability but also in the quality of work with post-harvest residues. Adjusting the mulching roller ensures effective mixing of soil with straw.

ATLAS tine

The U 638 and U 632 subsoiler tines are distinguished by exceptional wear resistance, achieved through the use of premium materials. The standard equipment for the Atlas tine includes a chisel, skid, and beam cover, with the Side wing shares available as an option. All wear-exposed parts of the Atlas tine are finished with carbide elements, and consumable parts are hardfaced to extend lifespan and minimize machine servicing time.

Atlas cemented carbide working elements as standard:
- Higher work culture
- Minimal loss of time related to parts replacement
- Reduced need for mounting screws
- Minimizing additional machine passes
- Operating time extended by 5 to 10 times.

Spring overload protection

Mulching roller

Hitch for tillage equipment in U632 subsoiler – compatible with disc harrows or other ag equipment.

Coupler for accompanying machine

The U 632 subsoiler features a coupling for a cooperating machine, enabling subsoiling in conjunction with a disc or active harrow and other machines equipped with a three-point tractor hitch. The machine depicted in the photos combines a subsoiler with a compact disc harrow, offering a working width of 3.0 meters and equipped with a heavy rubber roller. The combined machine weight is 1800 kg. The disc harrow roller ensures operational stability and maintains the predetermined depth of cultivation. The subsoiler loosens the soil beneath the plowing depth, while the discs handle post-harvest processing.

The machinery is made only of high-quality Swedish S500MC and S700MC steel.

Steel offering a competitive advantage

Increasingly larger and more powerful agricultural tractors subject the structural elements of agricultural machinery to significant stress, pushing them to their operational limits. Modern agricultural structures are expected to demonstrate high resistance to loads and an extended service life. Achieving a high-quality end product necessitates the use of superior-quality steel in production. Accordingly, we utilize high-quality Swedish fine-grained steels S500MC and S700MC, as well as carbon and boron steels for heat treatment and the wear-resistant Hardox. The use of these high-quality steel products ensures our agricultural equipment is highly durable and capable of operating at high speeds with high surface efficiency.

The farm machinery stands out for its weight compared to the competition.

Oversized agricultural structures

Rolmako tillage machines distinguish themselves from competitors due to their superior weight. The company's development team designs agricultural equipment to endure the most challenging working conditions. Rolmako machines efficiently cultivate land in demanding regions worldwide without requiring additional loads. The substantial amount of steel in their construction makes these tillage tools robust, enabling the utilization of high-power modern tractors and ensuring long-term farm investment.