A subsoiler is primarily used to loosen the deeper layers of the soil and break up compaction, whereas a chisel plough, in addition to deep loosening, also works more intensively in the topsoil, mixes crop residues and, in favourable conditions, can prepare the field for the next stage of cultivation in a single pass. For example, the Chisel plough U624 has a two-row tine section with side wing shares and a double spiked roller with hydraulic depth adjustment. This allows it to not only break up impermeable layers but also mix crop residues, break up clods, and level the field surface.

Yes, a Rolmako subsoiler can replace a plough in a no-till farming system, but not as a one-to-one replacement. It's important to remember that this operation produces a different effect than conventional ploughing because instead of inverting the soil, the soil loosening machine deeply loosens it and mixes it to a limited extent.

• When the priority is simply to break up compaction, a subsoiler is a very good solution.
• If you want to combine deep loosening with more intensive cultivation and preparing the field for the next stage, a chisel plough is often a better choice.

A subsoiler is best chosen based on the specific problem in the field and the desired effect after a single pass:

• plough pan and compacted soil in the deeper profile – a classic subsoiler, e.g., Rolmako U602, U608, U614, U619,
• the need for deeper loosening, mixing residues, and levelling the field – Chisel plough U624,
• hard, heavy soil – deep loosening machines with a higher weight and a more durable frame (e.g., U614, U624),
• stony soil – subsoilers with shear bolt or hydraulic overload protection,
• the need for greater versatility – the Multi-purpose subsoiler U638/U632 (subsoiler and cultivator in one), Rolmako subsoilers with a roller, e.g., U626 STORM, or with a coupler for an accompanying tilling machine, U602 and U608.

On subsoilers, the roller is not responsible for breaking up compaction itself, but it performs three functions: it regulates the tilling machine's working depth, crushes the resulting clods, and consolidates the top layer of the soil, which prevents excessive water evaporation after the operation.

• The strongest finishing effect after subsoiling – usually a double spiked roller.
• Even machine support without excessive weighting, e.g., on light and medium soils – pipe rollers or pipe-and-ring rollers.
• Stony fields – a roller made of steel rings.

Tine protection is selected according to field conditions:

• shear bolt – for lighter and medium soils where stones are encountered sporadically (a simpler and cheaper solution),
• Hydraulic overload protection – for more difficult and stony soils (the tine can move out of the way of an obstacle and return to work without downtime). Its advantage is the ability to adjust the hydraulic accumulator to the conditions in the field.
• Non-Stop spring protection – where non-stop operation in tougher conditions is important and frequent overloads occur (this protection is found, for example, on Rolmako Multi-purpose subsoilers U638/U632, where the tine is protected by two springs).

It depends on your expectations.

• Yes, if you need the deep loosener machine to be more versatile and achieve a better result in a single pass (additional discs can handle stubble cultivation, and a roller helps to maintain the working depth and preliminarily condition the soil, e.g., Rolmako subsoilers with a Twin Disc roller).
• No, if the goal is simply to break up compaction, without additional mixing and conditioning (the basic configuration of the subsoiler is usually sufficient).

Pay attention to warning signs in the field and locate the depth of the plough pan.

• Warning signs: standing water in spring, weaker root development, and increased plant sensitivity to water shortages.
• Locating the compaction: dig a soil pit (check if there is a harder, compacted zone beneath the topsoil and observe how the roots behave – do they penetrate deeply or stop and spread sideways) or use a sharpened rod (significant resistance in well-moistened soil can indicate compaction).

Subsoiling in wet conditions is not recommended. With excessive moisture, the soil begins to smear, which can produce the opposite of the intended effect (instead of loosening the soil, the subsoiler creates smooth-sided slots that quickly seal up again).

It is generally accepted to be once every 3–5 years on average, but there is no single, fixed frequency for subsoiling – the operation should only be repeated when signs of compaction reappear in the field.

When the soil is dry. In such conditions, the working elements lift the soil, causing it to crack and shatter in the deeper layers, instead of just cutting through the soil profile. What are the signs that the subsoiler is working too deep or too shallow?

• Too deep: excessive working resistance, increasing power demand and fuel consumption, and the in-field effect does not improve proportionally to the cost of the operation.
• Too shallow: the compacted layer is not effectively broken up, and the symptoms that prompted the treatment may persist afterwards.

This usually means that the machine is working too deep, or the soil is too hard or too moist for the set depth. To start with, you should:

• reduce the working depth,
• check the soil moisture,
• assess whether the compacted layer is actually as deep as the machine is set.

Typical reasons include selecting the wrong depth for the field conditions, excessive soil resistance, or improper machine support and adjustment. Start by:

• re-checking the actual depth of the plough pan,
• adjusting the depth setting,
• checking that the roller or other supporting elements are properly stabilising the machine's operation.

This most often happens when the soil is too wet or the machine is working too shallowly, merely cutting the profile but not breaking the compacted layer. In that case, you should:

• check the soil moisture,
• make sure the tine is working a few centimetres below the compacted zone,
• avoid carrying out the treatment without first digging a soil pit.

This is usually the result of working in conditions that are too dry and hard, or the absence of an element that crumbles and tidies the soil surface after the tines have passed. It is worth considering a configuration that not only loosens the soil but also provides a better surface finishing effect. At agricultural machine manufacturer Rolmako, we offer several different variants of subsoiler tines, so it is advisable to ask a manufacturer's advisor beforehand about selecting the right working elements for specific field conditions.

Most often, this means the subsoiling, deep loosening machine has loosened the deeper layer well, but the surface lacks consolidation and levelling. You should consider equipping the machine with a roller. Alternatively, correct the working depth if it was set too aggressively.