A Subsoiler (also known as a Grubber, Heavy Cultivator, or Chisel Plow) is a heavy-duty agricultural implement designed for deep primary tillage. Unlike a traditional moldboard plow (which inverts the soil), a subsoiler is designed to break up and loosen the soil at great depth without turning it over completely.
It is an essential tool in modern farming for managing soil compaction.
Its fundamental purpose is to eliminate soil compaction (the impermeable layer known as “hardpan”). This compacted layer often forms at the bottom of the normal plowing depth, caused by heavy machinery traffic and repeated tillage at the same depth.
Breaking Hardpan: The strong tines (shanks) penetrate deep into the soil (typically 25 cm – 50 cm / 10-20 inches) and shatter this restrictive layer.
Improving Drainage: By breaking up compaction, rainwater can infiltrate much more easily into the subsoil, preventing waterlogging (puddles) on the surface.
Enhancing Root Development: It allows plant roots (especially for deep-rooted crops like oilseed rape or sunflowers) to grow deeper into the soil to access water and nutrients.
Soil Aeration: It introduces oxygen into the deeper soil profiles, improving biological activity.
Stubble Cultivation: It is often used after harvest to loosen the soil and partially incorporate crop residues (stubble).
Frame: An extremely robust, heavy-duty steel frame built to withstand the immense draft forces required to pull the tines through compacted ground.
Tines / Shanks: These are the “legs” of the implement (like the 7 black components on the blue machine). They are made of very thick, hardened steel. At the bottom, they have replaceable tips or shares, which are the primary wear parts that do the breaking.
Wing Shares: Many tines are equipped with horizontal “wings” at their base. These help to lift and shatter a wider area of soil at the working depth, ensuring a full-width loosening effect.
Rear Roller: Most modern subsoilers have a heavy roller at the back (like the ringed roller on the blue machine). This roller crushes large clods left on the surface, levels the ground, and “seals” (lightly firms) the soil to conserve moisture.
Safety System: Because striking a large rock at deep depths can destroy the implement, tines have safety systems—either a shear bolt (which breaks and must be replaced) or a hydraulic or spring auto-reset system (which allows the tine to trip over the obstacle and reset itself).
Subsoiling is one of the most power-demanding (high-draft) tasks in farming.
A 3-meter (10 ft) wide subsoiler, working at a 40 cm (16 in) depth in heavy soil, typically requires a tractor with 180 HP to 250 HP or significantly more.
