The Difference between Middle Disc Harrow and Heavy Disc Harrow

The core difference between the middle disc harrow and the heavy disc harrow lies in the operational intensity, structural design, and applicable scenarios. Essentially, it is a "medium strength" and "high-strength" soil preparation tool that matches different soil conditions and cultivation needs. The following provides a detailed comparison from dimensions such as core parameters, structural characteristics, and applicable scenarios to help you distinguish clearly.

I. Core Differences Comparison Table

In comparison, the overall weight of the medium disc harrow and heavy disc harrow is relatively light, with a single group weight of 200-500kg(adjusted according to the width) and a single group weight of 600-1500kg+. Some large heavy harrow can reach 2000kg or more. The disc diameter is smaller (mainly 460-510mm), the thickness is 8-12mm, and the disc diameter is larger (commonly 560-660mm). The thickness is 12-16mm (partially thickened to 20mm), and the wear resistance is stronger. The spacing between the harrow blades is larger(180-220mm), and the spacing is smaller(150-180mm) when entering the soil shallowly. The depth of entry is deeper and more stable, with a conventional depth of 5-12cm and a maximum of 10-20cm. Some models can be deep. Up to 25cm The demand for supporting power is relatively low, and a tractor power of 30-60 horsepower can drive a high demand, requiring a tractor power of 60-120 horsepower+(large heavy harrows require more than 150 horsepower). The operation intensity is moderate, mainly focusing on "crushing soil, flat land and stubble". The high-strength structure design is mainly focused on "deep plowing, breaking compaction, and crushing large pieces of soil". The harrow frame is relatively lightweight, mostly consisting of single or double row discs, with spring pressure(some without pressure). The harrow frame is thick and sturdy, mostly consisting of double or three row discs, equipped with hydraulic pressure devices to enhance soil penetration force, and some are equipped with weighting blocks.

II. Homework objective: "Fine organization" vs "Deep fragmentation"

4Middle harrow: The core is "fine soil preparation", which does not pursue deep plowing, but focuses on solving "surface problems" , such as crushing soil blocks after shallow plowing, removing crop residues(corn stalks, wheat stubble), leveling the surface, breaking surface soil compaction, creating loose and uniform surface soil(0-10cm) for sowing, equivalent to "subsequent precision processing".

Heavy harrow: The core is "high-strength crushing", focusing on "deep improvement", such as crushing the hard soil layer of reclaimed land, large soil mounds left after deep plowing(large pieces of soil left after plowing), compacted land that has not been cultivated for many years, and even small stones(with a diameter of less than 5cm), which is equivalent to "early rough processing+deep loosening of soil". 

III. Structural difference: "Lightweight and flexible" vs "Heavy and durable"

Middle harrow: For flexible operation, the harrow frame is designed to be lightweight, with thin discs and wide spacing to avoid soil adhesion, and can be inserted into the soil without strong pressure, making it suitable for fast operation. For example, the common "24 piece medium-sized disc rake" has a width of 2.2-2.5m and can be pulled by a tractor with 30-40 horsepower, with a working speed of 5-8km/h.

Heavy harrow: In order to cope with hard soil and large soil blocks, the harrow frame is made of thickened steel, and the discs are thicker(impact resistant and wear-resistant), and the discs are deeply penetrated into the soil through hydraulic pressure. Some models can also add additional weighting blocks(50-100kg per piece). For example, the "36 piece heavy-duty hydraulic rake" has a width of 3.0-3.5m and must be driven by a tractor with over 60 horsepower. During operation, it needs to run steadily at low speed (3-5km/h) to avoid disc deformation.

IIIV. Applicable scenarios: "Conventional land preparation for cooked land" vs "Improvement of raw/hard land"

(1) Typical scene of a middle harrow:

1. After the harvest of conventional crops such as wheat, corn, soybeans, etc., stubble removal and shallow tillage are carried out to prepare for the next season's sowing;

2. Final leveling before sowing (such as vegetable greenhouses and seedling fields, which require fine surface soil);

3. Mildly compacted cultivated land (farmland that has been cultivated for many years, with only surface compaction and no need for deep cultivation).

(2) Typical scenario of heavy harrow:

1. Abandoned land, riverbank land, mine reclaimed land, and other "raw land reclamation" (breaking through hard soil layers and improving soil permeability);

2. Crushing large soil mounds after plowing (such as breaking clumps with a heavy rake after autumn plowing to avoid soil compaction after winter freezing and thawing);

3. Land with a lot of stones (broken small stones, cleared surface gravel to create conditions for cultivation);

4. The compacted land that has not been cultivated for many years (deep loosening of soil to restore soil aggregate structure).

V. Homework combination: "Subsequent connection sowing" vs "Early connection plowing"

Middle harrow : often used as the "last soil preparation process", sowing directly after the operation (such as live streaming of corn and soybeans), without the need for further refinement with other tools.

Heavy harrow: often used as the "first process after plowing", after crushing large soil blocks, it is necessary to further refine them with a medium harrow or rotary tiller before sowing (such as cotton, vegetables, and other crops that require high soil fineness).