A Howard/ Grimme Rotavator in a field

The Use Of Rotavators In Agriculture

A rotavator, a powerful tool in the world of agriculture and horticulture, offers a multitude of benefits for soil cultivation. Recognizing its impact requires diving into its history, mechanics, and flexible usage.

The Evolution of Rotavators

The roots of the rotavator reach back to the early 20th century, when Arthur Clifford Howard, an Australian engineer, developed the first powered rotary hoe. His invention forever changed how we approach soil cultivation, marking the birth of the modern rotavator.

From Howard’s initial design, the rotavator has continually evolved, adapting to meet the demands of modern agriculture and horticulture. Today, it stands as an essential tool for growers worldwide.

Understanding How Rotavators Work

A rotavator operates by using a set of blades or rotors, which rotate in a horizontal axis to break up, churn, and aerate the soil. When the rotavator is attached to a tractor, power is transferred from the tractor’s engine to the rotavator’s gearbox, spinning the blades at high speed and providing effective ground cultivation.

Rotavators can tackle a variety of soil conditions, from breaking new ground to preparing ploughed areas for planting. This versatility stems from their powerful action and adjustable parameters.

Adjusting the Rotavator for Optimal Use

Adjusting Forward Speed and RPM

The balance between a rotavator’s forward speed and RPM (revolutions per minute) is critical to its effectiveness. The rotavator’s RPM determines how rapidly its blades or tines rotate. When the RPM is higher, the blades turn more quickly, breaking up the soil more thoroughly and creating a finer tilth.

However, this increased RPM should be used along with a slow forward speed to allow the blades sufficient time to work the soil effectively.

If a coarser soil structure is desired, or if there are fewer soil compaction issues to address, a lower RPM could be used. This would allow for an increase in the forward speed, covering more ground in a shorter amount of time.

Understanding the specific needs of your soil and crop can help determine the optimal balance between forward speed and RPM for your situation.

It’s important to note that a very high forward speed can result in poorly tilled soil. This is because the rotavator may not have enough time to properly break up and turn over the soil. This scenario can leave behind an unevenly cultivated field and potentially damage the rotavator over time.

Different soil types may require different speed and RPM settings. Heavier, clay-based soils often benefit from slower forward speeds and higher RPMs to ensure thorough breakdown, while lighter, sandy soils might be sufficiently worked with a faster speed and lower RPM.

Adjustments may also be necessary based on soil moisture levels and the desired soil structure for specific crops.

The Importance of Soil Moisture

Soil moisture content can directly affect the operation of a rotavator. Too much moisture can cause clumping, while too little can make the soil hard and difficult to break up. Proper moisture levels ensure the blades can penetrate and mix the soil effectively.

Adjusting Working Depth

The working depth of a rotavator is another crucial adjustment. Depending on the crop and soil conditions, the depth may need to be adjusted to ensure optimal soil aeration and mixing. Deeper tilling makes fine soil tilth more difficult

Tractor Horsepower Requirement for Rotavators

The horsepower of the tractor should be matched to the requirements of the rotavator. Factors such as the width of the rotavator, soil type, rotavator rpm, forward speed and working depth all influence the horsepower needed for effective operation. Generally, wider working widths, deeper cultivation at higher rpm and faster forward speed all require higher horsepower.

A simplified guide for matching tractor horsepower to rotavator is 1 horsepower per 1 inch of rotavator width: A 100-inch wide rotavator will require a 100 horsepower tractor.

a 6m rotavator side view showing the many blades
A wide 6 meter rotavator like this will need a large 300 horsepower tractor to operate.

Different soil types can also affect horsepower requirements. Harder soils typically require more power to break up, while softer or sandier soils may require less. Understanding your soil and adjusting your tractor’s horsepower accordingly will optimize rotavator performance.

The Use of Rotavators in Agriculture

In larger agricultural settings, rotavators play a significant role in preparing fields for planting. Their ability to cultivate large areas of land quickly and effectively makes them invaluable for modern farming.

Crop Suitability for Rotavators

Vegetable Crops

Rotavators are particularly effective when used for vegetable cultivation. Their robust nature and ability to break down soil into a fine tilth make them ideally suited for preparing seed beds for vegetables, which often require a well-aerated, clod-free soil structure for optimal growth.

this rotavator is fitted with 4 large bedforming ridge bodies for potato preparations
This rotavator is used to create 3 large beds of soil which will be used to plant 6 drills of potatoes.

Cereal Crops

When it comes to cereal crops, rotavators may not be the first choice. This is because cereal crops, such as wheat or barley, can benefit from a more level seedbed which power harrows are particularly good at providing. Power harrows have a less aggressive action and can create a more even surface, which aids in consistent seeding and crop emergence.

Rotavators in Grassland Management

Rotavators also play a key role in grassland management, especially when converting grassland into arable land. The rotavator’s powerful blades can be employed to chop the top layer of burned off grassland before ploughing. This process helps to break down and eliminate grass sods, facilitating a smoother and more efficient transition from grassland to arable land.

The use of rotavators in agriculture also extends to soil management practices, including the incorporation of farmyard manure or crop residues, which can improve soil fertility and soil structure.

See the rotavator in the above images in action for potato planting operations in this short video


From their humble origins to their widespread use in modern agriculture, rotavators have proven to be versatile and powerful tools for soil cultivation. By understanding their operation and making the necessary adjustments, growers can optimize their use of rotavators to enhance soil quality, improve crop growth, and ultimately, increase yield and efficiency.