Power Harrow vs Rotary Hoe what suits me and what do I need?

Nov 14, 2023    Posted by Stewart Knight

It all depends on the type of finish you are trying to archive and whether you are trying to incorporate trash or stubble.

What is a power harrow?

The power harrow as the name suggests comes from traditional tillage of dragging vertical tynes across the soil to cultivate it, remove weeds and create a new fresh seed bed. Power being that it is driven from the tractor pto through a central gearbox down through the gear bed to create a line of vertical rotating tynes in which soil must pass through. These tynes also spin in opposing directions to move the soil between them to pulverise it. Most power harrows are fitted with a levelling board behind these tynes to hold the soil in the tynes for as long as possible to ensure all clods are broken up. Usually then followed by a roller.

What is a rotary hoe?

A rotary hoe on the other hand works by having a spinning rotor mounted horizontally to the ground which has L-shaped blades bolted to it. These blades slice into the earth chipping off small chunks at a time and spinning them around the rotor to pulverise them against the hood or rear doors of the machine to break them down to a seed bed.   

So what machine is for me?

Both machines are designed for secondary tillage to prepare a seed bed. However, a rotary hoe can also be used to incorporate crops for green soil (fodder crops that are sown to be chopped in to boost organic matter in the soil) or stubble from a previous crop. Due to their spinning motion, they will break up and incorporate stubble up to 280mm deep in most situations.  The downside to this spinning motion is that rotary hoes are hard wearing on blades and will tend to cause a hard pan as they are essentially forcing the soil into itself to break it up. For this reason, they are often pulled behind a set of subsoiler tynes to shatter the pan, lift the soil up and aerate it. This usually happens in soil preparation for root vegetables like potatoes/spuds or carrots. Alongside this, as you are spinning a rotor deep in the ground, they require a large amount of Hp.

Power harrows on the other hand have a much lower hp requirement as they work at a consistent depth and only have half the tynes moving soil at any one time. Simply put the soil is crushed between tynes not any part of the machine. This method leaves a level surface behind the machine and the soil is of a consistent tilth. However, a power harrow will not penetrate the soil itself it is simply a tool for fining down loose soil.   

Choosing the right features on your new machine

There are many variations between brands, but the basic concept is the same. Some brands run the rotor spindles closer together than others this allows the tyne phasing to be closer to 15 degrees for example so that each tyne is taking less of a bite into the soil with each pass meaning less hp requirement per meter of machine width and a finer finish behind the machine.

Other features to look for in a power harrow is to ensure that they have adequate stone guard protectors under the gear bed at the top of the spindles/ tyne holders. This ensures that large rocks won't become jammed between the tyne holder housing and the gear bed, destroying the bearings. A good overload clutch is also essential to prevent PTO driveline damage.

Other features to look for in a well-built power harrow is the ensure that the vertical spindles or tyne holders have the bearings mounted at the furthest points. Usually, the easiest way to determine this is on top of the gear bed there should be bolted bearing caps. This ensures the greatest protection against the gear bed twisting or warping under load which will cause metal fatigue and the drive gears to chip or even break in some instances. The sideboards are another feature to check on the power harrow as these are responsible for holding the soil in the blade and not allowing it to spill out the side. Some makes have boards that lift in a vertical motion if they encounter a stone or as the tynes wear down. Others have a hinge system that allows the board to come out as it goes up, this over time as the tynes wear will allow a ridge of soil to escape, which in turn won't leave a level paddock.       

Unsure if a rotary hoe or power harrow is the best unit for you reach out to the Delmade team we are very happy to answer questions you may have. Phone 1800 335 623.