Mowing and Mulching Slopes Up to 55 Degrees

Fifty-five degrees is a great deal steeper than most people picture. It is past the point where walking the face is comfortable and far past anything a tractor should be on. The reason the figure can be that high is simple: nobody is on the machine.

Conventional slope limits exist mostly to protect the operator. Tractor and ATV rollovers remain among the most serious causes of death and injury on New Zealand farms, and the honest safe limit for a tractor and topper is well below what people routinely attempt on a hill face. Take the operator off the machine and the binding constraint becomes traction and machine stability rather than whether someone survives a roll.

In practice this is why so much steep country ends up unmanaged. The face is not impossible to clear, it is just impossible to clear safely with the equipment most people have, so it gets deferred until it is solid gorse and nobody remembers deciding to let it go.

It is worth being precise about the figure, because operators in this category quote different numbers. GRazer's stated capability is up to 55 degrees, expressed in degrees rather than per cent, two very different things, and the source of a lot of confusion in this industry. Fifty-five per cent is roughly 29 degrees. Fifty-five degrees is nearly twice that.

Gradient is not the only thing that matters on the day. Ground moisture, surface stability and what is hidden under the vegetation all affect what is sensible, which is why one to two dry days are generally preferred and why conditions are assessed before work starts.

Before and after

BeforeAfter

Slopes up to 55 degrees before and after - drag to compare