Take a compact dairy or beef enterprise with conservation ground within easy reach of the cattle yard, and a harvesting system based on one or two self-loading forage wagons offers a highly cost-effective means of filling the silage clamp.

It may not be the fastest method; employing a contractor with a self-propelled harvester, fleet of tractors and trailers and a big loader on the clamp will always score on that count.

But as long as the draw is within a couple of miles, the forage wagon system will do the job cheaper.

Other plus points?

Enthusiasts like the steady pace of forage wagon harvesting because it allows time to properly fill and consolidate the clamp.

They say it is gentle on the grass, too, and being able to do the jobs with few revs on the clock does wonders for fuel economy.

A longer average chop length than is commonplace with forage harvesters is looked on favourably.

Although changes that enable choppers to produce a longer chop – and within a tighter range of lengths than the slicing mechanism of a loader wagon – has eroded that perceived advantage.

So, if a forage wagon is a candidate for some long-awaited SFP spending, what are the key features to consider?

Size? The biggest possible is the obvious answer, as it has a significant impact on performance.

But, then, so does travel speed and turn-around time.

In that case it may be worth losing a few cubic metres capacity for a wagon that can run down narrow lanes and B roads with ease and spin around easily to offload on to the silage clamp apron.

Tractor power is not so much an issue of pto performance – the pick-up and chopping system take little power – as of traction and stability in the field, especially when operating on banky ground and being in command of the heavily-laden wagon on the road.