If you're not familiar with farm tractors, choosing one that’s suitable for a small farm can be a daunting task. Will a compact tractor suffice and how important is tractor size?

A good starting point when choosing a small-farm tractor is to be clear just what you want a tractor for. If it is just to mow an acre or two, or to cart a few small bales of hay, then a ride-on mower or quad bike with a tow bar may be all you want.

However, if you need to cultivate soil, spread some fertiliser or feed out some large round bales, then you are likely to require what I like to term a ‘real tractor'.  Unlike most ride-ons, a real tractor is full unit construction where the engine, transmission and rear drive train are all housed in rugged castings.  It will also have a Power Take Off (PTO), a three-point linkage and external hydraulics capability.

For most small-farm operations, all your requirements can be found within the Compact Utility (compact) range of tractors. These are essentially small tractors of 15kW (kilowatt) to 50kW (20hp to 70hp) that have many of the exact same features that are found in larger, more expensive tractors. 

Is tractor size important?
The size of tractor you require is really determined by the job you want it to do, and the size of the implement that can do the job.  It often becomes more  an exercise in determining how much time you wish to spend doing a job, and choosing the appropriate implement and tractor to do it. It is however  important to match the size of the implement to the tractor, to ensure that both the tractor and implement operate at the optimum speed. Don’t fall into the  trap of purchasing an oversized implement for your tractor thinking it will get the job done quicker. This can labour the engine and transmission and force  you to operate in low range. 

For very small holdings, say of 4ha or less, a suitable tractor is certainly likely to be found in the 15kW to 25kW horsepower range. Tractors at the 50kW  end of the compact range can readily handle tasks found on farms 100 times this size.  For those one-off jobs requiring more horsepower, it makes more  sense to hire a contractor. 

Comparing horsepower ratings
Horsepower ratings quoted by manufacturers of compact tractors are normally gross horsepower values for the engine running at a stated engine speed, for  example, 30kW at 2800 rpm. Sometimes the figures quoted for tractors are the horsepower as measured at the PTO, these being approximately 75% that  of the gross values. The manufacturer’s data sheet will specify which one applies. If you are comparing two tractors that quote similar horsepower figures  but different stated engine speeds, the tractor that delivers the power at the lower engine speed is likely to be of more use, as it will have more torque.

2WD or 4WD?
Most modern compact tractors are four-wheel drive (4WD). While two-wheel drive (2WD) tractors have served agriculture well in the past, modern technology has made 4WD drivetrains much more reliable and affordable. A 4WD is particularly useful in slippery ground conditions simply through providing that little bit of extra traction via the front wheels, which is often all that is required when rear-wheel traction starts to falter.

For hill-country properties a 4WD is very strongly recommended. Most 4WDs offer much safer down-hill control due to engine braking effects via the front wheels. Driving uphill is often safer too since a 4WD is usually heavier in the front end. Both these aspects can be dangerously lacking in 2WD tractors.

Power Take Off (PTO)
A tractor PTO is a splined shaft found at the rear of a tractor that is powered by the tractor's engine. Various farming implements like rotary hoes can be  quickly connected to this shaft usually by means of a drive shaft attachment.  Some tractors also have a PTO located mid section for purposes like mid- mounted mower decks. PTOs may be of the 'standard' and the 'live-drive' type. The latter type is preferred, since it can operate regardless of whether the  tractor is moving, or clutch is engaged. 

Transmission type
Transmission types vary from conventional manual gearbox and clutch-actuated types to semi or fully automated 'hydrostatic' types. Given that modern  machinery is more reliable than ever, there will be little to differentiate the options other than price and convenience. If your use involves a lot of forwarding  and reversing, an automatic type might be preferable.

Power steering
Fortunately, most modern compact tractors have a power steering feature and it is well worth any extra cost.

Three point linkage
A tractor three-point linkage is found at the rear of the tractor. It is essentially a triangular attachment configuration consisting of a rigid 'top link' at the apex  and two lower arms to either side, via which an implement can be attached to the tractor. The lower arms are power driven via internal hydraulics in order to  raise or lower the attached implement.  Most compact tractor types have a 'category 1'  three-point linkage  and some of the larger tractors may sport a  combination 'category 1 - category 2'  type. In short, a three-point linkage is essential.

External hydraulics
This can be a slightly complicated area.  Ensure your tractor at least has a hydraulic outlet capable of powering a hydraulic cylinder.  Many implements  (such as a hydraulically adjustable tractor blade) utilise this feature. If you intend to fit a front-end loader or an external hydraulic motor, research the  tractor's hydraulic capabilities for its lifting capacity, speed of action, and its ability to operate several hydraulic functions simultaneously.  A tractor or  implement dealer will be able competently advise you on this.

In summary
While the initial monetary investment in a small-farm tractor can be high, if well maintained a tractor will easily last 30 years or more with minimal ongoing  costs. Compared to other farm machinery 'investments' like quad bikes that typically last only 5 to 10 years and have high annual maintenance costs, a  tractor usually works out to be one of the more cost effective investments you can make in farming.   

 In a future article we will look at what to look for and look out for when buying a tractor second hand.

The author, Roger has spent 20 plus years working in agriculture and horticulture since graduating from Massey University with an Agricultural Science degree. He has helped many farmers improve their farm productivity and profitability as well as often increasing the enjoyment they got out of farming.