The next two important factors to consider are what its load bearing capacity is, and whether it is an all-weather, all-terrain vehicle.

Why is weather so important? Because the nature of the soil is affected by the kind of weather you experience, where you live. In areas which receive a lot of rainfall, the ground can be very muddy. Again, where there is heavy snowfall, it affects the nature of the terrain you use the tractor on.

If your farm is located in hilly terrain, hauling of big loads could prove cumbersome. Also, an all-terrain vehicle is higher resale value.

As far as load bearing capacity is concerned, the HP rating of the engine gives an obvious indication. However, for all-terrain use, I would prefer a compactly built tractor to a heavy-duty design.

Whether you want to plow land, pull stumps or bale hay, or engage in other agricultural activities, such as digging shallow holes, cutting furrows, breaking up the soil or digging a rock using the bucket, a heavy duty tractor is likely to prove more than useful.

However, a light/ compact tractor used optimally could prove a good substitute for a big muscle tractor. So, even if you do need a heavy duty tractor, consider this option because it will also save you a lot of money. The machine has to have sufficient torque, to be able to haul big loads. Once you have decided on the HP rating of the tractor you want to buy, focus on other important details, such as the price of the machine, and the likely maintenance costs, you could have to incur. It makes sense to plan for a lower maintenance vehicle, at the time of purchase.

This is particularly helpful as add-on accessories, such as loaders or snow blowers are only going to reduce maneuverability. So, the basic unit of the tractor needs to be as compact as possible. This should involve a bit of imagination in design, such as in user-friendly placement of controls.

For an all-terrain vehicle, I would definitely look for 4 wheel-drive, especially as this would help extricate the tractor from slushy mud or snow. Also, on inclines and ditches, the tractor is likely to bank.

Maneuverability is also helped by power steering, if that's available on your tractor.

In short, buy a compactly built tractor that packs the HP you need. Standard 2-4 cylinder liquid-cooled diesel engines translate into pulling power, whether in mud or snow, not to mention digging, mowing, field mowing, loader work, excavations, etc. Look for free power steering and a 2-stage clutch. The 4-wheel drive spells stability on uneven terrain. Make sure they come with useful accessories, esp. the ones you need.