Crop Duster (Plane)
You should notice the crop duster circling the area from the start - try not to get caught in it's green trail as this stalls your car making you an easy target for opponents. If you're finding it particularly annoying (or, y'Know, just for fun), you can take it out. Either launch a mortar when it's directly above you (tricky), or drive onto the roof of the hangar. This should bring you directly level with the plane when it passes over the airfield - you can now use the rockets/cannon to bring it down.
The hangar usually contains a useful wrench, but can also be use as a ramp to gain some height and escape pursuers. See the tips above on how you can use the hangar to exact some revenge on the Crop Duster!
Wind Turbines are scattered throughout the arena, some in the middle, some on the outskirts. Unlike the original, when you destroy these ones, the fans don't home in on nearby enemies The parts that rain down when they've been destroyed do, however, cause damage, so take them out when there are any enemies nearby.
The barn is the largest structure in the level - when it's intact, you can use it as cover from incoming mortars. The porches the the left and right can also be taken out, scattering debris everywhere, so use this to shake off pursuers. When the central part of the barn has taken enough damage, ot will go on fire. A few seconds later it explodes, creating a makeshift ramp from the rubble. Use this to collect the special hoverving above the barn - just may sure you don't plogh into the fertiliser tanks!
There are a few crop sprayers through the level - they crawl back and forth along their patches of land. When you pass underneath them, it triggers a fertisliser spray which, if you're not quick enough, will damage and stall your car. Use this to your advantage and lure chasing enemies through the sprayers, when they stall, turn round and let them have it!
Make sure you also check out this nice little touch - anywhere the crop sprayer fires, little green plants sprout!
Nothing particulary unique about the orange trees, though lighter vehicles may find themselves trapped in them and will have to shoot their way out. Larger vehicles can usually just plough straight through - the the resulting debris can often make it easy to lose enemies that are chasing you.
The Canal & Water Jets
This works musch the same as the original - shoot the wheels at the edges of the canal and they produce a wave that travels along the canal, damaging any vehicles caught in it. However, whereas the wave started at the cabin in the original, here it starts at the water wheels themselves, firing off in both directions.
You can use this as much as you want, as long as you use the machine gun to activate the wheels. Use another weapon, or fire too much and the wheel will be destroyed - luckily there are lots of them scattered along the banks of the canal
Hay Bales are a reat new feature - hit them a few times and they ignite before rolling down the hill, damaging anything in their path. Make sure you check out the bales near the fertiliser tanks - they will often roll into the fertiliser tanks causing a chain reaction!