Land where Vehicles have been moving and you won't get a surprise. Like a place where Cattle have been fed from vehicles. Any grass above about 15" can trip you up. It (FLOOD Irrigation)is NOT the Most efficient form of irrigation. It will get water to a parched surface but it will quickly pass through the Root zone and be Unavailable to the Plant. It also has to be dead level laterally or it's uneven. Done in hot weather there will be a lot of evaporation Loss..
With the Planes we fly you don't need a great Length and it doesn't HAVE to be straight. It can have a gradual curve and Land BEFORE you run Out of fuel. Not after, IF you have a choice.
Brendan you have chopped and changed in your latest Post. Land in Paddocks by all means, but be aware of some traps like chains and Irrigation HOSES etc. Open Paddocks can Have small stumps, fallen branches and rocks and the odd piece of junk that may have fallen off something. Old bits of fencing wire. Nev