Of course you are Diesel, if its your land then you are perfectly within your right to stop people from coming onto it, unless as others have already said, there are public rights of way through it.
I however take a different view & consider myself fortunate to live this lifestyle. In this day & age there is no way that I could afford the luxury of living as I do, if it wasn't for taking over the family business, yes I work all hours but for me it provides a lifestyle that I wouldn't change for the world. If I can share some of that pleasure with my local community then I'm happy to do so. Don't get me wrong, I expect my privacy & don't like that from being invaded around the house, but if people want to cut through the farm to walk there dogs then thats fine by me, providing that the dogs are kept under control in the vicinity of my animals.
I've got a good repore with people in the two villages near us. I open the bottom field up for charity boot sales & the local model flying club use it on sundays normally, theres a bit of rough ground which the local boys use on a saturday only (to restrict noise) for moto X, god knows what they get up too down there, theyve got jumps & things. Local lads are also down there in the week with there airguns after the rabbits. We let a metal detecting society come in when we're turning over the fields. We even allow up to 5 caravans or motorhomes to stay in the copse providing that they are completely self sufficient, we do make a small charge of £5 per night for this as I do spend a bit of time maintaining the area for them. But do you know what, I think its lovely that I can do this for people & allow them to enjoy some of the pleasures that I do.
That said, I am having ongoing issues with the local hunt as I dont agree with hunting with hounds. In fact I dont allow any hunting on my land whatsoever with the use of either dogs or ferrets other than for shoot retrieval. We do allow falconry though which is a pleasure to watch & helps keep the birds away!