If you only ever go out to her pasture to bring her in for work that could be why. This happened some of my horses. So I used to go out to the field and just spend time with them so they didn’t think I was only coming to ride them. Also ignoring them in the field can help rouse their interest!
I would recommend trying join up first but if you get desperate try walking around her not to her. Take a lead rope with you then from a non kickable distance swing the leadrope and herd her up to a smaller pen. (I don't know if your paddoks are connected to your field)
Make the pasture smaller. Then when she does not pay any attention to you..chase her... If she gives you ear, eye or what ever... relax.... your timing has to be perfect but she wil learn that being with you means comfort and relaxing. Ingnoring you means work. Dont bring her inside right away when she comes to you. Reward her by Grooming and or play. Good luck!
Try round penning her and doing some liberty in there so she can learn to "face up" this will make a huge dofference to trying to catch her as when she goes to trot off you can ask her to face up.
And lots and lots of rewarding when she does even the smallest thing to show she's interested in you and wants to come to you. Just keep cooing to her and say she's a good movie.
Do lots of ground work with her. Like Ruby said, join up is good. Also try liberty but do LOTS of research before trying of it if you haven't tried it yet.
When u catch her reward her with food....maybe leave her in a round yard so she can’t run around. Also try join up again so she gains your trust again
I’ve tried everything, grain, treats, even leaving the gate open and she pays no attention
Have you tried using some treats to call her over?