Managing small acreage

[Raffles22]

We are trying to manage on aged horse and one shetland pony on just about an acre.  We have had to resort to ploughing up and reseeding one of the fields as it was very compacted (clay soil) and nothing grew on it all summer despite regular harrowing, re-seeding and feeding.

I've been told that adding lime to urine patches will neutralise the area, but this does not seem to be working.  The fields are cleaned daily after use, but I would still like to do more to minimilise the impact of the droppings/uring areas.  At lease they always use the same patches!

Any advice would be welcome.