Your horse is what it eats !
After years of keeping two horses on 2/3 of an acre, I think I have finally got the answer to getting the most out of our paddock. We divided it in half with a post and rail fence and I strip graze one half at a time using an electric fencer, giving them a fresh patch every day. When one half is eaten down, we swap the horses and fencer to the other half and collect the droppings and top the patches they haven't eaten (which are mainly where the droppings were) with our hoover/topper. Then apply one bag of fertiliser (we decide which one at the time, depending on the season, state of the grass, etc) and leave it for 6-8 weeks while the other half is being grazed.
With the area of grass at my disposal I have to use Nitrogen as otherwise I would not have enough grass to keep two horses going. I know a lot has been said about Nitrogen being bad for horses, but I am convinced that if you monitor the rate of growth of your grass, and the condition of your horse, and adjust your available grazing area accordingly you won't have a problem.
Regular topping after grazing helps to keep the rubbish down.
With time grassland loses its vigour, which can be cured by re-seeding with a suitable horse paddock mixture containing perennial ryegrass, timothy and creeping red fescue, the latter providing a thick knit bottom to the sward which helps reduce poaching. I use this to repair damage to the gateways, raking and harrowing in, then rolling.
FCS have 45 years experience in fertiliser sales and application and grassland maintenance - We have an on-site BAIS Registered FACTS Qualified Advisor and we offer friendly advice with no obligation to buy.