If your allotment hasn't been used for a couple of years it has effectively been lying fallow which used to be one of the rotation years for farmland before industrialisation, intensive growing and chemical based fertilisers became the norm after WW2.
If you feel the soil texture is good then go ahead and clear weeds to a compost heap and plant but bear in mind the need to rotate crops to avoid the build up pests and diseases and also depletion of nutrients. Mulching is always a good idea if you have enough composted material available and your horse poo is black gold so hang onto as much as you can and let it break down for a year or two before using as a mulch or feed.
You can consult the RHS website, Garden Organic or Tee Gee's almanac for crop rotation and soil prep info.
The only fertiliser I buy is a special liquid feed for citrus plants and bags of pelleted chicken manure. Eveyting else comes off our compost heaps and, when I can get it, local horse poo.
Thanks, Obelisk and TeeGee,
My fresh muck is more bronze gold at the moment. Still very fresh. and neat with not much straw. But I can see it has potential value so I'll hang on to most of it, mixing it generously into my heap which is getting well fed with greens and browns. I have about a dozen bags!
There's a few good local sources of better stuff, so I'll still willingly trade it for other goodies.
Silly question. Will it decompose much in the bags, or if I were to empty them out into a pile of just muck? How bad would the stink get if I opened it to the elements? I want it 'maturing' even if I'm currently short of green and brown, but i don't want to pee off local householders.