Sawdust

When I first got one of my previous allotments there was a pile of horse pee impregnated sawdust from the stables dumped on site and no-one wanted it. I had a new plot which i didn't fancy digging so all i did was dig holes with one spadeful of soil, plonked a seed tattie in hole, filled it with sawdust mix and put the soil I had taken out on top. I had a wonderful crop of lovely clean potatoes that year and it really helped break up the soil the second year! I suppose a sprinkling of sulphate of ammonia  would have given the same effect as hoss pee?