Question Author
Thank you all. I learned many years ago that soil is made up of three things only. Sand Silt and Clay plus of course any organic matter depending what the soil is to be used for. Small amounts in sports turf and lots of it in compost in gardening. Sand Silt Clay cannot be absorbed by the plant but the organic material rots down and is absorbed in liquid form. Bloody obvious really when I think about it. Doh Many thanks again Chris