Blimey James - Sorry to continue the correspondence and please end it if you feel so, but this is important. Life is variable as the quality and quantity of the dust which revives it. The mineralsation of complex proteins into the simple elements required for plant growth is a function of a complexity of life. The whole art of husbandry is regulation of the speed of that process. Return too much fertility to a field and we increase crop yield by diminishing that of a neighbouring field.