Nowhere on earth, nature produced a biological cycle as complex as soil. All civilizations born on few centimeters of living soil, humus, progress with fecundity of this thin layer and disappear with it.

Humus is the topsoil, vital to good soil fertility.

It is the result of transformations of organic matter on soil and in the soil, its combination with minerals and its microbial populations. There is support for functional and biological properties of soil and its production expectations. It is an expression of effective relations between the earth that gives life and other living organisms, it is the link between earth and man.

It makes sense for chemists, one for ecologists, one for the philosophers and poets.

For the peasants of the past it was essentially the old grease from the earth. The destruction of the humus is a tragedy whose extent and development embrace the throat of any informed observer. His study shows the overwhelming responsibility of man in this destruction. But the disaster is increasing so fast. He faces them we are not careful immediately to evolve to a point of no return that will mean the death of the planet, the death of man and death of civilizations. The remains of lost civilizations left by the man on every continent in every period of its history and especially where the deserts have followed a successful tenure, tell and retell with brutality, when the humus is exhausted, the Man succumbs to poverty and civilizations die.

Organic matter is taken and retaken by a hundred mouths, stomachs digested by a hundred successive, separated and converted into new substances feeder by billions of microbes and enters the common heritage of life to come where the soil is home.