The Nutrient cycle is really the core of our whole existence on this planet- and where humanity for the most part has come unstuck.
In essence it means that all nutrient (energy) remains in constant motion as each creature lives it uses nutrient and in its wastes and eventual death in turn provides nutrient to other creatures. On a small farm if we were to farm in a truly organic manner this would mean that we try to return as much of the nutrient we use as possible to the soil so that it in turn can be used to feed the farm as a whole. If we try to only import nutrient (in the form of stock feed and the like) and do not allow the end nutrient to leave the farm it follows that over time you will enrich the soil of the farm far beyond its original capacity. Of course this means that you are technically stealing nutrient from another source. This is the problem with industrial level farming where the soil is continually harvested for all it can provide and the nutrient is then shipped off to big cities where it is consumed and then flushed out to sea as sewage.
What a colossal waste!
Worst of all is that those industrial farms are then "fertilized" with chemicals made largely from petroleum and even then they are grudgingly given only as much as the next crop needs and no more. The soil is in no way improved or fed. The soil life dies and the soil is little more than a growing medium bare of life. Doubt me? Go dig a hole in a field on a large scale industrial farm and see how many worms and the like you find. Compare this to even a simple shovelful of soil from a good organic garden!
The point I am getting at is that you must feed the soil before you feed anything else on your farm! From your soil comes all other life on the farm. It is a living creature, like a coral reef, full of diverse life. Each contributes to the soil and enhances plant life. The plant life in turn feeds us as vegetables, our livestock as grass and makes compost to be returned to the soil. Trees reach deep down to the bedrock where they extract nutrient grasses cannot reach, they will then shed leaves and bark to create that wonderfully rich humus. Trees also attract wildlife which import nutrient in the form of droppings.
So on the perfect farm I would feed my soil. All my livestock would contribute through their manure- processed into a more readily usable fertilizer to feed the soil life. All household organic wastes are either fed to livestock or else directly composted. A variety of livestock is kept to provide a variety of manures each rich in their own elements. Cow manure is soft and easily makes good black soil, pig manure is rich in almost every area and chickens and pigeons manure is high in nitrogen and phosphorus. Best of all is human manure. The ultimate sin of humanity is to pump this, the best available nutrient of all, into the ocean out of pure squeamishness. It has long been proven that human wastes are easily processed and rendered harmless of any pathogens while also producing a valuable fuel gas, methane, at the same time! If I can (and I am still checking the council by-laws but it does look feasible) I will be emptying and spreading the contents of my septic tank onto a paddock left unstocked for three months. The sunlight and exposure to air will render it harmless in a short time and the results on the grass should be dynamic. Indeed, if possible I would like to be eventually buried on this farm, or perhaps mulched, to give some tree in the orchard a good head start.
On the perfect farm nothing should be wasted. All that you use should come from your farm and then returned to the soil when you are done with it. In time the soil will grow rich beyond anything you have ever seen and will abound with life. That is true farming and that is the Nutrient cycle.
"We must achieve the character and acquire the skills to live much poorer than we do. We must waste less. We must do more for ourselves and for each other. It is either that or continue merely to think and talk about changes that we are inviting catastrophe to make. The great obstacle is simply this: the conviction that we cannot change because we are dependant on what is wrong. But that is the addict's excuse, and we know that it will not do."