h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have been concerned for some time about the over use of chemical fertilisers alone in the growing of food.this is bound to lead to the soil being denuded of trace elements such as zinc, selnium,copper and many other similar elements that are essential for a good healthy diet.
One has to only look at the lack of humus in the soil of most arable farms to see the problem. Surely it only by the increased use of organic fertilisers in arable farming that it is possible to ensure that trace elements get into the food chain.