Nitrogen Fixation, Agriculture, and the Environment

This book tells the story of how humans have used their ingenuity throughout history to maintain soil fertility and to avoid famine through productive agriculture. The struggle to provide sufficient food has been a preoccupation of humanity since the earliest times. As circumstances have changed and as lifestyles have changed, the way in which the food supply has been ensured has also changed. The story of how different peoples have developed solutions to what is essentially the same problem tells us much about human beings of all kinds and in all ages. It shows us how humans have optimised the opportunities available to them by using the resources, both physical and intellectual, that have been available to them. It shows us the similarity amongst human beings of every era. It also demonstrates how one generation builds upon the knowledge of its predecessors to provide a solution that is appropriate to the new conditions, and it also illustrates the way in which science is gradually and painfully built by generations of researchers in a cooperative undertaking that slowly refines the models of reality used to analyse nature. Traditionally, agriculturalists have tended to be conservative, and this is very understandable. It is stupid to experiment with questionable new methods if you know that the old techniques work and that not using them will risk a year of famine. The Egyptian and the Britons depicted ploughing with very similar implements in figure 1.1 would probably have shared many ideas on how best to raise crops. A survey of how some ancient civilisations attempted to solve the problems of maintaining soil fertility is given in chapter 2. Many of their techniques are still applied somewhere in the world to this day. The main focus of this book will be on the story of the essential nutrient nitrogen because nitrogen is often the element whose supply limits the agricultural productivity of many food systems. Nitrogen is an element that many people know a little about. Nitrogen gas comprises about 80% of Earth’s atmosphere, though this was not known 250 years ago, nor would such a statement have made much sense then.