N H H H “I am tremendously impressed with this book. It will make a very significant contribution to the literature Enriching the Earth Vaclav Smil Enriching the Earth on the Haber–Bosch process of nitrogen synthesis, but perhaps even more significantly, will put into per- Fritz Haber, Carl Bosch, and the spective the importance of nitrogen fertilizer to humanity.” Transformation of World Food Production —E. T. York, Chancellor Emeritus, University System of Florida, and former Vice President for Agricul- tural Affairs, University of Florida Vaclav Smil “The history of an industrial process that creates ammonia from nitrogen and hydrogen sounds at best bor- The industrial synthesis of ammonia from nitrogen ing. However, in his sixteenth book, Vaclav Smil has done his usual outstanding job of creating a reading and hydrogen has been of greater fundamental impor- adventure. Starting with the statement that almost two-fifths of the global population owes its existence to tance to the modern world than the inventions of the the discovery of the Haber–Bosch process in the early twentieth century, the book reviews the history of the airplane, nuclear energy, space flight, or television. discovery, provides captivating details about the driving forces behind the discovery, and looks to the future. The expansion of the world’s population from 1.6 bil- Anyone with an interest in how humans modify their environment will find this book fascinating.” lion people in 1900 to today’s 6 billion would not —James N. Galloway, Professor and Chair, Environmental Sciences Department, University of Virginia have been possible without the synthesis of ammonia. In Enriching the Earth, Vaclav Smil begins “Dr. Smil is the world’s authority on nitrogenous fertilizer.” with a discussion of nitrogen’s unique status in the —Norman Borlaug, Nobel Peace Laureate and International Fertilizer Development Center Board Member biosphere, its role in crop production, and traditional means of supplying the nutrient. He then looks at Enriching the Earth various attempts to expand natural nitrogen flows “What is the most important technological innovation of the twentieth century—telecommunications, nuclear energy, computers, space flight, or molecular transformation of the genetic code? Vaclav Smil makes through mineral and synthetic fertilizers. The core of the case instead for the Haber–Bosch process, which allows industrial synthesis of ammonia from atmos- the book is a detailed narrative of the discovery of pheric nitrogen and provides the foundation of our human food supply. His detailed story of the scientific ammonia synthesis in 1908 by Fritz Haber—a dis- trail that led to the development of this process and its global impact is both enjoyable to read and an covery scientists had sought for over one hundred important contribution to the history of modern science and technology.” years—and its commercialization by Carl Bosch and —Kenneth G. Cassman, Professor and Head, Department of Agronomy, University of Nebraska the chemical company BASF. Smil also examines the emergence of the large-scale nitrogen fertilizer indus- “Vaclav Smil has written a fascinating review of Fritz Haber and Carl Bosch’s contribution to the world’s try and analyzes the extent of global dependence on food production through their discovery of the ammonia synthesis process. We hope that this book will the Haber–Bosch process and its biospheric conse- stimulate efforts to make best use of the derived nitrogen fertilizers.” quences. Finally, he looks at the role of nitrogen in —Luc M. Maene, Director General, International Fertilizer Industry Association Fritz Haber, Carl Bosch, civilization and, in a sad coda, describes the lives of Smil Fritz Haber and Carl Bosch after the discovery of and the Transformation ammonia synthesis. The MIT Press Massachusetts Institute of Technology Cambridge, Massachusetts 02142 Vaclav Smil is Distinguished Professor of http://mitpress.mit.edu of World Food Production Geography at the University of Manitoba. His many Cover: Photograph of Fritz Haber (left) reproduced courtesy of the Library & Information Centre, Royal Society of Chemistry, London. Photograph of Carl Bosch books include Feeding the World (MIT Press, 2000) courtesy of BASF Unternehmensarchiv, Ludwigshafen, Germany. SMIQH 0-262-19449-X and Energies (MIT Press, 1998). ,!7IA2G2-bjeejf!:t;K;k;K;k Enriching the Earth Also by Vaclav Smil China’s Energy Energy in the Developing World Energy Analysis in Agriculture Biomass Energies The Bad Earth Carbon Nitrogen Sulfur Energy Food Environment Energy in China’s Modernization General Energetics China’s Environmental Crisis Global Ecology Energy in World History Cycles of Life Energies Feeding the World Enriching the Earth Fritz Haber, Carl Bosch, and the Transformation of World Food Production Vaclav Smil The MIT Press Cambridge, Massachusetts London, England 2001 Massachusetts Institute of Technology All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from the publisher. This book was set in Sabon by Achorn Graphic Services, Inc., and was printed and bound in the United States of America. Printed on recycled paper. Library of Congress Cataloging-in-Publication Data Smil, Vaclav. Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world food production / Vaclav Smil. p. cm. Includes bibliographical references. ISBN 0-262-19432-5 (hc: alk. paper) 1. Nitrogen fertilizers. 2. Ammonia as fertilizer. I. Title. S651.S56 2000 631.8′4—dc21 00-026291 Cognitio contemplatioque naturae manca quodam modo atque inchoata sit, si nulla actio rerum consequatur. Knowledge and the study of nature would somehow be weak and incomplete if it were not followed by practical results. Marcus Tullius Cicero, De officiis, I(153) Contents Acknowledgments xi Transforming the World xiii 1 Nitrogen in Agriculture 1 Discovering the Basics Discovering Nitrogen 2 Nitrogen in Crop Production 5 Nitrogen and Legumes 13 Completing the Nitrogen Cycle 16 2 Traditional Sources of Nitrogen 21 Preindustrial Agricultures Recycling of Organic Matter 22 Farmyard Manures 25 Cultivation of Legumes 28 Nitrogen Balances in Traditional Farming 31 Limits to Recycling and Legume Cultivation 35 3 New Sources of the Nutrient 39 Searching for Fixed Nitrogen Guano 40 Sodium Nitrate 43 By-product Ammonia from Coking 48 Synthesis of Cyanamide 51 Electric Arc Process 53 Plant Nutrients and Future Food Supply 55 viii Contents 4 A Brilliant Discovery 61 Fritz Haber’s Synthesis of Ammonia Haber’s Predecessors 61 Fritz Haber 65 Haber’s First Experiments with Ammonia 68 Nernst and Haber 70 BASF and Haber 74 High-Pressure Catalytic Synthesis 77 5 Creating an Industry 83 Carl Bosch and BASF Carl Bosch 85 Designing High-Pressure Converters 87 Finding New Catalysts 93 Producing the Feedstocks and Oxidizing Ammonia 97 The First Ammonia Plant at Oppau 99 Ammonia Synthesis for War 103 6 Evolution of Ammonia Synthesis 109 Diffusion and Innovation Slow Diffusion of Ammonia Production: 1918–1950 111 Expansion and Changes Since 1950 116 Natural Gas–Based Ammonia Synthesis 118 Single-Train Plants with Centrifugal Compressors 122 Continuing Innovation 127 7 Synthetic Fertilizers 133 Varieties and Applications Nitrogen Fertilizers 134 Fertilizer Applications: Global Views 138 Fertilizer Nitrogen in Global Crop Production 143 Regional and National Perspectives 145 The Most Productive Agroecosystems 152 8 Our Dependence on Nitrogen 155 Agricultures and Populations How Many People Does Fertilizer Nitrogen Feed? 156 Human Protein Requirements 161 Contents ix Nitrogen in U.S. Agriculture 164 Nitrogen in Chinese Farming 167 Growing Dependence during the Twenty-first Century 172 9 Consequences of the Dependence 177 Human Interference in Nitrogen’s Biospheric Cycle Intensifying the Global Cycling of Nitrogen 178 What Happens to Fertilizer Nitrogen 180 Nitrogen Losses in Modern Farming 184 Excess Nitrogen and Human Health 188 Nitrogen and Natural Ecosystems 192 10 Nitrogen and Civilization 199 Managing the Nitrogen Cycle What Has Been Accomplished 201 More Efficient Fertilizing 206 Stabilized Populations 211 Rational Diets 214 A Long View 217 Postscript 223 Appendixes 233 Notes 253 Name Index 329 Subject Index 331 Acknowledgments As is always the case with interdisciplinary books, my most obvious debt is to hun- dreds of experts—in this case mostly chemists, chemical engineers, historians, agron- omists, and fertilizer, plant, and environmental scientists—whose work I have consulted, used, and cited in this book. Special thanks to Kristina Winzen of the BASF corporate archive in Ludwigshafen for making available the company’s records on the early history of nitrogen fixation; to Amitava Roy (president and CEO) and Jean Riley (senior librarian) of the Interna- tional Fertilizer Development Center (IFDC) in Muscle Shoals, Alabama, for access to the center’s excellent library; to Rick Strait, Director for Fertilizers & Synthesis Gas Chemicals of Kellogg Brown & Root in Houston, for information on advanced ammonia synthesis; to Svend Erik Nielsen, Ammonia Technology Supervisor of Haldor Topsøe in Lyngby, for publications on the company’s ammonia synthesis; to Patrick Luciani, Director of the Canadian Donner Foundation in Toronto, whose grant covered the cost of research trips to Ludwigshafen and Muscle Shoals; and to E. T. York (Chairman of the IFDC Board) and