Berman Hudson has more than three decades of experience as a soil scientist with the National Cooperative Soil Survey and as a soil science consultant to the forest product industry.

In addition to mapping soils in the field, the author served as Assistant State Soil Scientist of North Carolina; State Soil Scientist of Maryland; National Leader, Soil Survey Center, Lincoln, Nebraska; and Director, Soil Survey, Washington, DC.

Dr. Hudson has conducted soil studies in Zimbabwe, Ghana, Indonesia, Bulgaria, Denmark, and the Virgin Islands. As a consultant, he trained soil survey crews and supervised soil mapping activities for companies such as International Paper and Potlatch. With a PhD degree in soil science, he has published a number of influential research papers that altogether have been cited in more than 1,000 scientific articles.

This book describes the vital and often surprising roles soil has played and continues to play in the economy of Nature. The author shows how soil formation is affected by humble actors such as beavers and earthworms as well as by dramatic...

This book describes the vital and often surprising roles soil has played and continues to play in the economy of Nature. The author shows how soil formation is affected by humble actors such as beavers and earthworms as well as by dramatic events like the formation of continents, oxygenation of the atmosphere, glaciation, colonization of the land by plants, and the evolution of roots. Most rocks and minerals on the planet's surface are composed of just 8 chemical elements, but together they have generated new kinds of soil with different properties at different times and places. The author tells the story of soil in a way we can all understand, showing how it has affected the history of farming and everyday life, along with an introduction to the relevant chemistry and geological effects.

Chapter 1. What Is Soil and Why Does It Matter?

       "The dust lifted up out of the fields and drove gray plumes into the air…the finest dust did not settle back to earth, but disappeared into the darkening sky…the corn fought the wind with its weakened leaves until the roots were freed by the prying wind and then each stalk settled wearily sideways...and the wind cried and whimpered over the fallen corn."

The words above are from John Steinbeck’s 1939 novel, The Grapes of Wrath, for which he won both the National Book Award and the Pulitzer Prize. In this acclaimed work, Steinbeck gave a human face to the Dust Bowl, one of the worst environmental disasters in American history. The Dust Bowl is the name once given to a vast region of nearly 100 million acres that includes sections of Kansas, Oklahoma, Colorado, New Mexico, and Texas. For thousands of years most of this area had been covered in grass, but beginning in the 1800s, land-hungry farmers spread out across the region and soon the grass was gone; and with the coming of drought early in the 20^th century, the soil began to blow away.

The “dusters,� as the storms came to be called, began in the early 1930s after a long period of unusually high temperatures. The weather service reported 179 dust storms in 1933 alone and in 1935 a single storm destroyed five million acres of wheat in Kansas, Oklahoma, and Nebraska. Large storms carried clouds as far east as New York City. For three consecutive years, an average of nine storms a month hit Amarillo, Texas during the four-month period from January through April. Houses, barns, farm equipment, and fields were covered in layers of dust more than 20 feet thick. Even after the storms ended, so much dust would be suspended in the air that the sun remained invisible for several days. A woman from Garden City, Kansas, describes one such storm: “The doors and windows were all shut tight, yet those tiny particles seemed to seep through the very walls. It got into cupboards and clothes closets; our faces were as dirty as if we had rolled in the dirt; our hair was gray and stiff; and we ground dirt between our teeth.� The storms continued for almost a decade, wreaking havoc on the regional economy and exacting an enormous toll in human misery. Farms and ranches failed, forcing thousands of desperate families to load up their belongings and migrate west in search of better lives (Editors, Time-Life Books 1985).

Plowing up a vast area of grassland and exposing the bare soil to strong winds in a region with sporadic rainfall was a huge mistake, but fortunately it was done in a wealthy country with a surplus of land. America has an abundance of land and a relatively small population, but the world as a whole is not so fortunate. In 1900 there were 1.6 billion people on Earth. Within only a century, world population had nearly quadrupled, reaching 6.1 billion, and demographers working for the United Nations estimate that there will be 11.0 to 12.0 billion people in the world by 2100. Some think the UN estimates are too conservative and that world population will be even higher than their 11.2 billion projection.

In 1900, there were a little more than 2.0 hectares of arable land for each person on Earth; by 2100 this will have declined to around 0.3 hectare per person. Arable means land that currently is being used to grow crops or could be used for that purpose in the future. If you have trouble visualizing how big a hectare is, just remember that an American football field is about one-half hectare in size. We lose some arable land every year, but that is not the real problem; instead, as the world’s population grows larger, each person’s share keeps getting smaller. The table below shows how rapidly the amount of arable land per person has declined recently as a result of population growth...

 

Chapter 1. What Is Soil and Why Does It Matter?. 4

Chapter 2. The Earth’s Surface: A History. 17

Chapter 3. Rocks and Rock Weathering. 28

Chapter 4. Clay and How It Forms. 41

Chapter 5. To the Sea and Back.. 58

Chapter 6. The Living Surface. 72

Chapter 7. Parent Material and Climate. 90

Chapter 8. Organisms, Topography, and Time. 110

Chapter 9. How Soils Evolved.. 129

Chapter 10. Nitrogen: A Perverse Chemistry. 145