This book is a companion piece to a series of lectures which I reported on in a previous post: “Cattle grazing may restore grasslands and reverse desertification.”
Dr. Allan Savory, a biologist and former Zimbabwean farmer claims that mis-managed cattle grazing, such as has occurred in Africa, has turned grassland into desert, but properly managed cattle grazing can reverse the process, reclaim the desert, and turn it once again into productive grassland. Much of the book explains his triumphs and failures in his path of coming to that conclusion.
Savory’s basic thesis on grazing is this:
“In the past, large wild herds of herbivores such as caribou and buffalo migrated over the land to find food and avoid predators. These herds grazed, defecated, stomped and salivated as they moved across the grasslands, building soil and deepening plant roots. Once these herds had migrated onward they would not return to an area until it had recovered.”
“Unfortunately, over time, the wild herds disappeared and were replaced by small numbers of domestic, sedentary livestock. Without the timely stomping and excrement of large numbers of animals, the cycle of biological decay in these grasslands was interrupted and the once-rich soils turned into dry, exposed desert land.”
Savory begins the book by examining this proposition:
“Early humans blamed desertification on livestock. They believed that livestock numbers were too high and this resulted in their overgrazing grasslands, leading to desertification. This conviction so permeated society that it assumed scientific validity and remained the explanation for desertification for more than two centuries. Nobody questioned this explanation — until recently. It’s now time to examine the antiquated roots of these beliefs to see where the truth lies.”
Savory’s own field experience, first with the Northern Rhodesian Game Department of the British Colonial Service, suggested that the proposition was not true.
Some of Savory’s observations:
It was standard practice to burn the grasslands to keep them healthy. But Savory observed that “Burning grass was keeping mature plants alive but hurting the underlying soil.”
“More than any other factor, bare soil surfaces result in precipitation becoming less effective, and thus lead to desertification. …However, if plant litter and closely spaced vegetation covers that surface, runoff is slowed and more water soaks into the soil, even during heavy downpours of rain.”
Visible grass isn’t enough. “There still was too much soil exposure between plants. Grasses alone cannot prevent desertification. Litter — the trampled-down dead leaves and stems that make precipitation effective — is essential.”
Savory says: “My work shows that three management practices lead to desertification. In order of importance, they are: Overresting soils and plants. Overgrazing plants, and Burning.” He noticed that some American National Parks are suffering from the first practice. He gives several examples from rangeland in New Mexico, Arizona, and Utah, including an explanation of the distinction between overresting and overgrazing. Basically it is about the grazing duration rather than the number of animals.
Savory’s solution is to concentrate grazing in small areas and move the cattle frequently. That can be done by either fencing or herding. He has a section giving the pros and cons of each.
This book is an interesting and quick read that can be completed in about an hour. His book also shows that our federal land managers should rethink some of their practices.