Continuing our analysis of Alan Savory’s Four Key Insights.
Key Insight 4: The Role of Time
Damage from overgrazing and trampling has little relationship to animal numbers. Instead, the important factor is the time that plants and soils are exposed to the animals.
Traditionally, preventing overgrazing has always begun with limiting livestock numbers. The conventional recommendation has been to regulate numbers so that animals do not graze more than half of certain “key” species.
This take half-leave half theory was doomed to fail from the beginning. Animals simply do not graze individual plants that way. There will be some plants that won’t be grazed at all while others are grazed right down to their growing points at the base. So, the land continues to deteriorate under this approach to range management.
Meantime, conventional range managers judged their success by the presence of a few “desirable” species and the general appearance of the land. But, even their research plots are developing bare soil between the plants and showing signs of erosion. Some plants continue to be overgrazed in patches while others grow old and fibrous from being smothered by accumulations of oxidizing material.
So, conventional range managers attempt to solve the uneven grazing problem with periodic burning while burned areas continue to visibly erode. Very few species are present other than the so-called “desirables.” There is an almost complete absence of new plant seedlings. Production per animal is relatively high but production per acre is low and declining.
Back in the late 1950s French researcher Andre Voisin established that there was very little relationship between overgrazing and animal numbers. Instead, the primary factor was the time plants were exposed to the animals. Meantime, the “excessive animal numbers cause overgrazing” type of thinking continues unabated.
Voisin discovered that the critical time of exposure was determined by the growth rate of the plant. If the plants are growing fast, the animals need to be moved on more quickly and vice versa for periods of slow (or no) growth. And, in addition to grazing, trampling could be either good or bad depending on time.
Then Alan Savory reasoned out how time was involved in the grazing and trampling of wild herds of the past. Wild grazers bunch closely for protection from predators. They foul the ground with dung and urine. Since no animal likes to feed after itself, they kept on moving to fresh ground and would not return to the fouled area until the dung and urine had weathered and worn off.
First attempts to duplicate what the wild grazers did involved concentrating domestic animals so they were forced to eat all plants evenly. These went by names like Short-Duration Grazing or High Intensity-Low Frequency Grazing. Livestock condition suffered.
Later, Savory solved the over-grazing side by side with under-grazing phenomenon by combining the ideas of concentrating animals but not forcing them to graze plants evenly. This is accomplished by controlling the time that plants are exposed to the animals according to the rate at which the plants are growing.
He also has shown us that under-stocking (low livestock numbers) damages the land as much (sometimes even more) than over-stocking. It does this by causing perennial grasses to die from over-rest as old accumulated material blocks sunlight. In addition, too few animals scattered widely over the land do not provide the soil disturbance necessary for a healthy, fully productive range.
Source: Holistic Management: A New Framework for Decision Making By Allan Savory and Jody Butterfield
- The Myth that is Conventional Range Management (landandlivestock.wordpress.com)
- And the Myths Live on: Thoughts on the 2010 Meeting of the Texas Section of the Society for Range Management (landandlivestock.wordpress.com)
- Grazing the Impossible (landandlivestock.wordpress.com)
- The Value of Holistic Herding (landandlivestock.wordpress.com)