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Controlled intensive grazing in the savannah, Africa

Submitted by Nitya Jacob 30th November 2022 7:43
Cattle in the savannah


Controlled, intensive grazing is being promoted to regenerate vast savannah grasslands in parts of Africa. In this practice, herds of domesticated livestock are kept in one location for a certain duration. The herd intensively grazes the grasses and other vegetation, trampling and break down the soil and vegetation. The herd is moved to another location after some days and the intensively-grazed plot is allowed to regenerate for a few months.

Experts promoting this method say it opens up the soil for aeration and improves it porosity. The first allows in air to let the roots breathe. The second lets the soil absorb more rain. The result is faster and denser growth of perennial grasses and other vegetation.

Conventional wisdom has it that over-grazing is the main cause of the loss of savannah grasslands as it causes degradation and makes the savannah susceptible to desertification. It is recommended that livestock herds and areas for grazing be reduced to restore the savannah. But some experts such as Allan Savory feel that controlled grazing is a better solution as in xeric (dry) savannah areas land degradation would accelerate should cattle or wild grazers disappear because perennial grasses die out when they are not being grazed or occasionally trampled.

He and others suggest that planned grazing by bunched animals be allowed to restore grasslands, add to their productivity and biodiversity, and capacity to sequester carbon. There is evidence this ‘holistic management’ approach has its merits.

The hooves of tightly-bunched herds breaks the soil crust, ensuring that air and rain water can infiltrate better. It also breaks down leaves and other vegetation, speeding up their decomposition. The dung and urine from cattle provide fertilizer to feed the new grasses that establish in the microenvironment.

We actively discourage fire, said Jody Butterfield, author of Holistic Management Handbook – Health Land, Health Profits. This puts pollutants into the atmosphere (which in turn exacerbate climate change), and while overgrazing is a problem, the bigger problem in most of the savannah, too much soil remains undisturbed. As a result plant spacing gets wider, bare ground increases and so does soil surface evaporation and rainfall runoff and ‘droughts’. Holistic planned grazing matches herd movements on plant recovery times so that animals don’t remain for too long in one place, nor return to it before plants have regrown leaf and re-established the root sacrificed following the first grazing. Herd size and density is maximized to loosen soil.

More cattle, more grass, more water

Experts recommend four ways to keep perennial grasses healthy: mowing, burning, resting or grazing. For large areas such as the savannahs only grazing and resting are feasible even though fire is used on a large scale to manage African grasslands, basically due to the lack of animals; about 800 million ha of grasslands are burned each year adding huge quantities of carbon to the atmosphere and drying out the soil.

There is a problem with ‘resting’ (or non-disturbance by livestock or fire) as well. While this is conventionally proposed to restore perennial grasslands, and may result in an initial burst of growth, in a few years, rested perennial grasses grow rank and start to oxidize. Additionally, the soil surface seals with the first rainfall and stays sealed preventing water from seeping in. Rain quickly evaporates on flat land or, on slopes, runs off. Therefore, resting soils and forage is damaging in semi-arid seasonally humid or ‘brittle’ environments.

This leaves us with the option of livestock in regenerating savannahs. The root systems of perennial grasses react to disturbances on the surface (grazing and trampling) of the grass. If perennial grasses are grazed, the root system reacts with a survival mechanism: roots die back to provide energy for growing new leaf. However, if grazing continues in the new growth phase, it is likely the roots will not have time to grow back and the plant will then be ‘overgrazed’. On the other hand, perennial grasses that have been properly grazed, by giving them time to recover and regrow, can live several hundred years. In the process soil is built up and carbon is sequestered.

Grasslands where controlled intensive grazing has been carried out are properly grazed and impacted. They act like sponges, storing humus and carbon, while the roots perforate the soil and open it up, increasing porosity and infiltration capacity. The grazing breaks the sealed soil surface, or soil crust, as well as the ungrazed vegetation. Water can soak and used by plants, or eventually trickle down to feed springs, rivers, and boreholes or wells, thus increasing the residence time of the rainfall in the catchment and prolonging the hydrological cycle.

This sets off a virtuous cycle in semi-arid but seasonally humid environments of creating a wetter ecosystem. The wetter ecosystem is better for herbivores, because the native grasses green up sooner, stay green longer, grow, flower, set seed and die all in one season. In the next season they may not germinate at all if conditions aren’t exactly right.

If the perennial grasses of rangelands are reclaimed and allowed to grow, it will help retain water, provide much better forage and mitigate erosion and soil loss. This is where holistic planned grazing is effective, by timing recovery periods to the needs of perennial grasses.

In conclusion, the health of grasslands is best maintained by grazing animals rather than by fire or resting. Working with pastoralists it is possible to work out a system of controlled intensive grazing. The savannah can be a powerful medium to harvest sunlight through green, growing plants that cover soil, feed animals and people, and, through well planned grazing also sequester water and carbon. The priority is to invest in developing animal-maintained grasslands in which perennials dominate.

Dimbangombe Ranch

The Africa Centre for Holistic Management manages the Dimbangombe Ranch in Zimbabwe and follows the holistic grazing plan. The livestock (cattle, goats and sheep) is herded by day and placed in lion-proof enclosures at night. In the rainy season, the herd grazes an area for three days and returns to it after three months. The animals are herded and they remain in a group throughout the day, they churn up and break the soil and plants. In the long dry season, the timings are longer because plants grow more slowly. In the night-time enclosure, the herd creates very high impact as it stays in the same place for 3-7 days. This has been observed to result in stunning growth in the months afterward (or when it rains). In fact, night-time enclosures are used to prepare fields for planting and maize yields have increased by 3-7 times.

In addition to better grasslands, the controlled grazing in Dimbangombe for almost a decade has enabled the ranch to increase livestock numbers by 400%. The land has also improved and it is difficult to find bare patches in low-lying areas. Grasses have become less fibrous and leafier resulting in an enormous reduction in fires, and the Dimbangombe River has perennial pools with fish, ducks, and other wildlife year-round. Its upper catchment has become a wetland with new springs and reed thickets. Wild predators, lion, cheetah, leopard, and hyena, keep the wild grazing herbivores moving that enhances the effect of controlled intensive grazing; in the absence of predators the wild grazers become static and damage soils and plants through overgrazing and over trampling.

Johan Zeitsman

Flexibility is a big part of the new grazing concept. In another area in Zimbabwe, commercial farmer Johan Zietsman used strip-grazing. He herded cattle using cheap portable electric fences to create ultra-high herd densities; this had been impossible to achieve by regular herding. During the dry season, up to 3,000 cattle per ha trampled the old growth and covered the soil. Over a 10-hour period the animals were moved as many times.

The hoof action of the animals is different, less gentle and able to disturb the area in a regenerative way. At night the animals were left to ruminate over a larger portion of the lane being strip grazed. The ultra-high density and good planning – still based on recovery time – achieved higher productivity of both cattle and forage. The large ‘herd effect’ resulted in a very effective impact on the land compared to herds that graze at low density.

All animals grazed at the same time. Zietsman was been able to double his stocking rate with this innovative fencing layout and planned grazing with a minimal capital layout for the small costs of the movable live fencing. The results after one year were already significant: mature capping of the soil decreased from 43% to 1%; over-rested grass plants disappeared from 42%; palatable broad-leaved grass increased from 11% to 52% of the area, whereas unpalatable narrow-leafed grass decreased from 86% to 46%.

Inmaculada Ranch

This type of grazing is also practised in other semi-arid parts of the world with intense rainfall periods. On the large La Inmaculada Ranch, managed by the Aguirre family, in the Sonaran Desert of northern Mexico, where the annual rainfall is 300 mm, controlled intensive grazing has resulted in a vigorous return of perennial grasses as well as ironwood and mesquite, the latter providing high-protein forage in the dry season.

During the summer growing season when most of the rain falls, each paddock or grazing area is grazed only once, generally because growth is slow and recovery time for perennial grasses can be very long. They generally don’t stay longer than two or three days when growth is fast, but can stay more than a week when growth is slow.

The grazing is controlled so the cattle never consume all the new season’s growth and sufficient forage is left to be rationed out through the long dry or winter season. Since beginning to plan their grazing, the Aguirres have increased soil litter cover 23% to 63% and the density of perennial grasses more than fourfold, again bringing together productivity and sustainability.

(Excerpted from Transforming landscapes, transforming lives : the business of sustainable water buffer management).