By DENNIS McDONALD
Whoever could make … two blades of grass grow where only one grew before, would deserve better of mankind, and do more essential service to his country, than the whole race of politicians put together. — Jonathan Swift
IN GRAZING management circles, the botanist John Acocks is regarded as one of South Africa’s greats. ‘Greats’ are often known for throwing the odd cat among the pigeons. Acocks’s ‘cat’ was his statement that South Africa was understocked but overgrazed. For the most part, conventional wisdom has it that overstocking is to be blamed for any degeneration of rangelands. Acocks based his ideas on his perception of the past, and specifically on a past not contaminated by modern man (but, as I have argued previously, early man had equally altered the state of nature). He wrote as follows:
‘In the United States of America, it has been calculated that the original population of game, when the European arrived, was two and a half times as great as the present population of domestic livestock, both calculated in cattle units; and yet the vegetation was far better then than it is today. In this country we have no numerical records of the game population, but from general accounts, it was enormous; why then, when wild animals are replaced by domestic animals, does the veld deteriorate?
‘A few reasons have been suggested. Firstly, there were a large number of different species of wild animals, and presumably they did not all have the same grazing habits and preferences.
‘Secondly, the wild animals, with some exceptions, were dependent on natural surface waters; when these dried up, they had to move elsewhere or die, so that the veld was not grazed over and over again in search of the last overlooked stubble, and any rains which were too small to replenish surface waters were nevertheless available to the veld. The veld did get a chance to rest and grow.
‘Thirdly, the wild animals were free to roam and they had a habit of congregating in large herds and “trekking”, so that the veld was grazed heavily but intermittently, and not continuously.’
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Allan Savory, another ‘great’, and (as a young hothead) even more adept at rocking the boat, advocated shooting all the cattle in Rhodesia, ripping down all the fences, and restoring the original game population. Later, having become better known for a fencing design, the famous wagon wheel layout, he enigmatically stated in a Farmers Weekly article that his grazing method could be practised in a game reserve without any fences. Just that, no further elaboration.
Mysticism does for the guru what the less explicit does for porn – it greatly enhances the effect. After pondering the logistics of this for some time, I later learned that what he meant was that cattle could be herded by humans and bunched up to perform the function of the previously existing great herds. That is, they could be used to graze less selectively, trample down old grass, and so on – in other words, a reversal of roles. Here again we are imitating the ‘state of nature’.
So now, far from being seen as the villain in the piece, the cow became the essential tool for restoring veld. I am not trying to ridicule this, as it is more or less Savory’s own description of changes in his thinking. Without being able to change one’s ideas, there can be no progress. I merely want to focus on the fact that behind these ideas is the notion of conflict between man and the state of nature — or rather, notions about the state of nature. Among these ‘notions’, the idea of the Garden of Eden seems to feature. Besides, as Oscar Wilde said, ‘Caricature is the tribute which mediocrity pays to genius.’
‘We simulated the predator with livestock, and the perennial grassland returned. Just put the whole back, and there it was. You’ll find the scientific method never discovers anything. Observant, creative people make discoveries. But the scientific method protects us from cranks like me.’ – Allan Savory
However, what conventional wisdom and the heretics or cranks agree upon is that total rest of veld is bad, because some grasses sometimes die out due to underutilisation. Since this is not self-evident, and not always what happens, I will attempt to give a detailed description of this senescence process.
In most areas in South Africa, all the above-ground leaves and seed stems of grasses die off every year due to winter frost.There are always exceptions to the rule — some grass species can withstand the cold and, given sufficient moisture, will remain green throughout the winter. But in other areas, such as the warmer northern parts of the country, the above-ground material dies off in the dry winter period. While thi material dies off permanently, the root system is still alive.
When the rains return, new growth emerges from the bottom of these plants, and these green shoots need sunlight. If a particular grass plant has been heavily grazed during the winter, the new shoots have no difficulty in reaching sunlight. However, if ungrazed, those shoots will have to use up energy reserves to try and reach sunlight, and can fail to do so. These plants literally shade themselves to death.
‘Grass is what saves and holds the water that keeps life good and going … It keeps the falling rain from flushing away. Blades of grass take water from the air, and transpire it into the ground. That works the other way around, too. Because grass blades help put water back into the air so that rain can fall again.”– Theodore Roosevelt
This ‘suicidal process’ doesn’t happen all the time, nor in all circumstances. Mostly I would say it occurs when a high rainfall year is followed by a dry year. That is, after a large amount of bulk is produced in the good year, the meagre new growth in the following poor year struggles to emerge through the dead material. If one opens up such moribund plants, one often finds thin and narrow leaves trying to reach the light.
Figure 1: If left ungrazed or untrampled, this dry material will weather away rather than rot. If grazed, the ‘rotting’ process will begin in the stomach of the animal and the resultant dung will be further processed by dung beetles and placed underground, where it can provide nutrients for the plants in turn. This is one carbon cycle among many. All photographs supplied by the author.
Sometimes, plants of a certain species will die out in one area and survive a short distance away. Counter-intuitively, the deaths may occur on deeper soil because the plants there have grown more vigorously and produced more shade material the previous summer. This may also explain the other anomaly, namely that better or so-called climax grass species are more likely to become moribund.
Again, this is because they are the species that produce the most bulk. Generally, these grasses have broader leaves and a deeper root system. Although commonly known as climax grasses, they are not necessarily the most palatable all year round. Mostly they are palatable when the growth is new and fresh, and less so when frosted or when they have grown too abundantly.
Lower successional grasses generally have narrower leaves and poorer root systems. So, while they too may become moribund as a result of not being grazed, they are less likely than their nobler relatives to die off due to not being grazed down in the dormant period. The narrower leaves allow sunlight to penetrate down to the growth points even among the old material. This implies that the successional level of veld can be lowered by underutilisation, and may even allow bare patches to develop.
Figure 2: Tufts of dead grasses among new growth in a moderately grazed area. Some dead material is inevitable, and not necessarily a bad thing.
Figure 3: ‘The grass is not always greener on the other side of the fence.’ Well, sometimes it is. Heavily grazed veld in the foreground, and lightly grazed veld in a nature reserve in the background. Note the mass of dead grey grasses in the nature reserve. This is an unhealthy state.
Figure 4: In arid regions, dead grass plants, instead of rotting, ‘weather’ from the top down. Top left: the beginning stages. Bottom right: an advanced stage. These photographs do not depict the same plant(s), but were all taken in a road reserve where no grazing takes place.
Figure 5: Another photograph in a road reserve. Tufts of grass consist of numerous individual plants, commonly referred to as bunch grasses. A single plant germinates from a seed. It then forms Rhizomes under the soil, and this results in new plants surrounding it. In this example, the middle plants have died out from undergrazing or just old age. The dead centre is not due to overgrazing, as is often assumed. If anything, animals go for the fresh growth on the outside.
Figure 6: Left: Patches of dead grass. Right: Bare patches forming. These photos were taken in the same area as figure 2.
Figure 7: Left: Dead grey grasses on the edges of a bare area. The formation of this bare area was probably aggravated by animals walking over it over long periods and dispersing the litter. If the dead grasses on the right could be trampled down by a large herd of animals, the litter on the ground could help with the germination of seedlings.
Figure 8: Litter in the form of a round bale of teff was rolled out on a large bare patch. After some rain, pioneer grasses germinated within weeks where for years there had been nothing.
Figure 9: These photos were taken at more or less the same place on a tarred road. A fire had ‘jumped’ across the road, burning the road reserve and veld on either side. The photos were taken a few weeks later after a relatively light rain had fallen. What is glaringly evident is that the water penetration is much better in the road reserve than on the adjacent farmland. I attribute this to the fact that there was a vast accumulation of litter in the road reserve. Litter allows insects and micro-organisms to flourish on and in the soil. This farmland is more or less continuously grazed.
Figure 10: Litter on the soil aided by insects makes for porous friable soil that acts like a sponge for maximum water penetration.
Figure 11: One millimetre of rain on a square metre equals a litre. In a 400mm rainfall season, a square metre receives 400 litres of water. If the penetration of rain can be improved by 5 percent, each square metre will get 20 litres extra penetration. A hectare is 10 000 square metres, so the extra penetration will be 200 000 liters per hectare. Over an entire farm, this extra water penetration makes the difference between having perennial fountains or fountains that are seasonal.
It seems that total rest, as represented by the road reserve in figure x, is not so bad after all. The problem is that upright or standing dead material does cause the death of plants. It then takes some years for this dead material to fall over and form litter on the soil surface. Once it has done so, it again forms the ideal environment for germination to take place. This is rather like a person on a yo-yo diet. For a period, the veld goes backwards as plants die off, only to rebound a few years later. Perhaps there are ways of grazing to prevent the yo-yo effect.
Figure 12: Seedlings that have germinated in litter.
Roots ‘take out’ of the soil to produce leaf. Animals eat the leaves, and micro organisms partly break down this material in their stomachs. Dung beetles bury the dung in die soil where it is further broken down and once again becomes available to plants. This, in short, is the mineral cycle.
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FEATURED IMAGE: The ‘silver camp’ on Hanglip Farm. (c) Riaan de Villiers.
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