Climatically, Southern Africa varies from moist, high-altitude mountain vegetation to arid, low lying semi-desert. Thus the principles applied to veld management will vary in importance, and it would be fool-hardy to propose a fixed approach to veld utilization throughout the area. Not only is there variation from one region to another, but variations also occur within a region, and circumstances will always dictate completely flexible systems of management. No one system is suitable for all situations. Therefore, the purpose of this lecture is to provide a guide to veld management planning and operation, in the light of prevailing knowledge, and adjustments which should be made to suit local conditions.
2. THE VELD PLAN
Veld management plans should be projected into their final stage based on present knowledge. A phased development plan geared to the financial and managerial resources of the individual farmer should accompany the projected plan. Long-term planning of water development is essential; fencing, roads and other capital development all revolve around this. If you take, for example, the consideration of water utilization and distribution, there are various factors to consider such as the distances between water points within paddocks and the source and reticulation of water within the system.
The correct stocking rate is basic to the long-term success both of cattle and of veld management programmes. Herbage production varies both during any one season and between seasons, depending on rainfall. This will materially affect the number of stock which can be carried. The role played by browse can be significant. Experience has indicated the danger of exceeding correct stocking rates. Today we do distinguish between a stocking rate and carrying capacity. Carrying capacity is the measure of the productivity of the particular veld one is utilising; that is, herbage production per unit area. Stocking rate, however, is what the veld is being exposed to. For example, if the carrying capacity is one livestock unit to 5 hectares, and the stocking rate is 1 livestock unit to 10 hectares, we then say that the veld is understocked. On the other hand, if the carrying capacity is 1 livestock unit to 5 hectares, and the stocking rate is 1 livestock unit to 4 hectares, then we say that the veld is over-stocked. These are the important concepts, and should be remembered.
Where appropriate, and particularly in the lower rainfall areas, this is an important and intrinsic factor which must be catered for, especially from the point of view of stocking rates and possibly disease control. The multi- specific grazing habits of game can be a distinct advantage from the point of view of veld utilisation, but where ranchers in the bushveld have a certain amount of game on their ranches, certain factors have to be considered in making up, or drawing up veld management plans. The reason for this is that the game does not know the discipline of a fence, and can move from one paddock to the next without any form of control.
NUMBER OF HERDS
This obviously will vary with the type of livestock enterprise and animal numbers. In the average breeding unit, the optimum would be 3 herds, i.e. cows plus two groups of followers. In addition to the usual ‘ghost’ herd, however, the number of cow herds will increase in larger units. The ‘ghost’ herd which every farm has, but which is often forgotten and not taken into account in the planning exercise, comprises:-
- Bulls, when not with the cow herd.
- Dairy animals.
- Sick animals.
Although these numbers are often overlooked, they do, in fact, form another unit which should be catered for in the entire veld management system.
This varies depending upon the managerial factors, classes of stock and other related factors such as stocking rate, and pressures. It is important to remember that maximum summer gains and high reconception rates are vital to the profitability of all livestock enterprises.
- Breeding Herds: Under most farming/ranching conditions, herds should not exceed 300 – 400 breeding cows. In situations where the average paddock size is 120 hectares or smaller, the breeding herd should not exceed 150. This applies specifically during the early bulling season. In the late summer and winter, herd size can be increased, the limiting factors being handling facilities and the number of cattle days per hectare taken during the graze period. This latter point will be dealt with later in more detail.
- Followers: Concentration of followers, including male stock, is less critical than with the breeding cows. Slightly larger herds may consequently be run with higher stocking density.
- Number of Paddocks: This will vary with the veld types, which must be fenced, as far as is practicable. The optimum number is about 6 to 8 paddocks per herd. There is little economic justification for more than 8 paddocks per herd if the object of having paddocks is to rest the veld. This can clearly be seen from information which has already been made available.
Paddock size depends on:
- Farm size – small farmers will invariably have smaller paddocks than large farms.
- Type of livestock production, e.g. dairy, beef stud, ranching, sheep.
- Total livestock numbers being carried.
- Number of herds to be run.
- Veld management system to be implemented.
- Water availability and reticulation.
In practice, with commercial beef or sheep production, average paddock size varies from about 50ha in high rainfall areas to about 500ha in very dry areas.
Rest must at all times be extremely flexible and adapted to the local and .changing conditions In a situation where to all practical purposes herd and paddock size remain constant, adjusting the length of the grazing and rest periods becomes a major management tool in ensuring maximum animal production. Inflexible systems based on summer grazing and rest periods are dangerous, and are bound to fail where rainfall and seasonal growth patterns are constantly changing. Failure is always reflected in a poor lost animal performance.
This is difficult to put back or regain, either as depressed summer-weight gains and low conception and re-conception rates or as heavy winter-weight losses.
The grazing rate is also governed to some extent by herd size and paddock size. However, as a general guide under medium and high rainfall conditions, not more than 15 C.D.H’s should be taken in early summer. C.D.H. is the abbreviation for Cattle Days per Hectare. Cattle Days per Hectare is measured by multiplying the number of livestock units by the number of days spent in a paddock divided by the area of the paddock. As the rate of grass growth increases the amount of C.D.H. taken per graze can be increased to 25 in the midsummer and finally 37.5 in late summer. In winter 50 C.D.H. can be taken per graze. These C.D.H. figures will also vary according to tree density and available herbage. It is important to record the number of C.D.H. taken per paddock per season, in order that one can use this information to measure the success or failure of the particular veld management system, in subsequent seasons. This serves as a very good guide in assisting the farmer to make correct decisions in his veld management systems.
It is obvious that stocking pressure is a function of paddock and herd sizes and therefore can and must be taken into consideration when planning veld management systems. Stocking pressure plays a major role in influencing the performance of stock in a veld management system. This is particularly true of the early and mid-summer periods. In summer in high rainfall areas, the pressure should not exceed 3 LSU per hectare during the grazing period. In the winter, this can be increased to 5:1 hectare; in fact, this is necessary to achieve any appreciable litter laying effect. Litter-laying is vital for seedling development and moisture retention in the rainy period. In the bushveld the pressure should not exceed 1.5 to 1 hectare at any stage of the year. In really dry areas the pressure should be of the order of 1 to 1 hectare.
This is the most important principle of veld management and has often been the indirect cause of failure of many systems. As far as the high and middle veld areas are concerned, the tendency has been to rest veld for too long during the growing season. The problem does not arise on sweet veld and, in fact, longer rests are desirable in these areas in an attempt to stabilize the grazing-conditions. As a general guide, the area should have rest periods of between 30 and 45 days. Provided the veld is not severely degraded, this will be sufficient to maintain vigour and will, in addition, ensure good quality herbage and therefore optimum animal production.
One of the main shortcomings of rotational grazing, which incorporate long summer rests is the performance of animals which continually move on to grazing which has relatively low protein and energy content.
Fire has a definite role to play in grassland management. Much of the open grassland of Africa has
been kept open and in good condition by fire. Fire is necessary to prevent bush encroachment and
to remove top hamper, i.e. dead grass which smothers grass tufts and seedlings. Top hamper has
harmful effects on both stock and veld. The maintenance of a litter cover assumes increased
importance if the soil structure is poor or susceptible to capping. Extra caution must therefore be
exercised when veld burning is contemplated. However, experience has shown that, provided the
burn takes place soon after a good rain and while the litter is still damp, the top hamper can be
effectively removed with little damage to the litter cover. Fire has little or no part to play in the
management of low rainfall, lowveld country. This matter will be discussed in greater detail when we
talk about fire as a tool in veld management.
At no stage, either during planning or the operation of veld management schemes, can rules of thumb be substituted for sound common sense. Intelligent manipulation of flexible schemes offer the best chance of lasting success from the point of view of cattle and the veld.
3. THE USE OF FIRE
It is apparent to ecologists today that fire played a significant role in developing the landscape described by early travelers and settlers. Periodic and extensive fires coupled with wild life and early cultivation practices influenced the natural plant succession and prevented the invasion of bush into predominantly grassland areas. However, increased human population and the intensified use of agriculture curtailed extensive veld fires and reduced their effectiveness as a means of controlling bush. This, added to the effect of poor veld management practices, encouraged the woody plant species to encroach into the grassland areas. During this early settlement period, fire was a natural haphazard factor in the development of plant communities. Later, the concept of using fire in managing natural grazing was adopted mainly to produce a flush of green grass in the winter period. This practice had a drastic effect on the veld and was one of the underlying causes behind the research into the use of fire for veld management. The outcome was the establishment of principles of fire use and systems of veld management. An early system required the veld to be rested for a full year once in four years, and burned as a bush control measure immediately prior to the main rains. Fire was also advocated to level off the uneven utilisation of grass which results from selective grazing. More recently, fire has had a varied acceptance among people concerned with veld management. Fortunately, the concept of the total prevention of fire in veld management has been replaced by a reasoned, controlled use of fire. This is a refreshing change in attitude. However, it should always be appreciated that fire does destroy herbage and other plants that could be used by domestic and other animals. It is therefore important that the value of fire as a factor in veld management should be fully understood.
The principles of fire use must be fully understood and must be seen clearly in perspective. Above all, the objectives must be firmly defined and established. The purpose of this lecture is to clarify the function of fire in veld management, and to assist farmers to make correct decisions.
THE REMOVAL OF MORIBUND GRASS
Because we are dealing mainly with extensive systems of land use, areas of under-utilized grass would remain as a result of selective grazing, irrespective of management. If this standing dry grass is allowed to accumulate over the seasons, young grass shoots and basal buds will be shaded out, and eventually the grass tuft will die. This fact can be used to advantage, in that undesirable grasses can purposely be under-grazed so that they become moribund and die. In general, however, the tendency is for the accumulation of dry grass to occur in certain areas or on certain plants within an area, whether the plants are palatable or not, because of animal grazing behavior. Moribund or under-utilized grass can be removed by placing attractants, such as salt blocks or protein licks within these areas. The animals are thereby encouraged to trample the unused grass or through appetite stimulation, to encourage them to utilize the grass more fully. In cases where these areas are extensive and widely distributed, fire becomes the most practical method of removing excess herbage. A good example of this situation is seen in high veld vlei areas where extensive top hamper accumulates. This must be removed before animals can effectively use the grazing. The type of fire required for the removal of moribund grass should not be fierce. It is best set after the commencement of the rains or more specifically after a shower of rain while the litter layer covering the soil is still wet. In this way the top hamper is removed and the litter layer is left unburned.
The natural succession of vegetation in most parts of Africa is towards woodland. The effect of good veld management is to change the rate of woodland development. Poor management tends to hasten encroachment, but, even under good management, bush will eventually become a problem. Fire has a very harmful effect on trees. Not only does burning injure the bark but it also.damages branches, leaves and buds and kills tree seedlings. If damage is sufficiently great, the tree will die. Even if it does not die, it is physically weakened and is less competitive with grass. Thus fire can be used successfully to control bush, provided dry herbage is sufficient to produce a fierce fire. To accomplish a “hot burn” the fire should be set soon after the commencement of the rains, but emphasis should be on selecting a hot day for burning. Where the season permits, a second successive burn can be considered, particularly in areas of extensive bush encroachment. A double burn has a very severe effect on woody vegetation, but should be used only in problem areas and when a good season follows the first burn. These latter points must be observed to ensure adequate grass cover both for erosion control and to supply the material for a fierce burn. The main requirement should be remembered. Burning for bush control should be used only when encroachment is a problem and dry grass is abundantly available in sufficient quantity to provide a fierce, hot burn. Burning has been successful, in combination with goats, for the removal of thorn trees, Acacia karoo. In the Eastern Cape Province of South Africa, fire was used to damage the upper branches and thus to stimulate coppice growth from lower down. As the coppice was within reach, it was kept under control by careful management with goats. The overall effect was to reduce bush density and control further encroachment.
THE REMOVAL OF EXCESSIVE LITTER
In general, the development of a protective litter cover is very desirable because of poor grass cover in natural veld. This protective layer impedes rainfall runoff thereby increasing the infiltration and reducing erosion. The litter also forms an important source of food for soil micro-organisms. It also acts as an insulating layer which control undesirable increases in soil temperature and provides a seedbed for new seedlings. Situations can arise where excessive litter may smother or hinder grass seedling establishment. Moreover, the temperature control function may work in reverse and keep soil temperature too low, resulting in cold soil. This is likely to arise in cooler, higher-rainfall areas. When it does occur, excessive litter should be removed by an early summer burn on a dry day soon after the commencement of the rains. The burn should take place in the evening or early morning to prevent a fierce fire, which is definitely not required in this case.
INDUCED GRASS SEEDLING GERMINATION
The effects of fire on soil are very superficial. Australian research has indicated that an average fire produces a soil temperature in excess of 2000 C for approximately 12 millimeters. Within five minutes temperatures have returned to normal. The consequence is that grass seeds which burrow into the soil can escape. Those that do not possess this ability remain on the surface and are burned. Furthermore, a singeing induces certain grass seeds to germinate.
Once the grass cover has been destroyed by burning, the soil is exposed to the heat of the sun and, provided sufficient moisture is present, buried grass seeds will be encouraged to germinate in the absence of competition from surface seeds. These young grass plants will be in a better situation to develop a sound root system from below the surface and so stand a better chance of survival than those which develop their root system from the surface of the soil. It could be correctly argued that a number of grasses, such as Panicum, Brachiaria, Setaria, Eragrostis, and others are very useful grasses and should be encouraged. However, because their seeds do not possess awns or bristle-like hairs they are unable to burrow into the soil and will presumably be destroyed by fire. Some of these seeds fall into soil cracks or are carried into the soil by ants. Therefore, an adequate amount of seed survives to perpetuate the species. Other non-awned species are considerably less desirable than those mentioned, and the bulk of our more important grasses such as Hyparrhenia, Hyperthelia, (Thatching Grasses),Heterapogon, Themeda and Chloris have long awns and are thus encouraged by burning. The use of fire to promote grass seedling germination should fall into the same category as for the removal of moribund grass. Fire should be used immediately after rain when the litter layer is wet.
Ticks: Tick populations can be reduced by fire, but fire will never eliminate them. If fire could do sothere would be no ticks in Southern Africa. This has a past history of extensive fires. Fire cannot be used as a substitute for dipping.
GENERAL CONSIDERATIONS GOVERNING THE USE OF FIRE Low rainfall .areas:
The use of fire in low rainfall areas should be avoided because of the unreliable rainfall experienced. Considerable soil and plant damage can result if poor rains follow a burn. Nevertheless, fire can be used in certain situations if absolutely necessary, and provided adequate thought and care are exercised to prevent the fire from getting out of control.
The after-effects of fire are more damaging on heavy soils than they are on sand.
Rainfall infiltration is slower on heavy soils, and therefore the erosion hazard is greater after a burn. Heavy soils, furthermore, because of their darker color, absorb more heat than sands, therefore, if fire is to be used on heavy soil, it should be contemplated only if grass cover is adequate. The emphasis should be on retaining the litter cover intact. In the case of moribund grass emphasis should be on its removal.
Burns before the advent of rains, and particularly winter burns must be avoided because of the harmful effects resulting from prolonged periods of exposure before plants can cover the soil. An exception arises in wet vleis, where it is probably not possible to burn after the rains. However, because moisture is present, the grass soon flushes and covers the soil. Nevertheless, it must be emphasized that burning vleis before August encourages an increase in bulb plants – lilies, etc. A number of these are poisonous to cattle.
Rest after burn:
The vlei must be rested after a burn for not less than 6 weeks or until sufficient re-growth has occurred. This allows the grass to develop sufficient herbage to maintain plant vigour and so provide soil cover to reduce erosion.
These should be avoided because they encourage selective grazing, but they can be used to attract animals away from other, more sensitive, areas.
Frequency of burns:
The frequency of burning is not discussed here. This is determined by the need for fire. As a principle, it should be infrequent and used only in situations such as those discussed. Fire can be a useful servant if correctly used. It should not be used to cover up the defects of poor veld management systems. Emphasis should be on sound, well-planned veld- management, supported by the use of fire when necessary. It should be governed always by a clearly defined set of objectives. In a nutshell, when in doubt, do not use fire.
This lecture has covered the details of veld management planning. Although the details have been listed separately, they should all be considered when drawing up a veld management plan. Veld management plans are effective only when they are adhered to and the principles are applied correctly. It should be pointed out that a sound veld management system will result in better conception rates, improved calf weights; improved live-mass gains and an overall improvement in the veld, which is our main objective. Much of our country is destroyed annually by ignorant mismanagement.