agricultural production guidelines
m
Veld in KwaZulu-Natal
Co-ordinated Extension KwaZulu-Natal Veld 1.1 1999
VELD MANAGEMENT IN KWAZULU-NATAL:
AN INTRODUCTIONM B Hardy
Western Cape Department of Agriculture
Sourveld, Mixed Veld and Sweetveld
A Few Facts
Veld Management
INTRODUCTION
This Production Guideline introduces veld management principles. A detailed understanding of these principles is required to ensure acceptable livestock production whilst maintaining the productivity of veld. It must be stressed that there are no fixed recipes. Each farm, and specific area of the farm, must be treated as a separate entity with its own potential for animal production. There are, however, a number of ‘facts’ that the farmer (land manager) must include in the planning and execution of his veld management system.
SOURVELD, MIXED VELD AND SWEETVELD
As grass grows out, whether in spring or after defoliation, it matures. With increasing maturity the grass loses quality. The more rapidly it matures during a growing season, the sooner animal performance starts dropping and the sooner the farmer has to supply ‘winter’ licks and, eventually, additional fodder in the form of hay, silage and/or crop residues. An understanding of the above has resulted in the terms: sourveld, mixed veld and sweetveld.
Sourveld occurs mainly as a dense grassland in the high rainfall areas of KwaZulu-Natal (750mm to more than 1 000 mm per annum). The high rainfall results in rapid grass growth during the late spring and the summer. At high elevations the growing season is short because of low early-spring and low autumn temperatures. With rapid growth the grasses start to mature relatively early in the growing season and quality of the herbage declines. Animal performance declines due to reduced intake of the poor quality (‘sour’) herbage. Sourveld will maintain animals in productive condition for six to eight months each year. Additional fodder (in the form of hay, silage and/or crop residues) is usually supplied to the animals for the remaining part of the season.Sourveld
Mixed veld occurs in areas which are generally warmer and have lower rainfall than sourveld (i.e. parts of the midlands and in the northern areas of the Province). The vegetation is mainly grassveld but, in many areas, trees (mainly Acacia species) have encroached forming a savanna type vegetation. Rainfall is generally between 650 and 800 mm. Here the growing season is longer than in the sourveld areas, with the amount and timing of rainfall through the season having an important influence on grass production. Furthermore, grasses tend not to mature as rapidly in mixed veld as they do in the sourveld. The grasses in mixed veld therefore maintain their quality for a longer period during the growing season than the grasses in sourveld. Mixed veld tends to maintain animals in productive condition for between eight and ten months each year.Mixed veld
Sweetveld
Sweetveld occurs as savanna and bushveld vegetation
in the valley systems which dissect KwaZulu-Natal and in the ‘lowveld’
areas of the province. For the most part these areas are frost free. Rainfall
varies from 500 mm to 700 mm and is highly variable and uncertain so that
plant growth is erratic. In these conditions the grasses tend to maintain high
quality relative to the grasses in mixed veld and sourveld areas. Animals can
therefore be maintained in productive condition for 10 to 12 months of the
year provided sufficient herbage is available to them.
Animal performance
- While sourveld areas have the highest grazing capacity (i.e. the number of Animal Units which can be safely carried per hectare) and sweetveld areas the lowest, cattle perform best in sweetveld. Typically, during a single year (October to September) a yearling steer would be expected to gain between 160 and 200 kg in sweetveld, 120 to 150 kg in mixed veld and 90 to 120 kg in sourveld (provided that a suitable stocking rate has been applied).
- Sheep production systems tend to be confined to the sourveld and mixedveld areas of the province. Cattle perform better on the veld than sheep do. This is due mainly to the fact that cattle, being bulk grazers, are better adapted to grazing tall, low quality herbage than are sheep. Sheep, being selective grazers, prefer short, green, leafy herbage. In sourveld and mixed veld, the type of herbage required for acceptable performance for sheep can be obtained only through heavy, frequent grazing, and frequent burning. These practices are detrimental to the long term stability of the veld.
- Both cattle and sheep graze selectively. Sheep, however, graze more selectively and intensively than do cattle. The animals select for green, higher quality, leafy herbage, that is, herbage which has not yet grown out to maturity, and is not flowering or stalky. Certain areas of the farm will be ‘sweeter’ than others, due to, for example, a high proportion of palatable plants, and will therefore be the preferred grazing areas. Grazing of these preferred areas is referred to as ‘area selective’ grazing and, if allowed to continue, will lead to reduced vigour of the plants within the areas and their eventual replacement by species of low forage production potential and/or low acceptability to the animals.
- ‘Species selective’ grazing also occurs when individual grass plants are selected in preference to others. Frequent, intense grazing of the selected plants, will lead to these plants being lost from the veld and being replaced by non-productive, usually less acceptable, plants. Selective grazing is one of the main causes of veld degradation.
The veld
- The grasslands of mixed veld and sourveld are adapted to frequent burning. It is estimated that fires would have occurred at least once every three years in the period before the grasslands were used by subsistence and commercial pastoralists. These frequent fires were probably also largely responsible for preventing bush encroachment into the grassveld. Grazing reduces the amount of herbage available to burn at the end of winter and therefore reduces the intensity of burning. The bush encroachment problems which are now occurring in northern KwaZulu-Natal are probably largely as a result of the lower frequency and intensity of burning. By contrast, while the vegetation in sweetveld areas is also adapted to fire, burning should occur at lower frequencies than in sourveld and mixed veld. Fire is necessary in sweetveld to reduce bush densities in areas where bush encroachment has become a problem (in addition to preventing bush encroachment). Fire should also be used to remove moribund herbage which may have resulted from a sequence of high rainfall seasons.
- Grasses are adapted to infrequent severe defoliation i.e. to being severely defoliated once or twice during the growing season. Such grazing may be tolerated by the plants for a number of consecutive seasons.
- The grasses are not adapted to frequent severe defoliation through consecutive seasons. If the plants are frequently and severely grazed in one season they require at least a full growing season’s rest to regain their vigour and to continue to produce forage. Without this rest these grazed plants often will be replaced by plants which have low grazing value.
- If the grasses remain ungrazed, and are not burned for a number of consecutive growing seasons, they become moribund (they ‘smother’ themselves), eventually they will die out, and are usually replaced by unpalatable grasses, weeds and broad-leafed shrubs.
- Changes in species composition, due to either frequent severe defoliation (without providing adequate rest periods) or lack of defoliation, will result in changes in the quantity and the quality of forage on offer to animals. Such changes will influence the long-term livestock production potential of the farm.
- As previously mentioned, a rest period must be incorporated into the veld management programme. These rests are important, not only to provide the plants with an opportunity to regain vigour, but also to allow for the accumulation of fuel when planning to burn veld with the aim of controlling bush problems on the farm.
- Fire is an indispensable tool in veld management. It must be used to remove dead grass which is carried over from one growing season to the next, or which has accumulated as a result of a rest period, and for bush control. However, the fire must be used judiciously to achieve the objectives mentioned earlier.
The purpose of any farming operation is to make money. However, the veld must be managed to ensure that we can continue to produce the maximum amount of livestock products in the long term. Veld management systems, therefore, must be designed to minimize and combat the negative effects of livestock production on the long term production potential of the veld.
In trying to achieve long term economic animal production, one of the major management tools the farmer has is the decision regarding how many animals to allocate to a particular area of veld and for how long they will use that area of veld. The number of animals allocated by the farmer to an area of veld for a defined period of time is referred to as the stocking rate.Stocking rate
Stocking rate is the single most important factor influencing both the performance of the animals on veld and the response of the veld to grazing. While the ‘correct’ stocking rate is always difficult to judge, the farmer must also attempt to match the feed requirements of each group of animals with the grass production potential (quality and quantity) of each grazing area (camp) on the farm. There are, of course, many problems associated with matching animal requirements to the production potential of the veld.
Primary sub-division
Animals will select for those areas, species and
plant parts which they prefer (see ‘facts’ presented earlier). This
selective grazing will be influenced by the variations in veld which occur on
the farm, the degree to which animals are allowed to ‘choose’ where they
graze, the proportion of cattle and sheep in each group of animals, and the
seasonal changes in the quality and the quantity of feed on offer to the
animals.
The first major veld management recommendation then, is to separate, as far as is practically possible, the different Veld Type Units of the farm. A Veld Type Unit refers to an area of veld which has uniform palatability and productivity. As a guideline for such ‘primary’ sub-division of the farm, features such as changes in aspect, slope, soil type, rockiness, soil moisture, vegetation type and plant density should be identified, and then fenced off as separate units. It is important to point out, however, that certain Veld Type Units may be combined and fenced as a single camp. This would normally be done if the combined Veld Type Units had the same animal production potential, and/or because it is impractical to fence all the identified Veld Type Units on the farm. Such primary sub-division will allow for a more uniform grazing pattern (area selective grazing is limited) within each Veld Type Unit provided that the ‘correct’ stocking rate is applied. There is also the opportunity to rest veld if and when necessary, and to plan a burning strategy.
Secondary sub-division
Further sub-division of these primary sub-divisions
provides for even more flexibility in both veld and livestock management. The
more camps on the farm the more control the farmer has over the use of
available forage. The farmer, with experience and a good knowledge of the
production potential of each camp on the farm, may regulate the quantity and
the quality of forage by adjusting animal numbers and strategic burning. Such
‘secondary’ sub-division provides the additional advantage of controlling
species selective grazing. It must be stressed, however, that area selective
and species selective grazing will never be eliminated through adjusting
stocking rates, sub-dividing Veld Type Units and varying camp numbers. Certain
areas and plants will be selected for and severely grazed. It is imperative
that the farmer, through adequate sub-division of the farm, has the option of
resting certain areas to counter the detrimental effects of area and species
selective grazing. The grass produced in rested camps may be used as a ‘fodder
reserve’ during periodic droughts.
There are, of course, a number of important issues which may limit the amount of sub-division which the farmer is prepared to undertake on his farm. The most important of these is the high cost associated with fencing and the provision of water. Each farmer should evaluate the projected benefits of investing capital in the form of fences and additional water points. The following should be considered as a guide.
Earlier discussion has provided the ‘facts’ which indicate the need to be in a position to manage/control the production and the use of veld. Such management should lead to optimal plant production, and to the most efficient use of the veld by the animals. With increased quality and quantity of forage on offer to animals, weaning weights, calving percentage and length of the grazing season all should be increased. A 10% increase in weaning mass and 5% increase in calving percentage together, for example, should provide the additional income required to cover the costs of additional fencing and watering.
A second, probably equally important, issue is that with increased sub-division comes an increased management input requirement. The farmer must be aware of the potential of each sub-division to produce forage for livestock, in addition to having a knowledge of livestock requirements.
Grazing systems
* Commercial production systems
Camps which are severely grazed in one season may have to be rested for the whole of the following growing season, especially if the plants were grazed by sheep. If a rotational grazing system is being practiced, the farmer must ensure that animals do not either remain in a camp for too long or allow the grass to become too rank before the camp is grazed. In both situations, animal performance will be reduced, and the severe grazing which would result from animals being in a camp for too long would reduce the forage production potential of that camp, thus reducing the availability of forage on the farm for that season.How many camps are required per group of animals? The most important considerations are the severity of grazing, and the option of applying a rest period. In systems where sheep form the majority of the livestock on the farm (in terms of Animal Units) then the grazing of individual tufts tends to be severe and frequent. In this case, frequent, long rests are required to counter the effects of frequent severe grazing. The ‘two-block’ system is indicated (refer to Production Guideline 9.8 of this series). With the ‘two-block’ system, plants which were grazed severely in one year are given a full season's rest during the following growing season.
Where the majority of animals are cattle, or in a cattle-only farming operation, the grazing of individual plants is not as severe as with sheep. Provided that the stocking rate is set at the correct level it seems that veld grazed by cattle requires a rest once every four years. The absolute minimum number of camps would therefore be four for every three groups of animals. Each camp would be grazed continuously for three years and rested in the fourth year, the so-called 3 herd - 4 camp system, or ‘rotational resting’ system. It is likely, however, that area selective grazing will become a problem in the long-term and that this would result in a reduction in the production potential of the veld. It must be stressed that the ‘rotational resting’ system does not work in sheep production systems.
Ideally, it appears that a four block system is most appropriate for beef production enterprises in mixed veld and sourveld. Sub-division of ‘blocks’ will assist with the management of veld within a block.
Ultimately, the farmer should get to know the forage production potential of each camp on the farm and use that forage according to the feed requirements of his livestock.
* Communal grazing systems
The principles discussed earlier regarding the
maintenance of veld condition and productivity are the same irrespective of
whether the veld is use for commercial or communal grazing systems. In
communal grazing systems the objectives for maintaining livestock are not
aimed at direct financial gain to the farmer but rather to provide households
with, amongst other products, milk, draught power, dung, equity and bride
price (or lobola). Maximizing animal numbers rather than livestock
production is one of the main objectives. The veld in communal grazing systems
therefore tends to be heavily stocked and continuously grazed.
In high rainfall areas with relatively stable soils the inevitable consequence of such grazing practice is for the species composition of the veld to become dominated with plants which tend to have low palatability and/or can tolerate heavy grazing. While a high number of animals may be maintained under such circumstances animal performance in terms of, for example, calving, kidding and lambing percentages and livemass gain is poor.
In areas with low and erratic rainfall the condition of both the vegetation and the soil declines to the extent that the potential of the veld to carry livestock is severely reduced. Animal performance tracks rainfall so that when there is a series of ‘good’ rainfall years animal performance and numbers increase. Inevitably, however, animal performance and numbers decline dramatically during times of drought, severely impacting on the livelihoods of communal graziers.
GENERAL
It was mentioned earlier that stocking rate was one of the most important factors that the farmer could manipulate within any veld management programme. The higher the stocking rate the lower the individual animal production and the more chance there is of lowering the production potential of the veld.
The ratio of cattle to sheep is also an important consideration. In mixed veld and sourveld, the higher the proportion of cattle, the higher is the production per sheep. This is due to the ‘fact’ (stated earlier) that cattle perform better than do sheep in these veld types because cattle are better adapted to using the rank grass of relatively low quality. Sheep prefer to graze on short, green, leafy grass. The more cattle there are, the more evenly the grasses in each camp are grazed. Provided that there are sufficient cattle in the camp to graze the whole camp down to a ‘short leafy’ structure, the sheep will spread their grazing over the whole camp. This not only provides the sheep with a high quantity of high quality forage and so they perform well, but also they do not graze the grasses too severely. If, however, there are insufficient cattle to graze the veld uniformly, the cattle tend to select for areas/patches within the paddock, and the sheep will confine their grazing to these patches. Such grazing results in a low quantity of high quality forage for the sheep, and they will reflect this in poor performance. The veld within the grazed patches is severely grazed, and, if adequate rest periods are not provided, the veld starts to degrade and to lose its production potential.
The ‘correct’ cattle/sheep ratio to graze at, therefore, is the one which has sufficient cattle to keep the grass uniformly short throughout the camp. It is recommended [on an Animal Unit (AU) basis - where a 450 kg steer is taken as an AU and is equivalent to approximately five 50 kg sheep] that sheep should never be stocked in greater proportion to cattle.
SUMMARY
- Primary sub-division of the farm.
a) Identify the various Veld Type Units of the farm, i.e. those areas of uniform palatability and productivity.
b) Design a camping system which separates the different Veld Type Units (or groups of Veld Type Units which have similar production potential).
- Adjust stocking rates in each of the primary camps to match the production potential of those camps.
- Plan the grazing management system on the farm to allow for camps to be rested for a full growing season. How often a camp should be rested depends on the frequency and intensity of grazing during the growing season.
- Use fire to remove old, dead grass which accumulates during a rest year and/or to assist in combating bush encroachment (and bush thickening).
- Consider the need for further sub-division of camps to
assist in controlling the quantity and the quality of forage on offer to
the animals. Additional camps will also increase the flexibility of
managing the veld. Animals may be removed from a camp when the grazing has
been depleted, or put into a camp when it is ‘ready’ for grazing.
Camps may be withdrawn from grazing for strategic reasons such as
a) for accumulating a fodder reserve,
b) when resting is indicated, and
c) to ensure sufficient herbage when planning a burn to control bush.
Remember, any management is a ‘hands on’ operation. The farmer must be aware of the production potential of each area of veld on the farm and be aware of the consequences of grazing on that production potential. Regular inspection of the veld in each camp, and of the animals on the farm, will assist the farmer in developing an understanding of how the veld should be
managed for sustained economic livestock production. Such understanding allows the farmer to apply the veld management principles discussed in this document, and to plan a grazing system suited to the livestock production enterprise and to the productivity of the veld.
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