agricultural production guidelines
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Veld in KwaZulu-Natal
Co-ordinated Extension KwaZulu-Natal Veld 2.2 1999
VELD TYPE UNITS AND PLANNING THE PRIMARY AND SECONDARY CAMPS OF THE FARM
K G T Camp
KwaZulu-Natal Department of Agriculture
Planning the Primary and Secondary Camps of the Farm
INTRODUCTION
Areas of uniform palatability and productivity are referred to as Veld Type Units (VTU’s). A VTU is defined as an area of land within which the variation in natural resources is limited to the degree that the production (grazing capacity) and palatability will be uniform, and will differ from adjoining VTU’s.
The identification of the VTU’s is the primary step to take when planning a farm and a veld management system, and the VTU’s form the basic units of planning. All resource information relating to them is gathered and used to make decisions in the planning process.
Fortunately the natural factors which affect palatability and productivity of forage or, in other words, the boundaries of the VTU’s, are easy to identify. These factors are defined below.
- Climate: mainly rainfall and temperature; low rainfall, warm areas usually produce more palatable forage than moist, cold areas.
- Aspect: north-facing aspects usually produce more palatable forage than south-facing aspects, although the latter are likely to be the more productive of the two.
- Slope: steep, well-drained slopes usually produce more palatable forage but are less productive than bottomland areas.
- Soil: clay soils usually produce more palatable forage and usually produce more herbage than sandy soils, and deep soils are more productive than shallow soils.
- Vegetation: changes in vegetation do not necessarily indicate a change in VTU but may have been caused by different management practices (e.g. light versus heavy grazing) on the same potential VTU. Differences in vegetation due to management could be used to demarcate areas suitable for secondary subdivision.
The most efficient way to identify the different VTU’s on the farm is to use a stereoscope and aerial photos. Orthophotos (i.e. aerial photos with contours marked on them) can also be used.
Using the stereoscope, the identifying features are observed and marked on a photo with a chinagraph pencil. The steps to follow are given below.
- Delineate all flat plateaus,
- outline all bottomlands,
- separate aspects by marking hill crests and watercourses,
- mark the line of major changes of slope,
- outline rocky and bushy areas,
- mark changes of colour on the photo which appear to indicate a change in soil, and
- draw a dotted line along apparent vegetation changes.
The resultant lines will delineate the VTU’s of the farm (see Figures 1 and 2). Additional lines, which may be added after inspecting the farm, are mainly associated with important soil changes, but this does not occur very often.
The VTU’s must then be transferred to a map of the farm. Resource information can be gathered for the VTU’s and recorded. The information required for each VTU includes:
- a number,
- the area in hectares,
- the veld condition score, and
- the grazing capacity (ha/AU).
Procedures for gathering the relevant resource information are given in Production Guidelines A2.4 (veld condition assessment) and A2.5 (determining grazing capacity).
PLANNING THE PRIMARY AND SECONDARY CAMPS OF THE FARM
Primary camps
It has often been stated that the most important veld management principle for a farmer to apply is the correct stocking rate for his farm. This may be true, but it is virtually impossible to apply the correct stocking rate uniformly to most farms because of their great variation in topography, aspect and soil form. The result is that some areas of the farm are overgrazed and the veld deteriorates, while other areas are poorly or not grazed and the forage is wasted.To rectify this situation, areas that are reasonably homogeneous with respect to palatability are fenced into the primary camps of the farm. This is the most important reason for creating camps on a farm, that is, to control, or manage, the utilization of the veld on the farm.
The first step in planning is to identify the Veld Type Units (VTU’s) of the farm as discussed above. In the planning process the natural resources of the VTU’s should be fully described, including information such as size, vegetation type, veld condition score, grazing capacity (which reflects the veld condition) and carrying capacity. Using this information, VTU’s can be grouped into a larger unit, or primary camp, which will be reasonably uniform regarding palatability and veld condition (Figure 3). Several points must be considered when planning the primary camps:
- Major crests and watercourses indicate the division between aspects.
- Northern aspects should be split from southern aspects because of the usual marked difference in palatability, the north aspects producing more palatable forage than the southern aspects. Similarly, western aspects usually produce more palatable herbage than eastern aspects. Palatability of the forage produced on different aspects, from most to least palatable, is generally in the order of north, west, east, south. Be aware of the exceptions to this order which local knowledge or observation may indicate.
- Practical factors such as very small VTU’s within a group of larger, but very different VTU’s, must be considered. A small south-facing VTU enclosed by large north-facing VTU’s poses a problem of a small area which may remain unutilized. This cannot be avoided. However, a small north-facing VTU, within a large south-facing VTU, will be overgrazed relative to the rest of the VTU. If this VTU is too small to be camped separately it will have to be sacrificed.
A primary camp might consist of several VTU’s, and sometimes the nature of one or more VTU unavoidably differs from others in the camp. In this case the most import-ant VTU, which might be the largest, most palatable VTU, is used as an indicator VTU. Management decisions will then be made according to the condition of this, indicator, VTU.
Secondary camps
Further sub-division of primary camps into secondary camps is often necessary. There are several reasons for this.
- A primary camp might be too large for efficient management. It might encourage excessive movement of the herd, particularly during mating season.
- The period of stay in the camp might have to be too long in order to utilize the available grazing.
- Additional camps might be required on the farm to provide for all the stock groups the manager intends running.
- Additional camps might also be required to implement a particular veld management system.
When siting the fences for secondary camps the most suitable positions would be along the boundaries of internal VTU’s. In the case of a primary camp consisting of only one VTU, the most practical line should be selected.
Figure 1. An area of veld with many aspects and slopes.
Figure 2. Veld Type Units defined according to aspect and slope.
Figure 3. An example of the separation of an area into Veld Type Units with planning information recorded within the units.