Management of different Natural Veld types.
Prof Chris S Dannhauser
In the first two parts of this series different groups of grasses and different growing stages of veld were described.
There are three main groups of veld grasses:
- Grasses that are highly palatable, those that are preferred by grazing animals
- Medium palatable grasses, those that animals utilized when the highly palatable ones are finished.
- Unpalatable grasses are those not preferred by grazing animals, but if there is nothing else they will graze it and lose weight.
Depending of grazing strategy and veld management, the veld can be in different stages of development:
- Pioneer stage – This is a recovering stage that occurs after veld was completely overgrazed. The species growing here (grasses & weeds) are called pioneers. They are mostly annual species, drought resistant, with different levels of palatability (see Table 1).
- Sub climax stage – In this stage bi-annual or perennial species follow the pioneer species. Some of them are semi-palatable and others palatable
- Climax stage – Perennial species that establish later in the development process are climax species. Most of them are palatable and the best fodder plants in good veld.
This process can also develops in the opposite direction, from climax to pioneer stage if the veld is over stocked and over grazed.
Table 1 shows a few important grass species that grows in different part of the country. The table also shows in what successional stages of veld they will grow and their grazing values. A zero (0) shows it is not palatable and not grazed by animal, a 10 shows it is palatable and of good feeding value.
The veld manager should be able to identify the key species in his veld and how to manage them to prevent over grazed, because that can do permanent damage.
Table 1: The important grass species that grow in the different succession stages in the Highveld grassland.
|Succession stage||GRASS COMMON NAMES||BOTANICAL NAMES||Grazing value|
|ClimaxVeld||Red grassTurpentine grass||Themeda triandraCymbogon plurinoides||7-82|
|Sub- climax / Late pioneer veld||Finger grassThatch grassKweek/Couch grassWeeping love grass||Digitaria erianthaHyparrhenia hirtaCynodon dactylonEragrostis curvula||6443|
|Early pioneer veld||Natal Red TopThree awn grass||Melinus repensAristida spp||10|
Besides grazing the growth of grasses are also influenced by soil type, climate and other natural factors (like palatability) and that influence the carrying capacity of veld.
Map 1 indicates the veld carrying capacity in different regions, in the eastern part of our country. Example: 7 – 8 ha/MLU indicates that you need 7 – 8 ha to carry 1 MLU for 1 year. It shows how many hectares are needed to carry one MLU for a full year. Remember: MLU means a Matured Livestock Unit and 1 MLU is 1 cow or bull with a weight 450 kg and that utilize 10 kg of grass per day. At weaning stage a calf might be the equivalent of 0.7 MLU and 6 matured sheep are the equivalent of 1 MLU. For the sheep and goat farmers: SSU stands for Small Stock Unit and 6 SSU graze the same kilograms of grass per day as 1 MLU.
Map 1: Carrying capacity of veld in Eastern SA (Avenant, 2010).
To help the farmer/manager with the above mentioned information a veld management expert can be contacted.
In some cases farmers/managers tend to overestimate the potential, the vigour and the palatability, of the veld, which leads to overgrazing. It is thus important to use the norms given in Map 1 on your farm. For example if the farm is in the western Free State, we need 7 to 8 ha for 1 MLU. In Mpumalanga, with a higher rainfall, 3 – 4 ha per 1 MLU is enough.
On Map 1 and the following Map 2, there are yellow lines indicating three different rainfall zones. The three zones are: (i) on the left hand side of the map an area with an average rainfall of less than 500 mm/year, (ii) in the middle an area with an average rainfall of 500 to 650 mm/year and (iii) on the right hand side an area with an average rainfall of more than 650 mm/year
Like carrying capacity, the palatability of grasses is also important in veld management. Palatability is influenced by genetics and external factors, as mentioned earlier.
For this reason the veld of South Africa can be divided in: (i) Sweet veld, (ii) Mixed veld and (iii) Sour veld. The three different palatable regions, in the eastern part of the country, are shown in Map 2, and will be discussed to help farmers with good veld management practices.
The reasons for the presence of the three different veld types are mainly climate (rainfall & temperature), soil, topography and management.
3.3 SWEET VELD VERSUS SOUR VELD
The density and production of Sweet veld is lower, than that of Sour veld, and over utilization often occurs on Sweet veld. There are also some less palatable species in Sweet veld. If you keep animals too long in a camp, they will also graze the less palatable grasses (see Photo 1), and then will over graze the palatable ones.
Sour veld, on the other hand, has a dense cover and is more persistent to grazing (Photo 2). But Sour veld can also be over grazed with a high stocking density in summer.
Some people believe that you will have maximum animal production (high calving percentage and maximum growth) with maximum stocking density, thus as many animals as possible. That is not true, statistics showed that on farms where too many animals are kept (over grazing) the calving percentage is about 45% and even lower. On farms where a realistic grazing capacity is maintained and where enough grazable material is available the calving percentage can be as high as 95%.
To conclude, the information on Maps 1 & 2 should be kept in mind and should be applied to maintain good animal production.
Many farmers make use of planted pasture for additional grazing and to build up a fodder bank. This information will follow in a next edition of the series.
Prof Chris S Dannhauser
Sel no (+27) 082 873 4736