agricultural production guidelines
m
Veld in KwaZulu-Natal
Co-ordinated Extension KwaZulu-Natal Veld 4.2 1999
BIORESOURCE GROUPS 1 & 2: MOIST AND DRY COAST FOREST, THORN AND PALM VELD
C R Hurt
ARC - Range and Forage Institute, Cedara
Vegetation
Strucutre and Composition
Veld Benchmark
Animal Production
INTRODUCTION
The Moist (BRG1) and Dry (BRG2) areas of the Coast Forest, Thorn and Palm Veld occupy a narrow belt at elevations below 450 m along the coast of KwaZulu-Natal (refer to Figure 1 in Production Guideline 4.1 of this series). The area has, over the years, developed into an intensively-farmed region, widely used for the production of sugarcane, timber and tropical fruits, all of which thrive in the warm, humid climate.
VEGETATION STRUCTURE AND COMPOSITION
The natural vegetation of the coastal areas occurs in the form of dense forest or scrubby, fire-maintained savanna containing scattered bush clumps. Today, however, the natural vegetation has been largely replaced by sugarcane, timber plantations and alien plants. Forest patches are restricted to the dunes adjacent to the coastline and to a few relics on the hills immediately above the coastal plain. This Production Guideline describes the vegetation occurring in relatively less-disturbed areas along the coast, and outlines the general potential of the area for animal production.
The coastal forest occurs in a narrow band along the coast in areas that have not been disturbed by development. The trees are mainly short (up to 10 m high), but are extremely dense and tangled, particularly nearer the coast. A few forest grasses may be present (e.g. Setaria megaphylla (the broadleaved setaria) and Oplismenus hirtellus), but generally the coastal forest provides very little grazing, and therefore does not contribute significantly to commercial animal production. Common forest trees include; Millettia grandis (mzimbeet), Protorhus longifolia (red beech), Ficus natalensis (common wild fig), Celtis africana (white stinkwood), Trichilia emetica (Natal mahogany), Harpephyllum caffrum (wild plum), Erythrina caffra (coast coraltree), Brachylaena discolor (wild silver oak), Strelitzia nicolai (Natal strelitzia), Croton sylvaticus (forest croton), Albizia adianthifolia (flatcrown), Mimusops caffra (coast red milkwood), and Sideroxylon inerme (white milkwood).Coastal Forest
Thorn and Palm Veld
The Thorn and Palm Veld occurs as a savanna scrub where growing conditions are unsuited to forest development, or in areas which have suffered severe disturbance (e.g. fire, clearing for agriculture, mining). The vegetation consists of a tall grassland interspersed with bush clumps. The grass layer is dominated by Themeda triandra (redgrass), while Acacia karroo (sweet thorn) is usually the dominant woody tree or shrub. The bush clumps include most of the trees listed above, as well as Phoenix reclinata (wild date palms), Hyphaene natalensis (lala palms), Syzygium cordatum (waterberry) and Trema orientalis (pigeonwood).The herbaceous layer contains numerous forbs and bushes which considerably decrease the grazing capacity for commercial livestock. Heavy grazing causes an increase in the abundance of Aristida junciformis (ngongoni), which further decreases the grazing potential of the veld.
No formal benchmark has been described for the vegetation of these Bioresource Groups. The coastal grasslands are, however, known for their high species diversity. Veld in good condition could be expected to consist of the species whose abundances are listed in Table 1 (bearing in mind that these proportions are estimated, and could change as research provides more information on this vegetation type). In addition, Table 1 also presents other grass species which occur in these Bioresource Groups, but are not necessarily found in the benchmark. The species groupings (i.e. Increaser and Decreaser species), and concepts related to this classification, are explained in more detail in Production Guidelines 6.1 to 6.3 in this series. Potential key grass species and their weightings are presented in Table 2, and can be used in the Weighted Key Species method for determining veld condition (refer to Production Guideline 6.2 in this series for a description of this method).
Bioresource Groups 1 and 2 have a relatively low potential for livestock production, and then only for beef. Even beef animals are likely to require supple-
mentation from time to time. Here, Zebu-type cattle breeds are likely to be the best adapted to the hot, humid summers. The area is not suited to pure dairy breeds because of the extreme heat in summer. Dual-purpose, Zebu-type cattle would be best suited to dairy production in these BRG’s. Goats may be a reasonable proposition where adequate browse is available.
Because of the strong tendency for ngongoni to increase in abundance in veld in this region, it is unlikely that livestock-based systems will ever form a major component of agricultural systems established on veld alone. Tropical grass and legume pastures, on the other hand, grow well in this region and would provide a viable alternative to veld-based animal production systems.
VELD MANAGEMENT NORMS AND GENERAL INFORMATION FOR BRG’s 1& 2: MOIST AND DRY COAST FOREST, THORN AND PALM VELD
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BRG 1 |
BRG 2 |
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|
Total area (1 000 ha) Area of veld (1 000 ha) Potential grazing capacity (ha/AU) Current grazing capacity (ha/AU) Grazing season (days) Grazing cycle (days) Period of stay (days) Period of absence (days) AU grazing days per hectare Expected intake (kg/AU/annum) Livestock production potential (kg livemass per ha/annum) Excellent condition veld (90%) Moderate condition veld (60%) Poor condition veld (30%) |
1 006 99 1.8 3.0 275 30 10 20 112 2 750
75 50 25 |
912 90 2.0 3.3 275 30 10 20 112 2 750
59 39 20 |
|
|
Rested area |
Each camp should be rested once every four years |
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|
Winter grazing |
Licks are required when grazing rested veld in winter |
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Animal types |
Cattle (high potential); Sheep & Goats (low potential) |
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Burning |
Burn to remove moribund and excess herbage; control bush canopy |
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1 In areas where stocking rates are higher than those given for potential grazing capacity, the livestock production potential will not be achieved. This is particularly so where continuous grazing is practiced.
2 Current grazing capacity is based on the average condition of veld in the BRG as estimated in 1997.
3 Animal Unit (AU) grazing days per hectare are based on the estimated average CGC of the BRG.
4 Livestock production potential refers to the expected amount of live mass (kg) gain per hectare using a beef weaner production system (see the example of such a system in Production Guideline 2.6)
Table 1. Benchmark species abundances and species not occurring in the benchmark for grassland in Bioresource Groups 1 and 2 (Moist and Dry Coast Forest, Thorn and Palm Veld).
|
Scientific name |
Common name |
Relative abundance (%) |
|
Increaser Ib Cymbopogon validus Miscanthus capensis Urelytrum agropyroides |
Giant turpentine grass East-coast broomgrass Quinine grass |
2
4 |
|
Increaser Ia Alloteropsis semialata Cymbopogon excavatus Digitaria natalensis Eulalia villosa Hyparrhenia filipendula Trachypogon spicatus Tristachya leucothrix |
Blackseed grass Common turpentine grass Coast finger grass Golden velvetgrass Fine thatchgrass Giant speargrass Tridentgrass |
2
3 1 17 |
|
Decreaser Digitaria eriantha Diheteropogon amplectens Monocymbium ceresiiforme Panicum deustum Panicum maximum Themeda triandra |
Common fingergrass Broadleaved bluestem Wild oatgrass Broadleaved panic Guinea grass, uBabe Redgrass, rooigras |
6
1
5 40 |
|
Increaser IIa Eragrostis capensis Chloris gayana Heteropogon contortus |
Heartseed lovegrass Rhodes grass Speargrass |
2
4 |
|
Increaser IIb Eragrostis curvula Eragrostis plana Eragrostis racemosa Loudetia simplex Setaria sphacelata Sporobolus pyramidalis |
Weeping lovegrass Fan lovegrass Narrow-heart lovegrass Russet grass Golden setaria Catstail dropseed |
2
1 |
|
Increaser IIc Cynodon dactylon Paspalum scrobiculatum Forbs Sedges |
Couch grass Veld paspalum
|
2
1 4 |
|
Increaser III Aristida junciformis Elionurus muticus |
Ngongoni Wire lemongrass |
3
|
Table 2. Proposed key grass species and species weightings for grassland in Bioresource Groups 1 and 2 (Moist and Dry Coast Forest, Thorn and Palm Veld).
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Scientific name |
Common name |
Species weighting |
|
Aristida junciformis Cynodon dactylon Sporobolus pyramidalis Eragrostis curvula Heteropogon contortus Digitaria eriantha Themeda triandra Tristachya leucothrix |
Ngongoni Couch grass Mtshiki Weeping lovegrass Speargrass Common fingergrass Redgrass, rooigras Tridentgrass |
1 1 2 3 4 6 9 10 |