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agricultural production guidelines  veld in kwazulu-natal

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Veld in KwaZulu-Natal 

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Co-ordinated Extension

KwaZulu-Natal Veld 4.6 1999

M B Hardy
Western Cape Department of Agriculture

K G T Camp
KwaZulu-Natal Department of Agriculture

Vegetation Structure and Compositions
Veld Benchmark
Animal Production

 

INTRODUCTION

The areas covered by these Bioresource Groups are commonly referred to as Moist Tall Grassveld. They generally occur as a belt of varying width between the Dry Tall Grassveld (BRG’s 13, 14, 16 and 18) and the moist grassland vegetation of the Highland Sourveld (BRG’s 8 and 9), as well as in the central parts of the Province (refer to Figure 1 in Production Guideline 4.1 of this series).

The Moist Transitional Tall Grassveld (BRG 11) is a transitional zone which lies, with few exceptions, between the drier Tall Grassveld Bioresource Groups (BRG’s 13, 14, 16 and 18) and the Moist Highland Sourveld (BRG 8). Generally, the lower, adjacent area is Moist Tall Grassveld (BRG 12).

The Moist Tall Grassveld (BRG 12) is distributed widely over the province, generally lying adjacent to and at a higher elevation than the Dry Tall Grassveld. The northern-most part of this BRG lies close to the northern border of the province in the Pongola River valley, while the southern-most part is found at Creighton in the Mzimkhulu River valley. In many areas, such as in the Estcourt district, this BRG exists as a narrow belt between the Dry Tall Grassveld and the Highland Sourveld. It is readily recognised by its characteristics. Hyparrhenia hirta, an indicator species of this BRG, is very apparent in the transitional zone from the Highland Sourveld to the Dry Tall Grassveld.

The Moist Lowland Tall Grassveld (BRG 15) is found in northern KwaZulu-Natal at elevations between 450 m and 900 m a.s.l.. The main areas covered by this BRG include an area extending from Hlomo Hlomo to the Ngome forest and eastwards to the town of Nongoma. Other areas lie between Nongoma and Hluhluwe on the crests of hills and scattered patches lie on the crest of the Ubombo mountains.

 

VEGETATION STRUCTURE AND COMPOSITION

The vegetation may be described as a short to tall, open grassland, often with tall Acacia sieberana (paperbark thorn) trees scattered throughout. The grasses often reach a height in excess of 1 m. Fire has played a major role in maintaining the area as a grassland, in the absence of which, it would initially become dominated by acacias such as paperbark thorn, A. nilotica (scented thorn) and A. karroo (sweet thorn) and subsequently by scrub forest species (Note: the Acacia species dominated stage does not occur in BRG 11). Grazing also plays a role, and it is the interacting effects of fire and grazing that maintain the Moist Tall Grassveld as a grassland suited to extensive livestock production. The incorrect use of fire, combined with poor grazing practices, however, often reduces the livestock production potential of the veld.

Moist Transitional Tall Grassveld (BRG 11)
The most extensive plant association in the Moist Transitional Tall Grassveld (BRG 11) is Themeda-Hyparrhenia Grassland with Hyparrhenia hirta dominating much of the veld, particularly disturbed veld. Long-term overgrazing is indicated by a dominance in Eragrostis curvula, Eragrostis plana and Sporobolus africanus. Where selective overgrazing has occurred, particularly by sheep, Elionurus muticus has increased in relative abundance. On leached soils, particularly on south facing aspects, taller, sour grasses such as Cymbopogon excavatus is found and the palatability of these areas is low.

Moist Tall Grassveld (BRG 12)
The characteristic feature of the Moist Tall Grassveld BRG (12) is the abundance of thatch grass, Hyparrhenia hirta, and sparsely scattered paperbark acacias, Acacia sieberana. On road verges the tall thatch grass species are common, including Hyparrhenia dregeana, H. tamba and H. rufa. On dolerite hillsides Acacia caffra woodlands and thickets occur. Acacia karroo is found occasionally on dolerite hills and along watercourses. While bush encroachment in the form of Acacia species is limited to a few isolated areas, the alien weed Lantana camara is a problem plant.

Themeda triandra is the dominant grass on veld that has been well managed. Many species common to the Highland Sourveld and Moist Transitional Tall Grassveld are prominent, particularly in the moist upland areas. These include Diheteropogon filifolius, Harpochloa falx and Trachypogon spicatus. Eragrostis racemosa and Microchloa caffra are dominant on shallow soils. Cymbopogon excavatus and C. validus are found on south-facing aspects, often growing in clumps.

Overgrazed areas of veld become dominated by mtshiki species (i.e. Eragrostis curvula, E plana, Sporobolus africanus and S. pyramidalis). These areas have a reduced grazing capacity and the grazing value deteriorates early in the season. Hyparrhenia hirta is a highly palatable grass in the spring, but loses its grazing value as the flowering culms develop. The characteristic feature of this BRG in the summer months is the tuftiness of the veld, with tall ungrazed tufts of Hyparrhenia hirta in a short-grazed sward.

Selective over-grazing causes certain wiregrass species to become abundant. The commonest species is Elionurus muticus, while Aristida junciformis is a problem particularly close to the Midlands Mistbelt.

Moist Lowland Tall Grassveld (BRG 15)
Grassland dominates the veld in this BRG with bushed grassland in the areas transitional to Dry Tall Grassveld. Isolated patches of forest occur in the Hluhluwe Game Reserve and on the upper slopes of the Ubombo mountains. Hyparrhenia hirta is the dominant grass species while Alloteropsis semialata is fairly abundant at the highest elevations near the Ngome forest, which indicates that these are sourveld areas. Acacia mearnsii, Solanum mauritianum and Lantana camara are alien species common in the BRG. Rauvolfia caffra and Syzygium caudatum are indicator species found in this BRG while Phoenix reclinata is found in sub-groups closer to the sea.

 

VELD BENCHMARK

Veld in these Bioresource Groups which is considered to be in good condition (with respect to a stable fodder production potential) could be expected to have a species composition similar to that presented in Table 1. In addition, Table 1 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 detail in Production Guidelines 6.1 to 6.3 in this series.

Grassveld with the above composition is considered to be in optimum condition for animal production and may be used as a reference point against which other areas of grassveld (in the same ecological zone) may be compared for estimating grazing capacity. Although the botanical composition varies considerably, predominance of redgrass (Themeda triandra) is considered to indicate that the veld is in optimum condition. Abundances of other key grass species may be used in conjunction with redgrass to determine veld condition using the Weighted Key Species method (refer to Production Guideline 6.2 in this series for a description of this method). Key species and their weightings which are proposed for use in this veld type are presented in Table 2.

 

ANIMAL PRODUCTION

Rainfall tends to be unreliable, particularly in spring. Grass growth may commence as late in the season as October, and is normally slow until after the first good rains in early summer. New growth is highly nutritious and palatable to livestock. However, as the grass matures, it loses its nutritive value and becomes less palatable, although not to the same extent as in the moister, cooler grassveld areas such as in the Highland Sourveld. The decline in grass quality usually begins at the beginning of February, and it is therefore essential that good-quality licks be supplied to livestock at this time of the year to ensure continued animal mass gains. When rains occur early in spring (thus ensuring early-season grass growth), this type of grassveld provides grazing for about 9 to 11 months of the year (i.e. September/October to June/July). Most classes of animals are able to maintain mass when supplied with a good-quality lick during the winter months.

For these reasons, the grazing in Moist Tall Grassveld is considered to be ‘mixed’ (i.e. it provides forage for 9 to 11 months of the year). In general terms, cattle are the animals which are best adapted to using and maintaining this grassland, and this veld type is best adapted to the breeding, and, to a certain extent, the fattening of cattle. In spring and summer, growing animals (e.g. heifers and steers) can produce live mass gains of up to 1 kg/day, provided that sufficient grazing is available. Weaners of between 200 and 240 kg may be produced, and tend to be slightly heavier (approximately 20 kg) than those produced in the Highland Sourveld (mainly because they can be weaned later in the season). An important consideration is that the winter supplementary feeding period for the breeding herd is short (provided early rains occur), and therefore less expensive than during the same period in the Highland Sourveld.

These Bioresource Groups are not generally suited to sheep production. In certain areas, sheep can be incorporated into the system, provided the ratio of cattle to sheep (in terms of Animal Units) always favours cattle. Goat production becomes important in areas where woody bushes and shrubs provide sufficient browse for a contribution to animal production.

 

VELD MANAGEMENT NORMS AND GENERAL INFORMATION FOR BRG’s 11, 12 & 15: MOIST TRANSITIONAL TALL GRASSVELD, MOIST TALL GRASSVELD AND MOIST LOWLAND TALL GRASSVELD

		BRG 11	BRG 12	BRG 15
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%)		744 446 1.5 2.0 250 30 10 20 166 2 500   74 50 25	408 316 1.8 2.6 275 42 14 28 140 2 750   57 38 19	57 45 1.7 2.4 250 30 10 20 139 2 500   74 50 25
Rested area	Each camp should be rested once every four years
Winter grazing	Licks are required when grazing rested veld in winter
Animal types	Cattle (high potential); Sheep and Goats (low potential)
Burning	Burn to remove moribund and excess herbage

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 2. Proposed key grass species and species weightings for grassland in the Moist Tall Grassveld (BRG’s 11, 12 & 15).

Scientific name	Common name	Species weighting
Paspalum scrobiculatum Sporobolus africanus Hyparrhenia hirta Eragrostis plana Eragrostis chloromelas Heteropogon contortus Themeda triandra Tristachya leucothrix	Veld paspalum Ratstail dropseed Common thatchgrass Fan lovegrass Speargrass Redgrass, rooigras Tridentgrass	1 2 3 3 4 6 9 10

 

Table 1. Benchmark species abundances and species not occurring in the benchmark for grassland in Moist Transitional Tall Grassveld (BRG 11), the Moist Tall Grassveld (BRG 12) and the Moist Lowland Tall Grassveld (BRG 15)

Scientific name	Common name	Relative abundance (%)
		BRG 11	BRG 12	BRG 15
INCREASER Ib Cymbopogon validus Miscanthus capensis	Giant turpentine grass East-coast broomgrass			1
INCREASER Ia Alloteropsis semialata Cymbopogon excavatus Cymbopogon plurinodis Digitaria tricholaenoides Eulalia villosa Schizachyrium sanguineum Setaria nigrirostris Trachypogon spicatus Tristachya leucothrix	Blackseed grass Common turpentine grass Bushveld turpentine grass Purple finger grass Golden velvetgrass Red autumn grass Large seed setaria Giant speargrass Tridentgrass	1   1     2 2 19	1         1   17	2       1 1 1 3 17
DECREASER Andropogon appendiculatus Andropogon schirensis Bracharia serrata Diheteropogon amplectens Melinis nerviglumis Monocymbium ceresiiforme Themeda triandra	Bluegrass   Velvet signalgrass Broadleaved bluestem Bristleleaved redtop Wild oatgrass Redgrass, rooigras	1 2 1   48	1 1 1   50	1 1 1   4 38
INCREASER IIa Eragrostis capensis Heteropogon contortus	Heartseed lovegrass Speargrass	2 4	5 4	0 3
INCREASER IIb Digitaria monodactyla Eragrostis chloromelas Eragrostis curvula Eragrostis plana Eragrostis racemosa Hyparrhenia hirta Loudetia simplex Setaria sphacelata var. torta Sporobolus africanus Sporobolus pyramidalis Sporobolus stapfianus	One finger grass   Weeping lovegrass Fan lovegrass Narrow-heart lovegrass Common thatchgrass Common russet grass Creeping setaria Ratstail dropseed Catstail dropseed Fibrous dropseed	1 1 2 1   2	1 1 2 2   3 2	1     1 3 1 3   1
INCREASER IIc Aristida congesta subsp. barbicollis Cynodon dactylon Microchloa caffra Paspalum scrobiculatum Setaria sphacelata Forbs Sedges	Spreading bristlegrass Couch grass Pincushion grass Veld paspalum Golden setaria	1     5 2	1         4 3	2     5 3
INCREASER III Diheteropogon filifolius Elionurus muticus Rendlia altera	Wire bluestem Wire lemongrass Toothbrush grass	1 1		1 1 4

 

 

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