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Short-term effects of mixed grazing by cattle and sheep in highland sourveld.Hardy, Mark Benedict. January 1994 (has links)
Data derived from a long-term grazing trial were used to
determine short-term effects of mixed grazing by cattle and sheep
in Highland Sourveld.
Five cattle to sheep ratio treatments (viz. 1 :0, 3:1, 1 :1, 1 :3,
0:1) were applied, each at three stocking rates (viz. 0.5 (low),
0.71 (medium) and 1.0 (high) animal unit equivalents (AUE) ha¯¹).
Ratios were expressed in terms of AUE cattle: AUE sheep. Stocking
rate and ratio treatments were balanced at the start of each
grazing season. Fourteen-month old Hereford steers and 'two-tooth'
Merino wethers were used as experimental animals.
The trial comprised two components, viz. an animal production
component and a simulated component. The animal production
component was conducted only in the medium stocking rate
treatment where the effect cattle to sheep ratio on the
performance of cattle and sheep was determined for each of four
grazing seasons (viz. 1989/90,
four-paddock rotational grazing
The low and high stocking rate
1990/91, 1991/92, 1992/93). A
management system was applied.
treatments were implemented by
simulating a four-paddock rotational grazing system and using a
single paddock for each stocking rate/ratio combination. Grazing
of the simulated treatments coincided with the grazing of a
specific 'test' paddock in each ratio of the medium stocking rate
treatment. These 'test' paddocks and the simulated treatment
paddocks were monitored to determine the impact of mixed grazing
by cattle and sheep on individual grass plants and the sward.
The whole of the experimental area was rested during the growing
season prior to the start of the trial and all paddocks were
burnt in the dormant season just before the start of the first
grazing season. The trial therefore commenced with a with a
uniform sward of immature herbage in all paddocks allocated to
each group of animals. ln the second and subsequent growing
seasons only those paddocks which had been rested in the previous season were burned prior to the onset of growth in early spring.
Rainfall for the first three grazing seasons was similar to the
long-term mean of 790mm whilst the last season was considered
'dry' with 554mm recorded during 1992/93.
In all grazing seasons, as the proportion of cattle in the
species mix increased, sheep performance increased. A decline in
sheep performance was recorded in each ratio treatment from the
first to the third season. This decline was attributed to the
increased maturity and thus lower quality of herbage on offer to
the sheep, and the fact that only one paddock available to the
animals in the second and third grazing seasons had been burned
prior to the start of the season. Sheep performed best during
the 'dry' season where herbage quality was maintained for longer
into the grazing season than in previous seasons. In contrast,
cattle performance was affected by the stocking rate (animals
ha¯¹) of cattle rather than the presence of sheep. As the
quantity of herbage on offer per steer declined steer performance
declined.
Animal performance data were also used to predict the effects of
adding cattle to a sheep production enterprise and vice versa.
The general trends were that the introduction of cattle into a
low stocking rate, sheep-only production enterprise would allow
for an increase in the stocking rate of sheep while maintaining
the performance of the sheep. In this way the carrying capacity
of a farm may be improved.
Stocki ng rate and ratio treatments varied from those established
at the start of each grazing season due to the differential
performance of the cattle and sheep in each treatment. As the
proportion of cattle in the species mix increased, stocking rate
increased and the ratio widened in favour of cattle. Stocking
rate (AUE ha¯¹), calculated a posteriori for each season, was the
major influence on the severity of grazing on individual plants
and within patches. As stocking rate of cattle and sheep at the
various ratios increased, the extent and severity of grazing increased. At stocking rates in excess of O.8AUE ha¯¹ however,
sheep-only grazing resulted in a greater proportion of plants,
per species and per area, being grazed more severely than was the
case for an equivalent stocking rate (AUE ha¯¹
) of cattle.
Furthermore, cattle and sheep had similar effects on patch size
distribution when stocked at the same number of AUE ha¯¹.
There were no measurable effects of stocking rate and ratio on
proportional species composition and basal cover over a two year
monitoring period. A technique for estimating basal cover in
tufted grasslands was developed and is presented as an appendix
to the thesis.
Data were also used to evaluate the use of AUE as an integral
part of the grazing capaci ty concept. Results indicated that
cattle and sheep cannot be equated in terms of AUE when referring
to the grazing impact. It is suggested that the definition of
grazing capacity should include the species of livestock and
assume a grazing management system appropriate to the grazing
habit of the animals concerned.
Resul ts of the trial provide strong indications that, in the
long-term, the current recommendations of grazing cattle together
with sheep in order to prevent the degradation or loss of veld
condition which occurs in sheep-only grazing systems, will not
succeed. A four-paddock rotation grazing system does not appear
to be an appropriate veld management system for sustainable sheep
production in sour grassveld. An alternative approach to veld
management is suggested in which the sheep are confined to only
those areas of the farm which were burnt at the start of the
grazing season. Ideally, sheep should not allocated to the same
paddock for two consecutive grazing seasons. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.
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Patch grazing in the humid grasslands of KwaZulu-Natal.Lütge, Bernd Uwe. January 1995 (has links)
Patch grazing may be an important factor providing the focus from which wide-scale veld
degradation has occurred in the humid grasslands of KwaZulu-Natal. A number of discrete
studies were therefore initiated to examine the patch grazing patterns and selected factors
which may influence patch grazing at two sites in the humid grasslands of KwaZulu-Natal.
The sites were located at Ukulinga Research Farm, situated in the Southern Tall Grassveld,
and Kokstad Research Station in the Highland Sourveld.
An investigation into the frequency and intensity of gazing patches and non-patches at
Ukulinga Research Farm indicated that patch grazing was most evident and most extensive
during summer and autumn. As forage in the patches became limiting during winter animals
were forced to forage in areas not frequently grazed during the season. The patch grazing
pattern was further modified by the time of grazing commencement after a burn in early
spring. Early grazing significantly reduced the extent of patch grazing. With early stocking
animals were forced to graze less selectively while with increased delay in the
commencement of grazing, animals became increasingly patch-selective. Early grazing in
conjunction with an autumn rest and heavy grazing during winter could significantly reduce
patch grazing.
Urine and dung significantly influenced the patch grazing pattern. The sward surrounding
a urine deposit was preferentially grazed by both cattle and sheep for a period of at least six
months after deposition. Cattle rejected the sward surrounding cattle and sheep dung
immediately after deposition and for a period of up to six months. Sheep also rejected cattle
and sheep dung patches immediately after deposition. As dung deposits aged, sheep tended
to increase their grazing around both cattle and sheep dung pats, and after six months dung
did not seem to influence sheep grazing. Urine may be an important factor influencing patch
initiation and consequent patch development.
A study to examine the characteristics of patches and non-patches in the Highland Sourveld
revealed that patches were characterised by lower soil moisture, soil depth and hydraulic
conductivity, but by a higher soil nutrient status. Patches and non-patches could also be distinguished in terms of species composition and basal cover. Patches were characterised
by Increaser II species, especially Microchloa caffra and, non-patches by Increaser I species
such as Trachypogon spicatus, Alioteropsis semialata and Eulalia villosa.
Three seasons of patch grazing at Kokstad Research Station negatively influenced the vigour
of Themeda triandra in patches relative to the non-patches. The vigour of T. triandra in
patches was consistently low throughout a full season's rest. The vigour of T. triandra in
non-patches was initially significantly higher than the vigour in the patches and remained so
for c. 24 weeks. Vigour measurements at the start of the following season showed that
photosynthate accumulation had taken place and a full seasons rest proved to be sufficient in
restoring the vigour of T. triandra in patches to the same level as that in non-patches. A full
seasons rest did, however, not prevent animals from regrazing the same previously grazed
patches the following season. Growth in patches also started c. six weeks later than in nonpatches
and above-ground herbage production in patches was significantly lower than nonpatches
for at least 20 weeks after a bum. At the end of a full season's rest above-ground
herbage production in patches was still slightly lower than that in non-patches possibly due
to a difference in species composition between patches and non-patches.
Some implications of patch grazing are discussed together with an evaluation of some
management recommendations for the humid grasslands with the aim of reducing the
potential for patch degradation. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.
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Factors influencing choices of grazing lands made by livestock keepers in Enhlanokhombe in Ukhahlamba (Drakensberg), KwaZulu-Natal.Chonco, Johannes Mphumzeni. January 2009 (has links)
In South Africa, communal land still plays a significant role in the lives of many rural communities. While these communal lands have ostensibly been included within municipal frameworks, decisions about their utilisation still remains a practical reality for many livestock keepers. This research examined current herding and grazing practices, grazing areas being used in summer and winter, and factors taken into consideration by livestock keepers and herders when choosing grazing areas in the communal sub-ward of Okhombe, in the northern Drakensberg, KwaZulu-Natal. The aim of this research was to investigate the socio-cultural reasons of livestock keepers behind decision making about grazing areas. The primary research question pursued in the study was: How do livestock keepers select areas for livestock grazing in the sub-ward? Three sub-questions were developed to guide the research: What grazing and herding strategies are currently being used? Which areas are used for grazing, and in which season(s)? What are the considerations for choosing areas for livestock grazing? Data were collected from fifty-one (51) cattle keeping households in the sub-ward. Data were collected in five steps. The first two steps involved household and in-depth interviews using interview guides. The latter three steps involved a transect walks, one case study and focus group discussions to test and verify the data. The findings showed a wide range of livestock kept in Enhlanokhombe sub-ward. The majority (61%) of cattle keeping households had cattle and goats, which are important for ceremonial purposes. The primary reasons for keeping livestock involved agricultural, food and cultural purposes. The herding strategies found in the sub-ward involved family/relative member, hired herders and no herder, with the majority using family/relative members as herders. Three areas were used for livestock grazing were Maqoqa, Skidi and Mdlankomo. The key finding showed an increase in supplementary feeding, a decrease in traditional remedy usage and safety from theft as a new factor taken into consideration when selecting grazing land. Other factors involved presence of cropping fields, availability of grass and water, distance from home and family traditions. From these findings, one can conclude that there are clearly tensions between culture and changes in the society, culture and changes in economy; and livestock keepers' heritage and modern lifestyle. These tensions make livestock keepers' decision making processes harder. The grazing and herding strategies, and the choices of communal grazing areas are influenced by these changes. As a result, livestock keepers are shifting from their heritage and culture to being economic and adapting to modern world. The heritage and the clarity of gender roles are breaking down. Grazing and herding are, therefore, no longer simple and familiar, but complex and unfamiliar to livestock keepers. These findings have serious implications for extension, advisory and development approaches used when addressing livestock management among traditional livestock keepers. They imply that what is needed is a multi-dimensional and inclusive view of the livestock keepers' practices. Rather than relying on the long-held assumptions about livestock keepers, serious attention must be given to the tensions in communal livestock keeping and the complexity of communal grazing strategies. These must be deliberately and consciously used to inform interventions designed to improve communal grazing management. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
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A strategy for optimal beef production off sourveld.Buntting, Clive Bartle. 06 December 2013 (has links)
The economic necessity of a better production strategy on sourveld promoted this study. Production of marketable two-tooth steers in the summer season and overwintering of all cattle without excessive feed costs were motivating factors. The problems of economic beef production were identified as resulting from the seasonal flow of forage quality from
sourveld grass production. Season long rests, early burning and non-selective grazing of nutritious grass were identified as essential elements of a new utilization strategy. A 'forage reserve', built into the system to cater for fluctuations in grass production due to varied climatic conditions, is used as an indicator of the seasonal stocking rate. This
provides a barometer in relation to the economic and ecological carrying capacity of the property. Research was conducted on the winter utilization of rested veld and its effects on grass species composition and vigour in the following season. It was found that the winter grazing of the rested veld did not affect (P>0.05) the subsequent production in the three
seasons of this study on 'Stratherne' in the Dundee district, KwaZulu-Natal South Africa (30°17'E 28°17'S). The grass species composition of four transects was recorded in 1994, prior to the implementation of the grazing system under test. The same transects were recorded again in 2002 to determine the effect of the change in utilization on grass species composition. It was found that a more productive state was developing in response to the strategy implemented in this study. The general trend has been for sites to move from a Hyparrhenia hirta dominated state to a more productive one associated with species such as Themeda triandra. Summer mass gains of steers (147 kg and 143 kg over the two summers) have improved over the previous systems applied (average 119 kg), as a result of the more nutritious grazing. A greater proportion reached market readiness as two-year old to two and half year olds (97%) on veld, which is far superior to the 38% quoted from research using similar Bonsmara type steers from 'conventional' systems. Monitoring and flexibility are
important in the application of the strategy to conditions in Africa. The principles of adaptive management (monitoring, recording, constant learning and adaptation) will build a data base to ensure long-term success of the strategy. A change of focus in grazing strategy from needs of animals to the needs of plants is strongly advocated. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
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Impact of stocking rate, livestock type and livestock movement on sustainable utilisation of sourveld.Kirkman, Kevin Peter. 20 December 2013 (has links)
Data collected between 1992/93 and 1996/97 from two long-term grazing trials were
used to investigate the interaction between grazing animals and veld grass. In the first
trial, the impacts of stocking rate and time of stocking in spring on both livestock
performance and veld vigour (defined as the ability of a grass plant to regrow after
defoliation) and condition were investigated. In the second trial comparisons were
made, firstly between the impacts of sheep and cattle grazing, and secondly between
various types and frequencies of rest, on veld vigour and condition.
Treatments applied in the first trial comprised four stocking rates, namely 7, 10, 13
and 16 sheep ha¯¹ for the duration of the grazing season, and two times of stocking,
namely as early as possible after spring burning and three weeks later. Sheep grazed
each treatment continuously throughout the growing season. Treatments were applied
to alternate blocks in a two-year cycle with each block resting for a year within a
grazing cycle. Animal performance (mass gains over the season) was measured to
quantify livestock performance. Herbage availability was measured on a species basis
at intervals throughout each season using a dry-weight-rank procedure to determine
grazing patterns. Residual effects of the grazing treatments on vigour were determined
by measuring herbage regrowth on a species basis during the rest season which
followed a season of grazing and comparing these measures to a previously ungrazed
control treatment. Effects of the grazing treatment on proportional species
composition were determined using a nearest plant point technique. Stocking rate had a non-linear effect on livestock performance, with livestock
performance on the lightest stocking rate being less than on the two intermediate
stocking rates. The mass gains on the heaviest stocking rate were generally the
smallest. Delaying the time of stocking in spring resulted in smaller mass gains during
the resultant shorter season. The sheep from both the early and late time of stocking
groups had similar mean masses at the end of the season. The advantage of stocking
early can thus be attributed more to saving the cost of alternative feed for the interim
period than to additional mass gains due to stocking early. Quantification of livestock
performance in terms of selected and available feed quality, quantity and species
availability throughout each season was extremely complex due to multiple thresholds
in the measured variables and no simple cause and effect relations could be
established that would hold for spatial or temporal extrapolation.
The negative impact of grazing on veld vigour was severe. Stocking rate and time of
stocking had a secondary impact with the vigour loss positively related to increasing
grazing pressure. The main factor influencing vigour loss was grazing, irrespective of
time of stocking or stocking rate, as opposed to no grazing. The impact of grazing on
vigour was severely negative in the palatable species, variable in the species of
intermediate palatability and positive in the unpalatable species that were rarely, if
ever, grazed. The stocking rate and time of stocking rate had an impact on the
proportional species composition, with the more palatable species declining in
proportion. There was an observable relation between impact of grazing on vigour and
on species composition. Treatments applied in the second trial involved applying a full growing season rest in
alternate years, half a growing season rest (late season) in alternate years and no rest
to veld grazed by sheep or cattle at similar stocking rates. Residual effects of the
treatments on veld vigour were determined by measuring species regrowth using a
dry-weight-rank technique during the season following treatment application, and
comparing it to controls ungrazed for one and two seasons respectively. Changes in
proportional species composition were determined using a nearest plant point technique.
The vigour of veld grazed by sheep declined rapidly relative to veld grazed by cattle.
The vigour of palatable species was severely impacted, vigour of intermediate species
was variably impacted and vigour of unpalatable species increased dramatically on
veld grazed by sheep compared to the control treatments. Similar trends occurred in
veld grazed by cattle, but to a lesser degree. Resting was beneficial for vigour
recovery in both sheep and cattle treatments but it seems that the grazing treatment
between rests has a greater influence on the veld vigour and condition than the rest
itself. The veld grazed by sheep remained at a substantially lower productivity level
than veld grazed by cattle. This was particularly evident in the change in productivity
balance between palatable and unpalatable species in the sheep treatments, where
palatable species vigour declined and unpalatable species vigour increased relative to
veld grazing by cattle. Species composition of veld grazed by sheep deteriorated over
the trial period in contrast to the veld grazed by cattle, which improved in species
composition. Grazing management recommendations for sourveld should include a bias towards
cattle, optimising stocking rate for improved performance and resting for enhancing vigour of the palatable grasses. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1999.
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Summer supplementation of beef cattle on veld and kikuyu pastures.Reynolds, Richard Norman. 10 December 2013 (has links)
In KwaZulu-Natal the production of beef in summer from veld is a common
enterprise. Many techniques are available to optimise the productivity of this enterprise,
from improving the quality of the grazing resource (planted pastures) to improving the diet of
animals using nutritional supplements. To gain an insight into the production potential and
financial returns possible from such improvements a trial was established at the Ukulinga
Research Farm during two consecutive summer growing seasons (1997-1998 and 1998-1999).
The aim was to determine the optimum beef production system for the area from both
veld and kikuyu pastures. To evaluate the benefits of supplying supplementary nutrition, four
alternate feed supplements, namely: 1) a Standard commercially available molasses-based
protein/mineral/energy supplement; 2) a Brewers grain based protein/mineral/energy
supplement, and two supplements consisting of the Brewers grain ration with either; 3)
Avoparcin (an additive that improves dietary energy) or 4) Bentonite (an additive that
increases the bypass of protein) were compared. As stocking rate has been shown to
influence the quality of the diet consumed, the kikuyu pasture was grazed at both the
recommended (1.92 LSD ha¯¹) and half the recommended stocking rate for the region. In
addition, a commercial hormonal implant was applied to half of the cattle in each treatment.
Grazing was monitored using the falling plate disc meter to measure pasture bulk
density and laboratory analyses of herbage grab samples for digestibility and crude protein
percentage. Cattle were weighed on a weekly basis and their condition was scored prior to
slaughter. All enterprise costs and returns were recorded to facilitate financial analyses of the
five treatments.
Low rainfall and high midsummer temperatures had a detrimental effect on the
productivity of the grazing and hence it was difficult to optimise production in either season.
In the first season, a midsummer drought decreased the quality and quantity of both veld and
kikuyu, limiting mass gain during the latter part of the season. A delay in the onset of rain at
the start of the second season limited the available grazing season to 121 days as opposed to
154 days, though fodder production during the season was not limited.
Trends in herbage production (quality and quantity) from veld showed moderate
quality (Crude protein 7.02%; digestibility 50.2%) with an average available herbage of 1670
kg DM ha¯¹. As anticipated, kikuyu had higher quality (Crude protein 10.84%; digestibility
53.5%) and available herbage (2730 kg DM ha¯¹). These results were similar to regional
benchmarks. The variable rainfall highlighted both the drought tolerance of veld and the minimum water requirements of kikuyu pastures. Lighter stocking rates tended to reduce the
negative impact of moisture stress on Kikuyu pastures.
The best method of producing beef (averaged over two seasons) was from heavily
stocked Kikuyu pastures using the Standard supplement (1107.63 kg livemass ha¯¹). Cattle
grazing veld and utilising the Avoparcin supplement produced beef at a rate of 95.96 kg ha¯¹.
In comparison, the unsupplemented cattle grazing Kikuyu produced 834.87 kg ha¯¹, whilst veld grazing produced 64.43 kg ha¯¹. Hormonal implants significantly (P≤0.05) improved beef production from all sources of grazing. A lack of rain limited grazing time, causing all the cattle to be marketed whilst too lean - this negatively affected live mass gain and, hence,
net financial. Although improved biological production is desirable, it is important to ensure that these gains are financially sustainable. Within the trial environment, implanted cattle fed the Standard supplement and grazing Kikuyu pastures at a high stocking rate provided the highest average gross margin of R 859.59 ha¯¹. Changing to this production system from unsupplemented veld improved expected profit by R 632.58 ha¯¹ (averaged over both seasons). Further financial analyses indicated that beef purchase price had the greatest influence on the added profit from switching from the control treatment. From a scientific standpoint these data are conclusive but it is important to remember that consumer pressure and concerns can often limit the introduction of production
improvements. Such is the case with both hormonal implants and antibiotic feed additives (Avoparcin) although considering the impact of such limitations is speculative and beyond the scope of this trial. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.
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Keeping cattle in a changing rural landscape : communal rangeland management in Okhombe, KwaZulu-Natal, South Africa.Salomon, Monique Louise. January 2011 (has links)
A research journey involving people, cattle, and the landscape in rural Okhombe in the western
part of the province of KwaZulu-Natal and lying at the foot of the uKhahlamba Drakensberg
Mountain Range, South Africa, is the focus of this work. Using action research involving
community members as co-researchers, it investigates why a rotational resting system for
communal cattle grazing collapsed within six months of its launch. Despite having been
designed in a participatory manner, the rotational resting system was not applied by cattle
keepers.
As a backdrop to the concern around the rotational resting system, it is necessary to
understand how the current landscape of Okhombe was shaped. The history of the
uKhahlamba Drakensberg Region over the past two hundred years was, therefore, explored.
Four historical episodes were distinguished: economic expansion, nature conservation efforts,
colonial and apartheid legislation, and encounters between people all left their imprint on the
landscape. Digitized maps of aerial photographs of Okhombe, taken between 1945 and 2004,
showed how Government intervention changed people’s multifunctional use of the landscape
to concentrated settlements and cropping fields in the valley and cattle grazing on the
mountain slopes.
A survey in Enhlanokhombe, one of the sub-wards of Okhombe, further investigates how cattle
keepers use the rangeland commons, and what determines these practices. People are keeping
fewer cattle than in the past. A 24% decrease in cattle numbers was recorded between 2001
and 2008. Cattle keepers perceive stock theft as the most important threat. Yet, figures of stock
losses showed that cattle disease resulting in death is an equally pressing problem.
The decline in authority of traditional leaders and the view that herding is a family task have
compounded the dominant management practice of continuous grazing by cattle. Rotational resting was found to be unsuited to the majority of cattle keepers who want to keep a close
watch on their herds as they graze on the lower hill slopes. People in Okhombe disagreed about
the condition of the range and what comprised appropriate grazing management. A community
initiative has emerged to form cattle patrols to address stock theft. If successful, it may further
enhance collective action.
The concern with communal grazing management investigated in this research and in the
Okhombe Landcare project, of which it was part, aimed to reverse land degradation and
overgrazing. An analysis of digitized maps of Okhombe taken in the period between 1945 and
2004, however, showed that soil erosion did not increase rapidly as is commonly assumed by
conventional rangeland scientists and extension staff. Rather, an increase in bare soil coincided
with a period of drought.
The focus of the Okhombe Landcare project on combatting soil erosion and rehabilitate
degraded lands was underpinned by a particular interest in and need to conserve the
uKhahlamba Drakensberg as a near-pristine wilderness landscape which provides marketable
ecosystem goods and services. As such, cattle keeping in Okhombe can be described as being
embedded in a social-ecological system comprising a series of nested, self-organizing subsystems
which are interconnected. Sub-systems include the cattle production system, cattle
grazing management practices, the wider ecosystem, and government policies and regulations.
A spatial-temporal and systemic approach is proposed to make meaningful, policy-related
decisions regarding communal rangeland management in the future. Such an approach would
enable cattle keepers, other rangeland users, and outside stakeholders, such as extension
workers and policy makers, to respond effectively to changes in the landscape by taking into
consideration and balancing a complex set of biophysical, socio-political, and economic variables. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
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Rangeland and animal performance trends in highland sourveld.Short, Alan Douglas. January 2010 (has links)
Long-term trends in rangeland sward dynamics (species composition, structure, productivity)
were examined on three trials established between 1989 and 1996 at Kokstad Research
Station in the Highland Sourveld, while animal performance (average daily gain and gain per
hectare) was examined on two of the trials. The region enjoys moderate rainfall of 782mm per
annum, with hilly topography, and soil depths ranging from >1m to <20cm. The first trial was
labelled the simulation trial, as it simulated a four-paddock rotational grazing system, in
which animals spent two weeks in each of three paddocks while the fourth was rested for the
entire season. The rested paddock was rotated each year. The trial tested two stocking rates
(0.5 and 1.0 AU.ha-1) at five ratios of cattle to sheep, ranging from cattle only to sheep only.
The trial was unreplicated, and was established in 1989 on flat topography with deep soils.
The second trial (labelled the flat two-paddock trial) was established in 1992 adjacent to the
simulation trial. The trial examined two stocking rates of sheep weaners (0.5 and 1.0 AU.ha-1
seasonally) in a continuous grazing two-paddock system, in which one paddock of each
treatment was burned and grazed continuously while the second paddock was rested, to be
burned and grazed in the following season. The trial was replicated twice. The third trial
(labelled the steep two-paddock trial) mimicked the grazing system of the flat trial, but was
located on a steep (c. 20%) West-facing slope with shallow soils. The trial incorporated two
additional treatments: an intermediate stocking rate of 0.7 AU.ha-1 and an ungrazed treatment.
Species composition of the sward was recorded biennially on all trials using the nearest plant-point
technique with between 200 and 800 points per paddock. Sward standing crop was
measured in the rested seasons of the simulation trial and at the beginning, middle and end of
each season in one paddock of each two-paddock treatment of the two-paddock trials. In the
two-paddock trials, sward standing crop was measured within and outside permanently placed
exclosure cages. Animals were weighed fortnightly.
The response of species to grazing pressure or animal type was mediated by soil depth and
slope, as well as the grazing system. Tristachya leucothrix declined on all grazed treatments.
The ungrazed treatments remained relatively stable over ten years. On the low stocking rate
treatments of the steep trial, unpalatable species increased, but so did Themeda triandra. The
heavily grazed treatment of the steep trial was surprisingly stable, with little significant
change in relative abundance of key species other than an increase in the unpalatable
Alloteropsis semialata and decline in T. leucothrix. The medium stocking rate treatment on
the steep trial showed significant shifts in relative abundance of key species, with declines in
T. triandra and T. leucothrix and increases in A. semialata and the unpalatable wiregrass D.
filifolius. These trends were not repeated on the flat trial, however, with T. triandra and A.
semialata increasing and all other key species declining or remaining stable. On the
simulation trial, species responded largely unpredictably with species abundances often
fluctuating considerably over time. Microchloa caffra and A. semialata increased
substantially in both the low and high stocking rate sheep-only treatments, with a concurrent
decline in T. triandra in the high stocking rate but not the low.
Changes in composition over time, as measured by Euclidean distance, showed that shallow
soils, high stocking rates and a high proportion of sheep caused greater shifts in species
composition over time than deep soils, low stocking rates or more cattle. Three treatments, the
sheep-only treatments on the simulation trial and the high stocking rate on the steep trial,
showed an initial rapid shift in composition over about 6 years, before stabilising in
subsequent seasons. The flat trial showed no substantial shift in composition over time. This
general pattern of change was confirmed by Non-Metric Multidimensional Scaling.
On the simulation trial, total standing crop was influenced by stocking rate and by the
proportion of sheep in most seasons. On the two-paddock trials, increasing stocking rate
significantly reduced sward vigour, and vigour declined over time.
Stocking rate reduced total standing crop on both trials at the end of the 2004/05 seasons and
the crop of unpalatable species on the steep trial. Total palatable plants were unaffected by
stocking rate on both trials.
The classic Jones-Sandland model of animal performance as influenced solely by stocking
rate was not supported. Sheep performance was influenced by stocking rate and the
interaction of stocking rate and seasonal rainfall. There was no difference in average daily
gain between treatments over time, and hence cumulative animal production per hectare
increased with increasing stocking rate. Animal performance was possibly influenced by
many factors beyond the scope of this study, including the effect of predator attacks on
surviving animals, and resource availability such as shade and shelter and high-production
patches in some paddocks and not others. Scale effects on ecology are being increasingly
investigated and a meta-analysis of this type shows that, even in one research farm, slight
differences in management and environment can have significant effects on plant and animal
responses to grazing. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
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Grazing management in the communal rangelands of the Upper Thukela, Kwazulu-Natal.Tau, Mahlodi Solly. January 2005 (has links)
The grazing management project in the Okhombe ward of the Amazizi Tribal Authority
formed part of the National Department of Agriculture's LandCare program to address
communal natural resource management issues. Okhombe land is communal whereby
every member of the community is the legal owner of the rangeland with individual
ownership of stock with the chieftaincy playing a major role in land allocation. In order
to avoid critics of the past and address the top-down approach of the past interventions, a
participatory approach was conducted in the planning and implementation of the grazing
system. The service providers held a series of visioning workshops with the community
in an effort to better understand community resource use patterns, needs, constraints and
opportunities as part of the participatory approach. Issues identified by the community
were the need for fencing grazing camps, animal health improvement, subdivision of
rangeland and crop fields and the development of a rotational grazing system.
The main aims of this study were to develop a participatory grazing plan with the
community, develop and support institutional structures governing range management,
and build capacity of the community in range management. The effect of the current
grazing system on species composition was determined. In addition to these, the project
investigated the potential different fodder trees has on alleviating feed and nutritional
deficit, particularly during the dry winter months of the Upper Thukela.
Among the main achievements of this study was the development and strengthening of
local institutional structures and effective liaison by all structures with the Inkosi and the
tribal council. The community developed a rotational grazing plan, marked the camp
boundaries, produced digital maps and successfully built fence boundaries
(approximately 20 kms of fencing) to divide their land. The fence boundaries separated
the crop fields and rangeland, closed ward boundaries in the upland to prevent access by
cattle from neighbouring wards, and divided the land into three camps. Six crush pens
were constructed in each subward of the Okhombe ward. A communal herders fund
opened and fence construction improved crop yields due to a decrease in crop damage by
cattle.
Okhombe ward, located in the Highland Sourveld region of KwaZulu-Natal, experiences
feed and nutrition deficits to ruminants during winter. The prevailing species composition
in Okhombe was investigated as part of the grazing plan. The veld condition of the sites
ranged from poor (40.7%) in the bottomland to an averaged of 47.0% in upland sites. The
most distinctive feature of the rangeland in this area was the loss of highly palatable
Decreaser grass species (P <0.05), such as Themeda triandra in the bottom slopes «
1300 m) when compared to the upland (> 1800 m). The proportional abundance of
Decreaser species accounted for an averaged of 1.02% of the bottomland and an averaged
of 11.5% of the upland compared to the values of 49% in the benchmark (grassland in
optimal condition). The composition of the less palatable Increaser Il species was very
high at all elevations (1200 m -80.7%, 1400 m - 75.8% and 1700 m - 55.7%) when
compared to the low benchmark composition of 19%. The dominant grasses of the
bottom slopes were Increaser Il species, such as Eragrostis curvula, Eragrostis plana and
Sporobolus africanus and unpalatable Increaser III species such as Aristida junciformis.
A significant difference (P < 0.05) in the composition of Decreaser, Increaser I and
Increaser Il species was found between the bottom and slopes compared to the upland
region. However, the grass cover formed by these tufted species was generally high,
making it more resistant to physical degradation. The bottom slope ranged from
reasonable to excellent cover (16.9%), the middle slope ranged from reasonable (15.9%)
to a good cover of 18.1%, averaging 16.7% and a range of 16.1% to 17.9% for the upland
plateau.
In the agroforestry trial the potential of different fodder species for supplementing fodder
was examined. Leucaena leucocephala had the potential of being a suitable fodder tree
species for use in alley cropping (P < 0.05) compared to Morus alba and Acacia karroo.
Results from the partially intercropped treatments showed that L. leucocephala yield (665
kg ha-I) varied significantly (P < 0.05) from the A. karroo (378 kg ha-I) and M alba yield
(345 kg ha-I). Treatments that were fully intercropped varied, but no significant
difference (P > 0.05) were recorded. Morus alba produced the least yield of 345 kg ha-I,
A. karroo yielded 378 kg ha-1 and 1. leucocephala recorded the high of 664 kg ha-I.
Results from the second season showed similar trend in that 1. leucocephala yielded a
significant (P < 0.05) fodder production of 1715 kg ha-I in comparison to M. alba (1101
kg ha-I) and A karroo (1140 kg ha-I).
M alba yielded the least dry matter production (P < 0.05) but had high potential (P <
0.05) for addressing lack of firewood in rural areas. Morus alba yielded high fuel wood
production from both two seasons. There were no significant differences in fuel wood
yield (P > 0.05) from the partially intercropped M alba (507.9 kg ha-I) and 1.
leucocephala (455.0 kg ha-I) but the yield from both species varied significantly from the
A. karroo yield (103.kg ha-I). With regard to fully intercropped plots, fuel wood yield
from all tree species varied significantly, A karroo resulting in low yield (63 kg ha-I), 1.
leucocephala recorded 243 kg ha-l and M alba the highest yield of 444 kg ha-I. In the
second season, M. alba yielded an averaged fuel wood production of 728 kg ha-l and a
low of 439 kg ha-I from 1. leucocephala.
Acacia karroo, a slow growing indigenous tree, might be preferred by farmers due to its
less branches resulting in minimal light competition with crops. Leucaena leucocephala
tend to grow slowly in its initial establishment stage, but once roots become well
established, it grows fast and produces high quantity of fodder. The effect all fodder trees
had on crop yield was not negative during the trial period and further research on long
term effects of alley cropping is recommended. The conclusions drawn here were based
on tree growth and their likely impact in alley cropping.
Leucaena leucocephala was also recommended as a preferred species for rural ruminants
based on the forage quality study. The results showed high content of crude protein
(19.27%), low NDF content (50.38%) and very low tannin content (1.19%) from 1.
leucocephala compared to A. karroo with a high tannin content of 5.69%. Acacia karroo
had a crude protein content of 13.60%, NDF percentages of 44.16 and 34.64% of ADF
content. Morus alba also had a recommended chemical composition of 11.71% of CP,
42.86% of NDF, 36.96% of ADF and a low tannin content of 0.65%. L. leucocephala
foliage proven is readily degradable under different diet ranging within 24 hrs of intake
(P < 0.001) compared to other feeds. L. leucocephala had high dry matter loss degraded
from the rumen under Eragrostis hay diet with poor nutrients to high protein concentrates
diet. Under the Eragrostis hay diet for instance, L. leucocephala tend to degrade rapidly
with values of dry matter loss ranging from 32.2% to 39% at 4 hrs to 16 hrs, when
compared to low dry mater loss of 26% at 4 hrs to 31.33% at 16 hrs. Feeds such as M
alba tend to degrade slowly within 24 hrs of intake and rapidly degrades after the stated
period.
The ep content of maize stover was very low ranging from 1.60% in maize stalks to
2.63% in maize leaves. The fibre content in maize stover was very high when compared
to lower values in fodder samples. The NDF content ranged from 77.92% in maize leaves
to 81.60% in maize stalks. Maize leaves when compared to a combination of maize
leaves and maize stalks sole tend to degrade better within 24 hrs of intake. This was due
to low (P < 0.05) degradability rate of maize stalks compared to a combination of maize
stalks and leave and leaves sole and least NDF content in maize leaves might have
attributed to these results. Due to poor chemical compositions of these roughage samples,
the study recommended the establishment of fodder banks and agroforestry systems to
curb the nutrients deficit during winter.
In conclusion therefore, this study highlight that the sustainability of rural systems to
manage communal grazing land should be further explored. Most of the challenging
issues in communal range management are social in nature rather than technical concepts.
These include ways of improving social contributions from cattle to the community while
maintaining cultural values of the use of cattle. The interventions in communal range
management by service providers should understand the institutional arrangements within
a community and an attempt to strengthen such existing structures is recommended.
Further interventions by service providers in Okhombe ward should bring in the planning
discussions, experts from social sciences, to deal with understanding of community
dynamics. Complexities in communal range management involve dealing with non-stock
owners within project boundaries. Communities from neighbouring wards should not be
ignored and ways of improving communications and updating project details to them
should be formulated. Shortage of land and closing of ward boundaries to prevent access
to land by neighbouring wards is among community complexities to be explored.
Communities in rural lands do share land and in most cases boundaries are known but
invisible by an outsider to identify. It is important to strengthen and maintain every
success in communal lands as that may form core of the project. Successes on grazing
management by locals is far from being the improvement in veld but there are rather
various factors to the successes of grazing projects in rural areas. Examples of successes
based on Okhombe project are reduction in stock theft, improved in relationship between
community and locals institutions, a reduction in stock mortalities during winter and
improved animal health. Veld improvement is among successes but there are
accomplishments phases to fulfil before focusing on improvement of species
composition. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
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