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The effect of application of nitrogen, phosphorus, potassium and sulphur fertilisers to a perennial ryegrass sward on yield, quality and apparent intake by dairy cows.Findlay, Nicola Jean. January 2010 (has links)
Perennial ryegrass is an intensive, temperate pasture grass that responds well to applied fertiliser.
The purpose of this project was to study the effects of fertiliser on the productivity and quality of
perennial ryegrass in KwaZulu-Natal and how this impacts on animal intake. It was hypothesised
that over-application of fertiliser to a perennial ryegrass pasture would negatively affect the quality
of the herbage for grazing by dairy cattle and that intake would be affected. Thus the project
aimed to assess the effects of applied fertiliser on yield, quality and intake of an established
perennial ryegrass pasture.
The trial consisted of a set of six separate experiments. Each experiment focused on the
interaction between two of the major nutrient elements nitrogen (N), phosphorus (P), potassium
(K) and sulphur (S). The experiments (NxP, NxK, NxS, PxK, PxS and KxS) were managed
separately to avoid possible transfer of nutrients during grazing, which would result in the
contamination of treatments. Each factor had three levels (low, medium and high), giving a total of
nine treatments per experiment. Each of the experiments was replicated three times in a
randomised block design.
Increased fertiliser N application rates increased perennial ryegrass yield with a pattern of
diminishing return, where split applications above 40 kg N ha-1 produced smaller increases in yield
when compared with the response at lower applications of N. Applied P, K and S did not affect
yield, suggesting that even the lowest application levels were sufficient to not limit production.
Nitrogen application affected apparent intake, but it is suggested that this is due to the yield effect
rather than a direct effect of N on apparent intake. The application of P, K and S did not affect
apparent intake.
Results from this study showed that the quality of perennial ryegrass herbage, especially in terms
of feed value to dairy cows, can be significantly affected by applied fertiliser. The extent of the
response was affected by sampling date (i.e. time of year) and this must be taken into account
when planning a fertiliser management strategy. This is particularly so with respect to N fertiliser
recommendations.
Crude protein (CP) content of herbage increased with increasing levels of applied N and the
extent of the response was influenced by season. P, K and S did not affect CP concentration in
herbage, except in the PxK experiment where increased levels of K lowered herbage CP. Applied
N considerably increased the concentration of non-protein nitrogen (NPN) in perennial ryegrass
herbage. P and S did not affect NPN levels, whereas applied K decreased NPN content in the
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NxK and PxK experiments. Non-structural carbohydrate (NSC) content of herbage was decreased
by applied N but was unaffected by applications of P, K and S. Neither neutral detergent fibre
(NDF) nor acid detergent fibre (ADF) was affected by applied fertiliser. In this study herbage P
declined and herbage Ca increased with increasing levels of applied N. The addition of fertiliser K
resulted in lower herbage Ca values. There was no herbage S response to applied fertiliser in this
study.
Classification and regression tree (CART) analysis identified the primary determinant of apparent
intake in experiments containing N as a factor as the amount of material available to be grazed
and that NSC, NPN and ADF are also determinants of apparent intake. Cows do not regulate diet
choice within the short-term time frame of a meal. Thus intake is determined by short-term needs
rather than by meeting long-term nutrient requirements. Fibre creates physical fill within the
rumen, thus restricting intake. High NPN content is associated with high nitrate values. The
reduction in intake of herbage with high nitrate content may be due to reduced palatability or to a
negative feedback system limiting the intake of nitrate and ammonium. Increased NSC content is
associated with increased intake, possibly through the effect of sugar on herbage palatability.
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Traditional agriculture and its meaning in the lives of a farming community : the case of Embo.Maragelo, Ketshogile Pauline. January 2008 (has links)
For the majority of rural people, agricultural activities continue to be one of their main livelihood strategies. Production of food crops is not dependent on any formally acquired knowledge of farming but is solely based on indigenous agricultural knowledge passed from generation to generation through experience and careful observations. Resource-poor farmers, especially in rural areas, follow traditional farming methods to produce their food crops and these are specifically tailored to suit their environments. Embo is located in rural KwaZulu-Natal and falls under Mkhambathini municipality. The area is characterised by small-holder farmers who are mainly Ezemvelo Farmers Organisation (EFO) members. The purpose of this study was to review the farming practices followed by farmers in respect of food crop production and secondly to understand what influences the continual practice of such farming practices among rural farming communities of Embo in KwaZulu-Natal especially the EFO farmers. The study looked at what farmers see as traditional agriculture. A combination of qualitative and quantitative methods was used for the study. Data collection methods included participatory observations, semi structured face-to-face interviews and focus group discussions. The study found that farmers are happy to follow traditional farming methods to produce their food crops. Traditional farming tools such as the hoe and animal traction are the main implements used to prepare land. Household members are the main source of farm labour with men mainly responsible for ploughing activities while the bulk of planting, weeding and harvesting activities is the responsibility of women. Cropping patterns include intercropping and crop rotation with common crops being amadumbe, beans, maize and sweet potatoes. The majority of these crops are produced for both subsistence and commercial reasons. Amadumbe is an important commercial crop produced organically. Crop protection against pests is done through traditional methods where farmers mix some concoctions made from locally available resource in order to minimise losses. Kraal manure is the main soil fertility strategy followed by farmers. Landrace seeds are the main seed type used by the farmers. Local seed sources include own production and asking from other farmers. Crops with good qualities are selected in fields and maintained as seeds, which are then stored separate from those for home consumption. Harvesting is mainly done manually and for important crops such as tubers with short shelf lives, harvested through piecemeal methods. Farmers are able to generate some income from their efforts and this contributes to local economies and household food security. Farmers value their farming methods and see their farming as efficient despite challenges. There is a need to consider developing labour support groups in order to ease the burden of labour especially by women. In view of the importance of traditional farming in the lives of rural people, it is important that agricultural scientists and extension officers take into consideration the knowledge farmers already have so as to develop technologies suitable for farmers’ environments. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
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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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