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Effects of crop rotation and tillage system on the control of ryegrass (lolium multiflorum X perenne) in wheat (triticum aestivum) in the Swartland production area of South Africa's Western Cape ProvinceNteyi, Sinovuyo Mava January 2013 (has links)
A major challenge facing agriculture today is to sustain the productivity of agricultural systems with the reduction of weed invasion. The Swartland region in the Western Cape (South Africa) is intensively cropped, producing wheat (Triticum aestivum) as the major crop. As a result of the weedy ryegrass invasion the wheat yield is reduced. In addition, ryegrass has developed resistance to grass herbicides (graminicides). This situation has increased the need to use alternative practices for controlling the invasion of ryegrass in wheat fields. In this regard, crop rotation and tillage systems were proposed as techniques to suppress the ryegrass invasion. This could thus maintain a sustainable long-term wheat production system with less application of herbicides, decreased input costs and increased total grain yield. Against this background, the effects of crop rotation and tillage were determined on ryegrass seedling emergence in a field and shade netting experiment, while seed dormancy was determined in the laboratory. The objectives were to compare the wheat production of two crop rotations with mono-cropped wheat and assess the impact on the ryegrass population in no-till and minimum tillage systems. Analyses of variance on data sets of ryegrass seeds from 2009, 2010 and 2011 were used to determine germination and dormancy percentages in laboratory experiments. The performance of laboratory treatments was evaluated on the basis of germination percentage of seeds. In the field and shade netting experiments, analyses of variance for data from 2007, 2011 and 2012 were used to determine crop rotation x tillage system response. Field and shade netting performance were evaluated on the basis of ryegrass population inhibition and stimulation respectively. Ryegrass seeds from 2009 and 2010 showed higher germination percentages (80 per cent and 73 per cent) than 2011 (42 per cent). Primary dormancy prevented high germination of newly harvested seeds as dormancy release increase with age of the seed. Results of field and shade netting experiments showed stimulation of the ryegrass weed population in wheat monoculture under minimum tillage. However, when wheat was rotated with leguminous crops under both tillage systems (minimum-till and no-till) ryegrass was significantly inhibited. It was concluded that the critical period for weed competition is the first six weeks after planting. Results from this study provide a basis for producers of cereals to make good decisions with regards to timing weed control measures. It is essential to use competitive crop sequences which will inhibit weeds. The challenge is getting this practice adopted and implemented by producers as it will promote conservation agriculture within the region. This study promotes long-term sustainable wheat production systems with an efficient weed management programme that is environmentally friendly using less herbicides within the Swartland region.
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Tillage, soil texture and mineralogy effects on selected soil properties on four soil types in Limpopo Province, South AfricaMagagula, Siyabonga Isaac 21 June 2020 (has links)
MSCAGR (Soil Science) / Department of Soil Science / The effects of tillage on soil structure and associated soil properties such as soil respiration may differ in different soils. The study determined the effects of tillage, soil texture and mineralogy in selected soil properties on different soil types. Soil samples were collected from four different sites in the Limpopo province, South Africa. The soils were classified as Glenrosa with sandy loam texture, Dundee with loamy sand, Hutton with clay, and Shortlands with clay. Glenrosa and Dundee were dominated by quartz, while Hutton and Shortlands with kaolinite. Soil samples were taken from the surface 0 – 20 cm under conventional tillage and no-till land. Soil organic matter, texture, and mineralogy were determined. The soils were wetted to activate the microorganisms and incubated for 70 days at 30℃ and soil respiration was determined using alkali trap method on a weekly basis. The study was conducted in triplicates and arranged in a completely randomized design. Data was subjected to analysis of variance using general linear model procedure of Minitab version 19. Means were compared using paired t-test at (p ≤ 0.05). The Pearson correlation coefficient (r) was used to measure the strength of linear dependence between variables. There was a significant difference in soil organic matter (p≤0.000) among all studied soils. The mean values of soil organic matter were 2.19% in Hutton, 2.0% in Shortlands, 0.54% in Glenrosa, and 0.43% in Dundee. Quartz had a strong negative linear relationship (r = -0.66) with soil organic matter while kaolinite had a strong positive linear relationship (r = 0.96). Soil respiration increased in soils dominated with quartz and decreased in soils dominated with kaolinite. The soil respiration increased by 18.95 g CO2 m-2 d-1 in conventional tillage and decreased by 13.88 g CO2 m-2 d-1 in no-tillage due to increased exposure of soil organic matter under conventional. It was concluded that less intensive tillage such as no-tillage reduces soil respiration. / NRF
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An analysis of the financial implications of different tillage systems within different crop rotations in the Swartland area of the Western Cape, South AfricaKnott, Stuart Charles 04 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The pressure on the world’s natural resources is increased by an expanding global
population. The majority of the growth is expected to take place in Africa and Asia. This
creates the need for sustainable agricultural practices. To sustain food security, the limited
natural resources must be utilised efficiently to optimise agricultural productivity.
Conservation agriculture (CA) is one of the most holistic sustainable agricultural practices
yet. It reduces environmental degradation, and concurrently it could enhance farm
profitability. The practice of CA is able to improve food security while sustaining the
environment for the benefit of future generations of both consumers and producers. A large
proportion of the commercial grain producers in the Western Cape have adopted CA to
varying degrees. A purer form of CA practice is continually pursued to realise its full benefits.
Adoption has taken place in the absence of any policy support framework directed to CA,
and thus, has been market driven. The reasons for and rates of CA adoption in other regions
of the world differed, but was mostly successful, which highlights the driving forces behind
adoption of CA in the Middle Swartland.
The physical/biological benefits of CA are well known. The financial implications of the
various systems within CA, at farm-level are still unknown. This study implements trial data
from Langgewens experimental farm to evaluate the financial implications of various farming
systems over an extended period.
Farm systems are complex, consisting of numerous interrelated components. A whole-farm
budget model is developed within a systems approach to compare various farming systems
designed within CA principles. A trustworthy whole-farm model providing an accurate
representation of a real life farm requires insight across many scientific disciplines. Multidisciplinary
group discussions are used to bridge the gap between scientific knowledge. To
serve as a basis for comparison, the whole-farm model was based on a typical farm within
the Middle Swartland relative homogeneous farming area. Trial data on crop rotations and
tillage systems from Langgewens experimental farm served as starting point for the
research. The data was fitted for use in financial analysis and as input to the typical farm
model. A key role of the inter-disciplinary expert group was to ensure that data and the model
design accurately reflect the underlying physical/biological processes of CA.
The financial evaluation of the various farming systems showed that conventional
agricultural practices of monoculture and deep tillage are financially unsustainable. Farming
systems under conventional tillage returned negative net present values (NPV) and an
internal rate of return on capital investment (IRR) lower than the real interest rate. This
implies that investment in conventional tillage will ultimately lead to financial losses. The
financial benefits of CA are directly related to improved soil health, lower weed and pest
stress and improved yields. The CA farming systems were less susceptible to variations in
external factors, highlighting the resilience of the system that incorporates crop rotation and
no-till. The farming systems operated under conventional practices are expected to be
unsustainable over a long-term period of 20 years. / AFRIKAANSE OPSOMMING: Opsomming
Die druk op die aarde se natuurlike hulpbronne word verhoog deur ʼn groeiende wêreld
populasie. Die meeste van die groei word verwag in Afrika en Asië. Dit skep die nodigheid vir
volhoubare landboupraktyke. Om voedselsekerheid te volhou moet die beperkte natuurlike
hulpbronne doeltreffend benut word om landbouproduksie te optimeer.
Bewaringslandbou is die mees holistiese volhoubare landboupraktyk tot op hede. Dit
verminder omgewingsdegradasie terwyl boerderywinsgewendheid kan verbeter. Die praktyk
van bewaringslandbou is in staat om voedselsekuriteit te verbeter terwyl die omgewing
onderhou word tot voordeel van toekomstige generasies van beide produsente en
verbruikers. ʼn Groot gedeelte van kommersiële graanprodusente in die Wes-Kaap het
bewaringslandbou teen verskillende intensiteit aangeneem. ʼn Suiwer vorm van
bewaringslandbou word deurlopend nagejaag om die volle voordeel daarvan te benut. Die
aanneming van bewaringsboerdery het sonder regeringsbeleid plaasgevind en was dus
markgedrewe. Bewaringsboerdery is in ander wêrelddele vir verskillende redes aangeneem,
maar was meestal suksesvol. Dit beklemtoon die beweegrede vir die aanneming van
bewaringslandbou in die Middel Swartland.
Die fisies/biologiese voordele van bewaringslandbou is wel bekend. Die finansiële
implikasies van verskillende stelsels binne bewaringslandbou op plaasvlak is nog nie bekend
nie. Hierdie studie gebruik proefdata van Langgewensproefplaas om die finansiële
implikasies van verskillende boerderystelsels oor die langtermyn te evalueer.
Boerderystelsels is kompleks en bestaan uit interafhanklike komponente. ʼn Geheelplaas
begrotingsmodel is binne ʼn stelselsraamwerk ontwikkel om verskillende stelsels wat binne
bewaringslandboubeginsels ontwerp is, te evalueer. ʼn Geloofwaardige geheelplaasmodel
wat ʼn akkurate weerspieëling van realiteit verskaf benodig insig van verskeie wetenskaplike
dissiplines. Multidissiplinêre groepbesprekings is gebruik om die gaping tussen die
verskillende dissiplines te oorbrug. Die basis vir vergelyking wat gebruik is, is ʼn tipiese plaas
in die relatief homogene boerderygebied van die Middel Swartland. Proefdata van
verskillende gewasrotasie- en bewerkingstelsels is as die vertrekpunt vir die studie gebruik.
Die data is pasgemaak vir finansiële ontledings en om te dien as inset vir die
geheelplaasmodelle. ʼn Kern rol van die interdissiplinêre ekspert groep was om te verseker
dat die data en die model-ontwerp die onderliggende beginsels van bewaringslandbou
reflekteer.
Die finansiële evaluasie van die verskillende boerderystelsels wys dat konvensionele
landboupraktyke met monokultuur en diepbewerking nie finansieel volhoubaar is nie.
Boerdery stelsels onder konvensionele bewerking genereer ʼn negatiewe netto huidige
waarde en ʼn opbrengs op kapitaal investering wat laer as die inflasie vlak is. Dit beteken dat investering in konvensionele uiteindelik tot finansiële verlies kan lei. Die finansiële voordele
van bewaringslandbou is direk geassosieer met verbeterde grondgesondheid, laer onkruid
en plaag-druk en beter opbrengste. Die bewaringslandbou boerderystelsels is ook minder
blootgestel aan veranderinge in eksterne faktore wat die gehardheid van die stelsels wat
gewas-wisselbou en geenbewerking inkorporeer, beklemtoon. Die boerderystelsel onder
konvensionele praktyke sal na verwagting nie volhoubaar wees oor ʼn langer periode van 20
jaar nie.
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Profitability and social acceptability of tractor and animal draught enterprises operating on selected smallholder canal schemes in Vhembe District, Limpopo Province, South Africa.Maake, Matome Simeon. January 2015 (has links)
M. Tech. Agriculture / Shortly after World War two (WWII), the South African government responded to the mounting food production crisis in the homelands by introducing public tractor services. Establishment of irrigation schemes and provision of public tractor services for use by smallholders were two important government-initiated modernisation projects in the homelands. It was in line with the idea of modernisation that smallholder irrigation schemes were the prime target for public tractor services, and this lead to the rapid abandonment of the use of animal draught for cultivation on these schemes. By the time public tractor services were completely dismantled, cultivation on smallholder irrigation schemes had become almost entirely dependent on tractor draught. Thereafter, hiring the services of privately owned tractor enterprises became the principal way in which farmers on smallholder irrigation schemes in Limpopo Province cultivated their plots. The rising cost of hiring private tractors placed financial stress on the cropping enterprises of smallholder irrigators, generating interest in alternatives that were more affordable. Animal draught represents an attractive alternative to tractor draught. Whereas prevailing economic circumstances on smallholder irrigation schemes favour the adoption of cultivation systems that are cheaper than those offered by private tractor enterprises, it is not known whether animal draught land preparation enterprises are an appropriate alternative to the existing tractor enterprises from an economic and social perspective. In order to resolve this knowledge problem, the current study was done with the following two main objectives: to determine the profitability of the different types of land preparation enterprises operating on smallholder canal irrigation schemes in Vhembe District Municipality; and to determine the social acceptability of these different types of land preparation enterprises by measuring the perceptions of the quality of the cultivation services provided by these enterprises among plot holders on these schemes.
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Morphological and physiological responses of spring wheat (Triticum aestivum L.) to spatial arrangementsTolmay, John Peter Cleggenett 12 1900 (has links)
Thesis (PhD(Agric) (Agronomy))--Stellenbosch University, 2008. / The adoption of the no-till planting method brought about changes to the way the wheat crop is
established in the Mediterranean climate of the Western Cape. Row widths have to increase
from the normal narrow rows (170-180 mm) to at least 250 mm to allow for sufficient stubble
handling. Furthermore, planters are designed to place seed accurately in the soil at uniform
depth, which may increase seedling survival rates. The main objective of this study was to
determine the influence of the use of wide row widths on yield, the components of yield and
grain quality parameters and to revisit planting density recommendations to be used with the notill
planting method.
On-farm, producer managed trials which included cultivars, row widths and planting density
treatments were planted at Riversdale, Swellendam and Caledon in the Southern Cape region
and at Moorreesburg and Hopefield in the Swartland during the 2004 to 2006 production
seasons. All trials were factorial RCB designs with split-split plot arrangements. Grain yield,
grain protein, hectolitre mass (HLM) and the yield components, seedlings m-2, seedling survival
(%), number of heads m-2, number of heads plant-1, number of kernels head-1 and thousand
kernel mass (TKM) were determined at all sites in 2005 and 2006.
Seedling survival rates of 80% were easily achieved in all trials with the exception of Caledon and Swellendam in 2005. The no-till planting method may be efficient to improve on survival rates of 50-70% found with the conventional planting methods. The yield component response that raised the most concern was the clear trend of the reduction in the number of heads m-2 as row widths increased, which was significant in eight out of the nine experiments. The number of heads plant-1 decreased significantly as planting density increased in all experiments. Cultivars
differed in the grain quality parameters grain protein (%) and HLM but were influenced minimally
by the other treatments. Reductions in grain yield occurred in three out of eight trials in the
Southern Cape and in three out of six trials in the Swartland, with reductions of between 6.8%
and 33% in some seasons. The risk of yield loss due to wide row widths could not be excluded
by this study and therefore the row widths used by producers should remain as narrow as
practically possible. Grain yield response to increasing planting density differed between the two regions. No significant yield benefits were found in any of these trials if planting densities were increased above 175 target plants m-2. Planting densities may be reduced to between 70 and 87.5 kg seed ha-1 to achieve this target if the crop is planted in time and seedling survival rates of at least 80% can be achieved.
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Biomass production, yield and quality response of spring wheat to soil tillage, crop rotation and nitrogen fertilisation in the Swartland wheat producing area of South AfricaMaali, Safiah Hasan 03 1900 (has links)
Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2003. / 108 leaves printed on single pages, preliminary pages i-vi and numbered pages 1-1 to 1-5 to 9-1 to 9-3. Includes bibliography, list of abbreviations and 22 figures in color. Digitized at 300 dpi grayscale and 300 dpi 24-bit Color to pdf format (OCR), using an HP Scanjet 8250 Scanner. / ENGLISH ABSTRACT: A long term experiment was conducted at the Langgewens Experimental Farm, near Malmesbury in the Western Cape province of the Republic of South Africa. The
effect of soil tillage, crop rotation and nitrogen fertiliser rates on mineral-N levels in
the soil, nitrogen levels in plants, wheat growth and yield components, grain yield as
well as quality parameters of spring wheat were determined.
Although the tillage treatments tested were initiated in 1976, present crop rotations
and nitrogen application rates were only applied since 1990. Most of the data that are
discussed however was recorded during the 1997 to 2001 period.
The trial was designed as a randomised complete block with a split-plot arrangement
and four replicates. Main plots were tillage methods namely conventional tillage
(CT), tine tillage (TT), minimum tillage (MT) and no tillage (NT). Crop rotations
used were continuous wheat (WW) and wheatl lupin/wheat/canola (WLWC). Both soil and crop data were
recorded.
The results of this study showed the differences in total mineral-N content of the soil.
N-contents of wheat, wheat growth and yield components as well as wheat quality
parameters were found between tillage treatments, crop rotations used as well as N-
fertiliser rates applied. Response however, varied largely between years due to annual
variation in especially total precipitation and distribution of rainfall. The inclusion of
a legume crop (lupin) and canola in the rotation with wheat was found to have only a
small effect probably due to the fact that lupins were grown once in a four year cycle
only.
Application of different nitrogen rates did increase the mineral-N in the soil, but the
effect did not last very long in most years due to either N-leaching or plant uptake. To
ensure sufficient mineral-N levels, late application of N-fertiliser will therefore be
needed. Minimum tillage or reduced tillage performs better than conventional tillage
in low rainfall years. In general these tillage systems should be combined with crop
rotation to ensure that yields are comparable to that obtained with conventional
tillage. / AFRIKAANSE OPSOMMING:
Die ontwikkeling, graanopbrengs en bakkwaliteit van koring (Tritium aestivum L.) in reaksie
teenoor gewasratasie, metode van grondbewerking en N-bemestingspeil is in 'n lang tennyn
sllldie op Langgewens Proefplaas, naby Malmesbury in die Weskaap provinsie van die
Republiek van Suid-Afrika, bepaal.
Hoewel die verskillende grand bewcrkingsmetodes sedert 1976, en gewasrotasies en
slikstofpeile sedert 1990 toegepas is, is daar in hierdie studie gekonsentreer op data wal
gcdurcnde die periode 1997-2001 ingesamel is.
Die eksperiment is as 'n randomiseerde blok ontwerp met vier bewerkingsmetodes nl.
konvcnsionele bewerking (CT), tand bewerking (TT). minimum bewerking (MT) en geen
bewerking (NT), twee gewasratasies nl. monokuhuur koring (WW) en
koring/lupienelkoringiCanola (WLWC) en drie N-peie (60 kg N ha- ', 100 kg N ha- 1
, 140 kg N
ha- I uitgevoer. Aile stikstof is in die vorm van kalksteen-ammoniumnitraat toegedien.
Die reaksie van beide grondfaktore soos die minerale N inhoud en gewaskomponente 5005
biomassa produksie, opbrengs en kwaliteit teenoor bogenoemde faktore het '0 goeie
korrelasie getoon met die heersende klimaatstoestande.
Lae reenval jare (gebiede) sal volgens hierdie stlldie die grootste voordeel verkry met minder
intensiewe grand bewerkingstelsels. terwyl 'n frekwensie van meer as een peulgewas per
siklus van 4 jaar nodig sal wees om grondvrllgbaarhcidsvlakke betekenisvol te verhoog.
Stelsels van rninder intensiewe grondbewerking is ook tot 'n grater mate deur gewaswisseling
bevoordeel as konvensionele melOdes van grondbewerking.
Hocwel minerale-N vlakke in grond deur verskillende N-peile be'lnvloed is, was die
efTektiwiteit van toedienings laag en het verdeelde tocdienings groat voordele ingehou.
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