There is a desire to source novel legume species to combat the threat of dryland salinity to agriculture and the environment. There are already many legume weeds in temperate Australia and the potential negative impact of new species has created a justifiable impasse. Weed risk assessment presents a potential solution, but deficiencies in the current Australian system have hampered progress thus far. A greater emphasis on the impact of the weed species may be a means of solving this conflict. Therefore, this project attempted to predict the level of impact that a legume species would have upon temperate natural ecosystems. The weed impact of exotic legume species in natural ecosystems was determined by distributing a questionnaire to experts. Respondents reported that woody perennial legumes were more important than herbaceous legumes. Field measurements demonstrated that the abundance of legumes was correlated with their perceived impact in natural ecosystems. Thus, two test species lists were compiled, one of woody species and the other herbs. The woody species comprised three impact levels: major, moderate and no impact. The herbaceous species also comprised three lower impact levels: consequential, inconsequential and no impact. The identification of legume species with differing levels of impact subsequently allowed them to be compared with respect to a number of biological traits, with the aim of distinguishing impact groups based on these traits. Seedling growth was examined in the glasshouse under both high and low soil moisture. With high soil moisture, major and moderate impact legumes were distinguished by having a higher specific root length than no impact legumes. Consequential impact herbaceous legumes had lower specific leaf area than the lower impact groups. Moisture stress did not alter the comparisons between impact groups. Five reproductive traits were explored through a mixture of experimental, field sampling and literature research. Major and moderate impact legumes had a shorter juvenile period, higher seed dormancy, a smaller seed mass and higher seed production than no impact legumes. Major and moderate impact legumes could be differentiated by their seed mass and seed production. Consequential and inconsequential impact herbaceous species had higher seed production and seed dormancy than no impact species. To allow for important interactions with the environment, the ability of the test legumes to establish in temperate natural ecosystems with and without physical disturbance was studied. This provided some test of the conclusions reached from individual trait studies. The highest impact legumes were the most successful at establishing in the natural ecosystems studied. Disturbance had a positive effect on establishment, except for the major impact group where disturbance was not important. This study was able to highlight that for a legume to successfully naturalise in temperate Australia it must possess certain biological traits. Less success was achieved in distinguishing naturalised legumes of differing impact. However, growth form is important and seed mass appears a significant trait in regard to woody species. Both are easily measured traits and could be incorporated in weed risk assessment of legumes in the future. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1284153 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine 2007

The aims of this study were to compare 16 Atriplex accessions as fodder shrubs; to find a method of vegetative propagation for A. nummularia and A. canescens; and to find a non destructive way of monitoring dry matter (DM) production and structure. Characteristics evaluated included DM yield, structure, nutritive value and adaptation to different ecological conditions. The accessions were also compared for palatability using grazing sheep in a cafeteria system. Two methods of vegetative propagation were evaluated, namely in vitro tissue culture propagation (A. canescens and A. nummularia) and stem cuttings (A. nummularia). With all accessions the percentage leaves decreased and percentage twigs increased as the plants matured. Leaves were more nutritious than edible twigs. At an age of 15 months edible DM yield ranged from 0.71 t.ha-1 (A. canescens Rincon) to 5.78 t.ha-1 (A. rhagadioides). For most accessions crude protein (CP) content, neutral detergent fibre (NDF), in vitro DM digestibility (IVDMD) and ash contents were acceptable for livestock. The two most promising accessions were A. nummularia (CP content 15%, NDF 48%, IVDMD 60% and ash 20%) and A. canescens cultivar Santa Rita (CP content 13%, NDF 49%, IVDMD 58% and ash 18%). The two least promising accessions as fodder shrubs were A.glauca (CP content 8%, NDF 61%, IVDMD 42% and ash 16%) and A. canescens Rincon (CP content 10%, NDF 58%, IVDMD 44% and ash 15%). Survival at different locations were not only influenced by ecological and climatological conditions, but also by different management practices. Average survival ranged from 41% to 87%. Sampling for nutritive value varied between locations and had a stronger influence on the nutritive values than location. Accessions with the broadest adaption were A. amnicola, A. canescens (S.R.), A. halimus and A. nummularia. According to visual observation and utilization, A. amnicola, A. canescens (S.R.), A. cinerea, A. rhagadioides and A. semibaccata were the most palatable accessions. The sheep, contrary to expectations, were able to select equally nutritious diets over time. In vitro propagation of A. nummularia was more successful than A. canescens. The best medium for shoot multiplication and elongation for A. canescens was the Murashige and Skoog (MS) basal medium with 0.20 mg.1-l 6-benzylaminopurine (BA) and 1.0 mg.1-l naphthalene acetic acid (NAA), while a medium with 0.05 mg.1-l BA and 0.05 mg.1-l NAA was best for elongation and rooting. For multiplication of A. nummularia the MS basal medium with 0.20 mg.1-l BA and 0.05 mg.1-l NAA was the best, while the MS basal medium without any hormones was the best for elongation and rooting. Atriplex nummularia was successfully acclimatized. Vegetative propagation using stem cuttings was also possible for A. nummularia. The best results (up to 95% rooting) were obtained using terminal cuttings of new growth in the autumn or spring, treated with 3 g.kg-l indole-3 buteric acid (IBA). Suitable models for the prediction ofDM yield, using non-destructive measurements were found. The model: DM = 553.24X + 129.47, where, DM = dry matter yield (g.plant-l) and X = shrub volume (m3), gave very good predictions (r2 = 0.72; P = 0.0001). Other models, which were species specific, included: DM yield in relation to volume; height and diameter in relation to DM yield; and shrub volume related to DM yield, where each accession has its own intercept while, the slope were the same for all. Acceptable models were found for all accessions with the exception of A. semibaccata. Another model should be tested for this accession with its creeping growth form. / Dissertation (MSc Agric (Pasture Science))--University of Pretoria, 2000. / Production Animal Studies / Unrestricted

Master of Science

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim of this study was to determine the effect of a grass herbicide, a broadleaf herbicide with some grass control capabilities, method of tillage (tine and no-tillage) at planting of wheat as well as different medic cultivars on the regeneration, dry matter (OM) production and quality of a medic pasture. The trial was conducted at Langgewens experimental farm in the Swartland wheat producing area. Nine medic cultivars of three different species were evaluated after being sprayed with either haloxyfop-R-methyl (HAL) ester or imazamox (IMI) and subjected to either a tine tillage or a no tillage treatment at planting of wheat. Soil samples were taken during January 2000 to determine the size of the medic and weed seedbank as well as the degree of dormancy in the medic seeds, while OM samples were taken throughout the growing season to determine the OM production of the different medic cultivars and weed species. OM samples taken during October 1998 on the same pasture, were used to determine the crude protein (CP) and neutral detergent fibre (NOF) content of the pasture. The samples were subjected to in vitro digestion and the digestibility of pasture CP (OCP), NOF(ONOF) and DM (DOM)were determined. Results showed that seedling establishment differed between cultivars used, herbicide treatments applied as well as the crop stage in the rotation. The cultivars produced more seedlings where IMI was applied compared to HAL as well as where the area consisted of two year pasture compared to one year pasture (1998) and one year wheat (1999). After a year of pasture and a year of wheat, cultivars Sephi and Paraggio produced the most seedlings, while Caliph and Orion produced the least. Caliph however, showed a very high degree of seed dormancy while Orion's low seedling establishment was due to its sensitivity to the IMI herbicide used. Little difference was found between the nine cultivars early in the season (July - August) with regard to cumulative OM production, except for Orion, whose growth was severely damaged by the IMI treatment. At the end of the growing season (October), the cultivar Caliph's cumulative OM production (2010.1 kg/ha) was significantly higher than all the other cultivars, except for Parabinga (1053. 4 kg/ha). Oifferent pasture samples, of which the botanical composition was known, was analysed for CP, NOF, OOM, OCP and ONOF. There was no significant difference in pasture composition during 1998 but variation in the pasture composition did however cause the IMI treatment, compared to the HAL treatment, to have a lower ONOFand OOMcontent. A modelling procedure was used to predict the pasture quality parameters (CP, NOF, OOM,OCP and ONOF) from the pasture composition (medic hay, medic pods, grassy and broadleaf weeds). This prediction of CP, NOF, OOM, ONOF and OCP from the pasture components had a relative low accuracy (49 -74.1 %) and a further refinement of this model for possible use on farms in order to improve grazing management and animal production is advised. In conclusion it could be said that broadleaf weed control caused a definite increase in medic seed and OMproduction, but Orion should not be used with an IMI herbicide. All the cultivars, except for Orion, produced enough seedlings up to the second year to ensure sustainability of the medic pasture. All the cultivars, except for Orion, produced a sufficient amount of OM early in the growing season. Caliph however, produced by far the most OM later in the growing season. A reduction of broadleaf weeds and medic pods will increase the digestibility of NOFand OMand therefore increase the quality of the pasture. Pods however are an important part of summer forage and the aim should therefore rather be to reduce the number of broadleaf weeds in the pasture. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van 'n gras en breëblaar onkruiddoder (wat sekere grasse beheer), metode van bewerking tydens die saai van koring asook nege verskillende medic kultivars op die regenerasie, droë materiaal produksie en kwaliteit van medic weidings te bepaal. Die proef is gedoen op Langgewens proefplaas wat geleë is in die Swartland koring produserende gebied. Nege medic kultivars is geëvalueer nadat die weiding met of haloxyfop-R-metiel ester (HAL) of imazamox (IMI) onkruiddoders gespuit is en onderwerp is aan of 'n vlak tand of geen bewerking tydens die saai van koring. Grondmonsters is geneem in Januarie 2000 om die grootte van die medic en onkruid saadbank asook om die graad van dormansie in die verskillende medic kultivars se sade te bepaal. Droë materiaal monsters is gedurende die 2000 groeiseisoen geneem om die droë materiaal produksie van die verskillende medic kultivars asook onkruid spesies te bepaal. Droë materiaal monsters is gedurende Oktober 1998 geneem en gebruik om die ruproteïn (CP) en neutraaloplosbare vesel (NDF) inhoud van die weiding te bepaal. Die monsters is in vitro verteer en die verteerbaarheid van CP (OCP), NDF (ONOF) en droë materiaal (DOM) is bepaal. Resultate wys dat saailing vestiging verskil tussen die verskillende kultivars wat gebruik is, verskillende onkruiddoder behandelings asook die stadium van die weidings/koring. Die kultivars het meer geproduseer waar die weiding met IMI behandel is in vergelyking met waar HAL toegedien is, asook waar koring nog nie gesaai is nie. Na 'n jaar van weiding en 'n jaar van koring, het die kultivars Sephi en Paraggio die meeste saailinge, en Caliph en Orion die minste saailinge gehad. Caliph het egter 'n hoë graad van dormansie in sy saad getoon, terwyl die swak vestiging van Orion die gevolg is van die kultivar se hoë sensitiwiteit teenoor IMI. Min verskil is gevind tussen die nege kultivars, vroeg in die groei seisoen (Julie - Augustus), wat kumulatiewe droë materiaal produksie betref, behalwe vir Orion wat erg beskadig is deur die IMI behandeling. Aan die einde van die groeiseisoen (Oktober 2000) was die kumulatiewe droë materiaal produksie van die kultivar Caliph (2010.1 kg/ha) betekenisvol hoër as al die ander kultivars behalwe vir Parabinga (1053.4 kg/ha). Weidingsmonsters, waarvan die botaniese samestelling bekend was, is ontleed vir CP, NDF, DDM, DCP en DNDF. Daar is geen betekenisvolle verskille gevind in die botaniese samestelling van die weidingmonsters geneem in 1998 nie,maar die variasie in botaniese samestelling het veroorsaak dat IMI in vergelyking met HAL 'n laer DNDF and DDM inhoud het. 'n Model is opgestel wat die weidingskomponente (medic hooi, medic peule, gras en breëblaar onkruide) gebruik om die kwaliteits parameters (CP, NDF, DDM, DCP en DNDF) van die weiding te skat. Hierdie skatting van CP, NDF, DDM, DCP en DNDF deur van die weidingskomponente gebruik te maak het 'n relatiewe lae akuraatheid gehad (49 -74.1 %) en verdere verfyning van hierdie model vir moontlike gebruik op plase, ten einde weidings bestuur en diere produksie te verbeter, word voorgestel. Die gevolgtrekking kan gemaak word dat breëblaar onkruidbeheer 'n definitiewe verbetering in die medic saailing en droë materiaal produksie van die medies te weeg gebring het, maar die kultivar Orion behoort nie saam met 'n IMI gebruik te word nie. AI die getoetste kultivars, behalwe Orion, het voldoende saad oorlewing vertoon tot en met die tweede jaar van die rotasie om lewensvatbaarheid van die sisteem te verseker en alle kultivars, behalwe Orion, het voldoende droë materiaal produseer vroeg in die groeiseisoen. Caliph het egter laat in die groeiseisoen by verre die meeste droë materiaal geproduseer. 'n Vermindering in die hoeveelheid breëblaar onkruide en peule in die weiding sal tot 'n verhoging in die verteerbaarheid van NDF en DM lei en dus 'n verhoging in die kwaliteit van die weiding tot gevolg hê. Peule is egter 'n belangrike bron van voedsel aan weidende diere gedurende droë somermaande en die verbetering van weidings moet eerder gedoen word deur te poog om breëblaar onkruide te beheer.

Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2005. / The response of perennial ryegrass and white clover, grown under controlled conditions, to fertiliser N rates applied under variable soil temperature (6, 12 and 18 °C), soil water potential (-10, -20, -25 and -35 kPa) and seasonal growing (June/July and October/November) conditions as well as field conditions, were evaluated. Primary- (PDM), residual- (RDM) and total dry matter (TDM) production (g pot-1) were recorded over the first- and second regrowth cycles as well as the accumulative DM production over the two regrowth cycles, respectively. Leaf N content (%) was recorded at the end of first and second regrowth cycles. Tiller/stolon numbers and root dry mass (g pot-1) were recorded at the end of the second regrowth cycle. Soil ammonium-N and nitrate-N (mg kg-1) content was monitored after fertiliser N application. Decreasing soil temperatures resulted in decreased TDM production in both crops. Only perennial ryegrass was influenced by fertiliser N rate, with a general increase in dry matter production as fertiliser N rate was increased. Ryegrass TDM production did not differ between the 100 and 150 kg N ha-1 rates but were both higher (P=0.05) if compared to the 0 and 50 kg N ha-1 treatments. Soil nitrate levels 31 days after application of 150 kg N ha–1 were still sufficient to stimulate ryegrass RDM production. The 173.8% increase in ryegrass TDM production measured at 6 °C where 150 kg N ha-1 was applied compared to the 0 kg N ha-1 treatment illustrated the ability of ryegrass to respond to fertiliser N at low soil temperatures. Soil water potential of -20 kPa resulted in higher ryegrass PDM and TDM production compared to the -25 and -35 kPa levels. White clover PDM and TDM production were however not influenced by soil water potential or fertiliser N rate. Ryegrass TDM production increased (P=0.05) as fertiliser N rates were increased. The most favourable soil water level for both ryegrass and clover root development was found to be -35 kPa. Perennial ryegrass and white clover PDM, RDM and TDM production were higher during the October/November season compared to the June/July season. Increased fertiliser N rates resulted in increased (P=0.05) ryegrass PDM and TDM production. White clover dry matter production was not influenced by fertiliser N rates. In the field study the effect of 0, 50, 100 and 150 kg N ha-1 applied as a single application either in autumn, early winter, late winter, early spring or late spring on pasture dry matter production, clover content and selected quality parameters of a perennial ryegrass-white clover pasture were investigated. Soil nitrogen dynamics in the 0-100, 200-300 and 400-500 mm soil layers were studied for 49 days following fertiliser N application. The effect of 50 kg N ha-1 on soil N dynamics was generally the same as found at the 0 kg N ha-1 applications and may therefore be regarded as a low risk treatment. The application of 150 kg N ha-1 especially in autumn and early winter showed a tendency to exceed the absorption capacity of the pasture and thereby expose fertiliser N to possible leaching and contamination of natural resources. Increased fertiliser N rate resulted in a general increase in pasture dry matter production with the highest yields recorded where N was applied in early and late spring and the lowest in early winter. The application of 150 kg N ha-1 in early and late spring resulted in the highest TDM production, however, the 50 kg N ha-1 resulted in a more efficient conversion of N applied to additional DM produced. In contrast to DM production, the clover percentage generally decreased as fertiliser N rate was increased. The effect of season of application was inconsistent. Annual trends show that the clover percentage eventually recovered to the same levels as the 0 kg N ha-1 treatments. Due to the above minimum levels recorded for most mineral and quality parameters tested it is envisaged that treatment combinations as used in this study will not be at any disadvantage to pasture and animal productivity. The study has shown that the use of fertiliser N to boost perennial ryegrass-white clover productivity and thereby minimising the negative effect of the winter gap on fodder flow management during the cool season in the Western Cape Province, may be an important management tool. Except for late spring applications, all seasons of application reduced the negative impact of the winter gap on fodder availability. It is concluded that regression lines as summarised in Tables 7.2 and 8.2 show great potential to be instrumental in developing regression models, accurately predicting the effect of fertiliser N rate on pasture performance. Other factors to be considered includes the productivity of the pasture, initial clover content, expected clover content at the end of the first regrowth cycle after fertiliser N application and the quantity of additional fodder required. Additional requirements will be to maintain and 150 kg N ha-1) in winter, as the N uptake capacity of the pasture could be exceeded and thereby increasing the risk of N leaching, resulting in environmental pollution. The N response efficiency of the pasture is also the lowest at the 150 kg N ha-1 rates, thereby reducing the profitability of these treatments.

Bibliography: leaves 144-163. / xv, 163 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis examines genetic variation in growth rate and growth form among subterranean clover cultivars in winter. The effect of plant density and sowing time on growth rate and sward structure of subterranean clover in winter and the impact of grazing intensity on morphology and nutritive value of subterranean clover is studied. It explores also genetic variation in the nutritive value of subterranean clover. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy and Farming Systems, 1997

Orientador: Mara de Andrade Marinho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-25T22:47:44Z (GMT). No. of bitstreams: 1 Maluf_Cintia_M.pdf: 1111592 bytes, checksum: e0d85a87354d7219b73f0892099372c4 (MD5) Previous issue date: 2014 / Resumo: Esse trabalho aborda o tema da política de crédito rural no Brasil, tratando particularmente do Programa para Redução da Emissão de Gases de Efeito Estufa na Agricultura (Programa ABC), instituído pelo Governo Federal em 2010. O objetivo geral da pesquisa foi analisar as condições gerais de financiamento do Programa ABC. Os objetivos específicos foram analisar a oferta e contratação de crédito no período de 2010/2011 a 2012/2013, e realizar uma análise setorial sobre a bovinocultura de corte, uma das principais cadeias produtivas da agropecuária brasileira e maior emissor de gases de efeito estufa. Com relação ao objetivo geral, verificou-se o protagonismo da ação e a característica inovadora do Programa ABC, como uma política de crédito rural na qual o consentimento do recurso é condicionado à adoção de boas práticas de manejo. Variações anuais nas condições de financiamento do Programa ABC, a saber a taxa de juros e prazos de carência e pagamento, tornaram-no mais atrativo ao longo do tempo. A respeito da contratação do crédito, os dados de execução do Programa ABC evidenciaram uma crescente demanda. Do montante ofertado no período entre as safras 2010/2011 a 2012/2013, de R$13,05 bilhões, foram executados 37% distribuídos em 16.445 contratos. No entanto, foram identificados como fatores limitantes ao seu desenvolvimento, a escassez de informações acerca do retorno financeiro de práticas preconizadas como ILP e ILPF, as especificidades da elaboração e análise dos projetos, bem como os entraves decorrentes da regularização ambiental e fundiária das propriedades contratantes. Os resultados obtidos da análise setorial da bovinocultura de corte no âmbito do Programa ABC, permitiram concluir que os prazos estabelecidos ao crédito são adequados aos ciclos de produção; e que suas linhas apresentaram características competitivas em relação aos demais programas de crédito rural para investimentos na bovinocultura de corte. Foi verificado ainda que os estados de Goiás, Mato Grosso do Sul, Mato Grosso, Rio Grande do Sul e São Paulo podem vir a apresentar maior demanda para a contratação de recursos financeiros com vistas à implantação de sistemas integrados como ILP e ILPF. Contudo, a relação histórica entre a oferta de crédito oficial e o desenvolvimento da bovinocultura de corte brasileira sugere a necessidade de desenvolvimento de formas alternativas ao estímulo da mitigação da emissão de gases de efeito estufa, que não exclusivamente a oferta de financiamento. Neste contexto, ressalta-se a importância das pesquisas acerca das ações de coordenação da cadeia produtiva, a fim de sensibilizar consumidores quanto às externalidades positivas das atividades de baixo impacto, permitindo a precificação diferenciada dos produtos e consequente agregação de valor ao pecuarista / Abstract: This paper addresses the impact of rural credit policy in Brazil, in the area of Planning and Sustainable Rural Development, particularly in relation to the Federal-sponsored Program for the Reduction of Greenhouse Gases Emissions in Agriculture (so-called ABC Program). Established in 2010, the Program aims to set nation-wide targets for reducing greenhouse gases emissions. This research was based on the overall objective to analyze the general conditions of financing the ABC Program. The specific objectives were based on the analyzes of the supply financial credit and contracting credit in the period 2010/2011 a 2012/2013, and a sectoral analysis of beef cattle breeding ¿ the sector is a major emitter of greenhouse gases (carbon dioxide, methane, nitrous oxide, and fluorinated). With respect to the results, there was the role of action and innovative feature of the ABC Program as a rural credit policy in which the resource is conditional upon adoption of good management practices. Changes on the financing conditions offered by the ABC Program (i.e. interest rates and payback schedule) made it more attractive over time. Performance data of the ABC Program showed increased supply and borrowing of credit. The amount offered by the ABC Program between the 2010/2011 and 2012/2013 crops was U.S. $ 13.05 billion, of which 37 % were non-perfoming loans, distributed in 16,445 contracts. The main barriers for hiring ABC Program credit are the lack of knowledge about the Program, difficulties for developing and analyzing the projects, and barriers related to environmental and land regularization. In the time frame of the study, the hiring of credit increased, and the conditions for concession were adequate to finance production cycles from breeding to the complete cycle. The ABC Program showed competitive characteristics comparing with the other rural credit lines offered for beef cattle production. It was found that the states of Goiás, Mato Grosso do Sul, Mato Grosso, Rio Grande do Sul, and São Paulo may present increased demand financing integrated systems such as Integrated Crop-Livestock Systems and Integrated Crop-Livestock-Forestry Systems, as advocated by the Program. However, the historical relationship between the supply of rural credit and development of beef cattle in Brazil suggests the need to develop alternative forms of stimulus for mitigating the effects of greenhouse gases emissions. In this context, it emphasizes the importance of researching supply chain coordination; alerting consumers about the positive externalities of low-impact activities and allowing for differentiated product pricing and, ultimately, adding value to the farmer / Mestrado / Planejamento e Desenvolvimento Rural Sustentável / Mestra em Engenharia Agrícola

Thesis (D. Tech.) - Central University of Technology, Free State, 2009 / All over the African continent south of the Sahara Desert, African lion numbers are plummeting to levels where, over large areas of their remaining distribution range, extinction has become a real threat. The main reason for the decreasing numbers is the increasing conflict between livestock farmers and lions. Lions are forced to kill livestock where their natural prey has been squeezed out by livestock and associated farming practices, and the farmers find it necessary to protect their livelihoods, often through the indiscriminate killing of lions. In the Kgalagadi-South region of Botswana, lion/livestock interactions present a challenge to livestock owners and wildlife managers alike. The relatively low ecological carrying capacity and occupied lion habitats in the Kgalagadi Transfrontier Park (KTP) force some expelled young adult and sub-adult lions southwards into the adjoining Wildlife Management Area (WMA) KD/15, which separates the KTP and the communal grazing area. This WMA most likely also contains resident prides. Some of these predators sporadically enter the livestock grazing area. Similarly, large stock often enters the WMA. It is mostly these boundary transgressions that result in livestock killing, and the reaction of livestock owners often leads to the killing of lions. To gather information concerning the nature and extent of the situation, two questionnaires were prepared with the assistance of the Department of Biostatistics of the University of the Free State, South Africa. One questionnaire targeted livestock owners while the other was aimed at wildlife officials of the Department of Wildlife and National Parks in Botswana and SANParks in South Africa. Both covered the five-year period 2002-2006. A trial run was carried out to adjust to problem-specific circumstances before fieldwork commenced. Fieldwork was done during four consecutive seasons – in January, February, April and December 2007. Thirty livestock respondents and 13 wildlife officials were interviewed during the first two excursions into the study area. The third visit was to plot the cut-line between the WMA and the grazing area (by means of a Global Positioning System or GPS) and to make first-hand observations regarding movement over the cut-line. During all four visits the environmental (including grazing) conditions and density and distribution of wildlife and stock were observed in both the WMA and the grazing areas. The information gathered points towards a seemingly unsolvable situation. The exceptionally high daytime temperatures and food scarcity, brought about by erratic rainfall, overgrazing near boreholes, generally low carrying capacity and low phosphorus (P) levels, force large stock, i.e. cattle, horses, donkeys and mules, to graze far away from the safety of the cattle-posts during the cool hours of the night, thus making kraaling impractical. Such circumstances enhance exposure to lion predation especially in or near the WMA and the KTP fence. Some lions also penetrate deep into the grazing areas, especially in the arid western part of the study area. This study revealed certain weaknesses in current wildlife and livestock management practices in the study area, the sum of which put both farmers and the lion population under extreme pressure. Most of these shortcomings can be rectified without drastic invasive methods. Such adjustments can result in improved livestock and wildlife utilisation and protection of the lions. For example: the placement of mixed phosphorus and salt licks near cattle-posts to fulfil the need for vital micro and macro elements; addressing unnecessary livestock losses, which contribute to a lower income and less tolerance towards predation (e.g. botulism, which may stem from stock chewing on bones in their desire for more phosphorus, and losses to black-backed jackal, Canis mesomelas, in poorly maintained kraals); more drinking troughs at boreholes to prevent unnecessary shoving and minimise energy waste; and the introduction of more bulls to herds to increase the calving percentage. The study further concluded that there is little reason why stockowners should consider protecting lions. It suggests that significant value can be added to the wildlife (and the protection of lions) in the specific area by making farmers and other local residents share in the relatively untapped ecotourism potential of the area.

Over the past thirty years, price relativities and technological development have motivated an increase in the area of land allocated to cropping, as opposed to pasture production, throughout the central wheat belt of Western Australia. Nevertheless, reducing the proportion of pasture in these rotations has challenged the future productivity of farming systems in this area. First, the frequent application of selective herbicides for weed control in extended cropping rotations has promoted the development of herbicide resistance in a number of major agricultural weeds. Second, the primary use of annual plants has promoted the development of soil salinisation by allowing a significant proportion of rainfall to recharge saline water tables. The inclusion of perennial pasture phases between extended periods of cropping may mitigate or delay these constraints to production through (a) allowing the use of costeffective forms of non-selective weed control, and (b) through creating a buffer of dry soil that absorbs leakage occurring beneath subsequent crops. This study consequently explores the value of including perennial pasture phases in dryland agricultural systems in the eastern-central wheat belt of Western Australia, accounting for benefits related to herbicide resistance and water table management. A novel computational algorithm for the solution of multiple-phase optimal control problems is developed and used to conduct a conceptual analysis of the value of lucerne (Medicago sativa L.) pasture for managing annual ryegrass (Lolium rigidum Gaudin), the primary weed in wheat belt cropping systems. The competitiveness and fecundity of annual ryegrass provide strong economic incentives to maintain a low weed population, irrespective of herbicide-resistance status. Consequently, the ineffectiveness of selective herbicides primarily reduces the profitability of cropping by motivating the adoption of more costly non-selective forms of weed control. The inclusion of lucerne in land-use rotations is only optimal in the presence of severe herbicide resistance given (a) the low efficiency of alternative weed-management practices available during the pasture phase, relative to selective-herbicide application; (b) the significant cost of establishing this perennial pasture; and (c) the high relative profitability of cereal production in the absence of resistance. The value of lucerne, relative to annual pastures, for weed management is explored in greater detail through the use of compressed annealing to optimise a sophisticated simulation model. The profitability of candidate rotations is also manipulated to account for the long-term production losses accruing to the recharge of saline groundwaters that occurs beneath them. Sequences incorporating lucerne are only more profitable than those that include annual pasture at the standard set of parameter values if (a) annual ryegrass is resistant to all selective herbicides, (b) the water table is so shallow (approximately less than 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, or (c) sheep production is highly profitable. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost. Consistent with intuition, these benefits are reinforced by lower discount rates and higher rates of leakage occurring beneath annual-based systems. Formulation of an effective communication strategy to report these results to producers is justified given the complexity involved in determining the true magnitude of these intertemporal benefits through alternative means, such as field trials.

South African dairy farmers have generally used kikuyu pasture to tide them over from one ryegrass season to the next, and as a result of its resilient nature, have assumed careful management of it to be unnecessary. This has resulted in its mismanagement which is unaffordable in current times where the profitability of dairy farming is increasingly dependent on low input, pasture-based systems. Kikuyu pasture may play a larger role in supplying nutrients to dairy cattle over the summer months in future as the alternative home produced feed sources such as silage and perennial ryegrass become increasingly unaffordable. Improving animal production from kikuyu is difficult as there is little information relating kikuyu pasture management to dairy cow performance. Efficient utilization and quality of temperate pasture have been more comprehensibly researched. The relations discovered between the chemical compounds in temperate grass species have been applied to tropical pastures such as kikuyu with limited success and often confusing results. For example, crude fibre in kikuyu was found to be positively related to digestibility. In South Africa, much research has been done on the use of kikuyu in beef production systems. This information has been applied to dairy farming systems with limited success, owing to the higher metabolic demands of dairy animals. Pasture farming needs to become more precise to improve pasture quality and hence milk yields as research trials focussing on stocking rate and grazing system comparisons have yielded results that are too general with little application at the farming level. A need for integrated and flexible management of animals and pastures has been recognised. The grazing interval is a key aspect in improving pasture and animal performance and fixed rotation lengths and stocking rates have been identified as being detrimental to performance. The relation between growth stage and pasture quality has lead researchers to identify plant growth characteristics, such as pasture height and leaf stage, as signs of grazing readiness. At the four and a half leaves per tiller stage of regrowth, the chemical composition ofthe kikuyu plant is more in line with the requirements ofthe dairy cow, with the leaf to stem ratio at its highest. The primary limitation of kikuyu pasture is a lack of energy, particularly readily fermentable carbohydrate, which makes the fermentation of structural carbohydrates difficult and dry matter intakes are reduced. Other limitations to animal performance include high cell wall constituents, low calcium, magnesium and sodium content and antinutritional factors such as nitrate and insoluble oxalate. These deficiencies and antinutritional factors are in some cases unique to 5 kikuyu pasture, meaning that kikuyu specific supplementation may be the key to improving performance from dairy cattle grazing kikuyu pasture. The objectives are to evaluate current kikuyu management systems in South Africa and their impact on dairy cow performance and to evaluate the use of pasture height and burning as quality control tools. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.