Thesis (MScAgric (Animal Sciences))--Stellenbosch University, 2010. / ENGLISH ABSTRACT: South Africa is well-known for periodic dry periods and uncertain rainfall. Ensiling of crops is a method of preserving forage and ensures feed availability during periods when the supply of good quality forage is low. Cereal-based silages, especially in the Western Cape, South Africa, represent a significant proportion of feed consumed by ruminant animals, particularly high-producyion dairy cattle. However, farmers are still concerned about the technical challenges of ensiling cereal crops. Previous research done on lactic acid bacteria (LAB) inoculants used on cereal based silage has indicated a potential for improving silage fermentation, stability and degradability, thus enhancing feed conversion and production by ruminants. Two experiments were conducted to determine the effects of inoculating whole-crop oat silage with Lalsil® Cereal Lactobacilli (Lactobacillus buchneri (NCIMB 40788) and Pediococcus acidilactici (CNCM MA 18/5M)) LAB on (1) silage fermentation, (2) aerobic stability and (3) nutritional value of silage ensiled under a. micro-silos conditions and b. in a bunker under outdoor conditions of a Mediterranean summer. Oats (Avena sativa, cv SSH 405) were planted on 60 ha under dryland conditions at Elsenburg in the Western Cape province, South Africa. Whole-crop oats were harvested at the soft dough stage and length of the chopped material was 9 mm (Day of ensiling – Day 0). Chopped whole-crop oats were sampled, mixed thoroughly and divided into two portions. The Inoculant (Lalsil® Cereal) was applied to one portion to provide 5.79 x 109 colony forming units (CFU) of LAB per gram of fresh material. In the first experiment twenty - four glass silos (1.5 L glass jars) (WECK, GmbH u.Co., Wehr-Ofligen, W. Germany) were filled for each of the control and inoculant treatments. The glass silos were stored in a dark room in the laboratory at ambient temperature. Three glass silos were opened for each treatment on days 1, 2, 4, 8, 15, 30, 60 and 102 post-ensiling to determine fermentation dynamics. A parallel study was done with the same chopped whole-crop oats using the buried bag technique in a bunker silo. Whole-crop oats were ensiled in six net bags per treatment buried in a bunker filled with the same untreated whole crop oats. Bags, attached with nylon lines (3 m lengths) for easy retrieval were buried at 1m and 2 m depths in the same bunker. The net bags in the bunker were retrieved after 186 days of ensiling. Dry matter (DM), organic matter (OM), neutral detergent fibre (NDF), crude protein (CP), lactic acid levels, pH, water soluble carbohydrates (WSC) and in vitro organic matter degradability (IVOMD) for both studies were determined. Silage of both experiments was exposed to aerobic conditions for ten days to determine aerobic stability. It is concluded that the inoculant Lalsil® Cereal had the effect of reducing the rate of consumption of WSC during the anaerobic phase and aerobic exposure for both experiments. Silage spoilage due to yeasts and moulds was however more evident with the inoculated silage due the presence of sugars in the micro-silos experiment. / AFRIKAANSE OPSOMMING: Suid-Afrika is bekend vir droë periodes en wisselvallige reënval. Die inkuiling van gewasse is ‘n goeie manier om ruvoer te voorsien in tye van droogtes of tekorte. Kleingraan kuilvoer is veral bekend in die Wes-Kaap, Suid-Afrika en maak ‘n groot deel uit van die melkkoei se rantsoen. Landbouers is nog steeds bekommerd oor die tegniese aspekte wanneer dit kom by die inkuil van gewasse. Vorige navorsing het getoon dat die gebruik van ‘n melksuurbakteriese inokulant saam met die inkuiling van gewasse moontlik die potensiaal het om fermentasie, stabiliteit en degradering te verbeter en sodoende voeromset te verbeter. Twee eksperimente is uitgevoer om die effek van die inkuiling van hawerkuilvoer met Lalsil® Cereal Lactobacilli (Lactobacillus buchneri (NCIMB 40788) en Pediococcus acidilactici (CNCM MA 18/5M)) LAB te bepaal op (1) kuilvoer fermentasie, (2) aërobiese stabiliteit en (3) nutriëntwaarde van die kuilvoer ingekuil in a. mikrosilo’s en b. in ‘n bunker in die buitelug. Hawer (Avena sativa, cv SSH 405) is op 60 ha droë land geplant op Elsenburg in die Wes-Kaap, Suid-Afrika. Die hawer is ingekuil tydens die sagte deeg stadium en die gekapte materiaal was ongeveer 9 mm lank. Gekapte material was deeglik gemeng en in twee gedeel. Die inokulant (Lalsil® Cereal) is op die een gedeelte gesproei om 5.79 x 109 kolonie-vormende eenhede (KVE) melksuurbakterieë per gram vars materiaal te voorsien. Tydens die eerste eksperiment is 24 mikrosilo’s (1.5 L glas silo) (WECK, GmbH u.Co., Wehr-Ofligen, W. Duitsland) vir elke behandeling vol kuilvoer gemaak. Hierdie mikrosilo’s is gestoor in ‘n donker kamer teen kamertemperatuur. Drie mikrosilo’s is per behandeling oopgemaak op dag 1, 4, 8, 15, 30, 60 en 102 na inkuiling om die fermentasie-dinamika te bepaal. ‘n Parallelle studie is gedoen met dieselfde materiaal ingekuil in netsakke binne die bunker. Die materiaal was ingekuil in ses netsakke vir elke behandeling. Nylon toue (3 m) is aan die sakke vasgemaak om die uithaal daarvan op latere stadium te vergemaklik. Hierdie sakke is ingekuil op verskillende dieptes, 1 m en 2 m in dieselfde bunker. Die sakke is na 186 dae weer uitgehaal. Droë materiaal (DM), organiese materiaal (OM), neutraal bestande vesel (NBV), ruproteïen (RP), melksuurvlakke, pH, water oplosbare koolhidrate (WOK) en in vitro organiese materiaal verteerbaarheid (IVOMV) vir beide studies is bepaal. Kuilvoer van beide eksperimente is ook blootgestel aan aërobiese toestande vir 10 dae aan aërobiese toestande blootgestel om aërobiese stabiliteit te bepaal. Daar is bepaal dat die inokulant Lalsil® Cereal het die tempo van WOK verbruik verminder gedurende die anaërobies fase sowel as die aërobiese fase vir beide eksperimente. Kuilvoer wat bederf het as gevolg van giste en swamme was meer sigbaar by die inokulant behandelde kuilvoer as gevolg van die teenwoordigheid van suikers in die mikrosilo’s. (Sleutelwoorde: hawerkuilvoer, inokulant, mikrosilo’s, water oplosbare koolhidrate (WOK), in vitro organiese materiaal verteerbaarheid (IVOMV))

Inoculation with diazotrophic bacteria is well documented as a means to enhance growth and increase yields of various crops, especially when used as an alternative or a supplement to the use of nitrogenous fertilizers and agrochemicals for sustainable agriculture. Nitrogen is the most limiting nutrient for increasing crop productivity, and the use of chemical sources of N fertilizers is expensive, and may contribute to environmental pollution. Therefore, there is a need to identify diazotrophic inoculants as an alternative or supplement to N-fertilizers for sustainable agriculture. The search for effective diazotrophic bacterial strains for formulation as biofertilizers has been going on for over 40 years and a number of inoculant biofertilizers have been developed and are commercially available. In the current study, 195 free-living diazotrophic bacteria were isolated from soils collected from the rhizosphere and leaves of different crops in different areas within the KwaZulu-Natal Province, Republic of South Africa. Ninety five of the isolates were selected for further screening because they were able to grow on N-free media using different carbon sources. Isolates that were very slow to grow on N-free media were discarded. Of these, 95 isolates were screened in vitro for growth promotion traits tests including tests for ammonia production and acetylene reduction. The best 20 isolates that were also able to reduce acetylene into ethylene were selected for growth-promotion trials on maize under greenhouse conditions. Of the 20 isolates, ten isolates enhanced (P = 0.001) growth of maize above the Un-inoculated Control. Molecular tests were conducted to identify the ten most promising isolates selected in the in vitro study. In the greenhouse study, these diazotrophic isolates were screened for their ability to enhance various growth parameters of maize (Zea mays L.), following various inoculation techniques (drenching, seed treatment, foliar spray and combination of these). Inoculations with the five best diazotrophic isolates by various methods of application increased dry weight and leaf chlorophyll content (P < 0.001, P = 0.001), respectively, compared to the Untreated Control. Although, all methods of application of diazotrophic inoculants used in this study resulted in increased dry weight and leaf chlorophyll content, combined methods of application (seed treatment + drenching) and sole application (seed treatment) were significantly more (P < 0.05) efficient. The best five most promising isolates were identified for growth promotion of maize under greenhouse conditions. They were also assessed for their effects on germination of wheat in vitro and were further tested in combination with various levels of nitrogenous fertilizer for growth-promotion of wheat (Triticum aestivum L.). These five isolates were also investigated for their potential to enhance growth and yields of maize and wheat crops in field trials, when combined with a low dose of nitrogenous fertilizer. These isolates were further studied for their contribution for enhancing plant growth through nitrogen fixation by predicting N content in leaves using a chlorophyll content meter (CCM-200) and correlated to extractable chlorophyll level at R2 = 0.96. In this study, relative to the Un-inoculated Control, the best five isolates enhanced growth of maize and wheat when combined with a 33% N-fertilizer levels for a number of growth parameters: increased chlorophyll levels and heights of maize, shoot dry weight of maize and wheat; and enhanced root and shoot development of these crops in both greenhouse and field conditions. The best contributions of diazotrophic bacteria was achieved by Isolate LB5 + 0% NPK (41%), V9 + 65% NPK (28.9%), Isolate L1 + 50% NPK (25%), Isolate L1 + 25%NPK (22%) and LB5 + 75% NPK (15%) undergreenhouse conditions. At 30 or 60 DAP, isolates with 33%N-fertilizer caused relatively higher dry weight than the 100%NPK. Inoculation of Isolate StB5 without 33N% fertilizer cuased significant (P<0.005) increases in stover dry weight. In field studies, inoculation of diazotrophic bacteria alone or with 33%N-fertilizer resulted in relatively greater increases of dry weight, stover dry weight, number of spikes and yield at different growth stages higher than the Un-inoculated or Unfertilized Control. However, the increases were not statistically significant. The use of microbial inoculants in combination with low doses of nitrogenous fertilizers can enhance crop production without compromising yields. The isolates obtained in this study can effectively fix nitrogen and enhance plant growth. The use of microbial inoculants can contribute to the integrated production of cereal crops with reduced nitrogenous fertilizer inputs, as a key component of sustainable agriculture. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.

Made available in DSpace on 2017-07-10T19:25:13Z (GMT). No. of bitstreams: 1 henry.pdf: 2217836 bytes, checksum: f01d367fdd6ecd64b7d0ccf6ae52d669 (MD5) Previous issue date: 2012-07-02 / In Brazil, the grain harvest in 2007/08 was about 145 million tons, a record for the domestic agriculture. In 2008 soybeans led to participation in the value of production of temporary and permanent crops with 39.18% which were superseded by the 2009/2010, in which the Paraná state reached the first place in soybean production in Brazil. As possible benefits of diets containing soy we could mention the anticarcinogenic effects, reduction of cholesterol levels, protective effects against obesity and symptoms such as hot flashes during menopause, treatment of coronary heart disease and osteoporosis. According to this economic and health context, this work aimed the development of a hydrosoluble soybean extract fermented with probiotic microorganisms, plus inulin (prebiotic substance) and whey protein concentrate, in order to meet the consumers expectations on health, nutrition and functionality due to their symbiotic nature. Physical and chemical, microbiological, sensory analyzes and probiotic bacteria counting were carried out, considering different types of sugars such as sucrose and glucose. Twelve formulations were prepared from hydrosoluble soybean extract with whey protein concentrate and inulin, by varying the inoculated cultures (Lactobacillus acidophilus, Lactobacillus casei and SAB) and sugar (100% glucose treatment, 100% sucrose treatment, 50% glucose and 50% sucrose treatment, and 0% sugar treatment). The sensory evaluation experiment was completely randomized, applying analysis of variance-ANOVA and Means Test (Tuckey). In the fermentation process the formulation A5 (EHS 10%, 2.5% WPC, 2% inulin, sugar and inoculum SAB) presented the shortest time register, with 5 hours and 53 minutes to achieve the optimum pH. For an optimal therapeutic effect, it is estimated that the probiotic food must contain a number above than 107 CFU / mL, and all formulations reached this viable cell count during 28 days of storage, especially the Treatment A9 with an initial count of 1,20 x1014 CFU / mL. The increased acidity values reached 85 ºD, maintaining the pH value close to 4.31, which means a suitable pH. The results of the microbiological analyzes of fermented beverages were in accordance to the standards established by the Brazilian legislation, ensuring the safety of the samples. The rate of acceptance achieved by sensory evaluation of the beverages was above 70% considering the formulations A2 (EHS 10%, 2.5% WPC, 2% of inulin, 100% sucrose and L. casei inoculum) and A10 (EHS 10% 2.5% WPC, 2% of inulin, and 100% sucrose and L. acidophilus inoculum), which means that these formulations would be well accepted in the consumers market. / A safra brasileira de grãos 2007/08 foi de cerca de 145 milhões de toneladas, um recorde para a agricultura interna. No ano de 2008 a soja liderou a participação no valor da produção de lavouras temporárias e permanentes com 39,18%, participação que foi superada pela safra 2009/2010, na qual o Paraná garantiu o primeiro lugar na produção de soja no Brasil. Como possíveis benefícios de dietas contendo soja podem ser mencionados os efeitos anticarcinogênicos, redução dos níveis de colesterol, efeitos protetores contra a obesidade e sintomas como ondas de calor na menopausa, tratamento de doenças coronarianas e osteoporose. Diante deste contexto econômico e de saúde, almejou-se desenvolver uma bebida à base de extrato hidrossolúvel de soja fermentada com micro-organismos probióticos, acrescida de inulina (substância prebiótica) e proteína concentrada do soro do leite, visando atender às expectativas de consumidores quanto à saúde, nutrição e funcionalidade, devido ao seu caráter simbiótico. Foram realizadas análises físico-químicas, microbiológicas, sensoriais e contagem de bactérias probióticas, considerando-se diferentes tipos de açúcares, como sacarose e glicose. Foram elaboradas doze formulações a partir de extrato hidrossolúvel de soja, adicionado de proteína concentrada de soro de leite e inulina, variando as culturas inoculadas (fermentos lácteos Lactobacillus acidophilus, Lactobacillus casei e SAB) e o açúcar (Tratamento com 100% de glicose, tratamento com 100% de sacarose, tratamento com 50% de glicose e 50% de sacarose e tratamento com 0% de açúcar). O delineamento experimental na avaliação sensorial foi inteiramente casualizado, aplicando-se a análise de variância (ANOVA) e teste de médias (Tuckey). No processo de fermentação a formulação contendo 10% EHS, 2,5% WPC, 2% de inulina, sem açúcar e o inóculo SAB sobressaiu-se com o menor tempo, totalizando 5 horas e 53 minutos para alcançar o pH ótimo. Para obter um efeito terapêutico ótimo, estima-se que o alimento probiótico deva conter um número maior que 107 UFC/mL, sendo que todas as formulações elaboradas alcançaram este propósito durante os 28 dias de armazenamento, tendo como destaque a formulação A9 com uma contagem inicial de 1,20 x1014 UFC/mL. Os valores de acidez aumentaram até aproximadamente 85º D, mantendo o valor de pH próximo a 4,31, o que significa um pH adequado. Os resultados das análises microbiológicas das bebidas fermentadas apresentaram-se em conformidade com os padrões estabelecidos pela legislação brasileira, assegurando a inocuidade das amostras. O índice de aceitabilidade obtido pela avaliação sensorial das bebidas foi superior a 70% para as formulações A2 (10% EHS, 2,5% WPC, 2% de inulina, 100% sacarose e o inóculo L. casei ) e A10 (10% EHS, 2,5%WPC,2% de inulina, 100%sacarose e o inóculo L. acidófilos), o que significa que estas formulações seriam bem aceitas no mercado consumidor.

Made available in DSpace on 2017-05-12T14:48:38Z (GMT). No. of bitstreams: 1 henry.pdf: 2217836 bytes, checksum: f01d367fdd6ecd64b7d0ccf6ae52d669 (MD5) Previous issue date: 2012-07-02 / In Brazil, the grain harvest in 2007/08 was about 145 million tons, a record for the domestic agriculture. In 2008 soybeans led to participation in the value of production of temporary and permanent crops with 39.18% which were superseded by the 2009/2010, in which the Paraná state reached the first place in soybean production in Brazil. As possible benefits of diets containing soy we could mention the anticarcinogenic effects, reduction of cholesterol levels, protective effects against obesity and symptoms such as hot flashes during menopause, treatment of coronary heart disease and osteoporosis. According to this economic and health context, this work aimed the development of a hydrosoluble soybean extract fermented with probiotic microorganisms, plus inulin (prebiotic substance) and whey protein concentrate, in order to meet the consumers expectations on health, nutrition and functionality due to their symbiotic nature. Physical and chemical, microbiological, sensory analyzes and probiotic bacteria counting were carried out, considering different types of sugars such as sucrose and glucose. Twelve formulations were prepared from hydrosoluble soybean extract with whey protein concentrate and inulin, by varying the inoculated cultures (Lactobacillus acidophilus, Lactobacillus casei and SAB) and sugar (100% glucose treatment, 100% sucrose treatment, 50% glucose and 50% sucrose treatment, and 0% sugar treatment). The sensory evaluation experiment was completely randomized, applying analysis of variance-ANOVA and Means Test (Tuckey). In the fermentation process the formulation A5 (EHS 10%, 2.5% WPC, 2% inulin, sugar and inoculum SAB) presented the shortest time register, with 5 hours and 53 minutes to achieve the optimum pH. For an optimal therapeutic effect, it is estimated that the probiotic food must contain a number above than 107 CFU / mL, and all formulations reached this viable cell count during 28 days of storage, especially the Treatment A9 with an initial count of 1,20 x1014 CFU / mL. The increased acidity values reached 85 ºD, maintaining the pH value close to 4.31, which means a suitable pH. The results of the microbiological analyzes of fermented beverages were in accordance to the standards established by the Brazilian legislation, ensuring the safety of the samples. The rate of acceptance achieved by sensory evaluation of the beverages was above 70% considering the formulations A2 (EHS 10%, 2.5% WPC, 2% of inulin, 100% sucrose and L. casei inoculum) and A10 (EHS 10% 2.5% WPC, 2% of inulin, and 100% sucrose and L. acidophilus inoculum), which means that these formulations would be well accepted in the consumers market. / A safra brasileira de grãos 2007/08 foi de cerca de 145 milhões de toneladas, um recorde para a agricultura interna. No ano de 2008 a soja liderou a participação no valor da produção de lavouras temporárias e permanentes com 39,18%, participação que foi superada pela safra 2009/2010, na qual o Paraná garantiu o primeiro lugar na produção de soja no Brasil. Como possíveis benefícios de dietas contendo soja podem ser mencionados os efeitos anticarcinogênicos, redução dos níveis de colesterol, efeitos protetores contra a obesidade e sintomas como ondas de calor na menopausa, tratamento de doenças coronarianas e osteoporose. Diante deste contexto econômico e de saúde, almejou-se desenvolver uma bebida à base de extrato hidrossolúvel de soja fermentada com micro-organismos probióticos, acrescida de inulina (substância prebiótica) e proteína concentrada do soro do leite, visando atender às expectativas de consumidores quanto à saúde, nutrição e funcionalidade, devido ao seu caráter simbiótico. Foram realizadas análises físico-químicas, microbiológicas, sensoriais e contagem de bactérias probióticas, considerando-se diferentes tipos de açúcares, como sacarose e glicose. Foram elaboradas doze formulações a partir de extrato hidrossolúvel de soja, adicionado de proteína concentrada de soro de leite e inulina, variando as culturas inoculadas (fermentos lácteos Lactobacillus acidophilus, Lactobacillus casei e SAB) e o açúcar (Tratamento com 100% de glicose, tratamento com 100% de sacarose, tratamento com 50% de glicose e 50% de sacarose e tratamento com 0% de açúcar). O delineamento experimental na avaliação sensorial foi inteiramente casualizado, aplicando-se a análise de variância (ANOVA) e teste de médias (Tuckey). No processo de fermentação a formulação contendo 10% EHS, 2,5% WPC, 2% de inulina, sem açúcar e o inóculo SAB sobressaiu-se com o menor tempo, totalizando 5 horas e 53 minutos para alcançar o pH ótimo. Para obter um efeito terapêutico ótimo, estima-se que o alimento probiótico deva conter um número maior que 107 UFC/mL, sendo que todas as formulações elaboradas alcançaram este propósito durante os 28 dias de armazenamento, tendo como destaque a formulação A9 com uma contagem inicial de 1,20 x1014 UFC/mL. Os valores de acidez aumentaram até aproximadamente 85º D, mantendo o valor de pH próximo a 4,31, o que significa um pH adequado. Os resultados das análises microbiológicas das bebidas fermentadas apresentaram-se em conformidade com os padrões estabelecidos pela legislação brasileira, assegurando a inocuidade das amostras. O índice de aceitabilidade obtido pela avaliação sensorial das bebidas foi superior a 70% para as formulações A2 (10% EHS, 2,5% WPC, 2% de inulina, 100% sacarose e o inóculo L. casei ) e A10 (10% EHS, 2,5%WPC,2% de inulina, 100%sacarose e o inóculo L. acidófilos), o que significa que estas formulações seriam bem aceitas no mercado consumidor.

This diploma thesis in the theoretical part deals with classification of cast iron, problems of gray cast iron production, methods of inoculation and valuation of the gray iron quality by means of thermal analysis. The aim of practical part was to investigate effectiveness of inoculation of two different inoculants using thermal analysis. In terms of mechanical properties, hardness and ultimate tensile strength were measured. Metallographic specimen were evaluating by means of image analysis software.

A cause du prix élevé des engrais importés au Mali, le phosphate naturel de Tilemsi (PNT) constitue une source de phosphore, locale, peu coûteuse pour les paysans. Dans plusieurs zones, malgré ses bonnes caractéristiques physiques et chimiques, les plantes cultivées, particulièrement le blé, ont faiblement répondu à l’application du PNT. À cause du besoin croissant d’améliorer biologiquement l’absorption du P par le blé, nous présentons dans ce travail les résultats de l’utilisation de microorganismes solubilisant le phosphore (MSP) dans un essai d’inoculation au champ. Dans la rhizosphère (Zone d’interactions intenses entre les racines et les microorganismes) et le rhizoplan (les microorganismes du rhizoplan ont ceux qui sont directement liés à la surface externe des racines) de trois cultivars de blé du Mali, 7 à 12% des microorganismes étaient capables de solubiliser le PNT. Six bactéries et deux champignons ont été sélectionnés, pour leur fort pouvoir de solubilisation du PNT en milieu liquide et sur milieu solide, et testés au champ à Koygour (Diré) en 2000-2001. Deux champignons Aspergillus amovari (C1), Penicillium chrysogenum (C13) et une bactérie Pseudomonas sp. (BR2) ont significativement amélioré la taille du blé (cv. Tétra) après 6 semaines, ainsi que, le poids et le contenu en P de la matière sèche (paille et graines) après 90 jours de croissance. Des essais au champ ont été réalisés à Koygour (Diré) en 2001-2002. Les traitements d’inoculation incluent C1, C13, BR2, C1+BR2, C13+BR2 et un contrôle en présence et à l’absence de Glomus intraradices (Gi). Les traitements de phosphore incluent le PNT, le phosphate biammoniacal (DAP) et un contrôle non fertilisé. La colonisation des racines de blé par les mycorhizes à vésicules et arbuscules (MVA) a été significativement améliorée avec Glomus intraradices quand la source de P utilisée est le PNT. La présence de BR2 améliore encore plus la colonisation des racines par les MVA. En général, les quantités de graines et paille récoltées ont été significativement améliorées après inoculation avec les microorganismes solubilisant le PNT et Glomus intraradices. La plus forte concentration de P dans les graines a été obtenue avec la co-inoculation avec C1+BR2 et Gi en présence de PNT, tandis que, les plantes inoculées avec BR2+Gi présentaient les plus fortes quantités de P dans la paille en présence du DAP. / Because of the high price of imported P-fertilizers in Mali, the Tilemsi rock phosphate (TRP) is a cheaper locally available P source alternative for farmers. In many areas regardless of its good physical and chemical characteristics, crops and particularly wheat showed very slow response to TRP. With the broad aim of biologically improving P uptake by wheat, in this work we describe the use of TRP solubilizing microorganisms in field inoculation trials. In 3 different Malian wheat cultivars, 4 to 12% of the rhizosphere microorganisms were able to dissolve TRP. Six bacterial and two fungal isolates were selected for their high P-solubilizing activity in solid and liquid media, and were tested in a field in Koygour (Diré) in 2000-2001. Two fungal isolates Aspergillus niger (C1) and Penicillium chrysogenum (C13) and Pseudomonas sp. (BR2) significantly increased plant heights after 60 days, and the fresh and dry matter yields and P-uptake after 90 days of growth. Field assays were performed in Koygour (Diré) in 2001-2002. Inoculation treatments included C1, C13, BR2, C1+BR2, C13BR2, and a control in the presence or absence of the AM fungus Glomus intraradices. P treatments included Tilemsi rock phosphate (TRP), phosphate biammoniacal (DAP) and an unfertilized control. The colonization of wheat root with AM was significantly higher following inoculation with G. intraradices, and when TRP was the P source used. The presence of Pseudomonas strain (BR2) improved root colonization by the AM fungus. In general, straw and grain yield improved significantly following inoculation with AM and phosphate solubilizing microorganisms. The highest P concentration in wheat grain and straw was recorded in treatment including a combinaison of AM, BR2 and C1 in the presence of TRP.

162 leaves printed on single pages, preliminary pages i- vii and numbered pages 1-152. Includes bibliography and abbreviations. / Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner. / Thesis (PhD(Agric))--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Maize, forage sorghum, lucerne, oats, barley and triticale are the most common silage crops in South Africa, while tropical grasses like Eragrostis curvula and Digitaria eriantha are ensiled to a lesser extent. The aim of this study was to determine the effect of adding a lactic acid bacterial inoculant to E. curvula, D. eriantha, lucerne, forage sorghum, maize and oat silage. The effect of the addition of a lactic acid bacterial inoculant when ensiling E. curvula on the fermentation dynamics during ensiling and the aerobic stability of the silage was determined. The addition of the lactic acid bacterial inoculant to E. curvula at ensiling resulted in a more rapid lowering in pH and improved preservation. Inoculated silage had a higher lactic acid content, less protein breakdown and a lower butyric acid content compared to that of the control silage. Both silages were stable when exposed to air for five days. Digitaria eriantha was ensiled, with or without the addition of a lactic acid bacterial inoculant containing Lactobacillus plantarum. Streptococcus faecium and Pediococcus acidilactici together with the enzymes, cellulase, hemicellulase and amylase. The addition of the inoculant resulted in a more rapid drop in pH, a higher level of lactic acid, an increase in the number of lactic acid bacteria, less protein breakdown and lower numbers of enterobacteria, clostridial spores, yeast and mould compared to the control silage. Digitaria eriantha hay, control and inoculated silage diets were fed to 24 Merino rams (n = 8 per treatment) to determine intake and digestibility. The intake of diets consisting of 90.9% D. eriantha hay, control silage or inoculated silage, differed significantly (p<0.05) at 1395, 1540 and 1848 g DM/day, respectively. The in vivo organic matter digestibility (glkg) of D. eriantha hay, untreated silage and inoculated silage diets was 561, 546, 574, respectively. The addition of the bacterial inoculant when ensiling D.eriantha resulted in better preservation, improved aerobic stability, as well as a higher in vivo organic matter digestibility and intake of D. eriantha silage. The addition of an inoculant or molasses to lucerne (Medicago sativa), ensiled in laboratory silos was investigated. The addition of the additives resulted in an increased preservation rate as indicated by a more rapid lowering of pH, a faster rate of lactic acid production and less protein breakdown compared to control silage. The inoculant was more effective than the molasses in improving the rate of preservation. The aerobic stability of lucerne silage was not affected by inoculation or the addition of molasses. The addition of an inoculant to wilted big bale lucerne silage was studied. The inoculant improved silage quality as indicated by a lower pH, higher lactic acid content, lower ammonia nitrogen content and lower level of butyric acid in inoculated silage compared to the control lucerne silage. The composition of big round bale lucerne silage differed markedly from that of lucerne ensiled in laboratory silos as the former had a higher pH, ammonia nitrogen, butyric acid and acetic acid content and a lower lactic content. Whole crop forage sorghum cultivar FS2 was harvested at the late bloom (20.7% DM) and soft dough (28.9% DM) stages of maturity and ensiled in laboratory silos with the addition of commercial silage inoculants. At both stages of maturity the inoculants caused a more rapid rate of pH decline and a higher amount of lactic acid production. All the silages were well preserved. Silages of the sorghum ensiled at the late bloom stage with all treatments were stable after 5 days of aerobic exposure, whereas sorghum ensiled at the soft dough stage with the addition of the inoculants deteriorated upon aerobic exposure. It is concluded that addition of lactic acid bacterial inoculants to mature sorghum at ensiling might impair the aerobic stability of the silage. The yield, nutritional value and production potential of silage made from twenty one maize hybrids was compared. It was concluded that maize hybrids did differ in metabolizable energy content, rate of digestion, predicted intake and predicted milk production potential. The content of NDF and ADF did not differ between the maize hybrids used in this study and could therefore not be used to predict nutritional value or production potential. Maize was harvested at the hard dough stage and ensiled with or without the addition of a lactic acid bacterial inoculant in laboratory silos and in 210 litre drums. The adding of the inoculant to maize at ensiling did not result in a more rapid drop in pH and higher levels of lactic acid. The intake and growth of South African Mutton Merino lambs fed inoculated and untreated maize silage diets was determined. The average daily gain of lambs fed a diet consisting of either 60% control or inoculated maize silage over a growth period of 60 days was 239 ± 26 and 255 ± 44 g/day, respectively. Although the laboratory study showed very little effect of adding a lactic acid bacterial inoculant to maize at ensiling, lambs tended to consume more of the inoculated silage. In the second study the effect of the addition of a lactic acid bacterial inoculant with an enzyme to maize at ensiling on the fermentation dynamics during ensiling, aerobic stability of the silage, the intake, milk production and milk composition of Jersey cows fed maize silage diets was determined. The inoculant did not result in a more rapid lowering of the pH or a more rapid lactic acid production compared to untreated maize silage made in laboratory silos. Both the control and inoculated maize silages were well preserved. The addition of the inoculant to maize at ensiling improved the palatability, intake and the aerobic stability of maize silage compared to the untreated control maize silage. Milk production, milk composition, live weight and condition score of Jersey cows was not significantly affected by the addition of the inoculant to maize silage. The effect of the addition of an enzyme containing lactic acid bacterial inoculant to big bale oat (Avena sativa, cv Cederberg) silage on silage composition, silage intake, milk production and milk composition of Jersey cows was determined. The crop was cut at the bloom stage, wilted and ensiled in big round bales. The inoculant, Sil-All, was applied during the baling process on half of the bales. Silages were fed to Jersey cows in an intake and milk production study. Both the control and inoculated oat silages were well preserved. The inoculated oat silage had a lower level of butyric acid than the control oat silage. Cows fed the inoculated oat silage produced more (P=O.05) milk (17.7 kg/day) than cows fed the control oat silage (16.7 kg/day). The addition of a lactic acid bacterial inoculant to big bale oat silage improved silage composition and animal performance. This study clearly showed that the composition of silages made in bunker silos under commercial farm conditions differ largely from that of silages made in small scale laboratory silos. When the effect of silage additives on aerobic stability of silage is determined the evaluation should include studies on large scale bunker silages. Evaluation of silage additives should include intake and animal production studies. / AFRIKAANSE OPSOMMING: Mielies, voersorghum, lusem, hawer, gars en korog word algemeen as kuilvoer gewasse benut terwyl tropiese grasse soos Eragrostis curvula en Digitaria eriantha tot 'n mindere mate ingekuil word. Die doel van hierdie studie was om die invloed van 'n melksuurbakterieseinokulant op E. curvula-, D. eriantha-, lusem-, voersorghum-, mielie- en hawerkuilvoer te bepaal. Die invloed van 'n melksuurbakteriese-inokulant op die fermentasiedinamika en die aerobiese stabiliteit van E. curvula-kuilvoer is bepaal. Die toediening van die melksuurbakterieseinokulant tot E. curvula tydens inkuiling het 'n vinniger tempo van pH daling en beter preservering tot gevolg gehad in vergelyking met kontrole kuilvoer. Inokulant behandelde kuilvoer het 'n hoer melksuurinhoud, minder protei'en afbraak en 'n laer bottersuurinhoud as kontrole kuilvoer gehad. Beide kuilvoere was stabiel tydens blootstelling aan lug vir vyf dae. Digitaria eriantha is ingekuil met ofsonder die toediening van 'n melksuurbakteriese-inokulant wat Lactobacillus plantarum. Streptococcus faecium en Pediococcus acidilactici sowel as die ensieme, sellulase, hemisellulase and amilase bevat het. Die inokulant het 'n vinniger tempo van pH-daling, hoer vlakke van melksuur en melksuurbakterie, minder protei'en afbraak en laer getalle van enterobakterie, klostridiale spore, giste and swamme in vergelyking met die kontrole tot gevolg gehad. Digitaria eriantha hooi, kontrole kuilvoer en gei'nokuleerde kuilvoer diete is aan 24 Merino ramme (n = 8 per behandeling) gevoer vir bepaling van inname en verteerbaarheid. Die inname van diete wat uit 90.9% D. eriantha hooi, kontrole kuilvoer of gei'nokuleerde kuilvoer bestaan het, het betekenisvol (p<0.05) verskil en was 1395, 1540 en 1848 gDM/dag, respektiewelik. Die in vivo organiesemateriaal verteerbaarheid (gIkg) vanD. eriantha hooi, kontrole kuilvoer en geYnokuleerde kuilvoer was 561, 546, 574, respektiewelik. Die toediening van die bakteriese-inokulant tydens inkuiling vanD. eriantha het beter preservering, verbeterde aerobiese stabiliteit asook 'n hoer in vivo organiesemateriaal verteerbaarheid van D. eriantha kuilvoer tot gevolg gehad. Die effek van toediening van 'n melksuurbakteriese-inokulant en van molasse tot lusem (Medicago sativa) ingekuil in laboratoriumsilos is ondersoek. Die inokulant toediening en molasse toediening het die tempo van preservering versnel, die pH het vinniger gedaal, melksuur is teen 'n hoer tempo geproduseer en minder proteYen afbraak het plaasgevind in vergelyking met die kontrole kuilvoer. Die tempo van preservering is meer effektief deur toediening van die inokulant verhoog as deur die toediening van molasse. Die aerobiese stabiliteit van lusernkuilvoer is nie beYnvloed deur die toediening van inokulant ofmolasse nie. Die effek van die toediening van 'n melksuurbakteriese-inokulant tot groot rondebaal lusernkuilvoer is ondersoek. Die inokulant het die kwaliteit van die kuilvoer verbeter en het 'n laer pH, hoer melksuur, laer ammoniak stikstofen laer bottersuurinhoud in rondebaallusernkuilvoer tot gevolg gehad in vergelyking met kontrole kuilvoer. Groot rondebaallusernkuilvoer het grootliks verskil van lusernkuilvoer wat in laboratoriumsilos ingekuil is. Die rondebaal kuilvoer het 'n hoer pH, hoer ammoniak-stikstof-, bottersuur- en asynsuurinhoud en 'n laer melksuurinhoud gehad as laboratorium lusernkuilvoer. Voersorghum kultivar FS2 is op die laat blom (20.7% DM) en op die sagte deeg (28.9% DM) stadium met die byvoeging van melksuurbakteriese-inokulante ingekuil in laboratoriumsilos. Toediening van beide inokulante tot sorghum hetop beide die inkuilstadiums gelei tot 'n vinniger tempo van pHdaling en meer melksuurproduksie. Aile kuilvoere insluitend die kontrole kuilvoer was goed gepreserveer. Kontrole sowel geYnokuleerde sorghumkuilvoer ingekuil op die laat blomstadium was stabiel tydens aerobiese blootstelling vir 5 dae. Sorghumkuilvoer ingekuil op die sagtedeegstadium met die byvoeging van inokulante was onstabiel tydens aerobiese blootstelling. Die toediening van melksuurbakteriese-inokulante tot sorghum wat op die sagtedeegstadium ingekuil word kan aerobiese stabiliteit van die kuilvoer grootliks benadeel. Die opbrengs, voedingswaarde en produksiepotensiaal van kuilvoer gemaak van 21 mielie hibriede is vergelyk. Verskille in metaboliseerbare energie inhoud, tempo van vertering, voorspelde inname en voorspelde melkproduksie het tussen mielie hibriede voorgekom. Die neutraalbestandevesel- en suurbestandeveselinhoud het nie verskil tussen hibriede nie en derhalwe kon dit nie gebruik word om voedingswaarde ofproduksiepotensiaal te beraam rue. Mielies is op die hardedeegstadium met of sonder die toediening van 'n melksuurbakterieseinokulant in laboratoriumsilos en 210 liter dromme ingekui!. Die toediening van die inokulant het geen invloed op tempo van pH-daling ofproduksie van melksuur gehad nie. Die inname en groei van SA Vleismerino lammers wat 'n dieet bestaande uit 60% kontrole of inokulant behandelde mieliekuilvoer ontvang het, is bepaa!. Die gemiddelde daaglikse toename van lammers was 239 ± 26 and 255 ± 44 g/dag vir die kontrole en inokulant mieliekuilvoer dieet respektiewelik. Alhoewel die laboratoriumstudie weinig verskille tussen die kontrole en die geYnokuleerde mieliekuilvoer getoon het, het lammers geneig om meer van die geYnokuleerde mieliekuilvoer in te neem. In die tweede studie met mieliekuilvoer is die effek van toediening van 'n melksuurbakteriese-inokulant met ensieme, op die ferrnentasiedinamika tydens inkuiling, die aerobiese stabiliteit van mieliekuilvoer asook die inname, melkproduksie en melksamestelling van Jersey koeie bepaa!. Die inokulant het nie die tempo van pH daling en produksie van melksuurverhoog nie en beide kontrole en geYnokuleerde mieliekuilvoerwas goed gepreserveer. Die toediening van die inokulant tot mieliekuilvoer het die smaaklikheid, inname en die aerobiese stabiliteit van mieliekuilvoer verhoog in vergeiyking met kontrole mieliekuilvoer. Melkproduksie, melksamestelling, liggaamsmassa en kondisiepunt van Jersey koeie is nie betekenisvol beYnvloed deur die toediening van die inokulant tot mieliekuilvoer nie. Die effek van die toediening van 'n ensiem bevattende melksuurbakteriese-inokulant tot groot rondebaal hawer (Avena sativa, cv Cederberg) kuilvoer op die samestelling van kuilvoer, kuilvoerinname, melkproduksie en melksamestelling van Jersey koeie is bepaa!. Die gewas is gesny op die blomstadium, verwelk en as rondebaalkuilvoer gepreserveer. Die inokulant, Sil-All, is tydens die baalproses toegedien op die helfte van die bale. Kuilvoere is aan Jersey koeie gevoer in 'n inname en melkproduksiestudie. Beide die kontrole en geYnokuleerde hawerkuilvoer was goed gepreserveer. Die bottersuurinhoud van geYnokuleerde hawerkuilvoer was laer as die van die kontrole hawerkuilvoer. Koeie wat geYnokuleerde hawerkuilvoer gevoer is het meer (P=0.05) melk (17.7 kg/dag) geproduseer as koeie wat kontrole hawerkuilvoer ontvang het (16.7 kg/dag). Die toediening van 'n melksuurbakteriese-inokulant het kuilvoer kwaliteit en diereproduksie verbeter. Hierdie studie wys duidelike verskille uit tussen kuilvoer wat in bunkersilos onder kommersiele toestande ingekuil is, en kuilvoer wat in laboratoriumsilos gemaak is. Wanneer die effek van kuilvoerbymiddels op die aerobiese stabiliteit van kuilvoer bepaal word behoort finale evaluasie gedoen te word op kuilvoer gemaak in bunkersilos soos onder plaastoestande plaasvind. Evaluasie van kuilvoerbymiddels behoort inname en diereproduksiestudies in te sluit.

Herbicides have become a key component in modern agricultural production. Meanwhile, there is a concern that some herbicides persist past the growing season of the treated crop, and negatively influence the production of the subsequently planted crops. Amongst various herbicides used in western Canada, acetohydroxyacid synthase (AHAS)-inhibiting herbicides warrant special attention given their residual properties and acute plant toxicity at low concentrations in soil. Soil residual AHAS inhibitors have the potential to influence both leguminous host plants and their bacterial symbiotic partners; consequently, the use of an AHAS inhibitor in a given year can negatively influence the inoculation success and grain yield of legumes cropped in the following year. <p>The present thesis project focused on one of the AHAS inhibiting herbicides (flucarbazone) and studied its potential for carryover injury and negative influence on the success of inoculation in field pea. A series of growth chamber and field experiments were conducted to test the following null hypothesis: the presence of residual flucarbazone in soil does not affect nodulation of field pea by inoculum rhizobia. <p>A growth chamber experiment clearly demonstrated the susceptibility of field pea to the presence of flucarbazone in soil where the lowest concentration of flucarbazone amendment (5 ìg kg1) significantly reduced the crop growth. In contrast, a field study failed to reveal any negative effects of flucarbazone use on crop growth and N2 fixation. <p>It was concluded that if the weather and soil conditions favour decomposition of flucarbazone as described in the present study, flucarbazone applied at the recommended field rate will not persist into the following season at high enough concentrations to negatively influence field pea growth, grain yields, and inoculation success. To ensure safety of rotational crops, it is important to strictly adhere to the herbicide application guidelines. Additionally, producers are cautioned to be particularly aware of the environmental and soil conditions that may reduce the rate of herbicide degradation.

Herbicides have become a key component in modern agricultural production. Meanwhile, there is a concern that some herbicides persist past the growing season of the treated crop, and negatively influence the production of the subsequently planted crops. Amongst various herbicides used in western Canada, acetohydroxyacid synthase (AHAS)-inhibiting herbicides warrant special attention given their residual properties and acute plant toxicity at low concentrations in soil. Soil residual AHAS inhibitors have the potential to influence both leguminous host plants and their bacterial symbiotic partners; consequently, the use of an AHAS inhibitor in a given year can negatively influence the inoculation success and grain yield of legumes cropped in the following year. <p>The present thesis project focused on one of the AHAS inhibiting herbicides (flucarbazone) and studied its potential for carryover injury and negative influence on the success of inoculation in field pea. A series of growth chamber and field experiments were conducted to test the following null hypothesis: the presence of residual flucarbazone in soil does not affect nodulation of field pea by inoculum rhizobia. <p>A growth chamber experiment clearly demonstrated the susceptibility of field pea to the presence of flucarbazone in soil where the lowest concentration of flucarbazone amendment (5 ìg kg1) significantly reduced the crop growth. In contrast, a field study failed to reveal any negative effects of flucarbazone use on crop growth and N2 fixation. <p>It was concluded that if the weather and soil conditions favour decomposition of flucarbazone as described in the present study, flucarbazone applied at the recommended field rate will not persist into the following season at high enough concentrations to negatively influence field pea growth, grain yields, and inoculation success. To ensure safety of rotational crops, it is important to strictly adhere to the herbicide application guidelines. Additionally, producers are cautioned to be particularly aware of the environmental and soil conditions that may reduce the rate of herbicide degradation.