O emprego de culturas starter tem a finalidade de originar uma população microbiana que supere a microbiota contaminante ou mesmo natural da matéria-prima. O presente trabalho teve por objetivo estudar a influência de culturas starter compostas por diferentes combinações de microrganismos, assim como de uma bactéria lática não starter descrita como produtora de bacteriocina (Lactobacillus sake 2a) sobre a capacidade de sobrevivência de Staphylococcus aureus artificialmente inoculado e de diferentes grupos de microrganismos (coliformes totais, Escherichia coli, bolores e leveduras, mesófilos, bactérias láticas e Staphylococcus spp.), durante o período de maturação e vida-de-prateleira de salames tipo Italiano. Um total de 14 tratamentos tipos de salames foram preparadas (em duplicata), com as seguintes variáveis: adição ou não de 2 ou 3 culturas starter em partes iguais (FF1 + SL ou FF1 + SL + SPX, Chr. Hansen); adição ou não de uma cultura não starter; adição ou não de sais de cura. Dentre as formulações, 8 foram artificialmente contaminadas com S. aureus. As análises foram conduzidas no início do processamento (matéria-prima), durante a maturação (2º, 10º e 20º dia) e a vida-de-prateleira (a cada 10 dias, até o 90º dia). Observou-se que, apesar dos diferentes tratamentos testados, S. aureus não foi eliminado antes do término do período de maturação, permanecendo viável no produto até o final ou até boa parte de sua vida de prateleira, com uma redução que variou de 1,27 ciclos log (salames adicionados de 2 tipos culturas e sais de cura) e 1,08 ciclos log (salames adicionados de 3 tipos culturas e sais de cura). As produções adicionadas de Lactobacillus sake não puderam ser classificadas como salame tipo Italiano, por não terem alcançado o pH característico do produto, ao contrário do que ocorreu com os demais salames produzidos. A adição de sais de cura dificultou a inibição da maioria dos microrganismos, particularmente de S. aureus, exceto no caso das formulações com L. sake, para as quais observou-se um efeito sinérgico aditivo entre a cultura e os sais de cura, efeito entretanto insuficiente para garantir a segurança do produto. Os dados obtidos não permitiram concluir sobre a diferenças entre a adição ou não de culturas starter, bem como a sua composição, sobre a inibição dos microrganismos. Apesar do salame ser um produto que não fornece condições adequadas para a multiplicação microbiana, se houver uma alta contaminação inicial de S. aureus e, possivelmente, de outros patógenos, esta permanecerá no produto, podendo chegar ao consumidor com populações relativamente elevadas. / The use of starter cultures has the purpose of providing sufficient microbial numbers to ensure numerical dominance over the natural contaminating flora. The objective of this study was to evaluate the influence of starter cultures composed of different combinations of microorganisms and of a non starter bacteriocin producing lactic acid bacteria (Lactobacillus sake 2a) over the survival of an artificially inoculated Staphylococcus aureus strain and of different groups of microorganisms (total coliforms, Escherichia coli, yeasts and molds, mesophiles, lactic acid bacteria and Staphylococcus spp.), during the curing process and the shelf life of Italian salami. Fourteen formulations of salami were prepared (twice each), employing the following variables: addition or not of 2 or 3 starter cultures in equal parts (FF1 + SL or FF1 + SL + SPX, Chr. Hansen); addition or not of a non starter culture; addition or not of a curing agent composed of nitrite and nitrate. Eight of the formulations were artificially contaminated with S. aureus. Analysis proceeded in the beginning of the manufacturing process (meat), during the curing process (after the 2nd, the 10th and the 20th day) and during the shelf-life of the product (every 10 days, up to the 90th day). It was observed that, in spite of the different kinds of treatments tested, S. aureus was not eliminated during the curing process, remaining viable until the end of the shelf life, or at least during most part of it. Formulations added of L. sake could not be classified as salami, as they did not reach the typical pH of the product, pH that was reached by the other formulations prepared. Addition of curing salts made inhibition of most microorganisms difficult, particularly in the case of S. aureus, except for formulations added of L. sake, for which synergistic effect between the culture and the curing agent was observed, though unsatisfactory to ensure safety of the product. Data obtained was not enough to conclude about differences between effects of addition or not of starter cultures, and its composition, over inhibition of microorganisms. Even though salami is a product which does not provide good microbial growth conditions, when initial contamination of S. aureus, and possibly of other pathogens, is high, it will remain in the product that reaches consumers with high microbial loads.

O emprego de culturas starter tem a finalidade de originar uma população microbiana que supere a microbiota contaminante ou mesmo natural da matéria-prima. O presente trabalho teve por objetivo estudar a influência de culturas starter compostas por diferentes combinações de microrganismos, assim como de uma bactéria lática não starter descrita como produtora de bacteriocina (Lactobacillus sake 2a) sobre a capacidade de sobrevivência de Staphylococcus aureus artificialmente inoculado e de diferentes grupos de microrganismos (coliformes totais, Escherichia coli, bolores e leveduras, mesófilos, bactérias láticas e Staphylococcus spp.), durante o período de maturação e vida-de-prateleira de salames tipo Italiano. Um total de 14 tratamentos tipos de salames foram preparadas (em duplicata), com as seguintes variáveis: adição ou não de 2 ou 3 culturas starter em partes iguais (FF1 + SL ou FF1 + SL + SPX, Chr. Hansen); adição ou não de uma cultura não starter; adição ou não de sais de cura. Dentre as formulações, 8 foram artificialmente contaminadas com S. aureus. As análises foram conduzidas no início do processamento (matéria-prima), durante a maturação (2º, 10º e 20º dia) e a vida-de-prateleira (a cada 10 dias, até o 90º dia). Observou-se que, apesar dos diferentes tratamentos testados, S. aureus não foi eliminado antes do término do período de maturação, permanecendo viável no produto até o final ou até boa parte de sua vida de prateleira, com uma redução que variou de 1,27 ciclos log (salames adicionados de 2 tipos culturas e sais de cura) e 1,08 ciclos log (salames adicionados de 3 tipos culturas e sais de cura). As produções adicionadas de Lactobacillus sake não puderam ser classificadas como salame tipo Italiano, por não terem alcançado o pH característico do produto, ao contrário do que ocorreu com os demais salames produzidos. A adição de sais de cura dificultou a inibição da maioria dos microrganismos, particularmente de S. aureus, exceto no caso das formulações com L. sake, para as quais observou-se um efeito sinérgico aditivo entre a cultura e os sais de cura, efeito entretanto insuficiente para garantir a segurança do produto. Os dados obtidos não permitiram concluir sobre a diferenças entre a adição ou não de culturas starter, bem como a sua composição, sobre a inibição dos microrganismos. Apesar do salame ser um produto que não fornece condições adequadas para a multiplicação microbiana, se houver uma alta contaminação inicial de S. aureus e, possivelmente, de outros patógenos, esta permanecerá no produto, podendo chegar ao consumidor com populações relativamente elevadas. / The use of starter cultures has the purpose of providing sufficient microbial numbers to ensure numerical dominance over the natural contaminating flora. The objective of this study was to evaluate the influence of starter cultures composed of different combinations of microorganisms and of a non starter bacteriocin producing lactic acid bacteria (Lactobacillus sake 2a) over the survival of an artificially inoculated Staphylococcus aureus strain and of different groups of microorganisms (total coliforms, Escherichia coli, yeasts and molds, mesophiles, lactic acid bacteria and Staphylococcus spp.), during the curing process and the shelf life of Italian salami. Fourteen formulations of salami were prepared (twice each), employing the following variables: addition or not of 2 or 3 starter cultures in equal parts (FF1 + SL or FF1 + SL + SPX, Chr. Hansen); addition or not of a non starter culture; addition or not of a curing agent composed of nitrite and nitrate. Eight of the formulations were artificially contaminated with S. aureus. Analysis proceeded in the beginning of the manufacturing process (meat), during the curing process (after the 2nd, the 10th and the 20th day) and during the shelf-life of the product (every 10 days, up to the 90th day). It was observed that, in spite of the different kinds of treatments tested, S. aureus was not eliminated during the curing process, remaining viable until the end of the shelf life, or at least during most part of it. Formulations added of L. sake could not be classified as salami, as they did not reach the typical pH of the product, pH that was reached by the other formulations prepared. Addition of curing salts made inhibition of most microorganisms difficult, particularly in the case of S. aureus, except for formulations added of L. sake, for which synergistic effect between the culture and the curing agent was observed, though unsatisfactory to ensure safety of the product. Data obtained was not enough to conclude about differences between effects of addition or not of starter cultures, and its composition, over inhibition of microorganisms. Even though salami is a product which does not provide good microbial growth conditions, when initial contamination of S. aureus, and possibly of other pathogens, is high, it will remain in the product that reaches consumers with high microbial loads.

The thesis presents the design and analysis of a Twin Tensioner for a Belt-driven Integrated Starter-generator (B-ISG) system. The B-ISG is an emerging hybrid transmission closely resembling conventional serpentine belt drives. Models of the B-ISG system's geometric properties and dynamic and static states are derived and simulated. The objective is to reduce the magnitudes of static tension in the belt for the ISG-driving phase. A literature review of hybrid systems, serpentine belt drive modeling and automotive tensioners is included. A parametric study evaluates tensioner parameters with respect to their impact on static tensions. Design variables are selected from these for an optimization study. The optimization uses a genetic algorithm (GA) and a hybrid GA. Results of the optimization indicate the optimal system contains spans with static tensions that are significantly lower in magnitude than that of the original design. Implications of the research on future work are discussed in closing.

The thesis presents the design and analysis of a Twin Tensioner for a Belt-driven Integrated Starter-generator (B-ISG) system. The B-ISG is an emerging hybrid transmission closely resembling conventional serpentine belt drives. Models of the B-ISG system's geometric properties and dynamic and static states are derived and simulated. The objective is to reduce the magnitudes of static tension in the belt for the ISG-driving phase. A literature review of hybrid systems, serpentine belt drive modeling and automotive tensioners is included. A parametric study evaluates tensioner parameters with respect to their impact on static tensions. Design variables are selected from these for an optimization study. The optimization uses a genetic algorithm (GA) and a hybrid GA. Results of the optimization indicate the optimal system contains spans with static tensions that are significantly lower in magnitude than that of the original design. Implications of the research on future work are discussed in closing.

This work aimed to produce and to apply in dry fermented sausage a lactic acid starter culture using a pork plasma culture medium and to evaluate the effect of two levels (0.5% and 1%) of hydroalcoholic extract of marcela (Achyrocline satureioides) in the security and quality of dry fermented sausages. In the first experiment, the microorganism Lactobacillus plantarum was fermented with control of pH, during 36 hours, under continuous agitation of 100 rpm, at a temperature of 37 (± 0.1ºC). After entering in the stationary phase the culture was lyophilizated and applied in dry fermented sausage, evaluating its influence in the microbiological, physico-chemical and sensorial characteristics. For comparative effects, were elaborated treatments without addition of starter culture and with addition of a commercial culture. In the second experiment, dry fermented sausages had been elaborated with 0.5% and 1% of hydroalcoholic extract of marcela and without extract, considered as control. The parameters of pH, water activity, colour and weight loss were evaluated during the manufacture of the dry fermented sausages. During the storage the TBARS values were determined and verified the sensorial acceptance. The microorganism Lactobacillus plantarum had a maximum growth of 9.82 Log UFC.mL-1, after 30 hours of fermentation and it presented 90.05% of survival to the lyophilization. The dry fermented sausages elaborated with the starter culture produced had presented a decrease on pH significantly faster and a lower water activity than the others treatments. Moreover, the microorganism Lactobacillus plantarum improved significantly the flavor of the dry fermented sausages. The marcela extract addition decreased (p<0.05) the TBARS values during the storage of the dry fermented sausages, compared with the control. The treatment with 1% of marcela extract showed a bigger lipid stability than that with 0.5%, however it presented a reduction (p<0.05) in the sensorial acceptance. The two marcela extract levels had not influenced the parameters of pH, water activity, colour and weight loss. Therefore, this study indicated that the pork plasma culture medium is an alternative in the commercial production of lactic acid bacteria and that the starter culture produced provided a dry fermented sausage with greater microbiological security and better sensorial acceptance. The hydroalcoholic extract of marcela decreased the lipid oxidation and the concentration of 0.5% did not modify the sensorial characteristics, being able, therefore, to be used in the elaboration of safer dry fermented sausages to the consumers. / Este trabalho teve por objetivo produzir e aplicar em salame uma cultura starter ácido láctica utilizando um meio de cultura de plasma suíno e avaliar o efeito de dois níveis (0,5% e 1%) de extrato hidro-alcoólico de marcela (Achyrocline satureioides) na segurança e qualidade de salames. No primeiro experimento, o microrganismo Lactobacillus plantarum foi fermentado em um meio de cultura de plasma suíno, com controle de pH, durante 36 horas, sob agitação contínua a 100 rpm e temperatura de 37 (± 0,1ºC). Após entrar na fase estacionária a cultura foi liofilizada e aplicada em salame, avaliando sua influência nas características microbiológicas, físico-químicas e sensoriais. Para efeitos comparativos, foram elaborados tratamentos sem adição de cultura starter e com adição de uma cultura comercial. No segundo experimento, salames foram elaborados com 0,5% e 1% de extrato hidro-alcoólico de marcela e sem extrato, considerados como controle. Os parâmetros de pH, atividade de água, cor e perda de peso foram avaliados durante a fabricação dos salames. Durante o armazenamento os valores de TBARS foram determinados e foi verificada a aceitação sensorial. O microrganismo Lactobacillus plantarum teve um crescimento máximo de 9,82 Log UFC.mL-1, após 30 horas de fermentação e apresentou 90,05% de sobrevivência a liofilização. Os salames elaborados com a cultura starter produzida apresentaram uma queda de pH significativamente mais rápida e uma menor atividade de água que os demais tratamentos. Além disso, o microrganismo Lactobacillus plantarum significativamente melhorou o sabor dos salames. A adição de extrato de marcela diminuiu (p<0,05) os valores de TBARS durante o armazenamento dos salames, comparado ao controle. O tratamento com 1% de extrato de marcela mostrou uma maior estabilidade lipídica do que aquele com 0,5%, porém apresentou uma diminuição (p<0,05) na aceitação sensorial. Os dois níveis de extrato de marcela não influenciaram significativamente os parâmetros de pH, atividade de água, cor e perda de peso. Portanto, este estudo indicou que o meio de cultura de plasma suíno é uma alternativa na produção comercial de bactérias ácido lácticas e que a cultura starter produzida proporcionou salames de maior segurança microbiológica e melhor aceitação sensorial. O extrato hidro-alcoólico de marcela diminuiu a oxidação lipídica e a concentração de 0,5% não alterou as características sensoriais, podendo, portanto, ser utilizada na elaboração de salames mais seguros aos consumidores.

Master of Science / Department of Agronomy / David B. Mengel / This study was initiated to determine if potassium (K) deficiencies seen in soybeans (Glycine max (L.) Merr.) under no-till and strip-till production systems are impacting soybean yields, and if so, what fertilizer application practices including: rate of K application; broadcast or deep band methods of application; and the use of starter fertilizer at planting; could be used to correct the problem. The residual impacts of K fertilization and placement were also evaluated on corn (Zea mays L.) grown in rotation with soybeans. This research was conducted on-farm in cooperation with local producers. Soybeans sites in 2007 were near Harris, Ottawa and Westphalia, Kansas with corn planted in 2008 at the sites near Ottawa and Westphalia. Soybean sites in 2008 were located near Ottawa and Welda, Kansas. Selected sites were generally near or below the current soil test K critical level of 130 mg per kg extractable K, based on sampling histories provided by the cooperators. Sampling in the spring of 2007 confirmed these soil test (ST) K levels. Soybean leaf tissue potassium levels in 2007 were less than the critical level of 17 mg per kg in the unfertilized control plots, and were significantly greater when potassium fertilizer was deep banded or a high-rate of K fertilizer was broadcast. No significant difference in yield of soybeans due to K fertilization was seen, likely due to significant water stress during the grain fill period, which severely limited soybean yield in 2007. Soil test K levels at all the research sites increased dramatically between 2007 and 2008, even where no K was applied. Different weather conditions experienced these two years may have contributed to this occurrence. No residual impacts of K fertilization in 2007 on soybeans were seen in soil tests, corn leaf tissue K levels or corn yield in 2008. Soybean sites in 2008 also showed a dramatic increase in K ST levels in 2008 as compared to farmer records. No effects of K fertilization on soybean growth or yield were seen in 2008. The 2008 Ottawa soybean site had very low P soil tests. A significant response to P fertilization contained in the starter treatments was observed. This suggests that the dominant farmer practice of applying P and K fertilizer to corn, and not applying fertilizer directly to soybeans, even at low soil test levels, may not be supplying adequate P to soybeans, and is likely costing farmers yields and profits.

Submitted in fulfilment of the requirements for the Degree of Doctor of Technology: Biotechnology, Durban University of Technology, 2010. / Cassava, (Manihot esculenta Crantz), is used for the production of a variety of West African foods and ranks fourth in the list of major crops in developing countries after rice, wheat and maize. Gari is one of the most popular foods produced from cassava. Cassava may contain high levels of linamarin, a cyanogenic glucoside, which in its natural state is toxic to man. Therefore, some processing methods that can enhance the detoxification of cassava and lead to the improvement of the quality and hygienic safety of the food are vitally important for less toxic products to be obtained. Quality, safety and acceptability of traditional fermented foods may be improved through the use of starter cultures. There has been a trend recently to isolate wild-type strains from traditional products for use as starter cultures in food fermentation. A total of 74 bacterial strains and 21 yeast strains were isolated from a cassava mash fermentation process in a rural village in Benin, West Africa. These strains were assessed, together with 26 strains isolated at the CSIR from cassava samples sent from Benin previously, for phenotypic and technological properties. Twenty four presumptive lactic acid bacteria (LAB) were selected for further phenotypic, genotypic and technological characterization during a research visit to the BFE (now Max Rubner Institute of Nutrition and Food). After assessment, the strains VE 20, VE 36, VE 65b, VE 77 and VE 82 were chosen for further study as starter cultures. These L. plantarum strains were chosen on the basis of predominance and possession of suitable technological properties. The investigation of this study was complemented by further, similar studies on further Gari isolates in Germany by the BFE. That study was done independently from this study, but both studies served to select potential starter cultures for cassava fermentation for the production of Gari, as this was the common goal of the project. Thus, a wider final selection of potential starter cultures was decided on at the project level and this selection was further tested in fermentation experiments. A total of 17 strains were grown in optimized media in 2 L fermenters. These strains were freeze-dried and thereafter tested in lab-scale cassava mash fermentation trials. xiii The strains performed well in the small scale bucket fermentations. There was a rapid acidification evidenced by the increase in titratable acidity, ranging from 1.1 to 1.3 % at 24 hours, and 1.3 to 1.6 % at 48 hours. The effect of the starter was obvious in that it lowered the pH much faster and to lower levels than the control. It appeared that both the processing and starter culture addition played a role in the removal of cyanide during processing of the cassava into Gari. This was evident from the lower cyanide values obtained for fermentations that included starter cultures. The study also showed that especially the L. plantarum group strains could be produced as starter cultures at lower costs than compared to L. fermentum, W. paramesenteroides or L. mesenteroides strains. Overall the results of this study were crucial for the project in showing that a starter culture which is easy and economical to produce and which has the desired attributes is a feasible possibility for application in the field.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Barley malt is the predominant raw material for beer brewing world-wide. To meet consumer demand, a constant high quality malt product is required. Malt quality is determined by the degree of substrate hydrolysis during germination and mashing which serves as fermentable substrates for alcoholic fermentation during brewing. It is often difficult to sustain malt of high quality due to inconsistent malt batches and poor germination capacities of dormant barley. External additives such as chemicals and gibberellic acid have been used to overcome these difficulties but are unwanted in the beverage industry. Maltsters are consequently always in search of alternative solutions. Microbes produce diverse enzymes which can contribute to substrate hydrolysis during germination. The development of such starter cultures might provide a natural and economically feasible alternative to augment barley germination. Starter culture technology has been employed in the malting industry, although the main focus has been to improve the microbial stability of malt. The exploitation of cultures with hydrolytic capabilities to augment barley germination is consequently largely unexplored. The aim of this study was to develop a starter culture which can contribute to the enzymatic degradation of barley polymers. Geotrichum spp. and Lactobacillus plantarum were isolated from substrates rich in polymers present in barley and screened for enzymatic capabilities. Geotrichum spp. produced cellulase, xylanase, protease and β-glucanase activities, while L. plantarum harboured cell-bound and extracellular α-amylase activities. These cultures were added in different combinations during the malting of Erica and SSG 564 cultivars, but did not enhance germination significantly. Improved malt parameters did not correlate with microbial enzyme activities and the data were not repeatable. Preliminary plate assays could thus not be used to predict enzyme production in a malting environment. Cell-free supernatants with known enzyme activities of Aspergillus sp., Trichoderma reesei and Rhizopus sp. significantly enhanced malt quality. To our knowledge, the use of fungal supernatant to augment malt modification is a novel concept. Supernatant is more convenient than starter cultures and will aid to deliver more constant malt products than live cultures, as known enzyme levels are added. / AFRIKAANSE OPSOMMING: Garsmout is wêreldwyd die oorheersende roumateriaal vir bier brou. Om die aanvraag van verbruikers te bevredig, word 'n konstante hoë gehalte mout produk vereis. Die kwailiteit van mout word bepaal deur die graad van substraathidrolise gedurende ontkieming, wat dien as fermenteerbare substraat vir alkoholiese fermentasie tydens verbrouing. Dit is dikwels moeilik om ʼn konstante, hoë gehalte, moutproduk te lewer as gevolg van variasie in mout en die swak ontkiemingsvermoë van dormante gars. Hierdie probleem kan oorbrug word met eksterne toevoegings soos chemikalieë en gibberelliensuur, maar dit is nie ʼn gewensde praktyk in die broubedryf nie. Vermouters is gevolglik gedurig op soek na alternatiewe oplossings. Mikroörganismes produseer diverse ensieme wat kan bydra tot substraathidrolise gedurende ontkieming. Die ontwikkeling van sodanige suurselkulture is moontlik 'n natuurlike en ekonomies praktiese alternatief om die ontkieming van gars te stimuleer. Suurselkulture is reeds in die moutindustrie gebruik, alhoewel die fokus hoofsaaklik was om die mikrobiese stabiliteit van mout te verbeter. Die konsep om kulture met hidrolitiese vermoëns te gebruik om garsontkieming aan te vul is gevolglik grootliks onverken. Die doel van hierdie studie was om 'n suurselkultuur te ontwikkel wat kan bydra tot 'n ensiematiese afbraak van die polimere in gars. Geotrichum spp. en Lactobacillus plantarum is uit substrate ryk aan polimere teenwoordig in gars geïsoleer en vir hul ensiem aktiwiteite getoets. Geotrichum spp. het sellulase, xylanase, protease en β-glukanase aktiwiteit getoon, terwyl L. plantarum sel-gebonde en ekstrasellulêre α-amilase aktiwiteit getoon het. Hierdie kulture is in verskillende kombinasies tydens die vermouting van Erica en SSG 564 kultivars bygevoeg, maar het nie tot ʼn verbetering in die ontkieming van die gars gelei nie. Geen korrelasie is gevind tussen verbeterde mout parameters en mikrobiese ensiemaktiwiteit nie. Die resultate was ook nie herhaalbaar nie. Voorlopige plaattoetse kan dus nie as 'n maatstaf gebruik word om ensiem produksie deur suurselkulture in vermounting te voorspel nie. Sel-vrye supernatante van Aspergillus sp., Trichoderma reesei en Rhizopus sp., met bekende ensiem aktiwiteit, het die gehalte van mout aansienlik verbeter. Sover ons kennis strek is die gebruik van supernatante van fungi om die ontkieming van gars te stimuleer ʼn nuwe konsep. Supernatant is meer gerieflik as suurselkulture en sal help om konstante mout produkte te lewer aangesien ensiemvlakke beter beheer kan word.

Doctor of Philosophy / Department of Agronomy / Dorivar Ruiz Diaz / Winter annual weeds (WAW) could affect nitrogen supply for corn production. The objectives of first study were to determine the diversity and abundance of WAW and to evaluate the effect of delaying herbicide applications on nitrogen supply and no-till corn response. Research was conducted in 2010 and 2011 at 14 sites in eastern Kansas. A factorial arrangement of three herbicide application dates (Nov.-Mar., April, and May) and five N rates were used. The three most abundant WAW across sites were henbit, purslane speedwell, and horseweed. Delaying herbicide application until April significantly reduced early corn N uptake by 52 mg N plant-1, chlorophyll meter readings at silking by 3.4%, and grain yield by 0.48 Mg ha-1 across sites. An additional 16 to 17 kg N ha-1 was needed to maintain yield if herbicide application was delayed until April. Starter and foliar micronutrient fertilization can potentially increase corn and soybean yield. The objectives of the second study were to evaluate crop response from combinations of starter and foliar fertilizers that contain N-P-K mixtures with and without a blend of micronutrients at four sites for each crop under irrigated conditions. No early corn growth or yield increase was attributed to application of micronutrients (Fe, Mn, Zn, Cu, and B) beyond what was achieved with N-P-K starter fertilization. There was an increase in soybean height (8 cm) and yield (293 kg ha-1) with starter fertilizer containing N-P-K plus micronutrients over the control. No increase in corn or soybean yield was obtained with foliar fertilization. The objective of the third study was to compare soil mobility and changes in soybean nutrient concentration in the leaf and seed from Mn and Zn sources (EDTA and oxysulfate) at two sites. Zinc sources were more mobile in the soil. Both Zn sources increased seed Zn concentration. Manganese oxysulfate increased seed Mn concentration. However, soybean trifoliolate leaf and seed Mn concentration decreased with soil-applied Na2EDTA and MnEDTA. This response was attributed to formation of FeEDTA and increased Fe supply that reduced root Mn absorption. Manganese EDTA is not recommended for soil application.

The effects of whey-based and milk -based starter media, and low concentrations (0.02% each) of citrate, phosphate and calcium upon various milk coagulation properties were measured. Samples inoculated with milk-based starter medium had shorter coagulation times, faster rate of curd formation, and greater final curd firmness than those inoculated with externally neutralized whey-based starter. Starter medium treatment was statistically interacted with calcium for coagulation time and rate of curd formation. Citrate addition caused longer coagulation times, slower rates of curd formation, and weaker final coagula. Citrate interacted with calcium and phosphate for several of the parameters measured. Addition of phosphate did not affect any of the measured parameters but was involved in several significant two-factor interactions as was calcium addition.