Rich fens are an important, but threatened, habitat type in the boreal landscape. In this thesis I have examined responses of rich fen vascular plants and bryophytes after drainage and restoration. The effects of drainage on the rich fen flora were observed in a long time study and the responses were rapid and drastic. During an initial stage a rapid loss of brown mosses was observed, followed by increases of sedges and early successional bryophytes, and later by an expansion of dominants. Initial effects of hydrological restoration showed that rewetting can promote re-establishment of an ecologically functional rich fen flora, but has to be combined with other treatments, such as mowing or surface disturbance. After restoration, re-establishment of locally extinct species may be hampered by dispersal limitations. To test if reintroductions could help to overcome dispersal limitations I performed transplantation studies with four common rich fens bryophytes to a rewetted site. The results showed that the species were able to establish, and that survival and growth were promoted by desiccation protection and liming. I further examined competition among three of the most common bryophytes in natural boreal rich fens that usually occur mixed in a mosaic pattern but show small but important microtopographical niche separation. The results indicate similar competitive abilities among the species, and no case of competitative exclusion occurred. The results help to explain the coexistence of these species under natural conditions with microtopographic variation and repeated small scale natural disturbances. Restoring a functional flora in drained rich fens is a complex task, which requires understanding of underlying causes of substrate degradation in combination with suitable restoration measures. The thesis suggests how the results can be used in practical restoration work, and also stresses the need for monitoring of restoration experiments over longer time.

Using paleolimnological techniques, I have studied surface-water acidification and the effects of liming in Swedish lakes on a decadal to millennial time-scale. The overall objective was to contribute to the discussion on the fulfilment of goals within the Swedish liming program. One of the main goals of this program is to restore lakes to natural or nearly natural conditions, i.e. to a reference condition as termed in the EU Water Framework Directive. In this context, a key issue is to define reference conditions. This is a central theme of my thesis, as lake sediments offer a unique way to study past lake conditions. Past lake-water acidity of 12 reference lakes in the Swedish liming program (ISELAW) was determined using diatom analysis of sediment cores. Pollen, lead, and flyash from coal/oil combustion were used as indicators of impact from land use and atmospheric pollution. A general trend in these lakes is an initial decline in pH after lake formation due to natural soil processes, which was then followed by rather low pH values (pH 5.3-6.5). In six of the lakes pH increased as a result of expansion of agriculture (burning, forest grazing) 2000 to 1000 years ago. Local mining and long-range airborne pollution have also impacted the lakes since medieval time. These results show that the conditions of the study lakes were not natural prior to industrialization and recent (20th century) acidification. The ISELAW lakes were selected on the basis of representing typical limed lakes, and they have been limed and monitored since at least the 1980s. A comparison of chemical/biological monitoring data and the paleolimnological data gives somewhat diverging results. Most of the monitoring data suggest that the lakes were subjected to acidification during the 20th century, but the paleolimnological data can only identify clear evidence of acidification in five of the 12 lakes, hence, all lakes were probably not recently acidified. According to conclusions from monitoring the lakes have recovered following liming. The paleolimnological data give a more complex picture and three different responses have been identified: 1) a return to a diatom composition found in the lake one hundred to several thousand years ago; 2) very small shifts in the diatom composition; or 3) a diatom composition previously not found in the lake. The latter response raised the question whether liming can cause an unnatural diatom community. A comparison of diatoms in surface sediment samples of 31 limed lakes with pre-industrial reference samples from 291 lakes showed that liming does not create an unnatural diatom composition. These results illustrate that the goals for liming were not reached in all of the limed lakes, and that paleolimnology can play an important role for assessments of acidification and liming. The comparative study also highlights the importance of designing monitoring programs that can produce reliable and long data series. Given the results of the paleolimnological investigations, it is obvious that we cannot assume that the 19th century represented a natural or near natural state, and thus is a realistic reference conditions. Natural long-term lake development and previous land-use impacts need to be considered in defining reference conditions. Neither can we disregard the fact that humans always will impact nature. Although paleolimnological studies are time consuming, I believe that they could be simplified to the extent that paleolimnology could become a routine method for environmental management.

The diasporic resources and transnational flows of the Black diaspora have increasingly been of concern to scholars. However, the making of the Black diaspora in Canada has often been overlooked, and the use of sport to connect migrants to the homeland has been virtually ignored. This study uses African, Black and Caribbean diaspora lenses to examine the ways that first generation Caribbean-Canadians use cricket to maintain their association with people, places, spaces, and memories of home. In this multi-sited ethnography I examine a group I call the Mavericks Cricket and Social Club (MCSC), an assembly of first generation migrants from the Anglo-Caribbean. My objective to “follow the people” took me to parties, fundraising dances, banquets, and cricket games throughout the Greater Toronto Area on weekends from early May to late September in 2008 and 2009. I also traveled with approximately 30 MCSC members to observe and participate in tours and tournaments in Barbados, England, and St. Lucia and conducted 29 in-depth, semi-structured interviews with male players and male and female supporters. I found that the Caribbean diaspora is maintained through liming (hanging out) at cricket matches and social events. Speaking in their native Patois language, eating traditional Caribbean foods, and consuming alcohol are significant means of creating spaces in which Caribbean-Canadians can network with other members of the diaspora. Furthermore, diasporas are preserved through return visits, not only to their nations of origin, but to a more broadly defined homeland, found in other Caribbean countries, England, the United States and elsewhere in Canada. This study shows that while diasporas may form a unified communitas they also reinforce class, gender, nation and ethnicity hierarchies and exclusions in diasporic spaces. For example, women and Indo-Caribbeans are mainly absent from or marginalized at the cricket grounds, which celebrates a masculine, Afro-Caribbean culture. Corporeal practices such as sports, and their related social activities, can be deployed as diasporic resources that create a sense of deterritorialized community for first generation Caribbean migrants.

The diasporic resources and transnational flows of the Black diaspora have increasingly been of concern to scholars. However, the making of the Black diaspora in Canada has often been overlooked, and the use of sport to connect migrants to the homeland has been virtually ignored. This study uses African, Black and Caribbean diaspora lenses to examine the ways that first generation Caribbean-Canadians use cricket to maintain their association with people, places, spaces, and memories of home. In this multi-sited ethnography I examine a group I call the Mavericks Cricket and Social Club (MCSC), an assembly of first generation migrants from the Anglo-Caribbean. My objective to “follow the people” took me to parties, fundraising dances, banquets, and cricket games throughout the Greater Toronto Area on weekends from early May to late September in 2008 and 2009. I also traveled with approximately 30 MCSC members to observe and participate in tours and tournaments in Barbados, England, and St. Lucia and conducted 29 in-depth, semi-structured interviews with male players and male and female supporters. I found that the Caribbean diaspora is maintained through liming (hanging out) at cricket matches and social events. Speaking in their native Patois language, eating traditional Caribbean foods, and consuming alcohol are significant means of creating spaces in which Caribbean-Canadians can network with other members of the diaspora. Furthermore, diasporas are preserved through return visits, not only to their nations of origin, but to a more broadly defined homeland, found in other Caribbean countries, England, the United States and elsewhere in Canada. This study shows that while diasporas may form a unified communitas they also reinforce class, gender, nation and ethnicity hierarchies and exclusions in diasporic spaces. For example, women and Indo-Caribbeans are mainly absent from or marginalized at the cricket grounds, which celebrates a masculine, Afro-Caribbean culture. Corporeal practices such as sports, and their related social activities, can be deployed as diasporic resources that create a sense of deterritorialized community for first generation Caribbean migrants.

Soil acidity is a major land degradation problem that limits crop production globally. The high cost of traditional liming materials (calcitic limestone, dolomite etc.) and the vast areas of land that require liming have led to the exploratory utilisation of alkaline industrial by- products such as fly ash and stainless steel slag. The liming potential and effects of liming with fly ash (from the Duvha power station) and processed stainless steel slag (Calmasil) on two acid soils were investigated in this study. The quality of fly ash and Calmasil as liming materials and their potential impacts on the soil quality and plant growth were investigated. The effects of liming with these materials on soil pH, EC, extractable Al, Mn, base cations and trace elements were investigated in an incubation experiment. A glasshouse trial was conducted to assess the effects of these materials on the growth of an acid intolerant crop, perennial rye grass. The incubation and glasshouse study were of a factorial design with two acid soils (the Avalon and Inanda soils), three materials (fly ash, Calmasil and lime); and five application rates of 0, 50, 100, 200 and 400% of the recommended optimum liming rate (OLR) for the growth of perennial rye grass. Characterization of fly ash showed that the major elements (>5%) present (Si > Al > Fe) are not comparable to lime (Ca > Si > Mg) and that it has a low liming potential (calcium carbonate equivalence (CCE) of 9.6%) in comparison to lime. The chemical composition of Calmasil is comparable to lime with Ca > Si > Mg as the major elements and it has a very high liming potential (CCE = 97%). The incubation experiment showed that adding fly ash and Calmasil increased the pH of both soils. However, at the optimum liming rate (100% OLR), only the treatment with Calmasil in the Avalon soil attained pH levels within the desired pH range. Extractable Al and Mn decreased with addition of fly ash and Calmasil to levels comparable to lime in the incubated soils. Addition of fly ash and Calmasil also increased the extractable base cations of both soils. The yield-response of perennial rye grass to treatments in both soils was in the following order: fly ash > Calmasil > lime. Application of fly ash at > 200% OLR in the Avalon soil caused injury of ryegrass. Application of fly ash and Calmasil at lower rates has great agronomic potential in ameliorating soil acidity. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Der Einsatz von Branntkalk war noch vor wenigen Jahren Bestandteil der »guten fachlichen Praxis« in der Karpfenteichwirtschaft. Im Hinblick auf den Schutz von Tier- und Pflanzenarten sowie geschützte Biotope wurde der Branntkalkeinsatz seit einigen Jahren vorsorglich eingeschränkt. Der Bericht dokumentiert die Ergebnisse einer Untersuchung zur Wirkung unterschiedlich hoher Branntkalkgaben auf die Wirbellosenfauna, Amphibien, Libellen und Makrophyten in Praxisteichen sowie in der Lehr- und Versuchsteichanlage Königswartha. In Laborversuchen wurden auch die Auswirkungen unterschiedlicher Branntkalkmengen auf Amphibienlaich und -larven untersucht. Die schädigende Wirkung von Branntkalk ist abhängig von der Dosierung. Während Einzelgaben unter 500 kg/ha praktisch ohne Auswirkungen bleiben, sind bei Desinfektionskalkungen auch Artenschutzbelange zu beachten.

No description available.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2000. / Härtill 4 uppsatser.

Resumo: A escória de siderurgia, subproduto da indústria de siderurgia, abundante no Brasil, é um material corretivo de acidez do solo. Com o objetivo de estudar a escória como material corretivo e fonte de silício, acompanhando seus efeitos nos atributos químicos do solo, no estado nutricional e na produção da goiabeira (Psidium guajava L.), sendo utilizado também o calcário como comparação, foi realizado este trabalho. O experimento foi conduzido com goiabeiras 'Paluma' em Nova América-SP, num Argissolo Vermelho-Amarelo (V inicial = 54%), aplicado de forma superficial. Os tratamentos estudados foram as doses dos corretivos: 0,0; 0,5; 1,0; 1,5 e 2,0 vezes a quantidade para atingir a saturação por bases a 70%. Com base nos resultados obtidos, os corretivos promoveram a melhoria na fertilidade do solo, como aumento do pH, das concentrações de cálcio e magnésio trocáveis, soma de bases, saturação por bases, além de reduzir a acidez potencial, na profundidade de 0-10cm, após seis meses da sua aplicação. Para a camada de 10-20 cm, as alterações nos atributos químicos do solo ocorreram após doze meses da aplicação dos corretivos. Nas plantas, foram observados aumento nos teores de cálcio com oito meses da aplicação e no cálcio e magnésio aos vinte e um meses após a aplicação dos corretivos. Tanto a qualidade das goiabas, para os valores da relação sólidos solúveis e acidez titulável, quanto para os aspectos produtivos da goiabeira, para número de frutos e produção, apresentaram aumento devido à melhoria na fertilidade do solo. O emprego da escória de siderurgia mostrou-se eficiente na correção da acidez do solo, bem como na nutrição, produção e qualidade dos frutos da goiabeira 'Paluma', apresentando comportamento semelhante ao do calcário / Abstract: The slag, a by-product of the steel industry, abundant in Brazil, is corrective of soil acidity material. Aiming to study the slag as correction material and silicon source, monitoring their effects on soil chemical properties, nutritional status and yield of guava (Psidium guajava L.), and also the limestone used as a comparison, this work was realized. The experiment was conducted with guava trees 'Paluma' in Nova América-SP, Brazil, in on Ultisol (V initial = 54%). The treatments studied were the doses of lime applied: 0.0, 0.5, 1.0, 1.5 and 2.0 times the amount to reach the saturation to 70%. Based on the results, the corrective promoted the improvement in soil fertility such as pH increasing the pH, concentrations of calcium, exchangeable magnesium, bases sum, bases saturation; and reduced the potential acidity at a depth of 0-10 cm after six months of its implementation. For the 10-20 cm, layer the changes in soil chemical properties occurred after twelve months from the lime application. It was observed on increased levels of calcium in the plants in eight months of application and in calcium and magnesium at twenty-one months after liming. As the quality of guavas, for the values of soluble solids and titratable acidity ratio as the productive aspects of guava for fruit number and production increased due to improvement in soil fertility. The use of slag was shown to be effective in correcting soil acidity, as well as nutrition, yield and fruit quality of guava tree 'Paluma', showing a similar pattern to limestone / Orientador: Antonio Baldo Geraldo Martins / Coorientador: Renato de Mello Prado / Banca: Francisco Maximino Fernandes / Banca: José Antonio Alberto da Silva / Banca: Carlos Ruggiero / Banca: Simone Rodrigues da Silva / Doutor

A pecuária de corte do Rio Grande do Sul é baseada na utilização de pastagens naturais, que são caracterizadas pela marcante sazonalidade na produção. Tal cenário, proveniente das variações meteorológicas ao longo do ano, apresenta-se de forma ainda mais intensa em condições edáficas limitantes, como é o caso da Região do Basalto Superficial da Campanha gaúcha. O objetivo do presente trabalho foi avaliar a efetividade de práticas de manejo como o diferimento de primavera associado com a fertilização para minimizar os efeitos do déficit forrageiro do verão decorrentes do balanço hídrico negativo que normalmente ocorre na região. Foram utilizados 12 tratamentos baseados na aplicação em área diferida de diferentes níveis de calcário (0 e 1500 kg ha-1), fósforo (0 e 90 kg ha-1) e nitrogênio (0, 75, 150 e 300 kg ha-1), arranjados num fatorial incompleto. A aplicação dos fertilizantes e o início do diferimento ocorreram no dia 10/10/2009. Foi utilizado o delineamento em blocos casualisados com três repetições, utilizando-se como unidades amostrais parcelas com área de 30m² (3 x 10m). Foram realizadas 5 avaliações de massa de forragem, a intervalos médios de 15 dias (25/10/2009 a 08/01/2010). O tratamento testemunha apresentou uma taxa de acúmulo de forragem média de 17,7 kg ha dia-1 de matéria seca, demonstrando a efetividade do diferimento por si só em tais condições. O aumento dos dias de diferimento gerou diminuição na qualidade bromatológica da forragem. O calcário não proporcionou incrementos na produção de forragem, possivelmente em virtude do curto período de tempo entre a aplicação e o término das avaliações. A aplicação de nitrogênio ou fósforo isoladamente promoveu ganhos relativamente baixos para massa de forragem total e massa de forragem verde, mas a interação entre tais elementos potencializou esses efeitos, atingindo mais cedo a altura que otimiza a taxa de ingestão diária. A quantidade máxima de material verde (kg ha-1) foi atingida aos 75 dias para todos os tratamentos, sendo maior com fósforo e doses crescentes de nitrogênio. / The beef cattle industry in southern Brazil is based on the use of natural pastures, which are characterized by marked seasonality in production. This scenario, derived from weather variations throughout the year, is more intense in the limiting soil conditions, such as the basaltic shallow soils at Campanha region of Rio Grande do Sul. The aim of this study was to evaluate the effectiveness of management practices such as spring deferment associated with fertilization to minimize the effects of summer forage deficit arising from the negative water balance that normally occurs in this region. A total of 12 treatments based on the application of different levels of limestone (0 to 1500 kg ha-1), phosphorus (0 and 90 kg ha-1) and nitrogen (0, 75, 150 and 300 kg ha-1) were arranged in a incomplete factorial design distributed in a randomized complete block design with three replicates. Each plot measured 30 m² (3 x 10m). The start of the resting period and the application of fertilizers was done on 10/10/2009. Herbage mass was evaluated at average intervals of 15 days between 10/25/2009 and 08/01/2010. The control treatment showed a rate of herbage accumulation average of 17.7 kg/ha/day of dry matter, demonstrating the effectiveness of the deferral alone in such conditions. The increase of the resting time caused a decrease in forage quality. Limestone utilization doesn't increased forage production, possibly due to the short time between application and completion of evaluations. The application of nitrogen and phosphorus brought gains for relatively low herbage mass and green forage, but the interaction between these factors potentiated these effects, reaching the optimal height to maximize daily ingestion rate earlier. The maximum amount of green matter (kg/ha) was reached at 75 days for all treatments, being higher with increasing levels of nitrogen when phosphorous was applied.