Arid and semi-arid rangelands are important ecosystems that are consistently degraded through disturbances such as wildfires. After such disturbances, the invasion and dominance of annual grasses, like cheatgrass (Bromus tectorum L.), can lead to an overall loss of ecosystem productivity and an increase in fire frequency. To reduce weed dominance, native and introduced perennials species are typically be seeded in the fall. High mortality is seen from these seeded plant communities due to germinated seed being exposed to freezing, drought, fungal pathogens, and other biotic and abiotic stressors during winter months. We utilized wet-thermal accumulation models to first further validate the theory that germination from seeded plant populations occurs during periods of high environmental stress, and then to establish the practicality of abscisic acid seed coatings as a technology that could circumvent winter germination and mortality. In Chapter 1, we developed an excel workbook called Auto-Germ using Visual Basic for Applications, which allows users to estimate field germination timing based on wet-thermal accumulation models and field data. We then used Auto-Germ to model seed germination timing for 10 different species, across 6 years, and 10 Artemisia-steppe sites in the Great Basin of North America. We estimated that for the majority of the species analyzed, a mid to late-winter planting was required on average for the majority of the population to germinate in the spring. This planting time would be logistically difficult for many land managers, due to freezing and/or saturated soil conditions. In Chapter 2, we utilized wet-thermal accumulation models to evaluate the use of abscisic acid (ABA) to delay germination of Pseudoroegneria spicata (Pursh) Á. Löve (perennial native bunchgrass) across 4 years and 6 Artemisia-steppe sites. Germination models estimated that ABA seed treatments typically would delay germination of fall sown seed to late winter or early spring when conditions may be more favorable for plant establishment. Based on these results, we recommend both the use of wetthermal accumulation models as a tool in educating researchers and land managers in knowing when seeding practices should occur, and the further study of ABA seed coatings as a technology that may improve plant establishment of fall sown seeds.

Made available in DSpace on 2014-08-20T14:32:59Z (GMT). No. of bitstreams: 1 Dissertacao_Andre_Luiz_Radunz.pdf: 2353919 bytes, checksum: 1448629eb86ad56fa1ff43413ca14de1 (MD5) Previous issue date: 2012-02-16 / In order to reach the strengthening and the development of family agriculture as well as the premise of diversification of the productive sources, there appears as an alternative the cultivation of common vineyards destined to the production of home-grown wine, juices and derivatives. Attempts were made to evaluate the existing relationships among local meteorological variables and handling practices, dry pruning and green pruning and the effects on phenological behavior, productive aspects and on the quality of the cultivated grape under the conditions of the region of Pelotas/RS. For this purpose, a family based agricultural property was selected located in the 8TH district of Pelotas/RS, in which the experiment was carried out and where the experimental delineation was composed for a (2 x 2 x 2) factorial, these being: (Bordô and BRS Violeta) cultivar, period of dry pruning (normal and late) and green pruning (with and without defoliation). Evaluations were carried out during harvest of total soluble solids, of the mass of clusters, of the number of clusters of grapes per cluster and production per plant. Moreover, global solar radiation was measured in each treatment, reflected by the canopy and available at the level of clusters as well as the daily temperature of the vineyards, Results demonstrate that the period of dry pruning affected the production and the accumulation of total soluble solids and on cv. BRS Violeta, only the total soluble solids. When relating the period of dry pruning with defoliation over total soluble solids, these differed only in the treatment with defoliation, being greater in the late period. Defoliation carried out on cv. Bordô reduced the number of grapes per cluster. However, it increased weight of the clusters and presented no differences for the BRS Violeta . Defoliation associated with the normal period increased the production per plant and the number of clusters on Bordô and presented no differences on the cv. BRS Violeta. The results demonstration that the average albedo presented short variation 0,287, 0,280, 0,295, 0,297, 0,304 e 0,287 for the respectively treatments BNC, BTC, BTS, VNC, VTC and VTS, being B e V refer of the cultivars Bordô and BRS Violeta, N and T of the dry pruning and C and S with and without. The cv. BRS Violeta presented greater availability of solar radiation at the level of clusters and higher rate of total soluble solids during harvest when compared with cv. Bordô. The period of dry pruning did not represent difference in the quantity of solar radiation available at the level of clusters but the defoliation propitiated increase in incident radiation a the level of clusters for cv. Bordô and BRS Violeta. Solar radiation available at the level of clusters showed itself related to the accumulation of total soluble solids, being greater when the available radiation was greater on cv. Bordô. / A fim de atingir o fortalecimento e o desenvolvimento da agricultura familiar e a premissa da diversificação da matriz produtiva das unidades familiares, tem-se como alternativa o cultivo de videiras comuns destinadas à produção de vinhos coloniais, sucos e derivados. Buscou-se avaliar as relações existentes entre variáveis meteorológicas locais e as práticas de manejo, poda seca e poda verde, e seus efeitos no comportamento fenológico, nos aspectos produtivos e na qualidade da uva cultivada nas condições da região de Pelotas/RS. Para tanto, foi selecionada uma propriedade agrícola familiar localizada no 8º Distrito de Pelotas/RS, na qual foi realizado o experimento, sendo o delineamento experimental composto por um fatorial (2 x 2 x 2), sendo estes: cultivar (Bordô e BRS Violeta); época de poda seca (normal e tardia); e poda verde (com e sem desfolha). Foram realizadas durante a colheita avaliações de sólidos solúveis totais, da massa dos cachos, do número de cachos e de bagas por cacho e da produção por planta. Ainda em cada tratamento foi medida a radiação solar global, refletida pelo dossel e disponível ao nível dos cachos e também a temperatura diária no vinhedo. Os resultados demonstram que a época da poda seca exerceu influência sobre o comportamento fenológico, sobre a necessidade térmica e o número de dias para completar o ciclo. Na cv. Bordô a época da poda seca afetou a produção e o acúmulo de sólidos solúveis totais (SST) e na cv. BRS Violeta apenas o SST. Ao relacionar a época da poda seca com a desfolha, sobre os sólidos solúveis totais, estes diferiram apenas no tratamento com desfolha, sendo maior na época tardia. A desfolha realizada na cultivar Bordô reduziu o número de bagas por cacho, entretanto aumentou o peso de cachos e sem diferenças para a BRS Violeta . A desfolha associada à época normal aumentou a produção por planta e o número de cachos na Bordô e sem diferenças para a cultivar BRS Violeta. O albedo médio para os tratamentos BNC, BTC, BTS, VNC, VTC e VTS foi respectivamente, 0,287, 0,280, 0,295, 0,297, 0,304 e 0,287. A cultivar BRS Violeta apresentou maior disponibilidade de radiação solar ao nível dos cachos e maior teor de sólidos solúveis totais na colheita quando comparada a cultivar Bordô. A época de poda seca não representou diferença na quantidade de radiação solar disponível ao nível dos cachos, já a realização da desfolha propiciou aumento na radiação que incide ao nível dos cachos para a cv. Bordô. A radiação solar disponível ao nível dos cachos mostrou-se relacionada ao acúmulo de sólidos solúveis totais, sendo maior este acúmulo quando a radiação disponível foi maior na cultivar Bordô.

The theme of the diploma thesis is the study of physical properties of various building materials in buildings in low-energy construction. The work is mainly focused on the influence of the thermal accumulation properties of building materials used in buildings in order to achieve low energy consumption for heating. The thesis compares the energy characteristics of five different constructional material variants of the house.