Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Abstracted in Dissertation abstracts, v. 17 (1957) no. 11, p. 2362. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 59-61).

Thesis (M.S.)--University of Wisconsin--Madison, 1947. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 30-32).

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Bruce D. Maxwell. Includes bibliographical references.

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To our knowledge, this metagenomics study is the first of its kind to determine how cover crops and tillage management practices affect the soil microbiome in southern Illinois. Seven different cover crops were used over the course of two years from 2014 to 2015, and two different forms of tillage were used: Conventional Tillage (CT) and No-Tillage (NT). Four barcodes were used to generate libraries for the phylogenetic identification of fungi, bacteria, oomycetes, and fusaria: the ITS1, EF1a (Elongation Factor 1-a), and the V4 region of the 16s rRNA subunit. Targeted amplicon sequencing using 250 base pair Paired End (PE) reads yielded 14 x 106 base pair reads in total. Using these amplicons, we successfully unveiled the fungal and bacterial constituents of the studied field plots (database limitations considered) using the QIIME and NCBI Blast protocols. Specifically, this study had three goals 1) to determine if cover crops or tillage had a significant impact on the overall microbial diversity found in bulk soil samples taken from cover crop plots; 2) to determine if the incidence and abundance of individual bacterial or fungal taxa were affected by the cover crop or tillage treatment; 3) perform a bioinformatics methodology comparison for fungal identification using the ITS1 region between Qiime, and MEGAN protocols. Our results indicate many instances of cover crop or tillage interacting with one or more groupings of taxa. Significant whole community differences could be detected to the species (P=0.0335) and family (P=0.0001) taxonomic ranks of fungi using with the three most abundant families based on assigned reads being Mortierellaceae, Trichocomaceae, and Botryosphaeriaceae. Significant whole community interactions between tillage types and year at the level of phylum were observed between bacteria and archaea. Three main phyla constituting bacterial reads were Proteobacteria, Actinobacteria, and Acidobacteria. The primary driver in individual differences in bacterial populations appeared to be the year in which samples were taken either 2014 or 2015 (P=0.0001). This was attributed in part due to drastic fluctuations in weather from November 2014 to November 2015. Whole community differences and shifts could be observed based on cover crop down to the species level using both QIIME and NCBI BLAST protocols. The different dispersions and taxa found between cover crops imply that there is a relationship between certain organisms and the type of plant matter present. Tillage type, year, and cover crop were all found to have some degree of clustering based on reads taken from the four amplicons used. For comparison between NCBI and QIIME methodologies using the ITS1 region, the NCBI BLAST protocol provided the most overlap between taxa at the Order and Class taxonomic rankings. An upwards of 70% complementarity of taxa was found comparing the results after using the NCBI or the QIIME protocols. Whole community analysis using PERMANOVA revealed complementarity shifts based on treatment types when comparing both QIIME and NCBI protocols for taxonomic assignments visualized using PCoA plots. This comparison between the two methods for fungal community analysis using the ITS region, highlights the significant discrepancies as well as the complementarity of the two methodologies when analyzing fungal microbiomes.

Made available in DSpace on 2014-06-11T19:29:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-01-25Bitstream added on 2014-06-13T18:39:33Z : No. of bitstreams: 1 nascimento_ms_me_ilha.pdf: 349212 bytes, checksum: de4a97b4521dc8d83da87f2f700a3e24 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O nitrogênio é o nutriente absorvido em maior quantidade pelo feijoeiro e o molibdênio, além da importância no processo de fixação de nitrogênio atmosférico, está associado ao metabolismo deste nutriente. Assim, o trabalho foi desenvolvido com o objetivo de avaliar, na cultura do feijão, em sistema de plantio direto, o efeito da aplicação de doses de nitrogênio em cobertura (0, 30, 60, 90 e 120 kg ha-1) bem como a aplicação foliar de molibdênio (0, 80 e 160 g ha-1), aplicado em duas fases de desenvolvimento das plantas (fase de desenvolvimento V3 e fase de desenvolvimento V4) utilizando sementes do cultivar Pérola. O delineamento experimental utilizado foi o de blocos casualizados com 30 tratamentos e 4 repetições. O estudo foi realizado em área experimental pertencente à Faculdade de Engenharia Campus de Ilha Solteira - UNESP, localizada no município de Selvíria-MS, em solo originalmente sob vegetação de cerrado e cultivado anteriormente com a cultura do milho. Foram realizadas as seguintes avaliações: população de plantas, matéria seca de plantas, nitrogênio nas folhas e grãos, molibdênio nas folhas e grãos, altura de inserção da primeira vagem, comprimento da primeira vagem, componentes de produção (número de vagens/planta, número de grão/planta, número de grão/vagem e massa de 100 grãos) e rendimento de grãos. A aplicação de Mo via foliar não 2 interfere na produtividade, e a aplicação de doses crescentes de nitrogênio em cobertura proporciona aumento crescente no teor de nitrogênio nas folhas e na produtividade de grãos. Termos para Indexação: Phaseolus vulgaris L., doses de N... / Nitrogen is the nutrient most uptaken by common bean plant, and molybdenum besides its importance to N fixation process, is associated to N metabolism. Thus, this micronutrient lack produces symptoms like those caused by N deficiency. This research had the objective of evaluating, on common bean crop, the effect of N levels application in side dressing (0, 30, 60, 90 and 120 kg ha-1) as well as the leaf application of Mo (0, 80 and 160 g ha-1) in development phases V3 and V4 under no tillage system. The experimental design was the randomized blocks with 30 treatments and 4 repetitions. The research was carried out in Selvíria-MS on soil previously cropped with corn. Stand, dry matter weight, N in leaves and seeds, Mo in leaves and seeds, 1st pod insertion height, 1st pod length, number of pod per plant, number of seed per plant, number of seed per pod, weight of 100 seeds and yield were evaluated. The application of Mo on leaf does not interfere on the productivity. The application of increasing levels of nitrogen in side dressing causes a crescent increase in nitrogen level on leaves and on grains productivity

Within our ecosystems, soil biota control an array of functions, such as nutrient cycling and decomposition, and have been pursued as a soil quality indicator. Though microbial communities are known to be a reflection of their environment, small scales dynamics within an agricultural system have been overlooked for many years leading to gaps when inferring on relative microbial values. To further asses our current microbial knowledge, two experiments analyzing microbial phospholipid fatty acid (PLFA) structures and enzyme activities sought out to determine temporal fluctuations, cycles, and driving force behind simulated daily microbial parameter outputs. Across both studies, temporal effects, cyclical structures, and common driving forces were recorded, but further validation and characterization is needed to solidify the temporal dynamics of the microbial community. Overall, this information serves as a valuable step towards determining the most viable tillage systems based on environmental conditions, and physical proof of small scale microbial fluctuations.

Glyphosate (N-(phosphonomethyl)glycine)-containing herbicides are a common and highly effective method to terminate alfalfa (Medicago sativa) stands. With the development and use of glyphosate-resistant (Roundup Ready®) alfalfa, this tool is no longer an option. The purpose of this research was to determine the optimal strategy to rotate from glyphosate-resistant alfalfa into silage corn (Zea mays). Studies were conducted in 2012 and 2013 at sites near Cache Junction and Cornish, Utah to determine the effect of tillage type and timing [fall conventional till (FCT), spring conventional till (SCT), fall strip-till (FST), spring strip-till (SST), and no-till (NT)], 2,4-D plus dicamba herbicide timing (fall, spring, in-crop, and a control), and N rate (0, 56, 112, and 224 kg N ha-1) on soil penetration resistance (PR), alfalfa re-growth, and corn emergence rate index (ERI), silage yield, quality, and economic return. The fall, spring, and in-crop herbicide timings across all tillage treatments reduced alfalfa stem count and biomass by at least 95% and 98%, respectively. Tillage reduced PR compared to NT to or near the depth of tillage. The ERI was significantly higher under FCT, SCT, and SST and when herbicides were applied in fall or spring. Silage yield, quality, and economic return were the highest when spring herbicide timing was used with all tillage types and timings and the fall herbicide timing under conventional tillage. Increasing N rates increased crude protein, milk ha-1, and dry matter yield. However, optimal yield and quality can be obtained with no additional N fertilizer. First-year silage corn yield, quality, and economic return can be optimized under fall or spring conventional till, strip-till, and no-till at the spring herbicide timing along with the fall herbicide timing for conventional tillage with no additional N fertilizer.

Indiana University-Purdue University Indianapolis (IUPUI) / Nitrous oxide (N2O) is an atmospheric constituent that contributes to climate warming and stratospheric ozone depletion. A large fraction of the anthropogenic N2O emission originates from agricultural soils suggesting therefore a strong connection between N2O accumulation in the atmosphere and agricultural land management. During the last 2-3 decades, no-till (NT) farming and integration of cover crops into crop rotation represent two major developments in agriculture, but much remains to be learned about the impact of these management approaches on N2O emission and underlying biological soil factors. This dissertation focuses on the contribution of different components of the soil microflora to N2O production, and how different types of cover crops (legume vs grass) affect the soil microbial community composition, mineral N availability, and N2O emission in plowed (PT) and NT soils. To address these questions, several laboratory and greenhouse experiments were conducted. Results of these experiments documented soil microbial community responses to cover crop addition and could inform the selection of cover crops most suitable to soils under different tillage practices.