Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Soil and Land Systems, 2004. / "October, 2004" Includes bibliographical references (leaves 228-254).

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Soil and Land Systems, 2004. / "October, 2004" Includes bibliographical references (leaves 228-254). Also available in a print form.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1922. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed June 4, 2009)

The purpose of this study was to determine the uptake and distribution of nutrients during the growth of the Cayenne cultivar of Ananas comosus (L) Merr under field conditions in the Eastern Cape. The study was also done to help explain the apparent drop in the nutrient levels in the basal section of the "D"- leaf of the pineapple plant during the winter months and to determine the best part or parts of the plant to sample in order to measure the nutrient status of the pineapple plant at any stage of its growth. The investigation was conducted by selecting a plot within a production land on two farms in the pineapple growing region of the Eastern Cape. Plants were sampled from each plot at regular intervals from planting of the pineapple tops until the harvesting of the fruit of the first plant crop. Plant growth was measured and the nutrient concentrations in each section of the plant were determined. The total amounts of nutrients for each plant part were calculated and the nutrient uptake was compared and plotted on distribution diagrams.

Cocoyam [Colocasia esculenta (L.) Schott] is widely cultivated as a staple food in the tropical and subtropical regions of the world. The crop, however, remains unpopular and not well known outside KwaZulu-Natal Province of South Africa where it is cultivated mainly for subsistence. The aims of the study were to collect local landraces (accessions) of the crop from where it is found growing within the country for various studies and also to document its nutritional values as well as the safety/toxicity of the crop. The study was carried out using various methods. These included a comparative assessment of the proximate, mineral and antinutrient compositions of cooked and uncooked tubers of a typical commercially available cocoyam and potato found in South African markets. These investigations were repeated for the tubers and leaves of available landraces (seven accessions) of C. esculenta found growing in the farmers’ fields in KwaZulu-Natal Province. Also, an in vivo toxicological study on cooked accessions of the local landraces was conducted to determine possible toxicity effects after consumption using albino rats as a model. The results revealed that commercially available cocoyam and potato tubers have very close nutritional components. Analysis of the proximate composition of seven accessions (UFCe1- UFCe7) of cooked and uncooked tubers of cocoyam indicated that UFCe7 was better in ash, crude protein, crude fibre and crude lipid contents but with higher moisture which could make it more vulnerable to microbial attack. No tubers of the seven accessions appeared to be ii outstandingly better than the others based on their mineral compositions. However, in terms of antinutritional factors, UFCe1, UFCe3 and UFCe7 had the least amounts of oxalate, tannins and phytate in their cooked states. It was discovered however, that the leaves of the accessions of this vegetable contain substantial amount of minerals, and therefore, can contribute significantly to the nutrient requirements of humans and could be recommended as a cheap source of nutrients in South Africa. None of the accessions was outstandingly better than the others in terms of their mineral contents and anti-nutritional factors. Moreover, the current study has shown that boiling the leaves of cocoyam prior to consumption is an effective way of reducing the antinutrient contents of the leaves of the plant thereby making it safe for consumption. The findings also revealed that cooking C. esculenta leaves may increase the levels of protein, fibre and lipid contents while cooking may also decrease the mineral, carbohydrate and caloric contents of the leaves of the accessions. The leafy vegetable may, therefore, be recommended as a cheap source of plant protein. Cooking improved the nutritive value as a result of the reduction in antinutrient levels, thereby improving the food quality in all the tuber and leaf samples used for this study. At the same time, cooked samples also suffered loss of some nutrients with respect to the proximate and mineral compositions. However, supplementation from other food sources that are rich in these nutrients is necessary when these crops are cooked for consumption. Any of the cocoyam accessions may be recommended for consumption for improved protein and mineral nutrients while tubers of accession UFCe7 have also shown good promise in terms of protein and fibre content availability. The results of the in vivo study, using the liver and kidney functional endpoints of weanling albino rats (Rattus norvegicus) maintained on different accessions of cooked cocoyam-based iii diets (UFCe1-UFCe7) for 28 days, revealed that all the accessions produced selective alterations on the hepatorenal indices of weanling rats. The highest alterations were produced by UFCe4 while the least was from UFCe2. These alterations may have consequential effects on the normal functioning of the liver and kidney of the animals. The UFCe2 exhibited the least toxicity risk among the accessions of C. esculenta growing in KwaZulu-Natal Province of South Africa.

M.S.

Subtropical deforestation in Latin America is thought to be driven by demand for agricultural land, particularly to grow soybeans. However, existing remote sensing methods that can differentiate crop types to verify this hypothesis require high spatial or spectral resolution data, or extensive ground truth information to develop training sites, none of which are freely available for much of the world. I developed a new method of crop classification based on the phenological signatures of crops extracted from multi-temporal MODIS vegetation indices. I tested and refined this method using the USDA Cropland Data Layer from Kansas, USA as a reference. I then applied the method to classify crop types for a study site in Pellegrini, Santiago Del Estero, Argentina. The results show that this method is unable to effectively separate summer crops in Pellegrini, but can differentiate summer crops and non-summer crops. Unmet assumptions about agricultural practices are primarily responsible for the ineffective summer crop classification, underlining the need for researchers to have a complete understanding of ground conditions when designing a remote sensing analysis.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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Resumo: O objetivo desta tese foi avaliar a influência da aplicação superficial de corretivos em diferentes sistemas de produção sobre Sistema Plantio Direto, bem como o efeito de ambas as variáveis nos atributos físicos, na movimentação de bases, na correção da acidez do solo, nas frações da matéria orgânica do solo, além da nutrição e produtividade das culturas produtoras de grãos em região de inverno seco. O presente trabalho é a continuação de um experimento instalado no ano agrícola 2006/2007, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - UNESP, localizada no município de Botucatu (SP), e foi conduzido nos anos agrícolas 2008/2009, 2009/2010 e 2010/2011. O delineamento experimental foi blocos casualizados, no esquema de parcelas subdivididas, com 8 repetições. As parcelas foram constituídas por quatro sistemas de produção ("Safra - Forrageira"; "Safra - safrinha"; "Safra - Pousio" e; "Safra - Adubo Verde") e as subparcelas por duas fontes de corretivos de acidez e um controle (calcário; silicato de cálcio e magnésio; sem aplicação de corretivo). Foram realizadas as seguintes avaliações: produção de massa de matéria seca e teores de macronutrientes e silício em todas as culturas; componentes de produção das culturas graníferas; atributos químicos do solo aos 36 e 48 meses após a aplicação dos corretivos (outubro de 2006); atributos físicos do solo e fracionamento da matéria orgânica do solo após a colheita da terceira safra de outono/inverno (60 meses após a aplicação dos corretivos); e custo de produção das unidades experimentais. Com o presente estudo, pôde-se concluir que: A aplicação de corretivos influencia positivamente o teor de matéria orgânica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This thesis had the objective of evaluating the influence of superficial application of correction sources in different cropping rotations under no tillage system on soil physical properties, base mobility, acidity correction, organic matter fractioning as well as crop nutrition and yield in dry winter region. The present study was conducted in 2008/2009, 2009/2010 and 2010/2011 and it was a sequence of an experiment that had been conducted since 2006/2007 in College of Agricultural Sciences - FCA/UNESP, in Botucatu-SP, Brazil. The experimental design was the complete randomized block with subdivided plots and eight replications. Main plots consisted of four cropping rotations ("Season-Forage"; "Season-Offseason"; "Season-Fallow" and "Season-Green manure") and subplots by two sources for soil acidity correction (dolomitic lime, calcium/magnesium silicate) plus a control, with no correction. The following evaluations were conducted: dry matter production, macronutrient levels and silicon levels in all crops, yield components of grain crops, soil chemical attributes at 36 and 48 months after correction (October 2006), soil physical attributes and organic matter fractioning in fall/winter of 2011 (60 months after correction), and production costs. It was concluded that the application of correction sources positively influences organic matter levels, increasing stocks of total organic carbon, particulate organic carbon and mineralassociated carbon. Best results are observed under "Season-Forage" rotation, opposed to "Season-Fallow" system. Chemical benefits of correction sources on soil fertility are still observed 48 months after the application. Soil correction increases phosphorus levels in soil, although silicate is more efficient than lime. Crop rotations improve aggregate stability and reduce penetration... (Complete abstract click electronic access below) / Orientador: Carlos Alexandre Costa Crusciol / Coorientador: Ciro Antonio Rosolem / Banca: Godofredo Cesar Vitti / Banca: Sandro Roberto Brancalião / Banca:Jose Eduardo Cora / Banca: Leonardo Theodoro Bull / Doutor