Thesis ( M.Sc.(Horticulture)) -- University of Limpopo, 2017. / Refer to document / National Research Foundation of South Africa, and the Agricultural Research Council-Universities Collaboration Centre

Thermal desorption (TD), a remediation method used to remove hydrocarbons from contaminated soils, may cause changes in soil properties that threaten soil function and plant productivity. The goal of this research is to better understand the effect that TD treatment has on soils intended for agricultural use. A series of soil phosphorus (P) sorption and desorption experiments were conducted on soils before and after TD treatment to determine P availability for plant uptake and risk for run-off. TD-treated soils retained more P, likely due to mineral transformations of Fe- and Al-oxides. In addition, a three-year field study using mixtures of topsoil (A), crude-contaminated soil (SP), and TD-treated soils (TDU) was conducted. Yields were significantly greater in plots that included A in the mixture compared to SP and TDU soils alone. TD-treated soils can be a replacement for topsoil, but the addition of topsoil will reduce the time to successful reclamation.

This thesis estimates the production, cost, and profit functions for North Dakota agriculture using state-level input-output quantity and price data for the period 1960-2004. A Cobb-Douglas functional form with Hick-neutral technology change is used to measure the contribution of capital, land, labor, materials, energy, and chemical inputs quantities and output quantity using the primal production function; contribution of capital quantity, land quantity, output quantity, labor price, materials price, energy price, and chemical price to cost using the dual restricted cost function; and the contribution of capital quantity, land quantity, labor price, materials price, energy price, chemical price, output price to profit using the dual restricted profit function. In contrast to previous studies, quantile regression is used to explore the linear or nonlinear relationship between the independent and dependent variable by estimating parameter coefficients at each quantile using time-series data. Empirical findings suggest the cost function is the best model to examine the relationship between input prices, output quantity and cost using quantile regression for North Dakota agriculture, Further, the quantile regression suggests a linear and non-linear relationship between cost and certain independent variables.

Orientador: Renato de Melo Prado / Resumo: Os valores de referências dos teores de nutrientes foliares de nitrogênio (N), fósforo (P) e boro (B) obtidos por métodos uni, bi e multivariados são publicados sem ter a sua eficiência comprovada. Sendo importante usar o teste de acurácia (APD) de forma integrada para se realizar os ajustes necessários na metodologia para melhorar a eficiência dos diagnósticos, mas isso ainda não é conhecido para cultura do algodão. Diante disso, objetivou-se usar o método APD para disponibilizar valores de referência, pelo método Distribuição Normal Reduzida (DNR), Chance Matemática (CHMAT), Sistema Integrado de Diagnose e Recomendação (DRIS) e Diagnose da Composição Nutricional (CND), eficientes para a diagnose nutricional de N, P e B da cultura do algodão, em Chapadão do Sul - MS. Para obter os valores de referência foram amostradas 144 lavouras comerciais de algodão do município de Chapadão do Sul - MS. No diagnóstico nutricional do DRIS e CND foram usados os fatores 0,5 e 1,0 para ajustar o Índice de balanço Nutricional médio (IBNm). Na mesma região foram realizados três experimentos de calibração, constituídos de quatro doses para cada nutriente (N, P e B), com cinco repetições. Os experimentos foram utilizados para confrontar o diagnóstico obtido pelo método da DNR, CHMAT, DRIS e CND com o Verdadeiro Estado Nutricional (VEN) da planta. O VEN da planta foi definido como deficiente quando a planta apresentava Incremento Real na Produtividade (IRP) acima de 5%, ou 10%, e como suficiente ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The leaf nutrient content of nitrogen (N), phosphorus (P) and boron (B) reference values are reproduced by uni, bi and multivariate methods are published without their proven efficacy. It is important to use the accuracy test (APD) in an integrated manner to make the necessary adjustments to the methodology to improve diagnostic efficiency, but this is not yet known for cotton cultivation. Thus, we aim to use the APD method to provide efficient reference values, the Normal Reduced Distribution (DNR), Mathematical Chance (CHMAT), Integrated Diagnostic and Recommendation System (DRIS) and Diagnostic Nutritional Composition (CND) method. nutritional status of cotton crop N, P and B, in Chapadão do Sul - MS. To obtain the reference values, 144 commercial cotton crops in Chapadão do Sul - MS were sampled. No nutritional diagnosis of DRIS and CND was used by factors 0.5 and 1.0 to adjust the mean nutritional balance index (IBNm). In the same region, three calibration experiments were performed, consisting of four doses for each nutrient (N, P and B), with five replications. The experiments were used to compare or diagnose DNR, CHMAT, DRIS and CND methods with the plant's True Nutritional Status (VEN). Plant VEN was defined as deficient when a plant had a Real Productivity Increase (IRP) above 5%, or 10%, and as sufficient when the increase was lower. The adjustments applied in this study result in an increase of 31%, 98% and 89% for N, P and B, respectively. The CND was the most ef... (Complete abstract click electronic access below) / Doutor

Orientador: Marcelo Andreotti / Banca: Morel dos Passos e Carvalho / Banca: Rafael Montanari / Banca: Zigomar Menezes de Souza / Banca: Cassiano Garcia Roque / Resumo: Conhecer a variabilidade espacial dos atributos do solo que influenciam na produtividade do feijoeiro, num sistema plantio direto, é interessante, pois esta informação poderá auxiliar no manejo do mesmo. Portanto, o conhecimento da variabilidade do solo pode aperfeiçoar as aplicações de fertilizantes, reduzindo custos e a degradação ambiental. Assim, avaliar a produtividade vegetal de sistemas de integração lavoura pecuária, em função de atributos do solo, via uso da geoestatística, pode auxiliar na definição de quais atributos físico-químicos do solo mais interferem nesta produtividade e quais podem ser utilizados para determinar a qualidade do solo. O trabalho teve como objetivo avaliar a variabilidade e caracterizar a dependência espacial e temporal entre alguns atributos físicos e químicos do solo e a produção de forragem do capim-Marandu (Urochloa brizantha cv. Marandu), sobre a população de plantas e a produtividade do feijoeiro de inverno, bem como estudar as correlações lineares e espaciais entre tais atributos, visando identificar quais destes interferiram na produtividade da cultura do feijão, em um LATOSSOLO VERMELHO Distroférrico do Cerrado. A pesquisa foi desenvolvida na Faculdade de Engenharia de Ilha Solteira (FE/UNESP), localizada no município de Selvíria (MS). Foi realizada a análise estatística descritiva e geoestatística para os atributos, gerando semivariogramas, mapas de krigagem e cokrigagem. A quantidade de palhada remanescente do capim Marandu antecessor apresentou correlação linear inversa com a população e produtividade do feijoeiro de inverno. Entretanto, sem correlação espacial e temporal sobre tais atributos. A produtividade de feijão teve correlação linear direta com o pH e inversa com a macroporosidade na camada superficial do solo. Contudo, o ponto de vista... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Knowing the spatial variability of soil attributes that influence the common bean yield in a no-tillage system is interesting because this information may assist in the management of the soil. Therefore, knowledge of soil variability can optimize fertilizer applications, reducing costs and environmental degradation. Thus, to evaluate the productivity of vegetable integrated crop livestock due to soil attributes via the use of geostatistics, can help define which physical and chemical attributes of the soil affect this more productivity and which can be used to determine the quality soil. The study aimed to evaluate the variability and characterize the spatial and temporal dependence between some physical and chemical soil properties and forage production of grass marandu (Urochloa brizantha cv Marandu) on plant population and grain common bean yield of winter and study the linear and spatial correlations between these attributes, to identify which of these interfere with the yield of the common bean in an Oxisol of the Brazilian Savannah. The research was conducted at the Faculdade de Engenharia of Ilha Solteira (FE / UNESP), located in Selvíria (MS). We performed a descriptive statistical analysis and geostatistics for attributes, generating semivariograms, kriging and cokriging maps. The amount of trash remaining palisadegrass predecessor correlated inversely related to population and common bean yield of winter. However, no correlation of such spatial and temporal attributes. The common bean yield of irrigated winter in the Brazilian Savannah had direct linear correlation with soil pH in the 0 to 0,10 m positive spatial correlation with the pH of the soil layer from 0,10 to 0,20 m. / Doutor

This thesis is a collection of three essays that examine the macroeconomic impact of natural resource windfalls and the microeconomic impact of Chinese development finance. The aim is to understand how fiscal windfalls largely driven by events in the world affect economic development. The first chapter studies the impact of commodity related income gains on the number of exporters and the average export value per exporter within the manufacturing sector. A large body of theoretical and empirical literature showed that these windfalls could be detrimental to the manufacturing sector, but none untangled the margins through which the exports from the manufacturing sector adjusts to these windfalls. I exploit the exogenous variation in the windfalls generated by the increase in prices of all major commodities during the early 2000s to fill this gap in the literature. First, I find that manufacturing industries that historically had a relatively higher share of exports to value added ratio (more exportable) tend to be negatively affected relative to the other manufacturing industries at both margins. Secondly, the extensive margin is largely driven by entrants. i.e., the number of new exporting firms that enter more exportable industries decline relative to the less exportable industries. Thirdly, for the more exportable industries, the average export value per incumbent exporters industries decline while that of the new exporters increases relative to the less exportable industries. It has often been argued that countries that produce natural resources mobilize less non-resource tax revenues than other countries. In the second chapter, I exploit the arguably exogenous variation in the timing of giant oilfield discoveries to examine the impact of natural resource abundance on non-resource tax revenue. The timing of giant oilfield discoveries is arguably exogenous and thus renders them appealing to empirically examine this argument. This allows me to examine the performance of non-resource tax revenue effort before and immediately after discovery as well as the period corresponding to the inflow of revenues from the production. I find that non-resource tax revenues tend to increase in the period following the discovery before the onset of production and after production commences. This effect is due to an increase in non-resource indirect tax revenues. Further analysis shows that both the total and indirect non-resource tax revenues, experience an increase in only low- middle income countries. This effect is largely driven by an increase in the consumption of goods and services. Improvement in agricultural productivity plays a key role in the process of economic development. Investment in critical infrastructure has been documented in the literature as one of the pathways to boost agricultural productivity. In the third chapter, I study the causal impact of Chinese development finance on agricultural productivity in Tanzania, at the sub-national level. I combine household panel data with rich farm level information with geocoded Chinese development projects. I then exploit the within village level variation in the total number of Chinese financed development projects in a panel fixed effects model to examine their effects on agricultural productivity. I find a positive effect on agricultural productivity in villages that are located within 25 km of these projects. This is largely driven by economic infrastructure. The results are robust to alternative definitions of Chinese financed development projects. I also find that the potential mechanisms driving the results are agricultural commercialization and access to improved seeds. This suggests that these projects connect farmers to input and output markets.

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Understanding the antecedents determining technology adoption in agriculture is essential to promote technology adoption to improve agricultural productivity in developing nations. The aims of this research were to understand the meaning of technology adoption for people involved in farming activities in developing nations, the antecedents determining technology adoption, their effect and how their interaction influences decision-making with regards to technology implementation in agriculture in developing nations. This study was qualitative in nature and followed an exploratory approach. This allowed the researcher to gain and understand new insights about the antecedents determining technology adoption in agriculture in developing nations. A total of 12 synchronous online semi-structured interviews were conducted with farmers and agriculture technicians from developing nations where the reliance on the agriculture sector is high. These interviews were analysed using thematic content analysis approach which led to the development of ‘The antecedents determining technology adoption in agriculture in developing nations’ Framework. This Framework refuted literature findings which highlighted the existence of four antecedents determining technology adoption in agriculture in these nations. Five predominant antecedents namely: awareness; financial assistance; applicability of technology; training and technical support; and demonstrations were identified in this study. This framework explains that the interaction of the identified antecedents is essential to foster technology adoption among farmers in developing nations and is important for stakeholders since it can provide a better understanding and guidance for the creation of integrated strategies to improve technology adoption in agriculture in developing nations. / Mini Dissertation (MBA)--University of Pretoria, 2021. / Gordon Institute of Business Science (GIBS) / MBA / Unrestricted

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