Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Pasture Science))--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

Orientador: João Antonio Galbiatti / Banca: José Eduardo Pitelli Turco / Banca: Emerson Fachini / Resumo: Este trabalho teve o objetivo de avaliar os efeitos do biofertilizante bovino e da irrigação em plantas de alface, para uma possível substituição de fertilizantes minerais por orgânicos e, ainda, diminuição de água para irrigação. O experimento foi conduzido em dois ambientes distintos: campo e ambiente protegido, em área experimental pertencente ao Departamento de Engenharia Rural da FCAV/UNESP, Câmpus de Jaboticabal-SP. O delineamento experimental foi em blocos casualizados, esquema fatorial 6x2, sendo 6 adubações (4 doses crescentes de biofertilizante bovino: 60, 90, 120 e 150m3ha-1 e duas testemunhas: sem adubação e adubação mineral) e 2 lâminas de irrigação (80 e 100% da evapotranspiração de referência) em 4 blocos, utilizando-se a cultura da alface (Lactuca sativa L.). As variáveis analisadas foram altura, diâmetro da cabeça, clorofila, número de folhas, matéria fresca e matéria seca da parte aérea da planta. Foi realizada a análise da variância pelo teste F, a comparação de médias pelo teste de Tukey (p<0,05) e a regressão polinomial. O experimento de campo foi o que demonstrou resultados mais expressivos em relação à adubação orgânica. É possível obter uma produção satisfatória da planta de alface com biofertilizantes. A dose de biofertilizante recomendada para esse experimento é a de 90m3ha-1 e a melhor irrigação a de 80% da evapotranspiração. No ambiente protegido não houve significância em relação às adubações. Para a irrigação, a lâmina de água recomendada é a de 100% da evapotranspiração de referência / Abstract: This work aimed to evaluate the effects of bovine biofertilizer and irrigation in lettuce for a possible replacement for organic fertilizers, and also decrease of water for irrigation. The experiment was conducted in two distinct environments: field and greenhouse in the experimental area of the Department of Rural Engineering FCAV / UNESP, Jaboticabal-SP. The experimental design was randomized blocks, factorial scheme 6x2, 6 fertilizers (4 increasing doses of bovine biofertilizer: 60, 90, 120 and 150m3ha-1 and two witnesses: without fertilizer and mineral fertilizer) and two irrigation levels (80 and 100% of reference evapotranspiration) in four blocks, using the lettuce (Lactuca sativa L.). The variables analyzed were: height, head diameter, chlorophyll, leaf number, fresh weight and dry weight of plant tops. Was performed by analysis of variance F test comparison of means by Tukey test (p <0.05) and polynomial regression. The field experiment demonstrated the most significant results in relation to fertilization. Is can obtain a satisfactory production of lettuce plant with biofertilizers. The biofertilizer dose recommended for this experiment is to 90m3ha-1 and the best irrigation 80% of evapotranspiration. In the greenhouse there was no significance in relation to fertilization. For irrigation, the recommended is for 100% of reference evapotranspiration / Mestre

Nitrogen-based fertilizer industry in United States is undergoing major changes the demand for which is primarily driven by agriculture. Traditionally, this industry sources anhydrous ammonia through imports from Canada and U.S.-Gulf, the latter comprises bulk of imports, or produces domestically to be supplied as is or converted into urea or UAN variations of nitrogen-based fertilizer with various combinations with other minerals. With change in composition of crops and increasing acreage of crops that are fertilizer intensive, there is an increased demand for nitrogen-based fertilizer in order to promote foliar growth as a standalone form, for example Urea, or in combination, for example Di-ammonium phosphate (DAP). Second compelling reason for change in industry is reduction in prices of natural-gas, in part due to oil exploration, that makes it cheaper to produce anhydrous ammonia domestically. Anhydrous ammonia is perquisite for making other types of nitrogen-based fertilizer and highly energy intensive. Thus, lower natural-gas prices provide incentive for domestic firms to either expand existing fertilizer plants or opens up the possibility of new entrants. Many companies/firms have recently announced their plans to expand existing plants or open new units, exerting competitive pressure on an industry that already has lot of surplus capacity but highly competitive in terms of production costs and technology used. It is to be noted that natural-gas prices are volatile; therefore, any commitment to expand or open new plant is subject to volatility in demand, natural-gas prices, and import price of fertilizers. The purpose of this dissertation is to analyze spatial competition among U.S. nitrogen-based fertilizer plants and their respective market boundaries. This dissertation also derives the structure of the supply chain for nitrogen-based fertilizer in the United States (at macro level); and the stochastic spatial-optimization model to account for risk in random variables. Locational information is used to account for spatial nature of problem, and linear and mixed-integer based optimization techniques are applied to arrive at current and most likely future cases. Combination of linear optimization, and mixed-integer, and geographical information systems helps in determining regional areas where competition is expected to be ruinous and most intense; and provide insights on viability of newly announced fertilizer plants that are most likely to be successful and significantly impact the structure of overall supply chain. / Upper Great Plains Transportation Institute (UGPTI)

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CREAMS-NT, a modified version of the field-scale model for Chemicals, Runoff, and Erosion from Agricultural Management Systems (CREAMS) model, was developed to simulate the nitrogen (N) transformations and subsequent nutrient transport processes which occur in the soil following organic waste applications. CREAMS-NT accounts for nutrient addition through fertilization and rainfall and losses of N by volatilization, denitrification, plant uptake, leaching, and overland flow. Data required by CREAMS-NT includes runoff volume, sediment yield, percolation, and soil environmental conditions which is generated by the hydrologic and erosion components of the original CREAMS model. The mineralization, nitrification, denitrification, ar1d volatilization processes are simulated using firstâ order knetic equations adjusted for the effects of soil environmental conditions including temperature, moisture, pH, soil/sludge contact, and soil cation exchange capacity. Prior to a runoff event, soil ammnonium-N (NH4 â N) is partitioned between adsorbed and desorbed phases. CREAMS-NT predicts the transport of organic-N, NH4 â N, and sediment=bound phosphorus (P3b) in runoff using enrichment ratios. The transport of soluble nutrients, nitrate-N (NO3 â N), NH4 â N, and soluble P (PTF), is estimated using extraction coefficients. / Master of Science

This research was focused on increasing the efficiency of upland cotton production in the northern cotton belt through the use of new fertilizer formulations, placement, and timings. The objectives of the experiments reported in this thesis were to: 1) evaluate the effects of side-dress potassium (K), sulfur (S), and boron (B) formulation and application timing on tissue nutrient levels during the bloom period; 2) evaluate lint yield response of cotton to different formulations of nitrogen (N), K, S and B applied at side-dress; and 3) compare 5x5 banding (5 cm beside and 5cm below the seed) and deep placement of complete N-P-K-S blends to current nutrient management strategies on early season plant growth, nodes above white flower, total nodes, petiole nutrient concentrations during bloom, and lint yield. Tissue S and B concentrations were increased more often than K concentrations when the nutrients were applied with side-dress N. When evaluating P and K placement, petiole P levels were found to be significantly higher in unfertilized plots when no side-dress N was applied. Phosphorus and K placement and/or rate had no effect on lint yield when N was applied at side-dress during the study. Environmental conditions potentially influenced the response to P and K placement as 5x5 placement produced yields significantly higher during 2013 growing season at location 1, while deep placement produced significantly higher yields in 2014 at location 3. As a result, Virginia nutrient management recommendations for cotton have been updated to incorporate management strategies to maximize lint yields. / Master of Science

Call number: LD2668 .T4 1984 H38 / Master of Science