Corn (Zea mays L.) production under monoculture and conventional tillage systems may land to soil degradation and nitrate (NO$ sb3 sp-$) pollution of surface and groundwater. This study evaluated the impact of no-till and conventional tillage, monoculture corn and soybean, corn-soybean rotations and corn-soybean-alfalfa rotations, and three fertilizer N rates applied to monoculture corn or soybean, and corn in rotation, on soil NO$ sb3$-N and NH$ sb4$-N levels. Experimental sites were a Ste-Rosalie clay (Humic Gleysol) and an Ormstown silty clay loam (Humic Gleysol). Results obtained from fall 1992 to spring 1995 showed that tillage had no effect on soil N levels under corn. Soil N levels under corn showed a linear response to added N, specially in the fall. Soil N levels under corn did not change considerably during the non-growing season. Higher spring NO$ sb3$-N levels, particularly in plots under conventional tillage and alfalfa or soybean, compared to fall values indicated greater nitrification and/or mineralization than denitrification, immobilization or leaching. Low NH$ sb4$-N levels indicated that nitrification processes were active. No consistent estimation could be made of fertilizer N credits for corn from either soybean or alfalfa based on NO$ sb3$-N levels in soil.

This study examines the grower’s decision to invest in precision agriculture technologies especially in-season variable rate nitrogen applications based on NDVI data collected from UAVs. NDVI, yield, soil, and other field data were collected from multiple corn and wheat fields located throughout North Dakota. Each field was divided into management zones to determine profitability of utilizing the technology based on in-season nitrogen applications for the grower’s field practice, high, low, and no applications. Results show that using the NDVI data collected from UAVs can be profitable when the grower decides to make the decision to apply nitrogen in a sidedress application.

No description available.

A incorporação e encapsulamento de fertilizantes em blendas poliméricas são métodos que podem ser usados para reduzir perdas e minimizar a poluição ambiental. Neste trabalho, blendas de Proteína Isolada de Soja (SPI) e Poli(ácido lático) (PLA) foram usadas para incorporar o fertilizante NPK (nitrogênio, fósforo e potássio) granular. A influência de concentração dos biopolímeros na mistura foi examinada por Calorimetria exploratória Diferencial (DSC), Análise Termogravimétrica (TGA) e Microscopia Eletrônica de Varredura (SEM). A incorporação efetiva dos nutrientes no solo é dependente do controle da liberação dos mesmos. Porém as aplicações destes nutrientes estão relacionadas aos métodos e às condições do solo. Um método para reduzir perdas de nutrientes é a liberação controlada dos mesmos. Sendo assim, a preparação de blendas baseadas em biopolímeros constituídos de SPI e PLA, para a liberação controlada, se torna viável. SPI e PLA ou SPI, PLA e NPK foram misturados previamente com plastificante e processados através de mistura mecânica, em um misturador de alto torque do tipo Haake , a temperatura de processo foi mantida a 165 ºC durante 5 minutos à velocidade de 90 rpm. Estes parâmetros foram aplicados para todas as blendas. As blendas foram preparadas seguindo a razão SPI/PLA de 1,5, 2,3 e 4,0, usando diferentes porcentagens de plastificante (5 a 16%). Para a mistura que contém NPK o mesmo método foi utilizado. A adição do fertilizante ocorreu após da fusão do PLA. A taxa de liberação dos nutrientes foi calculada pela condutividade do sistema, decorrente da ionização dos sais dos fertilizantes. A concentração dos íons monitorados aumentou com o tempo, evidenciando a liberação dos fertilizantes. Os testes dinâmicos foram realizados sob agitação contínua com 100 mL de água, 1,6 ±0,2g de amostra e 180 horas. A taxa de liberação é uma função da morfologia das blendas e pode ser controlada pela porosidade das mesmas. O uso de blendas como veículo para o fertilizante diminui a liberação deste de forma apreciável (aproximadamente oito vezes) quando comparado ao componente puro. A redução acontece quando a fase amorfa aumenta, esta fase está relacionada à SPI. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-29T19:38:04Z No. of bitstreams: 1 Dissertacao Luciane Calabria.pdf: 2695342 bytes, checksum: 30e97111b374f9a53e5091c1e5632c46 (MD5) / Made available in DSpace on 2014-05-29T19:38:05Z (GMT). No. of bitstreams: 1 Dissertacao Luciane Calabria.pdf: 2695342 bytes, checksum: 30e97111b374f9a53e5091c1e5632c46 (MD5) / The incorporation and encapsulation of fertilizers in polymers blends are methods that can be used to reduce losses and to minimize environmental pollution. In this work, blends of Soy Protein Isolate (SPI) and Polylactide Acid (PLA) were used to incorporate the granular fertilizer NPK (nitrogen, phosphorus and potassium). The blends were obtained from mechanical mixture in a Haake´s high shear mixer. The influence of concentration of the biopolymers in the blends, was examined by differential scanning calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The morphology of the blends can control the diffusion of the fertilizers, also modulating the release. The effective incorporation of the nutrients to the soil is related to the control release control. However, the applications of these nutrients are linked to the methods and the soil conditions. One method for to reduce losses of nutrients is the slow-release. In this way, the preparation of biopolymers blends based in Soy Protein Isolate (SPI) and Polylactide Acid (PLA) for the controlled-release becomes viable. SPI and PLA or SPI, PLA and NPK were previously mixed whit plasticizers and submited to mechanical mixture, in a Haake high shear mixer. The process was performed at 165 ºC for 5 minutes at speed of 90 rpm. These parameters were applied for all blends containing SPI/PLA rate of 1.5, 2.3 and 4.0. For some blends 5 to 15% of plasticizer was added to study its effects. For the blend containing NPK the same method was utilized with addiction of the fertilizer, after the fusion of the PLA. The release rate of nutrients was estimated by the conductivity promoted by the ionization of thefertilizer salts. The ions concentration increase with time due to the release of the fertilizers. The dynamic tests were conducted in a beaker under continuously agitation with 100 mL of water, 1.6 ±0.2g. of sample and 180 hours. The release rate is a function of the blends morphology, and it can be controlled by the porosity. The use of blends as vehicle decreases the release of the fertilizer when compared to the pure component, for about eight times. The relationship increase with the amorphous phase which is related to the SPI.

A incorporação e encapsulamento de fertilizantes em blendas poliméricas são métodos que podem ser usados para reduzir perdas e minimizar a poluição ambiental. Neste trabalho, blendas de Proteína Isolada de Soja (SPI) e Poli(ácido lático) (PLA) foram usadas para incorporar o fertilizante NPK (nitrogênio, fósforo e potássio) granular. A influência de concentração dos biopolímeros na mistura foi examinada por Calorimetria exploratória Diferencial (DSC), Análise Termogravimétrica (TGA) e Microscopia Eletrônica de Varredura (SEM). A incorporação efetiva dos nutrientes no solo é dependente do controle da liberação dos mesmos. Porém as aplicações destes nutrientes estão relacionadas aos métodos e às condições do solo. Um método para reduzir perdas de nutrientes é a liberação controlada dos mesmos. Sendo assim, a preparação de blendas baseadas em biopolímeros constituídos de SPI e PLA, para a liberação controlada, se torna viável. SPI e PLA ou SPI, PLA e NPK foram misturados previamente com plastificante e processados através de mistura mecânica, em um misturador de alto torque do tipo Haake , a temperatura de processo foi mantida a 165 ºC durante 5 minutos à velocidade de 90 rpm. Estes parâmetros foram aplicados para todas as blendas. As blendas foram preparadas seguindo a razão SPI/PLA de 1,5, 2,3 e 4,0, usando diferentes porcentagens de plastificante (5 a 16%). Para a mistura que contém NPK o mesmo método foi utilizado. A adição do fertilizante ocorreu após da fusão do PLA. A taxa de liberação dos nutrientes foi calculada pela condutividade do sistema, decorrente da ionização dos sais dos fertilizantes. A concentração dos íons monitorados aumentou com o tempo, evidenciando a liberação dos fertilizantes. Os testes dinâmicos foram realizados sob agitação contínua com 100 mL de água, 1,6 ±0,2g de amostra e 180 horas. A taxa de liberação é uma função da morfologia das blendas e pode ser controlada pela porosidade das mesmas. O uso de blendas como veículo para o fertilizante diminui a liberação deste de forma apreciável (aproximadamente oito vezes) quando comparado ao componente puro. A redução acontece quando a fase amorfa aumenta, esta fase está relacionada à SPI. / The incorporation and encapsulation of fertilizers in polymers blends are methods that can be used to reduce losses and to minimize environmental pollution. In this work, blends of Soy Protein Isolate (SPI) and Polylactide Acid (PLA) were used to incorporate the granular fertilizer NPK (nitrogen, phosphorus and potassium). The blends were obtained from mechanical mixture in a Haake´s high shear mixer. The influence of concentration of the biopolymers in the blends, was examined by differential scanning calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The morphology of the blends can control the diffusion of the fertilizers, also modulating the release. The effective incorporation of the nutrients to the soil is related to the control release control. However, the applications of these nutrients are linked to the methods and the soil conditions. One method for to reduce losses of nutrients is the slow-release. In this way, the preparation of biopolymers blends based in Soy Protein Isolate (SPI) and Polylactide Acid (PLA) for the controlled-release becomes viable. SPI and PLA or SPI, PLA and NPK were previously mixed whit plasticizers and submited to mechanical mixture, in a Haake high shear mixer. The process was performed at 165 ºC for 5 minutes at speed of 90 rpm. These parameters were applied for all blends containing SPI/PLA rate of 1.5, 2.3 and 4.0. For some blends 5 to 15% of plasticizer was added to study its effects. For the blend containing NPK the same method was utilized with addiction of the fertilizer, after the fusion of the PLA. The release rate of nutrients was estimated by the conductivity promoted by the ionization of thefertilizer salts. The ions concentration increase with time due to the release of the fertilizers. The dynamic tests were conducted in a beaker under continuously agitation with 100 mL of water, 1.6 ±0.2g. of sample and 180 hours. The release rate is a function of the blends morphology, and it can be controlled by the porosity. The use of blends as vehicle decreases the release of the fertilizer when compared to the pure component, for about eight times. The relationship increase with the amorphous phase which is related to the SPI.