Corn is a dominating feature in the landscape of the Midwestern United States. Associated with this crop are a plethora of products from fertilizers to pesticides that help farmers maximize grain yield while minimizing costs. A widely accepted form of protection from major pests in the United States is genetically modified corn that has been altered so that it contains genetic material from another species, a soil bacterium, Bacillus thuringiensis Berliner (Bt corn), in order to produce proteins that are toxic to some insect pests. Additional insecticides that are commonly used to protect corn include a neonicotinoid seed coating, clothianidin, and a pyrethroid insecticide applied in-furrow, tefluthrin. The goal of my dissertation was to measure the environmental fate of the Cry1Ab Bt corn protein, clothianidin, and tefluthrin and determine if measured concentrations could be causing effects to non-target species. The Cry1Ab proteins persisted only during the corn growing season in soil, runoff water and sediment with the highest concentrations measured during pollination. Clothianidin was detected in all matrices and remained persistent throughout the year in soil pore water. Tefluthrin was consistently detected in soil, runoff water, and runoff sediment during the corn growing season, but was not found in groundwater or soil pore water. No acute toxicity was observed to any species when exposed to the Cry1Ab protein in corn plant leaf tissue, therefore little risk was anticipated. Non-target species exposed to clothianidin resulted in limited ecological risk from field exposures. Tefluthrin results indicated elevated risk for non-target species exposed to tefluthrin at concentrations that were measured in the field study. There was no increase in toxicity to tefluthrin when non-target species were exposed to a combination of all three insecticides. In summary, the genetically modified corn insecticidal proteins and clothianidin were not found at environmental concentrations exceeding benchmark values for ecological effects, but tefluthrin was consistently detected in the environment at levels that could be causing toxicity to non-target species, especially if it is able to travel off-site.

O objetivo foi avaliar níveis de nitrogênio (N), fósforo (P) e potássio (K) em milho (Zea mays L.) com alto potencial genético para produtividade, sendo convencional e geneticamente modificado, visando recomendações de manejo da nutrição sob os pontos de vista técnico e econômico. Foram conduzidos seis experimentos, estudando cinco níveis de fornecimento dos nutrientes N, P e K, sendo T1= omissão completa do N; T2= 50 kg ha-1 de N; T3= 100 kg ha-1 de N; T4= 150 kg ha-1 de N; T5= 200 kg ha-1de N; T6= omissão completa do P; T7= 40 kg ha-1 de P2O5; T8= 80 kg ha-1 de P2O5; T9= 120 kg ha-1 de P2O5; T10= 160 kg ha-1 de P2O5; T11= omissão completa do K; T12= 50 kg ha-1 de K2O; T13= 100 kg ha-1 de K2O; T14= 150 kg ha-1 de K2O; T15= 200 kg ha-1 de K2O, e dois híbridos, o DKB390 convencional e o DKB390PRO, totalizando 20 unidades experimentais para cada ensaio. Avaliou-se índice de coloração verde com clorofilometro no estádio R1, altura de planta, rendimento de grãos, teor foliar de N, P e K no estádio R1 e teor de P e K no solo em pós-colheita em 3 profundidades (0-10 cm, 10-20 cm e 20-40 cm). Também foi determinado os custos de produção relacionando o híbrido convencional e o geneticamente modificado. Para o híbrido convencional DKB390 a aplicação de N provocou aumentos lineares do teor de N na folha, implicando em resposta quadrática para o rendimento de grãos atingindo produção máxima de 10718 kg ha-1 para dose de 135 kg de N ha-1. Para os níveis aplicados de P, a resposta foi de forma linear crescente no solo, na folha e no rendimento de grãos para o intervalo avaliado (0 a 160 kg ha-1 de P2O5). Para o K, o rendimento expressou resposta linear crescente, por outro lado os níveis de K na folha e no solo apresentaram respostas quadrática. Para o híbrido geneticamente modificado DKB390PRO, os níveis de N aplicados provocaram resposta quadrática para o teor de N na folha com correlação positiva para o índice de coloração verde, refletindo sobre o rendimento de grãos, cuja a produção máxima foi de 11.082 kg ha-1 para a dose de 164 kg ha-1de N. Para o P, os níveis utilizados proporcionaram resposta linear crescente para o teor foliar de P, sendo que o rendimento de grãos teve resposta quadrática produzindo 9.791 kg ha-1 na dose de 95 kg ha-1de P2O5. No solo obteve-se resposta linear crescente para as profundidades 0-10 cm e 20-40 cm sendo quadrática para 10-20 cm. Para o K a resposta foi linear crescente na folha e quadrática no rendimento de grãos com produção máxima de 9.401 kg ha-1 na dose de 93 kg ha-1 K2O. Para o solo, as respostas alcançadas tiveram comportamento quadrático para as profundidades de 0-10 cm e 10-20 cm sendo linear crescente na de 20-40cm. Para produtividades maiores que 10.041kg ha-1, o custo esperado de DKB390PRO foi menor, ou seja, o produtor tem que ter o compromisso de atingir elevadas produtividades quando se utiliza híbridos de alta tecnologia. / The goal of this research was to analyses levels of nitrogen, phosphorus and potassium in corn (Zea mays L.) for conventional and genetically modified productivity, with the goal providing recommendation for nutrients applications from a technical and economic perspective. Six experiments were conducted: two hybrids were used, one conventional, DKB390, and one genetically modified, DKB390PRO. Each hybrid was tested for 3 different nutrients, N, P, and K. Five application rates were tested for each nutrient: T1= complete omission of the nutrient N; T2= 50 kg ha-1 of N; T3= 100 kg ha-1 of N; T4= 150 kg ha-1 of N; T5= 200 kg ha-1 of N; T6= complete omission of the nutrient P; T7= 40 kg ha-1 of P2O5; T8= 80 kg ha-1 of P2O5; T9= 120 kg ha-1 of P2O5; T10= 160 kg ha-1 of P2O5; T11= complete omission of the nutrient K; T12= 50 kg ha-1 of K2O; T13= 100 kg ha-1 of K2O; T14= 150 kg ha-1 of K2O; T15= 200 kg ha-1 of K2O, Green coloring index with SPAD in R1 stage, plant height, grain yield, N, P and K amount in leaf in R1 stage, and P and K amount in soil post harvest in three depths 0-10 cm, 10-20 cm and 20-40 cm were evaluated. Production costs comparing conventional and genetically modified hybrids were also studied. Nitrogen application for the conventional DKB390 caused a linear increase in the amount of N in the leaves, resulting in a quadratic response for grain yield reaching maximum production of 10718 kg ha-1 for an application of 135 kg ha-1. The response to P levels used was an increasing linear relationship in the leaves as well as ingrain yield for the interval studied (0 to 160 kg ha-1 of P2O5). K applications produced an increasing linear response for yield and a quadratic response in the leaves and soil. N application used produced a quadratic response in the leaves for the genetically modified hybrid, DKB390PROwith positive correlation for the green coloring index, reflected in grain yield, whose maximum production was 11082 kg ha-1 for the application rate of 164 kg ha-1 of N. The rates of P applied induced a linear response in P concentrations in the leaves, while grain yield had a quadratic response producing 9791 kg ha-1 for the application rate of 95 kg ha-1 of P2O5 and in soil the response was increasingly linear for the depths 0-10 and 20-40 cm and quadratic for 10-20 cm. Responses in the leaves were increasingly linear for K , quadratic in grain yield with maximum production of 9401 kg ha-1 in the application rate of 93 kg ha-1 K2O, and for soil the responses were quadratic for the depths of 0-10 and 10-20 cm being increasingly linear in the 20-40cm. The expected cost of DKB390PRO is less for yields greater than 10, 041 kg ha-1, and producers should be committed to these higher yields when using high technology hybrids.

The aim of the thesis was to evaluate and to compare the rate of corn borer and the production capability of 4 hybrids of corn (Zeamays L.) of different earliness. For the comparison a variety test was layed out in the land of my father in Klimětice (Central Bohemia). Before the harvest a sampling for detection of dry matter content in the biomass has been made to determinate the date of harvest. The number of samplings depended on the attainment of required dry matter content in the biomass. By the harvest the yield and dry matter content of the biomass, yield and percentage of corn ears, dry matter yield and the starch yield were determined. In the experiments the differences in infestation of corn borer were determined. Further differences in observed parameters were found out, which were dependent on the different utility trends and earliness of the given hybrids. The result was the appreciation of the given hybrids and determining of their suitability for their growing in conditions of my fathers lands.

O objetivo foi avaliar níveis de nitrogênio (N), fósforo (P) e potássio (K) em milho (Zea mays L.) com alto potencial genético para produtividade, sendo convencional e geneticamente modificado, visando recomendações de manejo da nutrição sob os pontos de vista técnico e econômico. Foram conduzidos seis experimentos, estudando cinco níveis de fornecimento dos nutrientes N, P e K, sendo T1= omissão completa do N; T2= 50 kg ha-1 de N; T3= 100 kg ha-1 de N; T4= 150 kg ha-1 de N; T5= 200 kg ha-1de N; T6= omissão completa do P; T7= 40 kg ha-1 de P2O5; T8= 80 kg ha-1 de P2O5; T9= 120 kg ha-1 de P2O5; T10= 160 kg ha-1 de P2O5; T11= omissão completa do K; T12= 50 kg ha-1 de K2O; T13= 100 kg ha-1 de K2O; T14= 150 kg ha-1 de K2O; T15= 200 kg ha-1 de K2O, e dois híbridos, o DKB390 convencional e o DKB390PRO, totalizando 20 unidades experimentais para cada ensaio. Avaliou-se índice de coloração verde com clorofilometro no estádio R1, altura de planta, rendimento de grãos, teor foliar de N, P e K no estádio R1 e teor de P e K no solo em pós-colheita em 3 profundidades (0-10 cm, 10-20 cm e 20-40 cm). Também foi determinado os custos de produção relacionando o híbrido convencional e o geneticamente modificado. Para o híbrido convencional DKB390 a aplicação de N provocou aumentos lineares do teor de N na folha, implicando em resposta quadrática para o rendimento de grãos atingindo produção máxima de 10718 kg ha-1 para dose de 135 kg de N ha-1. Para os níveis aplicados de P, a resposta foi de forma linear crescente no solo, na folha e no rendimento de grãos para o intervalo avaliado (0 a 160 kg ha-1 de P2O5). Para o K, o rendimento expressou resposta linear crescente, por outro lado os níveis de K na folha e no solo apresentaram respostas quadrática. Para o híbrido geneticamente modificado DKB390PRO, os níveis de N aplicados provocaram resposta quadrática para o teor de N na folha com correlação positiva para o índice de coloração verde, refletindo sobre o rendimento de grãos, cuja a produção máxima foi de 11.082 kg ha-1 para a dose de 164 kg ha-1de N. Para o P, os níveis utilizados proporcionaram resposta linear crescente para o teor foliar de P, sendo que o rendimento de grãos teve resposta quadrática produzindo 9.791 kg ha-1 na dose de 95 kg ha-1de P2O5. No solo obteve-se resposta linear crescente para as profundidades 0-10 cm e 20-40 cm sendo quadrática para 10-20 cm. Para o K a resposta foi linear crescente na folha e quadrática no rendimento de grãos com produção máxima de 9.401 kg ha-1 na dose de 93 kg ha-1 K2O. Para o solo, as respostas alcançadas tiveram comportamento quadrático para as profundidades de 0-10 cm e 10-20 cm sendo linear crescente na de 20-40cm. Para produtividades maiores que 10.041kg ha-1, o custo esperado de DKB390PRO foi menor, ou seja, o produtor tem que ter o compromisso de atingir elevadas produtividades quando se utiliza híbridos de alta tecnologia. / The goal of this research was to analyses levels of nitrogen, phosphorus and potassium in corn (Zea mays L.) for conventional and genetically modified productivity, with the goal providing recommendation for nutrients applications from a technical and economic perspective. Six experiments were conducted: two hybrids were used, one conventional, DKB390, and one genetically modified, DKB390PRO. Each hybrid was tested for 3 different nutrients, N, P, and K. Five application rates were tested for each nutrient: T1= complete omission of the nutrient N; T2= 50 kg ha-1 of N; T3= 100 kg ha-1 of N; T4= 150 kg ha-1 of N; T5= 200 kg ha-1 of N; T6= complete omission of the nutrient P; T7= 40 kg ha-1 of P2O5; T8= 80 kg ha-1 of P2O5; T9= 120 kg ha-1 of P2O5; T10= 160 kg ha-1 of P2O5; T11= complete omission of the nutrient K; T12= 50 kg ha-1 of K2O; T13= 100 kg ha-1 of K2O; T14= 150 kg ha-1 of K2O; T15= 200 kg ha-1 of K2O, Green coloring index with SPAD in R1 stage, plant height, grain yield, N, P and K amount in leaf in R1 stage, and P and K amount in soil post harvest in three depths 0-10 cm, 10-20 cm and 20-40 cm were evaluated. Production costs comparing conventional and genetically modified hybrids were also studied. Nitrogen application for the conventional DKB390 caused a linear increase in the amount of N in the leaves, resulting in a quadratic response for grain yield reaching maximum production of 10718 kg ha-1 for an application of 135 kg ha-1. The response to P levels used was an increasing linear relationship in the leaves as well as ingrain yield for the interval studied (0 to 160 kg ha-1 of P2O5). K applications produced an increasing linear response for yield and a quadratic response in the leaves and soil. N application used produced a quadratic response in the leaves for the genetically modified hybrid, DKB390PROwith positive correlation for the green coloring index, reflected in grain yield, whose maximum production was 11082 kg ha-1 for the application rate of 164 kg ha-1 of N. The rates of P applied induced a linear response in P concentrations in the leaves, while grain yield had a quadratic response producing 9791 kg ha-1 for the application rate of 95 kg ha-1 of P2O5 and in soil the response was increasingly linear for the depths 0-10 and 20-40 cm and quadratic for 10-20 cm. Responses in the leaves were increasingly linear for K , quadratic in grain yield with maximum production of 9401 kg ha-1 in the application rate of 93 kg ha-1 K2O, and for soil the responses were quadratic for the depths of 0-10 and 10-20 cm being increasingly linear in the 20-40cm. The expected cost of DKB390PRO is less for yields greater than 10, 041 kg ha-1, and producers should be committed to these higher yields when using high technology hybrids.