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RESISTÊNCIA DE COLMO À PENETRAÇÃO COMO PREDITOR DA QUALIDADE DE COLMOS EM MILHO / RESISTÊNCIA DE COLMO À PENETRAÇÃO COMO PREDITOR DA QUALIDADE DE COLMOS EM MILHOOliveira, Rodrigo Martins de 22 December 2015 (has links)
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Previous issue date: 2015-12-22 / Annual losses of up to 25% of world corn production are stimated as a result of stalk lodging
and root lodging. The use of resistant hybrids is the main method of control, though only use
the visual evaluation is very limited. In this context, it is crucial to find methods to evaluate the
quality of stalks with high correlationship with stalk loding that could be effective to detect
level differences of resistance to stalk lodging. The objective of this study was to estimate the
correlationship between agronomic characteristics and attributes associated with stalk lodging of corn hybrids and their inbred lines. Additionally, select genotypes that simultaneously have the highest number of characteristics associated with stalk quality and grain yield by principal component analysis. There were performed four experiments using corn hybrids and one experiment with inbred lines for evaluation of corn stalk penetration resistance as predictor of corn stalk quality in the 2013/2014 season. The experimental design was a randomized block design with twelve treatments and four reps for experiments with hybrid and sixteen treatments and three reps for the experiment with inbred lines. The results of the hybrids and inbred lines experiments were submited to Pearson correlation analysis through the GENES statistical software, and principal component analysis was performad by the R sorftware 2.15.2. The physical stalk quality represented mainly by stalk lodging, root lodging and corn stalk penetration resistance proved to be limiting for the selection of superior corn genotypes,because corn stalk lodging affected negatively the grain yield in corn hybrids. The stalk penetration resistance evaluation in inbred lines showed a significant negative correlation of 60% with stalk lodging, which makes this evaluation suitable for use to select inbred lines with enhanced physical quality of the stalks, enabling the detection of differences in stalk lodging resistance levels from the inbred lines. Using the principal component analysis was possible the
identification of the corn inbred lines L2, L3, L6, L13 and L14, also the hybrids P30F53YH,30A37PW, DKB240PRO2 and H14 with the most favorable characteristics for stalk physical quality for corn grain yield. / Estima-se perdas anuais de até 25% na produção mundial de milho em consequência do acamamento e do quebramento do colmo. A utilização de híbridos resistentes é o principal
método de controle, embora utilizar apenas a avaliação visual seja bastante limitada. Dessa forma, é imprescindível encontrar metodologias para avaliar a qualidade dos colmos com alta
correlação com o quebramento de colmo à campo e que seja eficaz na detecção de diferenças nos níveis de resistência ao quebramento. O objetivo deste trabalho foi estimar as correlações entre características agronômicas e atributos associados ao quebramento de colmos de híbridos
e linhagens endogâmicas de milho. Adicionalmente, selecionar genótipos que reúnam simultaneamente o maior número de características associadas à qualidade de colmos e ao
rendimento de grãos através da análise de componentes principais. Foram realizados quatro experimentos de híbridos de milho e um de linhagens endogâmicas para avaliação da resistência dos colmos ao quebramento como preditor da qualidade de colmos em milho na safra 2013/2014. O delineamento experimental foi o de blocos ao acaso com doze tratamentos e quatro repetições para os experimentos com híbridos e dezesseis tratamentos e três repetições para o experimento com linhagens endogâmicas. Os dados dos experimentos de híbridos e de linhagens foram submetidos à análise de correlação de Pearson através do software estatístico
GENES, e a análise de componentes principais através do software R versão 2.15.2. A qualidade física dos colmos representada principalmente pelas características quebramento de colmo, acamamento e resistência do colmo à penetração demonstraram ser limitantes para a seleção de genótipos superiores de milho, pois o quebramento dos colmos nos híbridos de milho afetou negativamente o rendimento de grãos nos experimentos. A avaliação da resistência à penetração do colmo nas linhagens endogâmicas teve correlação significativa e negativa de 60% com o quebramento de colmo, o que a torna passível de utilização para a seleção de linhagens com maior qualidade física dos colmos, possibilitando a detecção de diferenças nos níveis de resistência ao quebramento dos colmos entre as linhagens endogâmicas. Através da análise de componentes principais foi possível a identificação das linhagens endogâmicas de milho L2, L3, L6, L13 e L14 e os híbridos P30F53YH, 30A37PW, DKB240PRO2 e H14 com o maior número de características favoráveis para qualidade física dos colmos e potencial para o rendimento de grãos.
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Estratégias para reduzir as emissões gasosas e melhorar o aproveitamento do nitrogênio de dejetos de suínos pelo milho / Strategies to reduce the gaseous emissions and improve the nitrogen use pig slurry in no-till cornMiola, Ezequiel César Carvalho 28 February 2014 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / While promoting increased farm production, applications of pig slurry (PS), in notillage
systems (NT), may represent an important source of environmental contamination.
Therefore, the pursuit of technological strategies to minimize this potential polluter of DLS is
one of the main current challenges in pig farming. Given this context, the aim of this study
was to evaluate how the subsurface injection of PS in NT and the use of the nitrification
inhibitor dicyandiamide (DCD) affects emissions of nitrous oxide (N2O), N losses by
ammonia (NH3) volatilization and nitrogen (N) supply to corn. The study was conducted at
the Federal University of Santa Maria during the growing seasons of corn in 2011/12 and
2012/13. Two experiments were conducted, one in a Typic Paleudult (Site I) and another in a
Typic Paleudult (Site II). In both sites, we used the experimental design of randomized blocks
with four replications of the following treatments: Pig slurry surface (PSs), PSs + DCD, pig
slurry injected into the subsurface (PSi), PSi + DCD, control without fertilizers or DCD
(Control) and mineral fertilization (urea). The injection of PS reduced NH3 emissions by 70%,
but increased N2O-N from 2.628 to 6.198 g N2O N ha-1, compared to surface application. The
addition of DCD to PS, at the time of its application to the soil, reduced N2O emissions by
28% when the PS were applied on the soil surface and 66% when injected, but did not
influenced the emissions of NH3. The emission factor (EF) of N2O was higher when the PS
were injected (3.6%) than when applied to the surface of the soil (1.3%), whereas the DCD
reduced such EF to 0.9% and 0.8%, respectively. The injection of PS in the soil increased N
use efficiency and the yield of corn grains compared to surface application, while the DCD
did not affect these two attributes. When N2O emissions from each treatment were related to
corn yield, the best results from an environmental point of view were obtained when the
injection of PS was associated with the use of DCD. From these results it is concluded that the
injection of PS in the soil under NT associated with DCD, is a promising alternative
compared to current technology for the application of PS on the soil surface and without
DCD. However, this strategy can only be recommended and widespread safely to producers if
their agronomic and environmental benefits are followed by an economic analysis as well as
an analysis of the environmental impact of the additional demand for energy and fuel to make
the mechanical operation injection of PS in the soil. / Ao mesmo tempo em que promovem o incremento da produção agrícola, as aplicações
de dejetos líquidos de suínos (DLS), em sistema plantio direto (SPD), podem representar uma
importante fonte de contaminação ambiental. Por isso, a busca de estratégias tecnológicas
para minimizar esse potencial poluidor dos DLS constitui um dos principais desafios atuais da
suinocultura. Diante deste contexto, o objetivo do presente trabalho foi avaliar como a injeção
subsuperficial de DLS em SPD e o uso do inibidor de nitrificação dicianodiamida (DCD)
afetam as emissões de óxido nitroso (N2O), as perdas de N por volatilização de amônia (NH3)
e o fornecimento de nitrogênio (N) ao milho. O estudo foi conduzido na Universidade Federal
de Santa Maria (UFSM), durante as safras agrícolas de milho de 2011/12 e 2012/13. Foram
conduzidos dois experimentos, sendo um em Argissolo Vermelho Distrófico arênico e outro
em Argissolo Vermelho Alumínico úmbrico. Em ambos os locais, utilizou-se o delineamento
experimental de blocos ao acaso com quatro repetições dos seguintes tratamentos: DLS
aplicados na superfície do solo (DLSSup.), DLSSup.+DCD, DLS injetados em subsuperfície
(DLSInj.), DLSInj.+DCD, testemunha e adubação mineral. A injeção dos DLS reduziu as
emissões de NH3 em 70 %, mas aumentou as de N-N2O de 2.628 para 6.198 g N2O N ha-1
, em
comparação à aplicação superficial. A adição da DCD aos DLS, no momento da sua aplicação
ao solo, reduziu as emissões de N2O em 28 % quando os DLS foram aplicados na superfície
do solo e em 66 % quando injetados, mas não influenciou as emissões de NH3. O fator de
emissão (FE) de N2O foi mais elevado quando os DLS foram injetados (3,6 %) do que quando
aplicados na superfície do solo (1,3 %), sendo que a DCD reduziu tais FE para 0,9 % e 0,8 %,
respectivamente. A injeção dos DLS no solo aumentou a eficiência de uso do N e a
produtividade de grãos de milho em comparação à aplicação superficial, enquanto que a DCD
não afetou estes dois atributos. Quando as emissões de N2O de cada tratamento foram
relacionadas à produtividade do milho, os melhores resultados do ponto de vista ambiental
foram obtidos quando a injeção dos DLS foi associada ao uso da DCD. A partir desses
resultados conclui-se que a injeção dos DLS no solo em SPD, associada à DCD, constitui uma
alternativa promissora, em relação à tecnologia atual de aplicação dos DLS na superfície do
solo e sem DCD. Contudo essa estratégia somente poderá ser recomendada e difundida com
segurança aos produtores se os seus benefícios agronômicos e ambientais, forem seguidos de
uma análise econômica e também de uma análise de impacto ambiental decorrente da
demanda adicional de energia e combustível para poder realizar a operação mecânica de
injeção dos DLS no solo.
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The Influence of Cover Crop Termination Strategies and Supplemental Nitrogen on Sweet Corn Yield and Nitrogen Use EfficiencySunuwar, Sachina 13 May 2022 (has links) (PDF)
Cover crops are instrumental in nutrient management and soil health. A field experiment was conducted from fall 2020 to summer 2021 to evaluate the efficiency of different cover crop termination techniques and supplemental nitrogen on sweet corn yield, ear quality and nitrogen use efficiency. The four termination types are herbicide and disk tillage (HDT), herbicide no-till (HNT), cultivation disk till (CDT), and roller crimped no-till (RCNT). These termination types were each divided into four different nitrogen treatment: 0%, 33%, 67% and 100% of the recommended doses (145 kg haˉ¹). Sweet corn yield was highest and % unfilled tip was lowest when cover crops terminated by CDT, followed by RCNT, HNT and HDT. The highest ear weight obtained when 100% of the recommended nitrogen rate was applied to the sweet corn. However, the highest nitrogen use efficiency was obtained when 67% of the recommended nitrogen application rate was used.
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An Empirical Model for Estimating Corn Yield Loss from Compaction Events with Tires vs. Tracks High Axle LoadsKlopfenstein, Andrew A. 30 August 2016 (has links)
No description available.
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INVESTIGATION OF CORN YIELD IMPROVEMENT FOLLOWING CEREAL RYE USING STARTER NITROGEN FERTILIZERHouston L Miller (7830965) 20 November 2019 (has links)
Cereal rye (CR), the most common and effective nitrogen (N) scavenging
cover crop option in the Midwest, is often utilized in cropping systems to
reduce nitrate loss for environmental benefits. To increase environmental
efficiency in Midwest corn cropping systems, we must increase the overall
adoption of CR. However, due to the yield reduction potential (6%) for corn
planted after CR termination, CR is primarily recommended before soybean. To
increase CR adoption, we must develop adaptive fertilizer management practices
that achieve competitive grain yields relative to cropping systems where CR is
not adopted. Therefore, the objectives of this study are to determine (1) the
effect of CR and starter nitrogen rate on corn growth and nitrogen content. (2)
the optimum starter nitrogen rate to achieve agronomic optimum corn yield
following CR. (3) the impact of phosphorus (P) at starter on plant growth,
nitrogen content, and yield with the inclusion of CR. For our study, five
starter N rates were applied in a 5x5 cm band to both CR and non-CR plots,
concentrations ranged from 0-84 kg N ha<sup>-1 </sup>in 28 kg N ha<sup>-1</sup>
intervals. Total N applied was the same for each treatment, relative to its
location, and was split between starter N at planting and sidedress applied at
growth stage V6 relatively. Although CR termination took place at least two
weeks before planting, CR decreased corn grain yield at one of three locations
by an average of 8%, nitrogen recovery efficiency (NRE) by 27%, and R6 total N content
by 23%, relative to the conventional control (non-CR 0N), when no starter N was
applied. At one of three locations, starter N rates of 56 kg N ha<sup>-1</sup>,
56 kg N ha<sup>-1 </sup>plus 17 kg P ha<sup>-1</sup>, and 84 kg N ha<sup>-1</sup>
increased corn grain yield, in CR plots, and 56 kg N ha<sup>-1</sup> plus 17 kg
P ha<sup>-1</sup> increased corn grain yield in non-CR plots. Phosphorus increased
corn grain N content at growth stage R6 in one of three locations and did not
impact corn grain yield at all locations. We conclude that the inclusion of
starter N at planting has the potential to increase agronomic productivity in
CR corn cropping systems in soil environments with a high capacity to
mineralize soil N. However, further research is required to refine our starter
N results to find an optimum starter N rate to apply before planting corn
following CR.
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