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Njoroge, Kiarie. "Earliness and yield in Katumani maize". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305695.
Pełny tekst źródłaGrifo, Anabela Dias Ramalho Vale Leitão. "Inputs and yield optimization on irrigated maize". Doctoral thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/18319.
Pełny tekst źródłaRaymond, Fred Douglas. "Reducing Corn Yield Variability and Enhancing Yield Increases Through the Use of Corn-Specific Growth Models". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/36304.
Pełny tekst źródłaMaster of Science
Gonçalves, Júlia Alves Roque. "Yield gap explaining factors and solutions to improve yields in a maize farm in Portugal". Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/21289.
Pełny tekst źródłaOver the decades, it has been found that agricultural intensification, that is, the increase in production per hectare, is substantially urgent and necessary, justified by the observed and expected population increase and the impossibility of agricultural expansion. One of the methods for achieving this goal is the study and investigation of yield gaps, which may be explained by unfavorable soil and climate conditions, or less adequate input management. Given the socio-economic importance of maize crop in Portugal and the need for case studies that exemplify agricultural intensification methods, this dissertation aims to discover which are the reducing factors that justify the gap between the maximum and actual yields, known as yield gaps, which were analyzed between plots and years, and how large was the yield gap over the 10 years. Through a database of irrigation appropriations, nitrogen applications, sowing dates and climate data, collected over 10 years and provided by Milho Amarelo company, located in the Santarem region, other variables were calculated, such as degree-day accumulation, cultural evapotranspiration and intercepted radiation. These data were analyzed annually according to the whole cycle and according to different phenological phases (vegetative and reproductive). Once all variables were obtained and organized, statistical methods of bivariate and multivariate analysis were performed. The magnitude of yield gap was calculated according to the Approach 2 indicated by FAO 41. The results show that interaction of sowing dates with climatic conditions are in the nature of this deviation, with gap’s magnitude ranging from 5% to 20%, depending on the climatic conditions of the year
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Martinez, Ascanio Ana Karine <1979>. "Fine Mapping of qroot-yield-1.06, a QTL for Root, Plant Vigor and Yield in Maize". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7160/.
Pełny tekst źródłaFall, Sidi 1951. "Induced water stress effects on grain yield and yield components of twelve maize (Zea mays L.) genotypes". Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277913.
Pełny tekst źródłaEsteves, Mariana Canavarro Reis Teixeira. "Precision agriculture : a spatial econometric analysis of a portuguese maize yield". Master's thesis, Instituto Superior de Economia e Gestão, 2021. http://hdl.handle.net/10400.5/22844.
Pełny tekst źródłaNowadays, maize is the most important cereal in the world and its production has been increasing both worldwide and in Portugal, over the years. The constant technological development has led to the creation of new techniques such as precision agriculture, to better meet the global needs of this primordial cereal as well as optimize its production. This research was developed jointly with the firm Agro Analítica from the agriculture sector, whose area of expertise is Precision Agriculture and System Optimization. In this manner, the present work aims to estimate a function for the maize yield identifying the relevant determining factors, and their effect, on maize productivity on an exploitation of a firm in Azinhaga, Golegã, district of Santarém, Portugal for the year 2020. Using appropriate software, this dissertation applies the most recent spatial econometric methods to cross-sectional data, in order to properly include spatial dependence in the estimation. Thus, the appropriate models were estimated: Spatial Lag Model (SLM), Spatial Error Model (SEM) and SARAR(1,1) Model, whose use was recommended by the diagnosis to OLS (Ordinary Least Square) residuals. The elected model was the SARAR(1,1), capturing the spatial dependence and heteroscedasticity in the data, with an accuracy of approximately 90%. In this framework, it was concluded that maize yield, in the year and area under study, is positively influenced by factors such as the sowing density, applied sulfur trioxide (SO3) and a specific variety of seed. Regarding the fertilization, nitrogen and potassium, and irrigation of the crop, presented a non-linear (quadratic) relationship with the maize yield. Also influencing the yield, there are weather-related variables measured by stage of the maize life cycle, that prove to be significant at explaining the variable under study such as the relative humidity, the temperature, and the wind velocity.
Atualmente, o milho é o cereal mais importante do mundo tendo a sua produção vindo a aumentar tanto a nível mundial como em Portugal ao longo dos anos. O constante desenvolvimento tecnológico resultou na criação de novas técnicas, como a agricultura de precisão, para melhor satisfazer as necessidades globais deste cereal primordial bem como otimizar a sua produção. Esta investigação foi desenvolvida em conjunto com a empresa Agro Analítica do sector da agricultura, cuja área de especialização é Agricultura de Precisão e Otimização de Sistemas. Desta forma, o presente trabalho visa estimar uma função que explique a produtividade do milho identificando os fatores, e o seu efeito na produtividade do milho, numa exploração da empresa em Azinhaga, Golegã, distrito de Santarém, Portugal, para o ano 2020. Utilizando o software apropriado, esta dissertação aplica os mais recentes métodos e ferramentas econométricas espaciais para dados cross-section (dados transversais), de modo a incluir devidamente a dependência espacial na estimação. Assim, foram estimados os modelos apropriados: Modelo Spatial Lag (SLM), Modelo Spatial Error (SEM) e Modelo SARAR(1,1) (Kelejian & Prucha, 2010), cuja utilização foi recomendada pelo diagnóstico aos reísduos OLS (Ordinary Least Square). O modelo escolhido foi o SARAR(1,1), captando a dependência espacial e heterocedasticidade presente nos dados. Desta forma, concluiu-se que a produtividade do milho, no ano e na área em estudo, encontra-se positivamente influenciado por fatores como a densidade de sementeira, o trióxido de enxofre aplicado (SO3) e uma variedade específica de sementes. Quanto à fertilização, com azoto e potássio, e quanto à irrigação da cultura, estes fatores apresentaram uma relação não linear (quadrática) com a produtividade do milho. Também influenciando a produtividade, existem variáveis relacionadas com o clima, medidas pela fase do ciclo de vida do milho, que provaram ser significativas para explicar a variável em estudo, tal como a humidade relativa, a temperatura e a velocidade do vento.
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Obopile, Motshwari. "INTERACTIONS AMONG MAIZE PHENOLOGIES, TRANSGENIC BACILLUS THURINGIENSIS MAIZE AND SEED TREATMENT FOR MANAGEMENT OF PESTS AND DISEASES OF MAIZE". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243020914.
Pełny tekst źródłaShah, Syed Jafar. "Preference of lactating dairy cows for grass or maize silages". Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367569.
Pełny tekst źródłaOgola, J. B. Ochanda. "Improving water use efficiency of maize through proper nitrogen management". Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340024.
Pełny tekst źródłaJones, Ashley D. "An analysis of Stochastic Maize production functions in Kenya". Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8627.
Pełny tekst źródłaDepartment of Agricultural Economics
Timothy J. Dalton
In Kenya, agriculture governs the country’s fiscal economy, and this reliance on agriculture can cause both economic and hunger problems, a result of the country’s dependence upon rainfall for agricultural production. Kenyans must find ways to combat severe drought conditions; this can be accomplished through the adoption of inputs that decrease the probability of crop failure. The objective of this research is to determine whether variability exists in Kenyan maize yields, and whether or not specific inputs, specifically hybrid varieties, are either variance/skewness increasing or decreasing. The data used for this study was collected from a survey, designed by Egerton University’s Tegemeo Institute of Agricultural Policy and Development and Michigan State University, and administered in Kenya in the following years: 1997, 2000, 2004, and 2007. The survey identified factors of crop and field level production, such as inputs, crop mix, marketing data, and demographic information. This research makes use of only the 2007 data, comprising 1,397 households in total. The objectives of this thesis aim to go beyond the scope of typical production function regressions where yield is a function of a set of inputs, by examining further moments of yield, variance, and skewness to determine whether variability exists in Kenyan maize yields. Results indicate that variability does exist within Kenyan maize yields, often a result of differing input levels among households. In terms of overall impact of each variable on mean, variance, and skewness of maize yields, seed quantity, nitrogen use, and hybrid seed contribute the most to influencing these factors. In contrast, years of experience with hybrid maize, land tenure, terraced land and labor have the least influence on mean, variance and skewness within this research. Results also bring to light the popular debate against hybrid varieties versus open pollinated (OPV) or traditional varieties, and identify hybrid varieties as a source of variability in mean, variance and skewness of yields. Hybrid varieties should be paired with the knowledge of how to maximize yield in conjunction with other inputs, to give Kenya the opportunity to see substantial productivity gains throughout the country, especially in arid and semi-arid regions.
Souza, Tamires Teles de. "Simulação de cenários agrícolas futuros para a cultura do milho no Brasil com base em projeções de mudanças climáticas". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-17072018-134305/.
Pełny tekst źródłaMaize (Zea mays) is considered one of the most important crops cultivated worldwide due to its chemical composition, nutritional value and its productive potential, thus presenting considerable relevance in socioeconomic aspects. Several factors interfere in the performance of the crop and, among them, the climate is among those that offer the greatest challenges for crop planning and management. Given the importance of culture in the national and global context, it is important to consider the future projections of grain production in the face of climate change and, consequently, food security in the coming years. Thus, the impact of climate change on maize crop growth and development was evaluated in this study using a plant growth model based on biophysical processes. For the calibration of the model, data obtained experimentally were used and the simulation of climate change scenarios was performed according to the AgMIP program approach. We worked with the CERES-MAIZE / DSSAT model, and three regional climate circulation models (GCM\'s) and two economic (or emission) scenarios for the period 2040-2069 (representing 2050). Based on the results obtained, it can be concluded that if management practices remain as present, corn yields should decrease in the middle of the century, however, the decrease in real incomes may not be as dramatic as predicted in cases where that only the climatic factor is considered. For this economic and technological factors must be considered to increase incomes. The increase in [CO2] will have a positive effect on crop growth, but it does not appear to be sufficient to compensate for the negative effects of future climate, notably the increase in air temperature.
Le, Roux Noelien. "Seasonal maize yield simulations for South Africa using a multi-model esemble system". Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-11302009-211655/.
Pełny tekst źródłaOrdóñez, Raziel Antonio. "Response of yield and physiological attributes to nitrogen availability and heat in maize". Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/314179.
Pełny tekst źródłaEn un futuro próximo la producción de los cultivos deberá ser sustancialmente incrementada para poder abastecer la demanda de alimentos. Como futuros aumentos en el área de producción no es posible, la única forma, es aumentar de manera significativa los rendimientos de los cultivos. Las projeccions con modelos climáticos sugieren que la frecuencia de altas temperaturas serán cada vez mayores en la nayoría de las regiones donde se producen cultivos extensivos, y se encuentra muy bien documentado los efectos deletéreos de las altas temperaturas sobre la productividad de los cultivos. En este contexto, será fundamental la identificación de genotipos y esrategias de manejo para mitigar los efectos de altas temperaturas sobre productividad de los cultivos. A nivel mundial, la fertilización nitrogenada (N) es una de las prácticas de manejo ampliamente utilizada en los sistemas agrícolas. En muchas regiones, los cultivos son frecuentemente fertilizados para maximizar la productividad. Sin embargo, han habido pocos esfuerzos para elucidar en qué medida el nivel de fertilidad del suelo puede afectar la magnitud de las altas temperaturas sobre la productividad de los cultivos. El análisis de una posible interacción entre las altas temperaturas y el nivel de nitrógeno en el suelo puede ser relevante para el diseño de estrategias apropiadas de fertilización no sólo para aumentar la producción a través de mejorar las condiciones de crecimiento sino también para mitigar los posibles efectos negativos impuestos por las altas temperaturas. El objetivo general de esta tesis fue evaluar la variabilidad genotípica en los componentes del rendimiento, y la susceptibilidad de los determinantes del rendimiento al estrés térmico combinado con diferentes disponibilidades de N en el cultivo de maíz. El tema fue explorado a lo largo de 11 experimentos en campo llevados a cabo durante 4 años consecutivos y en dos localidades contrastante en altitud, para ello se utilizaron 12 híbridos de maíz de grupos contrastante en madurez bajo diferentes condiciones de fertilización nitrogenada, además de un control sin fertilizar. En 4 de los experimentos de campo, en una combinación de genotipos y regímenes de nitrógeno se impusieron diferentes estreses de altas temperaturas, para ello se cubrió el área designada para los tratamientos con plástico transparente de polietileno (100 μm de espesor) montada en estructuras de madera de 3-3.5 m de altura. Además, en varios experimentos se impusieron diferentes tratamientos de manipulación de fuente-sumidero para determinar el origen de la limitación del rendimiento impuesto por efectos de las elevadas temperaturas. Las diferencias en rendimiento entre los híbridos no se relacionaron con la duración del ciclo. Sin embargo, si la comparación se limita a la media de los rendimientos observados de todos los híbridos de ciclo corto y largo, se confirma que los híbridos de ciclo corto tuvieron menor producción en comparación con los de ciclo largo. Paralelamente, pero en experimentos independientemente se determinó que los híbridos de ciclo largo pueden ser una verdadera opción para agricultores en condiciones de elevadas alturas tal como en los valles del pirineo (en caso de poder asumir un mayor riesgo que lo habitual de perder la cosecha en otoños con fríos excepcionales), adicionalmente los híbridos de ciclo corto pueden ser una alternativa razonable de producción para agricultores en la plana de Lleida (y otros ambientes similares). En el conjunto de condiciones evaluadas, el rendimiento estuvo mayormente afectado por la captura mas que por la partición o el uso eficiente de los recursos, en los cuales la relación fue positiva y de igual magnitud en ambos componentes del rendimiento (a pesar de que el número de granos fue más plástico que el peso de los granos), al igual que ocurrió con la concentración de proteína en los granos. La relación negativa entre el rendimiento y NUE encontrado en el contexto de la amplia gama de condiciones no se opone a la idea de que los híbridos en el futuro deberán ser más eficientes en NU y que formas de seleccionar para mejorar NUE deberán ser desarrolladas para los sistemas agrícolas futuros en los que se espera que el N será de menor disposición mientras que los rendimientos deben seguir aumentado. Recientemente fue propuesta una alternativa de fenotipeo para mejorar la eficiencia del uso del nitrógeno (el nitrógeno específico crítico en las hojas, SLNc), y esta variable fue utilitzada para evaluar la variabilidad genética. Se determinó que existe una amplia variación genética para SLNc, y parcialmente estuvo relacionado con las diferencias genotípicas en la absorción del nitrógeno. Esto implica que SLNc difícilmente sería una buena alternativa para fenotipeo de grandes poblaciones y mejorar el uso eficiente del nitrógeno. Se demostró por primera vez en esta tesis, que en el cultivo de maíz, la sensibilidad del rendimiento al estrés térmico fue aumentada con la fertilización nitrogenada. Esta conclusión se basa en experimentos de campo con tratamientos con una magnitud de variación similares a las que se esperada en condiciones reales. El efecto fue a través de afectar en las plantas la capacidad para el cuajado de los granos y en menor medida el crecimiento; y esto fue independiente a cualquier (adicional potencial) efecto por el desfase entre la floración masculina yfemenina, o por la disponibilidad y viabilidad del polen. El efecto del estrés térmico en el tamaño potencial de los granos fue directamente a través de afectar su capacidad para crecer. Estas conclusiones se alcanzaron debido tanto a las interpretaciones de los efectos de las altas temperaturas en las relaciones fuente- sumidero propias de las plantas, así como también de resultados de las manipulaciones en la relación fuente-sumidero durante el llenado de grano. El estrés térmico resultó en una reducción del tamaño de los granos incluso cuando se aumentó la relación fuente sumidero (mediante la inducción de aborto tardío de pocos granos sin afectar mucho el crecimiento post-floración), y ese efecto directo no fue empeorado por la defoliación ni revertido por el desgrane, y la penalización no exhibió una respuesta jerarquica clara: fue similar para todos los granos independientemente del tamaño potencial.
La producció de cultius ha d’incrementar-se substancialment a curt termini per mantenir l’equilibri amb la demanda alimentaria mundial. Atès que un gran increment de superfície cultivada sembla impensable, l’increment de producció ha de venir per un increment en el rendiment. Els models climàtics suggereixen que temperatures més elevades que les actuals seran habituals en moltes regions del mon on es conreen cultius per a gra, i en aquests, estan ben documentats efectes deleteris degut a les altes temperatures. En aquest escenari, és crític la identificació d’aspectes genetics i de la gestió d’eines per mitigar el efecte de les elevades temperatures sobre el rendiment. La fertilització nitrogenada (N) és una de les pràctiques de maneig més esteses en els cereals de gra arreu del món i en moltes regions els conreus per a gra es fertilitzen bé per a maximitzar la producció. Malgrat això, els esforços per explicar fins a que punt la fertilitat del sòl pot afectar l’efecte de l’elevada temperatura sobre el cultiu son limitats. Analitzar la possible interacció entre la fertilització i les temperatures pot ser rellevant per dissenyar estratègies de fertilització més apropiades no solament per a incrementar la productivitat sino per a mitigar les possibles penalitzacions de les altes temperatures sobre el rendiment. L’objectiu general d’aquesta tesi és l’avaluació de la variabilitat genotípica en els components del rendiment i la susceptibilitat d’aquests components del rendiment al estrès tèrmic de forma combinada amb la disponibilitat de nitrogen en blat de moro. L’estudi es va portar a terme mitjançant 11 experiments de camp, portats a terme durant 4 anys, en dos localitats contrastants en altitud, sota diferents règims de fertilització nitrogenada en 12 diferents híbrids de blat de moro de diferents grups de maduració. En 4 dels experiments de camp es van imposar diferents estresses de temperatures elevades en combinació amb diferents hibrids de panis i diferents règims de nitrogen, mitjançant l’envoltament d’una zona determinada amb estructures de fusta de 3-3,5m d’altura cobertes amb polietilè transparent (100 micres). En varis dels experiments es van realitzar també manipulacions font-embornall de manera factorial per establir l’origen de las penalitzacions en rendiment dels diferents tractaments. Les diferències en la resposta del rendiment dels diferents híbrids no van estar relacionades amb la duració del cicle del híbrid, no obstant això si la comparació es restringeix a la mitjana de tots els híbrids de cicle- curt i els de cicle-llarg, els híbrids de cicle-curt van tenir produccions més baixes que els de cicle-llarg. En paral·lel, però en un grup d’experiments independent és va observar que els híbrids de cicle (relativament)-llarg podrien ser una bona opció pels agricultors que cultiven en altituds elevades (si estan preparats per assumir un risc més elevat del habitual de pèrdues degudes a tardors excepcionalment fredes). Així mateix, els híbrids de cicle-curt podrien ser una alternativa de producció raonable per pagesos en la plana de Lleida (i altres ambients similars). En general pel conjunt de les condicions estudiades, el rendiment de gra va resultar estar més afectat per la captura de los recursos (aigua, N, etc.) que pel seu repartiment o per l’ús eficient dels mateixos, i va ser positivament relacionat amb ambdós components de rendiment amb igual magnitud (encara que el numero de grans va ser més plàstic que el pes del grans) així com amb la concentració de proteïna al gra. La relació negativa entre el rendiment i l’eficiència del l’ús del nitrogen (nitrogen use efficiency, NUE) trobada en aquest context d’ample varietat de condicions, no pot descartar el fet de que híbrids futurs haurien de ser més eficients en l’ús del nitrogen. Per tant cal desenvolupar noves eines de selecció per millorar NUE pels futurs híbrids i sistemes agrícoles en els que es preveu que el N estarà menys disponible, al mateix temps que s’ha de continuar incrementant el rendiment. Un estudi recent va proposar l’estudi del contingut específic de nitrogen en fulla (critical Specific Leaf Nitrogen, SLNc). Aquest estudi va demostrar que existeix una gran variabilitat genètica per SLNc, en part relacionada amb diferencies genètiques en l’absorció de N. Aquest implicaria que el SNLc difícilment podria ser una bona alternativa per l’estudi del fenotip de grans poblacions per millorar l’eficiència del l’ús del nitrogen. En aquesta tesi s’ha demostrat per primera vegada en blat de moro que la sensibilitat del rendiment al estrès tèrmic és va incrementar amb la fertilització nitrogenada. Aquesta conclusió està basada en experiments de camp amb condicions realistes, reflectint de manera molt similar les variacions ambientals esperades (tèrmiques, aigua, N, etc.). L’efecte es va observar en la capacitat de les plantes per establir grans i en menor grau en permetre maximitzar el pes del gra i va ser independent de qualsevol efecte potencial del acoblament en la fecundació (sortida de sedes – alliberació del polen) o en la quantitat i viabilitat del pol·len. L’estrés tèrmic va afectar la grandària del gra afectant directament la seva capacitat de creixement. A aquesta conclusió s´hi va arribar a partir de les interpretacions del efecte de temperatures elevades sobre les relacions font-embornall de les plantes i dels resultats de les manipulacions de las relacions font-embornall durant l’etapa d’omplenament del gra. L’estrès tèrmic va reduir la grandària del gra inclús quan es va incrementar la relació font-embornall (induint la aborció tardana dels pocs grans al temps que no s’afecta el creixement després de la sortida de sedes) i aquest efecte directe no va ser empitjorat ni per la defoliació ni per el desgranat i la penalització no va mostrar cap resposta jeràrquica clara: va ser similar en grans amb diferent grandària potencial.
Silva, Adilson Nunes da. "Nitrogen impacts on maize yield and nutrient use efficiency in contrasting stress environments". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-22042015-153310/.
Pełny tekst źródłaAdubação nitrogenada (N) e o estresse hídrico tem grande influência no rendimento de grãos de milho, assim, estudos sobre genótipos e o manejo dessa cultura são muito importantes para o aumento da produtividade. Este estudo é apresentado em três capítulos. Os dois primeiros foram desenvolvidos nos Estados Unidos e o terceiro no Brasil. Os objetivos são apresentados na seguinte ordem: (1) o objetivo principal foi entender quais características, se existirem, diferem entre híbridos tolerantes e não-tolerantes à seca, com semelhança em maturidade, que regem a absorção de nutrientes e concentrações destes sob diferentes tratamentos de cultivo e sua influência na produção de grãos. (2) O objetivo principal foi investigar as respostas fisiológicas (fotossíntese (A) e transpiração (E)) e a produção de milho em genótipos, com semelhante maturidade, tolerantes e não tolerantes ao déficit hídrico (P1151 vs. P1162 e P1498 vs. 33D49) em relação a variação de densidade de plantas e doses de N. (3) O principal objetivo foi investigar as respostas de milho à aplicação de nitrogênio em cobertura, ureia fertilizante (15N), em diferentes estádios fenológicos. O objetivo secundário foi: verificar a correlação entre as clorofilas e carotenoides com SPAD (avaliado em V14 e V16) e destas com a biomassa total (BM), índice de colheita (IC), produção de grãos (PG) e do conteúdo de N nos grãos. Como resultados: (1 e 2) Todos os híbridos responderam de forma semelhante para para PG em relação aos tratamentos. O Híbrido P1151 demonstrou semelhantes A e E e menor area foliar do que seu semelhante em maturidade (P1162). Híbrido P1498 pareceu ser capaz de manter a taxa de transpiração foliar e de fotossíntese mais elevadas do que 33D49, durante o período de enchimento de grãos. Este híbrido apresentou uma melhor persistência na captação de água pela raiz no final da estação de cultivo. Geralmente maiores BM e PG na maturidade foram relacionadas a menores intervalos de diferenciação floral e a maior acumulação, na estação seca, de macronutrientes (P e S) no colmo, sendo as ultimas características consideradas como mecanismos de tolerância à seca. (3) A cultura do milho respondeu de forma semelhante em relação a PG à aplicação de N. O teor de nitrogênio nos grãos derivado do 15N fertilizante e a eficiência de uso do fertilizante nitrogenado foram maiores em relação a aplicação de N nos primeiros estádios. Houve correlação positiva e siginificativa para SPAD com a maioria dos pigmentos no estádio de avaliação V16. Provando ser um instrumento eficaz de avaliação indireta de clorofilas e carotenóides em estágios iniciais. A clorofila b, avaliada em V16, apresentou correlação positiva significativa (p<0,05) com teor de N nos grãos, PG, e BM, a clorofila total em V16 também apresentou uma correlação positiva com o teor de N nos grãos, no entanto, as clorofilas a e total, avaliadas em V14, apresentaram correlação negativa com PG. Assim, a medição do teor de pigmentos com o objetivo de estudar as condições nutricionais e previr a produção de grãos deve ser realizada após o estágio V14.
Micheri, Pietro Hunger. "Dunite in annual crops : physiological changes, nutritional status in soybean and maize yield /". Botucatu, 2019. http://hdl.handle.net/11449/191103.
Pełny tekst źródłaBanca: Patricia Preira Dias
Banca: Claudio Hideo Martins da Costa
Resumo: A crescente demanda por fertilizantes concomitante ao aumento dos preços desse insumo e a escassez de suas fontes levam a incessante busca por fontes alternativas de nutrientes para as plantas. Os afloramentos rochosos no Brasil coincidem com as localidades de áreas produtivas, tornando o acesso fácil dos produtores rurais à essas fontes, uma vez que o maior custo do pó de rocha está relacionado ao frete. Portanto, uma das alternativas estudadas é o uso de pó de dunito, rico em magnésio em culturas anuais, como soja e milho. Estas são uma das principais culturas do Brasil em área de produção. O objetivo desse estudo foi avaliar os efeitos de doses de pó de dunito no teor foliar de Magnésio (Mg) e Silício (Si), teores foliares de açúcares redutores, sacarose e amido, e atributos químicos de solo em dois tipos de solo. Os tratamentos consistiram em cinco doses de pó de dunito (0, 42, 208, 542 and 1542 mg kg-1) no solo argiloso e (0, 150, 238, 411 and 933 mg kg-1) no solo arenoso, respectivamente. Em ambos os solos, os teores de Mg e Si foliar, os açúcares redutores e glicose nas folhas, assim como pH, Mg, e Si do solo e os componentes de produção aumentaram com o aumento das doses de dunito. A melhor nutrição de Mg fornece menor teor de amido foliar e consequentemente melhor partição de metabolitos na planta, levando ao melhor desenvolvimento, enchimento e produção de grãos de soja.
Abstract: The growing demand for fertilizers, coupled with the increase in fertilizer prices and the scarcity of fertilizer sources, lead to the incessant search for alternative sources of nutrients for the plants. The rocky outcrops in Brazil coincide with the localities of agriculture productive areas, making access easy for rural producers to these sources, since the higher cost of rock dust is related to the transport. Therefore, one of the alternatives studied is the use of dunite powder, rich in magnesium in annual crops such as soybean and corn. These are one of the main crops of Brazil in production area. The aim of this study was to evaluate the effect of dunite rates on Magnesium (Mg), Silicon (Si), foliar contents of reducing sugars, sucrose, and starch, soil chemical attributes and soybean yield in two soil types. The treatments consisted in the five rates of Dunite (0, 42, 208, 542 and 1542 mg kg-1) in a clayey soil, and five rates of Dunite (0, 150, 238, 411 and 933 mg kg-1) in a sandy soil. In both soils, the Mg and Si leaves concentration, foliar reducing sugars, and glucose, as well as soil pH, Mg, and Si, and the yield components increased with input rates. The best Mg nutrition provides lower foliar starch levels, consequently, the best partition of metabolites to plant leads to better development, filling and yield of soybeans.
Mestre
Pelletier, Bernard 1964. "Management practices, soil quality and maize yield in smallholder farming systems of central Malawi". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37809.
Pełny tekst źródłaKgasago, Hans. "Effect of planting dates and densities on yield and yield components of short and ultra-short growth period maize (Zea mays L.)". Diss., University of Pretoria, 2007. http://hdl.handle.net/2263/28056.
Pełny tekst źródłaDissertation (M Inst Agrar (Agronomy))--University of Pretoria, 2007.
Plant Production and Soil Science
M Inst Agrar
unrestricted
Mulenga, Peter Chikombo. "Effects of applied micronutrients and liming on grain yield and plant composition on three ferralsols on North-Western Zambia". Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301213.
Pełny tekst źródłaMashego, Suzan. "Maize grain yield under conventional and site-specific nutrient management in a dryland farming system : Agronomic implications". Thesis, University of Limpopo (Turfloop campus), 2013. http://hdl.handle.net/10386/1120.
Pełny tekst źródłaLarge amount of pre-plant nitrogen (N) fertilizer results in low nutrient-use-efficiency due to poor synchrony between soil N supply and maize demand, especially during N sensitive growth stages. Optimum maize production is dependent on adequate N availability to the crop during the critical vegetative and reproductive growth stages. High N fertilizer prices and maize yield decline are the main challenges faced by the Limpopo Province farmers. The objectives of this study were to compare growth and yield of maize under conventional and site-specific N management in a dryland farming system. The study was conducted in Leeukraal, Towoomba, Ga-Marishane and Radium in the Limpopo Province, South Africa. Experimental plots were laid out in a randomized complete block design, with four replications. Phosphorus was applied through band placement using a planter in all plots at a rate of 42 kg P/ha. Hybrid maize SNK 2147 was planted on a 20 by 20 m plot with Inter-row and Intra-row spacing of 0.9 and 0.35 m respectively. Treatments consisted of 3 N management strategies as follows, (i) No N application (N0), (ii) Site-specific N at a rate ranging between 18 and 33 kg N/ha (N1) and (iii) Conventional N application at 58 kg N/ha (N2). Treatment N2 was applied at a uniform rate during maize planting. Sufficiency index as an indication for N deficiency was determined using CCM-200 for treatment N1. The sufficiency index was determined during leaf stage V6, V10 and V14, and thereafter N was applied only when needed. Data were subjected to analysis of variance through Statistical Analysis System package. Mean separation tests were computed using Duncan’s Multiple Range Test. Maize grain yield at Leeukraal of 5.2 t/ha for N1 was higher than 3.2 and 4.0 t/ha of N0 and N2, respectively. There was no difference amongst the three N management approaches on the grain yield at Towoomba. The grain yield at Ga-Marishane for N1 of 2.2 t/ha was significantly higher than 1.7 t/ha of the N0. Conventional management approach, which is a traditional approach used by farmers in the Limpopo Province, had 2.6 t/ha grain yield that was significantly higher than the N0 and N1. The maize growth and yield under N2 and N1 was compared, N1 required between 43 and 69% lesser N fertilizer as compared to N2. Therefore site-specific nutrient management approach sustains and improves growth and yield of maize using minimal inputs of N compared to conventional approach. This therefore saves input costs and avoids unnecessary environmental consequences. Key words: maize yield, nitrogen management, site-specific approach
Vlaamse Interuniveritatire Raad and Limpopo Department of Agriculture
Kanton, Roger Adamu Lure. "Growth, yield components and resource use by morphologically contrasting maize-pea sole crops and intercrops". Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408994.
Pełny tekst źródłaAndréa, Maria Carolina da Silva. "Model-based approach for maize yield gap analysis related to climate variability and nitrogen management". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-09112016-135415/.
Pełny tekst źródłaPara alcançar a segurança alimentar e atender necessidades ambientais, os índices médios de produtividade de importantes culturas na alimentação como a do milho devem aumentar em detrimento da expansão de áreas cultivadas. A cultura do milho possui como principais fatores responsáveis pelos baixos índices de produtividade no Brasil os deficits hídrico e de nitrogênio (N). O conceito de quebra de produtividade (yield gaps) é a diferença entre a máxima produtividade que pode ser atingida em dado local, seja ela limitada pela água (Yw) ou não (Yp), e a produtividade média observada em condições práticas (Ya). Esse conceito é de grande importância para caracterização de limites de alcance de máximas produtividades e definição de estratégias de manejo para mitigação dos mesmos. A produtividade potencial (Yp) é aquela determinada pelas condições de temperatura, radiação solar, fotoperíodo e potencial genético; à produtividade limitada pela água (Yw) adiciona-se a limitação hídrica imposta por cultivos em sequeiro. Nesse estudo buscou-se caracterizara variabilidade das quebras de produtividade referentes às condições ambientais e de manejo; bem como avaliar o retorno econômico e energético do manejo dessas quebras por meio da aplicação mecanizada de fertilizante nitrogenado em seis municípios localizados na região Centro-Sul do país nas duas épocas de cultivo da cultura do milho (safra e safrinha). Quebras de produtividade referentes à restrição hídrica (CYg = Yp - Yw) e impostos pelas condições de manejo (MYg =Yw - Ya) foram determinadas com auxílio da utilização do sistema de modelos integrados DSSAT (Decision Suport System for Agrotechnology Transfer).O modelo da cultura do milho (CSM CERES-MAIZE) foi calibrado com dados de ensaio de cultivares, obtidos para os últimos anos em todas as regiões avaliadas. Na 1ª safra, os indices de Yp foram mais altos e os indices de Yw foram mais altos e variáveis devido à variabilidade climática.A quebra de produtividade relativa ao manejo foi mais limitante do que a quebra relativa ao deficit hídrico em quase todos os municípios avaliados. Em ambas as safras de cultivo, maiores e menores MYg foram encontrados em dois municípios das regiões Sul e Centro-Oeste do país, respectivamente. Apesar de ambas as regiões apresentarem altas produtividades medias (Ya), diferentes condições ambientais determinaram as maiores diferenças absolutas entre seus indices de Yp, Yw e MYg. Ao avaliar a rentabilidade (R$ kg-1; MJ kg-1; R$ ha-1; MJ ha-1) da aplicação de N como estratégia de redução de MYg, observou-se o comportamento da variação dos rendimentos de produtividade com o aumento das doses de N. Em termos gerais, os rendimentos decrescentes apresentaram maior eficiência de uso do insumo (por massa colhida e por unidade de área) nas menores doses de N (20-80 kg ha-1). Lucros econômicos e energéticos (sem considerar sua taxa de variação com relação ao aumento do custo de aplicação) foram encontrados até doses mais altas de N (90-400 kg ha-1), sendo que esse limite é diretamente influenciado pelas condições climáticas locais. O manejo local dos MYg pode ser mais ou menos viável em função da combinação das condições ambientais e de manejo usual locais. Em termos gerais, o custo de aplicação de N é maior na 2ª safra devido às condições climáticas mais limitantes, porém municípios com manejo eficiente da quebra de produtividade foram encontrados mesmo nas condições de cultivo do milho safrinha.
Kgasago, Hans. "Effect of planting dates and densities on yield and yield components of short and ultra-short growth period of maize (Zea mays L.)". Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-09202007-163045.
Pełny tekst źródłaFujisao, Kazuhiko. "A Study on Maize Productivity under Continuous Cultivation in Farmers’ Fields in Sainyabuli Province, Northern Laos". Kyoto University, 2018. http://hdl.handle.net/2433/232345.
Pełny tekst źródłaBello, Zaid Adekunle. "Effect of soil nutrient status on growth, reproductive development and yield components of maize in a long term field trial". Diss., University of Pretoria, 2008. http://hdl.handle.net/2263/28237.
Pełny tekst źródłaDissertation (MSc(Agric))--University of Pretoria, 2008.
Plant Production and Soil Science
unrestricted
Neto, Francisco Bezerra. "Effects of spatial arrangement and density on efficiency, yield and yield components, dry matter partitioning and growth of an annual cotton/cowpea/maize intercrop". Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186205.
Pełny tekst źródłaDoyle, Steven Doyle. "Relationships Between Cropping Practices, Soil Quality, and Maize (Zea mays L) Yield in Morogoro Region, Tanzania". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1528987286318244.
Pełny tekst źródłaHu, Tongxi Hu. "Impacts of climate variabilities on maize yield across the US: Insights from a Bayesian modeling analysis". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531995498285494.
Pełny tekst źródłaJackson, Brian A. "Nitrogen mineralization of incorporated bahiagrass sod and its effect on nitrogen uptake and yield of maize". [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001441.
Pełny tekst źródłaNgoma, Justine. "Effect on Climate Change on Maize Production in Zambia". Thesis, Linköping University, Linköping University, Department of Water and Environmental Studies, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16058.
Pełny tekst źródłaMaize is one of the crops that is grown by most farmers in Zambia being the staple food for the majority of Zambians. However, despite the crop being so important, its production is dependent on climatic conditions. This means that any change in climate can affect the production either negatively or positively. This research therefore, focused on determining how the change in temperature and rainfall affect maize production on the Copper belt, Eastern, Lusaka and Southern provinces of Zambia and investigate the main adaptation measures implemented by both the government and non-governmental sectors. Also, assess through the review of National Agricultural Policy and action plans, how the government has documented issues of climate change. In order to obtain the needed data, interviews were conducted with different officials from both the government and non-governmental sectors. However, from the estimate of the impact of temperature and rainfall on maize production, the results did not show with any significance that either temperature or rainfall has effect on maize production. In fact, it was found that quantifying the effects of climate change on maize production is not easy due to difficulties in quantifying other factors that may also have large impact on maize production. It was therefore, not possible to conclude whether or to what extent climate change has effects on maize production. However from the interviews conducted, it was found that both the government and non-governmental sectors have introduced different activities in their programmes to ensure that farmers are food secure, though the ministry of agriculture has no policy document on how to handle the problem of climate change to address different issues of the sector. In fact, most offices in the ministry do not have much documented information on climate change which could also be seen from the review of National Agricultural Policy and action plans where climate change issue has not been emphasized. Though both the Government and non-governmental sectors have implemented some adaptation measures, it cannot easily be concluded whether the implemented measures are adequate or not due to the fact that we are not sure of the expected effects in different parts of the country. Nevertheless, to enhance food security with or without adverse effects of climate change on maize production, it was recommended that members of staff at all levels under MACO should be trained in the area of climate change for them to have a wider understanding of the issue and work responsively and that much research should be done to open up the mind of the people and help policy makers make effective plans.
Sullivan, Madsen Paul. "Effects of and Influences on Microbial Populations of Missouri Maize Fields". BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7706.
Pełny tekst źródłaNndwambi, F. H. "Evaluation of dryland maize / pigeonpea intercropping under variable phosphorus application rates". Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1233.
Pełny tekst źródłaInformation on the performance of the maize and pigeonpea intercropping system under dryland conditions of South Africa is scanty. The aim of this study was to determine the optimum P level and productivity of pigeonpea and maize under the dryland intercropping system. Five P rates (0, 15, 30, 45, and 60 kg P ha-1) were applied to both sole and pigeonpea intercropped with maize in a randomized complete block design with 4 replicates. Growth parameters and yield and yield attributes of pigeonpea and maize were measured to determine performance of both crops. There were significant differences in grain yield of pigeonpea as influenced by P rates in both seasons. Highest grain yields of 781 kg ha-1 during 2009/10 and 894 kg ha-1 during 2010/11 were obtained at P rate of 45 kg ha-1. Cropping system significantly influenced grain yield of pigeonpea in 2010/11 season with 37.1% higher pigeonpea grain yield from intercropped plots than in sole pigeonpea plots. There was 21.8% increase in grain yield of pigeonpea across two seasons as influenced by P rate. Maize grain yield showed little response to P rate only during the first season. However, highest maize grain yield of 1699 kg ha-1 was obtained at 60 kg P ha-1 during the 2009/10 season. Maize grain yield was only significantly influenced by cropping system during the 2010/11 season where sole plots achieved higher grain yield of 4148 kg ha-1 compared to 3297 kg ha-1 from intercrop plots. The results revealed that P application increased grain yield of pigeonpea significantly, especially in intercropped plots. The calculated total land equivalent ratio (LER) for the two crops gave positive and higher than one values, which suggests a favourable grain yield advantage for maize/pigeon pea intercrop.
Sitoe, Manuel Mulhuli. "Improving dryland maize (Zea mays L.) water productivity in the Chokwe District of Mozambique through better nutrient management". Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/37296.
Pełny tekst źródłaDissertation (MSc Agric)--University of Pretoria, 2012.
gm2014
Plant Production and Soil Science
unrestricted
Xu, Zhihong, i n/a. "Nitrogen Cycling in Leucaena Alley Cropping". Griffith University. Division of Australian Environmental Studies, 1991. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20050906.155955.
Pełny tekst źródłaGuiomar, Pedro Manuel Carvalho Nunes. "Avaliação do comportamento de cultivares de milho na presença da helmintosporiose causada por Exserohilum turcicum (Pass.) Leonard & Suggs". Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4102.
Pełny tekst źródłaThe Northern leaf blight (NLB) caused by Exserohilum turcicum is one of the maize key diseases in all regions of production. In this dissertation, the susceptibility of four maize cultivars to reference isolates of E. turcicum was established under controlled conditions and the grain yield of the same cultivars evaluated and submitted to six treatments. Four treatments were engaged with fungicides (carbendazim+flusilazol or tebuconazol), one with NPK fertilizer and the sixth as a control. Field trials were conducted in Odemira and Coimbra, both places with known endemic presence of NLB in recent years. The susceptibility of cultivars to E. turcicum was evaluated with the Pioneer scale “Scoring Northern Leaf Blight” and the grain yield determined as 1000 grains weight and as specific weight. In the inoculation trials all cultivars showed the same level of susceptibility. The Coimbra trial didn‟t show any incidents of NLB. In the Odemira tests significant differences in disease severity were registered amongst cultivars and between treatments. The lower disease severity was recorded in the PR34P88 cultivar and in the treatment with two applications of tebuconazol. The treatments also led to significant differences in specific weight and 1000 grains weight. The grain yield varied significantly depending on the location and the cultivar
Xu, Zhihong. "Nitrogen Cycling in Leucaena Alley Cropping". Thesis, Griffith University, 1991. http://hdl.handle.net/10072/365424.
Pełny tekst źródłaThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Division of Australian Environmental Studies
Full Text
Cahill, Sheri Ms. "Nitrogen Use Efficiency and Yield Effects of Urea Formaldehyde Polymer (UFP) Fertilizer in Winter Wheat and Maize". NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-10092006-092341/.
Pełny tekst źródłaEkwamu, Adipala. "Variations in field populations, disease development, and yield losses associated with Exserohilum turcicum on maize in Uganda /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487759914758548.
Pełny tekst źródłaMampana, Reedah Makgwadi. "Cropping system effects on soil water, soil temperature and dryland maize productivity". Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/43165.
Pełny tekst źródłaDissertation (MScAgric)--University of Pretoria, 2014.
lk2014
Plant Production and Soil Science
MScAgric
Unrestricted
Zanin, Claitson Gustavo. "Área foliar, senescência e uniformidade de desenvolvimento na adaptação ao adensamento de plantas de cultivares de milho com bases genéticas contrastantes". Universidade do Estado de Santa Catarina, 2007. http://tede.udesc.br/handle/handle/1240.
Pełny tekst źródłaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
The increment in plant density is an alternative to maximize solar radiation interception and to increase maize grain yield. However, it can also reduce the crop photosynthetic activity and limit its efficiency to convert carbohydrates to grain production. Increases in maize hybrid s tolerance to crowding have been reported in different production areas around the world. Two traits that may contribute to this feature are the slower leaf senescence during grain filling and the higher uniformity in plant growth and development during the crop cycle. This work was carried out aiming to quantify the effects of plant population increment on the leaf area, grain yield and the variation coefficient of agronomic traits of maize cultivars with contrasting genetic variability. The trial was set in Lages, SC, Brazil. A randomized block experimental design disposed in split-plots was used. Three cultivars were evaluated in the main plot: an open-pollinated variety (Fortuna), a double-cross hybrid (Ag 303) and a single-cross hybrid (P30F53). Five plant populations were tested in the split-plot: 25,000, 50,000, 75,000, 100,000, and 125,000 plants ha-1. The experiment was sowed on 10-26-2005, with a row spacing of 0.70 m. When the crop had four expanded leaves, 10 plants of each split-plot that were in the same growth stage were labeled. These plants were used to measure leaf area and to follow the crop growth, determining the variation coefficient of leaf area, growth stage and plant height. These variables were estimated 10 times, at the growth stages of V4, V8, V12, V16, R1 (silking) and 14, 28, 42, 56 and 70 days after silking. After harvesting, the variation coefficient and grain production per plant were determined based on the 10 selected plants. In addition to that, grain production and yield components were determined. The data were submitted to the variance analysis by the F test, at the 5.0% significance level (P<0.05). The means were compared by the Tukey s test (P<0.05), by polynomial regression and linear correlation. The response of grain yield to increment in plant population was quadratic, regardless of cultivar. Grain yield of the singlecross hybrid (SCH) was higher and more responsive to increase in plant density than grain yield of the double-cross hybrid (DCH) and the open-pollinated variety (OPV). The plant densities that optimized grain yield were 86,665 plants ha-1, 53,044 plants ha-1 and 85,000 plants ha-1 for the SCH, DCH and OPV, respectively. The SCH presented higher leaf area values than the other cultivars 56 days after silking, when plant populations greater than 50,000 plants ha-1 were used. The highest variation coefficient value for grain production per plant was registered at 125,000 plants ha-1 and the lowest at 25,000 plants ha-1. The SCH presented smaller variation coefficient than the DCH and OPV for plant height and leaf area at silking, and for grain yield per plant. The higher morphologic uniformity of the SCH probably contributed to reduce intra-specific competition for water, light and nutrients, establishing a stronger sink after flowering. The SCH greater demand for photosynthetic products possibly favored the maintenance of leaf activity for a higer period, delaying senescence. Therefore, the slower leaf senescence and the more uniform plant growth contributed to the SCH higher grain yield and to the higher productivity differences between the SCH and the other two cultivars in the highest plant densities (75,000, 100,000 e 125,000 plants ha-1)
O incremento na densidade de plantas é uma forma de maximizar a interceptação da radiação solar e o rendimento de grãos do milho. Contudo, ele também pode reduzir a atividade fotossintética da planta e a eficiência de conversão dos fotoassimilados à produção de grãos. Aumentos na tolerância de híbridos de milho ao adensamento têm sido reportados em diferentes regiões produtoras no mundo. Duas características que podem contribuir para isto são a senescência foliar mais lenta no enchimento de grãos e a maior uniformidade no crescimento e desenvolvimento das plantas durante o ciclo da cultura. Este trabalho foi conduzido com os objetivos de quantificar o efeito do incremento da população de plantas sobre a área foliar, o rendimento de grãos e o coeficiente de variação de características agronômicas de cultivares de milho com bases genéticas contrastantes. O experimento foi conduzido no município de Lages-SC. O delineamento experimental utilizado foi o de blocos casualizados dispostos em parcelas subdivididas. Na parcela principal foram testadas três cultivares de milho: uma variedade de polinização aberta (Fortuna), um híbrido duplo (Ag303) e um híbrido simples (P30F53). Cinco populações de plantas foram avaliadas nas subparcelas: 25.000, 50.000, 75.000, 100.000 e 125.000 plantas ha-1. O experimento foi implantado no dia 26 de outubro de 2005, com espaçamento entre linhas de 0,70 m. Quando a cultura estava com quatro folhas expandidas, marcou-se 10 plantas de cada subparcela que estivessem no mesmo estádio fenológico. Estas plantas foram utilizadas para as avaliações de área foliar, bem como para o acompanhamento do crescimento, determinando-se o coeficiente de variação para área foliar, estádio fenológico e estatura de planta. Estas variáveis foram avaliadas 10 vezes, nos estádios V4, V8, V12, V16, R1 (espigamento) e aos 14, 28, 42, 56 e 70 dias após o espigamento. Após a colheita, foram determinados o coeficiente de variação e a produção de grãos por planta, nas 10 plantas selecionadas. Além disso, determinou-se a produção de grãos na área útil, bem como os componentes do rendimento. Os dados foram submetidos à análise de variância pelo teste F, ao nível de significância de 5% (P<0,05). As médias foram analisadas pelo teste de Tukey, a 5% de probabilidade de erro (P<0,05), por regressão polinomial e por correlação linear. A reposta do rendimento de grãos das três cultivares ao incremento na densidade de plantas foi quadrática. O rendimento de grãos do híbrido simples (HS) foi maior e mais responsivo ao incremento na população de plantas do que o híbrido duplo (HD) e da variedade de polinização aberta (VPA). As populações que otimizaram o rendimento de grãos foram de 86.665 plantas ha-1, 53.044 plantas ha-1 e 85.000 plantas ha-1 para o HS, HD e VPA, respectivamente. O HS apresentou maior valor de área foliar do que as demais cultivares aos 56 dias após o espigamento, nas densidades superiores a 50.000 plantas ha-1. Os maiores coeficientes de variação para produção de grãos por planta foram obtidos na densidade de 125.000 plantas ha-1 e os menores na de 25.000 plantas ha-1. O HS apresentou menor coeficiente de variação do que o HD e a VPA para estatura de planta e área foliar no espigamento, bem como para produção de grãos por planta. As maiores uniformidades morfológica e fenológica do HS provavelmente contribuiu para reduzir a competição intra-específica por água, luz e nutrientes, favorecendo o estabelecimento de um dreno mais forte logo após a floração. A maior demanda por fotoassimilados do HS possivelmente favoreceu a manutenção da atividade fotossintética das folhas por um período mais longo, retardando a senescência foliar. Portanto, a senescência foliar mais lenta e o desenvolvimento uniforme das plantas contribuíram para o maior rendimento de grãos do HS e para as maiores diferenças de produtividade registradas entre o HS e o HD e a VPA nas densidades mais altas (75.000, 100.000 e 125.000 plantas ha-1)
Njaimwe, Arnold Ngare. "Tillage and crop rotation impacts on soil, quality parameters and maize yield in Zanyokwe Irrigation Scheme, South Africa". Thesis, University of Fort Hare, 2010. http://hdl.handle.net/10353/460.
Pełny tekst źródłaMahama, George Yakubu. "Impact of cover crops and nitrogen application on nitrous oxide fluxes and grain yield of sorghum and maize". Diss., Kansas State University, 2015. http://hdl.handle.net/2097/18939.
Pełny tekst źródłaDepartment of Agronomy
P. V. Vara Prasad
Leguminous cover crops systems have been envisaged as a critical component of sustainable agriculture due to their potential to increase soil productivity through cycling of carbon (C) and nitrogen (N) in agricultural systems. The objectives of this study were to evaluate the performance of leguminous summer cover crops; cowpea [Vigna unguiculata (L.) Walp.], pigeon pea [Cajanus cajan (L.) Millsp], sunn hemp (Crotalaria juncea L.) and double-cropped grain crops; grain sorghum [Sorghum bicolor (L.) Moench] and soybean [Glycine max (L.) Merr.] after winter wheat (Triticum aestivum L.) and to determine the effects of these crops and varying N rates in the cropping system on nitrous oxide (N[subscript]2O) emissions, growth and yield of succeeding grain sorghum and maize (Zea mays L.) crop, soil aggregation, aggregate-associated C, and N. Field and laboratory studies were conducted for two years. The cover crops and double-cropped grain crops were planted immediately after winter wheat harvest. The cover crops were terminated at the beginning of flowering. Nitrogen fertilizer (urea 46% N) rates of 0, 45, 90, 135, and 180 kg N ha[superscript]-1 were applied to grain sorghum or maize in fallow plots. Pigeon pea and grain sorghum had more C accumulation than cowpea, sunn hemp and double-cropped soybean. Pigeon pea and cowpea had more N uptake than sunn hemp and the double-cropped grain crops. Fallow with N fertilizer application produced significantly greater N[subscript]2O emissions than all the cover crops systems. Nitrous oxide emissions were relatively similar in the various cover crop systems and fallow with 0 kg N ha[superscript]-1. Grain yield of sorghum and maize in all the cover crop and double cropped soybean systems was similar to that in the fallow with 45 kg N ha[superscript]-1. Both grain sorghum and maize in the double-cropped soybean system and fallow with 90 kg N ha[superscript]-1 or 135 kg N ha[superscript]-1 gave profitable economic net returns over the years. The double-cropped grain sorghum system increased aggregate-associated C and whole soil total C, and all the cover crop and the double-cropped soybean systems increased aggregate-associated N and soil N pools. Inclusion of leguminous cover crops without N fertilizer application reduced N[subscript]2O emissions and provided additional C accumulation and N uptake, contributing to increased grain yield of the following cereal grain crop.
Thobatsi, Jacob Thobatsi. "Growth and yield responses of maize (Zea mays L.) and cowpea (Vigna unguiculata L.) in an intercropping system". Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-10122009-184005.
Pełny tekst źródłaMishiyi, Sibongile Gift. "Nodulation, dry matter accumulation and grain yield of cowpea and lablab varieties under sole and intercropping system with maize". Thesis, University of Limpopo (Turfloop Campus), 2006. http://hdl.handle.net/10386/694.
Pełny tekst źródłaIntercropping is the growing of two or more crops simultaneously on the same field, and it is a common traditional practice among resource-poor farmers throughout the Limpopo Province of South Africa. Field studies were conducted at two locations in the province namely, the University of Limpopo experimental farm at Syferkuil, and a farmer’s field at Dalmada during the 2002/2003 growing season, to determine patterns of nodulation in cowpea and lablab varieties under sole culture and in an intercropping system with maize, variety SNK2147 and also to assess biomass accumulation and grain yielding abilities of the component crops in the system. The experiments were established as a randomized complete block design with three replications at each location. Treatments examined were sole maize, two cowpea cultivars: Bechuana white and Glenda; two lablab cultivars, Rongai and Common. The legumes were intercropped alternately within 90 cm inter-row spacing of maize, thus creating a distance of 45 cm between the maize and the legume rows. Cropping system had no effect on cowpea grain yield at Syferkuil, but at Dalmada cowpea yield was reduced. Maize grain yield was significantly affected by the cropping system at both Syferkuil and Dalmada. At both locations, the yields of all the intercropped maize were lower than those of the sole crop maize. The dry matter production of different cropping systems was generally similar during the different sampling dates.
the National Research Foundation,and the Gauteng Department of Agriculture Conservation and Environment
Mditshwa, Sithembele. "Estimating maize grain yield from crop growth stages using remote sensing and GIS in the Free State Province, South Africa". Thesis, University of Fort Hare, 2017. http://hdl.handle.net/10353/6016.
Pełny tekst źródłaDuarte, Yury Catalani Nepomuceno. "Modelos de simulação da cultura do milho - uso na determinação das quebras de produtividade (Yield Gaps) e na previsão de safra da cultura no Brasil". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-15052018-104958/.
Pełny tekst źródłaMaize is the most important cereal cultivated in the world, being its production system very complex and its productivity directly affected by climatic and crop management factors. In order to quantify the impacts caused by water and crop management deficits on maize yield, the use of crop simulation models is very useful. For properly apply these models, a solid basis of meteorological data is required. In this sense, the present study had as objectives: i) to evaluate two meteorological gridded data, NASA-POWER and DailyGridded, by comparing them with measured data from surface stations; (ii) to calibrate, evaluate and combine the MZA-FAO, CSM DSSAT Ceres-Maize and APSIM-Maize simulation models to estimate the maize potential and attainable yields in Brazil; iii) to evaluate the impact caused by the different sowing dates and soil types on maize yield; iv) to develop and evaluate a crop forecasting system based on crop simulation models and climatological data; v) to map the potential and the attainable maize yields in Brazil, identifying the most suitable regions for cultivation, and vi) to determine and map maize yields and yield gaps (YG) in Brazil. Comparing the gridded climatic data with observed ones, on a daily basis, a good agreement was found for all weather variables, including rainfall, with R2 = 0.58 and d = 0,85. The performances of the combination of the models at the end of the calibration and evaluation phases were better than those obtained with the individual models, with relatively low mean absolute error (EAM = 627 kg ha-1) and with good precision (R2 = 0.62) and accuracy (d = 1.00). During the evaluation of different sowing dates and soil types on maize yield, it was observed that this variable depends on the region and presents the maximum values and, consequently, the minimum risk during the sowings in the beginning of the rainy season of each site. The crop forecasting system, based on crop simulation models, had its best performance for simulating maize yields when the sowings were performed at the beginning of the main season and at the end of the second season, when it was able to predict yield satisfactorily 25 days before harvest. For the YG analysis, 152 sites were assessed and their potential and attainable yields were compared to the actual yields reported by IBGE. The highest YGs caused by water deficit occurred for sandy soils and during the autumn and winter months, usually dry in most of Brazilian regions, reaching values above 12000 kg ha-1. For YG caused by crop management, the values were higher in the less technified regions, such as in the North and Northeast regions, with values above 6000 kg ha-1. In contrast, more traditional maize production regions, such as the South and Center-West, presented YG caused by crop management, lower than 3500 kg ha-1 in most cases.
Abou, El Goud Amal Karam Sayed Ahmed. "Effect of endomycorrhizal fungi and compost on the yield and quality of maize and sunflower plants in poor nutrients soil". Kassel Kassel Univ. Press, 2010. http://d-nb.info/1003132960/04.
Pełny tekst źródłaBello, ZAID Adekunle. "Effect of soil nutrient status on growth, reproductive development and yield components of maize in a long term field trial". Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-02122009-105701.
Pełny tekst źródłaZheng, Jinsen. "NITROGEN MANAGEMENT IN MAIZE-BASED SYSTEMS OF THE TANZANIAN HIGHLANDS: BALANCING FOOD AND ENVIRONMENTAL OBJECTIVES". Kyoto University, 2019. http://hdl.handle.net/2433/236626.
Pełny tekst źródłaKyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21465号
農博第2308号
新制||農||1064(附属図書館)
学位論文||H31||N5160(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 舟川 晋也, 教授 間藤 徹, 教授 縄田 栄治
学位規則第4条第1項該当
Santoro, Maria Julia. "CORN GRAIN YIELD COMPONENTS AND NUTRIENT ACCUMULATION IN RESPONSE TO NITROGEN, PLANT DENSITY AND HYBRID". UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/100.
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