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Perkins, Seth A. "Crop model review and sweet sorghum crop model parameter development." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/14037.
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Master of ScienceDepartment of Biological and Agricultural Engineering
Kyle Douglas-Mankin
Opportunities for alternative biofuel feedstocks are widespread for a number of reasons: increased environmental and economic concerns over corn production and processing, limitations in the use of corn-based ethanol to 57 billion L (15 billion gal) by the Energy Independence and Security Act (US Congress, 2007), and target requirements of 136 billion L (36 billion gal) of renewable fuel production by 2022. The objective of this study was to select the most promising among currently available crop models that have the potential to model sweet sorghum biomass production in the central US, specifically Kansas, Oklahoma, and Texas, and to develop and test sweet sorghum crop parameters for this model. Five crop models were selected (CropSyst, CERE-Sorghum, APSIM, ALMANAC, and SORKAM), and the models were compared based on ease of use, model support, and availability of inputs and outputs from sweet sorghum biomass data and literature. After reviewing the five models, ALMANAC was selected as the best suited for the development and testing of sweet sorghum crop parameters. The results of the model comparison show that more data are needed about sweet sorghum physiological development stages and specific growth/development factors before the other models reviewed in this study can be readily used for sweet sorghum crop modeling. This study used a unique method to calibrate the sweet sorghum crop parameter development site. Ten years of crop performance data (Corn and Grain Sorghum) for Kansas Counties (Riley and Ellis) were used to select an optimum soil water (SW) estimation method (Saxton and Rawls, Ritchie et al., and a method that added 0.01 m m [superscript]-1 to the minimum SW value given in the SSURGO soil database) and evapotranspiration (ET) method (Penman-Montieth, Priestley-Taylor, and Hargraeves and Samani) combination for use in the sweet sorghum parameter development. ALMANAC general parameters for corn and grain sorghum were used for the calibration/selection of the SW/ET combination. Variations in the harvest indexes were used to simulate variations in geo-climate region grain yield. A step through comparison method was utilized to select the appropriate SW/ET combination. Once the SW/ET combination was selected the combination was used to develop the sweet sorghum crop parameters. Two main conclusions can be drawn from the sweet sorghum crop parameter development study. First, the combination of Saxton and Rawls (2006) and Priestley-Taylor (1972) (SR-PT) methods has the potential for wide applicability in the US Central Plains for simulating grain yields using ALMANAC. Secondly, from the development of the sweet sorghum crop model parameters, ALMANAC modeled biomass yields with reasonable accuracy; differences from observed biomass values ranged from 0.89 to 1.76 Mg ha [superscript]-1 (2.8 to 9.8%) in Kansas (Riley County), Oklahoma (Texas County), and Texas (Hale County). Future research for sweet sorghum physiology, Radiation Use Efficiency/Vapor Pressure Deficit relationships, and weather data integration would be useful in improving sweet sorghum biomass modeling.
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Lamsal, Abhishes. "Crop model parameter estimation and sensitivity analysis for large scale data using supercomputers." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34576.
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Doctor of PhilosophyDepartment of Agronomy
Stephen M. Welch
Global crop production must be doubled by 2050 to feed 9 billion people. Novel crop improvement methods and management strategies are the sine qua non for achieving this goal. This requires reliable quantitative methods for predicting the behavior of crop cultivars in novel, time-varying environments. In the last century, two different mathematical prediction approaches emerged (1) quantitative genetics (QG) and (2) ecophysiological crop modeling (ECM). These methods are completely disjoint in terms of both their mathematics and their strengths and weaknesses. However, in the period from 1996 to 2006 a method for melding them emerged to support breeding programs. The method involves two steps: (1) exploiting ECM’s to describe the intricate, dynamic and environmentally responsive biological mechanisms determining crop growth and development on daily/hourly time scales; (2) using QG to link genetic markers to the values of ECM constants (called genotype-specific parameters, GSP’s) that encode the responses of different varieties to the environment. This can require huge amounts of computation because ECM’s have many GSP’s as well as site-specific properties (SSP’s, e.g. soil water holding capacity). Moreover, one cannot employ QG methods, unless the GSP’s from hundreds to thousands of lines are known. Thus, the overall objective of this study is to identify better ways to reduce the computational burden without minimizing ECM predictability. The study has three parts: (1) using the extended Fourier Amplitude Sensitivity Test (eFAST) to globally identify parameters of the CERES-Sorghum model that require accurate estimation under wet and dry environments; (2) developing a novel estimation method (Holographic Genetic Algorithm, HGA) applicable to both GSP and SSP estimation and testing it with the CROPGRO-Soybean model using 182 soybean lines planted in 352 site-years (7,426 yield observations); and (3) examining the behavior under estimation of the anthesis data prediction component of the CERES-Maize model. The latter study used 5,266 maize Nested Associated Mapping lines and a total 49,491 anthesis date observations from 11 plantings. Three major problems were discovered that challenge the ability to link QG and ECM’s: 1) model expressibility, 2) parameter equifinality, and 3) parameter instability. Poor expressibility is the structural inability of a model to accurately predict an observation. It can only be solved by model changes. Parameter equifinality occurs when multiple parameter values produce equivalent model predictions. This can be solved by using eFAST as a guide to reduce the numbers of interacting parameters and by collecting additional data types. When parameters are unstable, it is impossible to know what values to use in environments other than those used in calibration. All of the methods that will have to be applied to solve these problems will expand the amount of data used with ECM’s. This will require better optimization methods to estimate model parameters efficiently. The HGA developed in this study will be a good foundation to build on. Thus, future research should be directed towards solving these issues to enable ECM’s to be used as tools to support breeders, farmers, and researchers addressing global food security issues.
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Coppa, Isabel Patricia Maria, and Isabel coppa@csw com au. "The use of remote sensing data for broad acre grain crop monitoring in Southeast Australia." RMIT University. Mathematical and Geospatial Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070201.095831.
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In 2025, there will be almost 8 billion people to feed as the worlds population rapidly increases. To meet domestic and export demands, Australian grain productivity needs to approximately triple in the next 20 years, and this production needs to occur in an environmentally sustainable manner. The advent of Hi-tech Precision Farming in Australia has shown promise in recent time to optimize the use of resources. Most
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Abebe, Yibekal Alemayehu. "Managing the soil water balance of hot pepper (Capsicum annuum L.) to improve water productivity." Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/25257.
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A series of field, rainshelter, growth cabinet and modelling studies were conducted to investigate hot pepper response to different irrigation regimes and row spacings; to generate crop-specific model parameters; and to calibrate and validate the Soil Water Balance (SWB) model. Soil, climate and management data of five hot pepper growing regions of Ethiopia were identified to develop irrigation calendars and estimate water requirements of hot pepper under different growing conditions. High irrigation regimes increased fresh and dry fruit yield, fruit number, harvest index and top dry matter production. Yield loss could be prevented by irrigating at 20-25% depletion of plant available water, confirming the sensitivity of the crop to mild soil water stress. High plant density markedly increased fresh and dry fruit yield, water-use efficiency and dry matter production. Average fruit mass, succulence and specific leaf area were neither affected by row spacing nor by irrigation regimes. There were marked differences among the cultivars in fruit yields despite comparable top dry mass production. Average dry fruit mass, fruit number per plant and succulence were significantly affected by cultivar differences. The absence of interaction effects among cultivar and irrigation regimes, cultivars and row spacing, and irrigation regimes and row spacing for most parameters suggest that appropriate irrigation regimes and row spacing that maximize productivity of hot pepper can be devised across cultivars. To facilitate irrigation scheduling, a simple canopy cover based procedure was used to determine FAO-type crop factors and growth periods for different growth stages of five hot pepper cultivars. Growth analysis was done to calculate crop-specific model parameters for the SWB model and the model was successfully calibrated and validated for five hot pepper cultivars under different irrigation regimes or row spacings. FAO basal crop coefficients (Kcb) and crop-specific model parameters for new hot pepper cultivars can now be estimated from the database, using canopy characteristics, day degrees to maturity and dry matter production. Growth cabinet studies were used to determine cardinal temperatures, namely the base, optimum and cut-off temperatures for various developmental stages. Hot pepper cultivars were observed to require different cardinal temperatures for various developmental stages. Data on thermal time requirement for flowering and maturity between plants in growth cabinet and open field experiments matched closely. Simulated water requirements for hot pepper cultivar Mareko Fana production ranged between 517 mm at Melkassa and 775 mm at Alemaya. The simulated irrigation interval ranged between 9 days at Alemaya and 6 days at Bako, and the average irrigation amount per irrigation ranged between 27.9 mm at Bako and 35.0 mm at Zeway.Thesis (PhD)--University of Pretoria, 2010.
Plant Production and Soil Science
unrestricted
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Rabe, Nicole J., and University of Lethbridge Faculty of Arts and Science. "Remote sensing of crop biophysical parameters for site-specific agriculture." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2003, 2003. http://hdl.handle.net/10133/195.
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Support for sustainable agriculture by farmers and consumers is increasing as environmental and socio-economic issues rise due to more intensive farm practices. Site-specific crop management is an important component of sutainable agriculture, within which remote sensing can play an integral role. Field and image data were acquired over a farm in Saskatchewan as part of a national research project to demonstrate the advantages of site-specific agriculture for farmers. This research involved the estimation of crop biophysical parameters from airborne hyperspectral imagery using Spectral Mixture Analysis (SMA), a relatively new sub-pixel scale image processing method that derives the fraction of sunlit canopy, soil and shadow that is contributing to a pixel's relectance. SMA of three crop types (peas, wheat and canola) performed slightly better than conventional vegetation indices in predicting leaf area index (LAI) and biomass using Probe-1 imagery acquired early in the growing season. Other potential advantages for SMA were also indentified, and it was conclude that future research is warranted to assess the full potential of SMA in a multi-temporal sense throughout the growing season.xiv, 194 leaves : ill. (some col.) ; 29 cm.
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Jalali-Farahani, Hamid Reza 1960. "Crop water stress parameters for turfgrass and their environmental dependability." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/191950.
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The concept of crop water stress index (CWSI) was explored using empirical and theoretical models to evaluate bermudagrass water status. The empirical methods were simplifications of the crop energy balance equation. Measured field data were employed to develop the empirical CWSI parameters. Field data were collected from turf plots under three levels of irrigation for the 1986 growing season in Tucson, Arizona. The simplest empirical model of Idso gave the highest variance in estimates of CWSI for all treatments with the estimates being highly influenced by net radiation. An improved empirical model was developed when net radiation was included in the statistical analysis of the canopy temperature minus air temperature limits. In general, the most accurate estimates of CWSI were obtained by using the energy balance equation with constant values of potential canopy and aerodynamic resistances. Various methods were used to evaluate these resistances. Further research is needed to test the perfomance of the theoretically-derived CWSI and to develop more general methods of evaluating the resistances.
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Burkart, Andreas [Verfasser]. "Multitemporal assessment of crop parameters using multisensorial flying platforms / Andreas Burkart." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1096330075/34.
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Varella, Hubert Vincent. "Inversion d’un modèle de culture pour estimer spatialement les propriétés des sols et améliorer la prédiction de variables agro-environnementales." Thesis, Avignon, 2009. http://www.theses.fr/2009AVIG0638/document.
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Les modèles de culture constituent des outils indispensables pour comprendre l’influence des conditions agropédoclimatiques sur le système sol-plante à différentes échelles spatiales et temporelles. A l’échelle locale de la parcelle agricole, le modèle peut être utilisé dans le cadre de l’agriculture de précision pour optimiser les pratiques de fertilisation azotée de façon à maximiser le rendement ou le revenu tout en minimisant le lessivage des nitrates vers la nappe. Cependant, la pertinence de l’utilisation du modèle repose sur la qualité des prédictions réalisées, basée entre autres sur une bonne détermination des paramètres d’entrée du modèle. Dans le cadre de l’agriculture de précision, les paramètres concernant les propriétés des sols sont les plus délicates à connaître en tout point de la parcelle et il existe très peu de cartes de sols permettant de les déterminer de manière précise. Néanmoins, dans ce contexte, on peut disposer d’observations acquises automatiquement sur l’état du système sol-plante, telles que des images de télédétection, les cartes de rendement ou les mesures de résistivité électrique du sol. Il existe alors une alternative intéressante pour estimer les propriétés des sols à l’échelle de la parcelle qui consiste à inverser le modèle de culture à partir de ces observations pour retrouver les valeurs des propriétés des sols. L’objectif de cette thèse consiste (i) dans un premier temps à analyser les performances d’estimation des propriétés des sols par inversion du modèle STICS à partir de différents jeux d’observations sur des cultures de blé et de betterave sucrière, en mettant en oeuvre une méthode bayésienne de type Importance Sampling, (ii) dans un second temps à mesurer l’amélioration des prédictions de variables agro-environnementales réalisées par le modèle à partir des valeurs estimées des paramètres. Nous montrons que l’analyse de sensibilité globale permet de quantifier la quantité d’information contenue dans les jeux d’observations et les performances réalisées en matière d’estimation des paramètres. Ce sont les propriétés liées au fonctionnement hydrique du sol (humidité à la capacité au champ, profondeur de sol, conditions initiales) qui bénéficient globalement de la meilleure performance d’estimation par inversion. La performance d’estimation, évaluée par comparaison avec l’estimation fournie par l’information a priori, dépend fortement du jeu d’observation et est significativement améliorée lorsque les observations sont faites sur une culture de betterave, les conditions climatiques sont sèches ou la profondeur de sol est faible. Les prédictions agro-environnementales, notamment la quantité et la qualité du rendement, peuvent être grandement améliorées lorsque les propriétés du sol sont estimées par inversion, car les variables prédites par le modèle sont également sensibles aux propriétés liées à l’état hydrique du sol. Pour finir, nous montrons dans un travail exploratoire que la prise en compte d’une information sur la structure spatiale des propriétés du sol fournie par les mesures de résistivité électrique, peut permettre d’améliorer l’estimation spatialisée des propriétés du sol. Les observations acquises automatiquement sur le couvert végétal et la résistivité électrique du sol se révèlent être pertinentes pour estimer les propriétés du sol par inversion du modèle et améliorer les prédictions des variables agro-environnementales sur lesquelles reposent les règles de choix des pratiques agricolesDynamic crop models are very useful to predict the behavior of crops in their environment and are widely used in a lot of agro-environmental work. These models have many parameters and their spatial application require a good knowledge of these parameters,especially of the soil parameters. These parameters can be estimated from soil analysis at different points but this is very costly and requires a lot of experimental work. Nevertheless,observations on crops provided by new techniques like remote sensing or yield monitoring, is a possibility for estimating soil parameters through the inversion of crop models. In my work, the STICS crop model is studied for the wheat and the sugar beet and it includes more than 200 parameters. After a previous work based on a large experimental database for calibrate parameters related to the characteristics of the crop, I started my study with a global sensitivity analysis of the observed variables (leaf area index LAI and absorbed nitrogen QN provided by remote sensing data, and yield at harvest provided by yield monitoring) to the soil parameters, in order to determine which of them have to be estimated. This study was made in different climatic and agronomic conditions and it reveals that 7 soil parameters (4 related to the water and 3 related to the nitrogen) have a clearly influence on the variance of the observed variables and have to be therefore estimated. For estimating these 7 soil parameters, I chose a Bayesian data assimilation method (because I have prior information on these parameters) named Importance Sampling by using observations, on wheat and sugar beet crop, of LAI and QN at various dates and yield at harvest acquired on different climatic and agronomic conditions. The quality of parameter estimation is then determined by comparing the result of parameter estimation with only prio rinformation and the result with the posterior information provided by the Bayesian data assimilation method. The result of the parameter estimation show that the whole set of parameter has a better quality of estimation when observations on sugar beet are assimilated. At the same time, global sensitivity analysis of the observed variables to the 7 soil parameters have been performed, allowing me to build a criterion based on sensitivity indices (provided by the global sensitivity analysis) able to rank the parameters with respect to their quality of estimate. This criterion constitutes an interesting tool for determining which parameters it is possible to estimate to reduce probably the uncertainties on the predictions. The prediction of the crop behaviour when estimating the soil parameters is then studied. Indeed, the quality of prediction of agro-environmental variables of the STICS crop model (yield, protein of the grain and nitrogen balance at harvest) is determined by comparing the result of the prediction using the prior information on the parameters and the result using the posterior information. As for the estimation of soil parameters, the prediction of the variable is made on different climatic and agronomic conditions. According to the result of parameter estimation, assimilating observations on sugar beet lead to a better quality ofprediction of the variables than observations on wheat. It was also shown that the number ofcrop seasons observed and the number of observations improve the quality of the prediction
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Maqrot, Sara. "Méthodes d'optimisation combinatoire en programmation mathématique : Application à la conception des systèmes de verger-maraîcher." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30131.
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Dans le cadre du développement durable et des innovations dans les systèmes agroalimentaires, les systèmes mixtes horticoles (vergers et maraîchage) visent à répondre aux enjeux actuels auxquels l'agriculture est confrontée, à savoir une diminution de la pollution des sols, une meilleure gestion des ressources (eau, énergies) et un enrichissement de la biodiversité, tout en continuant d'assurer des fonctions alimentaires. Ils combinent des productions à la fois diversifiées et relativement intensifiées, leur permettant de s'insérer en périphérie urbaine. Ces systèmes agroforestiers reposent sur un ensemble complexe d'interactions modifiant l'utilisation de la lumière, de l'eau et des nutriments. La conception d'un tel système doit donc optimiser l'utilisation de ces ressources en maximisant les interactions positives (facilitations) et en minimisant celles négatives (compétitions). Nous définissons le problème de verger-maraîcher comme un problème d'allocation des arbres et des cultures dans les dimensions spatio-temporelles. Nous proposons trois formulations mathématiques : modèle quadratique en variables binaires (BQP), modèle linéaire en variables mixtes (MILP) et modèle linéaire en variables binaires (01LP). Les limites des méthodes exactes pour résoudre ce problème sont présentées, montrant la nécessité d'appliquer des méthodes approchées, capables de résoudre des systèmes à grande échelle avec des solutions de bonne qualité en temps raisonnable. Pour cela, nous avons développé un solveur open source, baryonyx, qui est une version parallèle de l'heuristique de Wedelin (généralisée). Nous avons utilisé l'analyse de sensibilité pour identifier les paramètres les plus influents. Une fois trouvés, nous avons fixé les autres et utilisé un algorithme génétique pour régler les plus importants sur un ensemble d'instances d'entraînement. Le jeu de paramètres optimisé peut alors être utilisé pour résoudre d'autres instances de plus grande taille du même type de problème. baryonyx avec son réglage automatique obtient des résultats améliorant l'état-de-l'art sur des problèmes de partitionnement. Les résultats sont plus mitigés sur le problème de verger-maraîchage, bien que capable de passer à l'échelleMixed fruit-vegetable cropping systems (MFVCS) are a promising way of ensuring environmentally sustainable agricultural production systems in response to the challenge of being able to fulfill local market requirements. They combine productions and make a better use of biodiversity. These agroforestry systems are based on a complex set of interactions modifying the utilization of light, water and nutrients. Thus, designing such systems requires to optimize the use of these resources : by maximizing positive interactions (facilitations) and minimizing negative ones (competitions). To reach these objectives, the system's design has to include the spatial and temporal dimensions, taking into account the evolution of above- and belowground interactions over a time horizon. For that, we define the MFVCAP using a discrete representation of the land and the interactions between vegetable crops and fruit trees. We formulate the problem as three models : binary quadratic program (BQP), mixed integer linear programming (MILP) and binary linear programming (01LP). We explore large models using exact solvers. The limits of exact methods in solving the MFVCS problem show the need for approximate methods, able to solve a large-scale system with solutions of good quality in reasonable time, which could be used in interactive design with farmers and advisers. We have implemented a C++ open-source solver, called baryonyx, which is a parallel version of a (generalized) Wedelin heuristic. We used a sensitivity analysis method to find useful continuous parameters. Once found, we fixed other parameters and let a genetic optimization algorithm using derivatives adjust the useful ones in order to get the best solutions for a given time limit. The optimized configuration could be used to solve larger instances of the same problem type. Baryonyx got competitive results compared to state-of-the-art exact and approximate solvers on crew and bus driver scheduling problems expressed as set partitioning problems. The results are less convincing on MFVCS but still able to produce valid solutions on large instances
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Portz, Gustavo. "Use of crop canopy sensors in the measurement of sugarcane parameters aiming site-specific nitrogen fertilization management." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-17092015-101022/.
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Plant canopy sensors have emerged as a new tool for in field on-the-go spatially localized prediction of plant biomass and nitrogen (N) uptake by crops in an indirectly and plant indestructible way as base for N variable rate fertilization. Sensors based on the combination of specific reflectance bands from the electromagnetic spectrum constitute the vast majority of canopy sensors, and this principle has already been validated in many crops. Alternatively to this concept, the use of ultrasonic distance sensors to measure crop canopy height has been presented as an option to estimate biomass. Based on that, the aim of this thesis was to validate and refine canopy sensor systems on automated diagnosis of plant parameters aimed the application of N fertilizer according sugarcane needs. Therefore, it was necessary to: 1) validate the prior calibration made for the reflectance sensor (Portz et al., 2012) and to establish the best time to use the sensor over the crop; 2) test the use of the reflectance sensor in comparative strips trials of uniform and sensor based N variable rate application testing algorithms with positive and negative slope and measuring productivity at the end of the season; 3) obtain the relationship between crop canopy height with accumulated biomass and N uptake by the crop during the initial growing season; 4) explore the plant height measured with an ultrasonic sensor comparing the results of biomass and N uptake prediction with those obtained with the reflectance sensor. The experiments were conducted on commercial sugarcane fields, and in strips of the crop with N variable rate application. The experiments were installed over clayey and sandy soils in dry and rainy seasons being all evaluated with the reflectance sensor Yara N-Sensor model ALS (N-Sensor® ALS, Yara International ASA) and partly in comparison with an ultrasonic sensing system Polaroid 6500 (Polaroid, Minnetonka, MN, USA), when the crop had stalk height between 0.2 and 0.9 m. The reflectance sensor calibration fitted with the previous published data showing the interval between 0.3 - 0.5m as the most appropriate to use this sensor over sugarcane. The positive slope algorithm was superior to the negative, except in the situation of clayey soil in rainy season where the response from the negative slope algorithm was higher. The sugarcane plant height was highly correlated with biomass and N uptake by the crop, being possible to estimate the plants canopy height indirectly by the use of an ultrasonic sensor. Comparing the sensor systems, canopy reflectance was better in the early stages of crop as canopy height was more suitable for estimating the cultural parameters when the plants already covered soil in between the rows (+ 0.6 m stalk height), being the sensor systems complementary when fertilization is widely spread in the early crop growth period.Sensores de dossel tem se apresentado como uma nova ferramenta para a predição espacialmente localizada, em tempo real, de forma indireta e indestrutiva da biomassa vegetal e extração de nitrogênio (N) pelas culturas como base para a aplicação de fertilizantes nitrogenados em taxas variáveis. Sensores baseados na combinação de faixas específicas de reflectância do espectro eletromagnético constituem a grande maioria dos sensores de dossel sendo este princípio já validado para uso em muitas culturas. Alternativamente a este conceito, a medição da altura do dossel cultural com o uso de sensor ultrassónico se apresenta como uma alternativa para a estimativa de biomassa vegetal. Com base nisso o objetivo desta tese foi de validar e aperfeiçoar sistemas sensores para a automação do diagnóstico visando à aplicação de fertilizante nitrogenado em função da necessidade da cana-de-açúcar. Para tanto, foi necessário: 1) validar a previa calibração feita ao sensor de reflectância (PORTZ et al., 2012) assim como estabelecer o melhor momento para uso do sensor na cultura; 2) ensaiar o uso do sensor em faixas comparativas entre taxa fixa e variável testando algoritmos de aplicação com inclinação positiva e negativa para dose de N mensurando produtividade; 3) obter a relação entre altura de dossel da cultura com, biomassa acumulada e extração de nitrogênio pela planta; 4) explorar a altura de plantas mensurada com um sensor ultrassónico comparando os resultados de predição de biomassa e extração de nitrogênio com aqueles obtidos com sensor de refletância. Os experimentos foram conduzidos em talhões comerciais de cana-de-açúcar e em forma de faixas da cultura, com aplicação em taxa variada de doses de N. Os experimentos foram instalados em solos de textura argilosa e arenosa nas épocas seca e chuvosa do ano sendo todos avaliados com o sensor Yara N-Sensor, modelo ALS (N-Sensor® ALS, Yara International ASA), e em parte comparando com um sistema sensor ultrassónico Polaroid 6500 (Polaroid, Minnetonka, MN, EUA) quando a cultura apresentava altura de colmos entre 0,2 e 0,9 m. Os dados coletados para a calibração do sensor de reflectância se encaixaram exatamente aos dados já publicados mostrando-se o intervalo entre 0.3 e 0.5 m o mais indicado ao uso deste sensor. O algoritmo com inclinação positiva se mostrou superior ao negativo exceto na situação de solo argiloso em estação chuvosa onde a resposta do algoritmo negativo foi maior. A altura de planta de cana-de-açúcar se mostrou altamente correlacionável com biomassa e extração de nitrogênio pela cultura, sendo possível estimar a altura do dossel das plantas de forma indireta pelo uso do sensor ultrassónico. Comparando-se os sistemas sensores, reflectância de dossel se mostrou melhor em estádios iniciais da cultura enquanto altura de dossel se mostrou mais indicada para estimar os parâmetros culturais quando as plantas já recobriam as entrelinhas (+0.6 m colmo), mostrando-se os sistemas sensores complementares quando o período de fertilização for mais amplo na fase inicial da cultura.
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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.
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Intensive tillage and monoculture cropping practices reduce soil C accumulation hence increasing soil vulnerability to chemical, physical and biological degradation. This study focussed on enhancing biomass production of wheat and oat winter cover crops as a means of increasing C sequestration in the low organic C soils of the central part of Eastern Cape Province. The specific objectives were (i) to evaluate the short-term effects of no till and cereal-fallow based crop rotations on; soil organic matter related parameters, pH and electrical conductivity, (ii) soil bulk density, water retention and aggregate stability, (iii) soil microbial biomass C and N, mineralizable N, soil respiration, and dehydrogenase enzyme activity, (iv) grain yield, soil nutrient concentration (N, P and K) and their uptake by maize, and (v) to identify soil parameters with high sensitivity to tillage under maize-fallow-maize, maize-wheat-maize and maize-oat-maize rotational cover cropping practices. The experiment was laid out as a split-plot arrangement in a randomized complete block design with 4 replicates. Tillage treatments (CT and NT) were applied on the main plots which measured 8 × 18 m while crop rotation treatments were applied in the subplots which measured 8 × 6 m. The rotation treatments were maize-fallow-maize (MFM), maize-wheat-maize (MWM) and maize-oat-maize (MOM). Weed control in NT plots involved preplant application of glyphosate to control mainly the grass weeds while post emergence weed management was done using Atrazine (485 atrazine and 15 g l-1 triazines). Initial weed control in CT plots was achieved through ploughing to a depth of 20 cm followed by disking while post emergence weed iii management was done by hand hoeing. Soil parameters measured were; (i) particulate organic matter (POM), soil organic carbon (SOC), total nitrogen (TN), pH and electrical conductivity (EC), (ii) soil bulk density (b), moisture at field capacity (FC), aggregate mean weight diameter (MWD) determined by fast wetting (FW), slow wetting (SW), mechanical breakdown by shaking (MB) and the stability index (SI), (iii) soil microbial biomass C (MBC) and N (MBN), mineralizable N (MN), soil respiration (SR), and dehydrogenase enzyme activity (DHEA). No-till increased POM and TN compared to CT in Lenye and Burnshill, respectively. The MWM and the MOM rotations increased TN relative to the MFM rotation in Lenye. The MWM and MOM rotations enhanced SOC relative to MFM in all sampled soil depths at Burnshill and similar observations were made under MOM rotation in the 5-20 cm depth in Lenye. The MWM and MOM rotations tended to depress soil pH relative to the MFM rotation in both sampled soil depths in Lenye while NT reduced soil pH relative to CT on the surface soil layer in Burnshill. Soil EC and pH varied with depth across tillage practices but both parameters remained within the ideal range for successful crop production over the study period. Soil stability index (SI) and aggregate MWD determined by FW, SW and MB were higher in Lenye compared to Burnshill. The MOM rotation enhanced the SI relative to MFM and MWM rotations at both sites. Scanning electron microscope (SEM) showed that more organic C was incorporated into the soil under NT and MOM rotation compared to CT and MFM rotation which had few organic coatings on the soil particles. Microbial properties varied with plant biomass input as influenced by tillage and type of rotational cover crop at both sites. Like in other past studies, NT showed higher levels of MBC, MBN, NM and SR at the soil surface layer compared to CT in Burnshill. No till increased MN iv relative to CT in both sampled soil depths in Lenye and resulted in higher DHEA compared to CT in Burnshill. The MOM rotation increased MBC, MBN, MN relative to MFM rotation especially within surface soil layer. Similar observations were made with respect to MN and SR in both sampled soil layers at Lenye. By contrast, the DHEA was higher under the MFM relative to the MWM and MOM rotations in Lenye but similar under the MFM and MOM rotations in Burnshill. Maize grain yield was not affected by both tillage and crop rotations but varied with cropping season. Comparable grain yields observed under the two tillage practices with similar fertilizer application rates indicated the advantage of NT over CT in saving on labour costs in maize production without compromising yields. High plant biomass retention under NT relative to CT contributed to high soil N and P levels under the former compared to the latter tillage practice especially on soil surface layer at both study sites. Principal component analysis (PCA) revealed that soil chemical and biological parameters closely linked to organic matter, namely SOC, MN, MBC and MBN showed the highest sensitivity to tillage and crop rotation treatments. Soil aggregate MWD determined by SW and b were the physical parameters which were highly altered by agronomic management practice. The MWM and MOM rotations were clustered together and clearly separated from the MFM rotation and this observed trend only applied to the 0-5 and 5-20 cm depths in Lenye site only. No till, MWM and MOM rotations enhanced POM, SOC and TN relative to CT and MFM rotation suggesting these practices have greater potential to improve soil chemical properties compared to intensive tillage and maize monoculture based production practices. Reduced soil b under MOM rotation and improved SI under NT compared to MFM and CT, respectively v indicate that these practices have the potential to improve degraded soils. Although not significantly different, NT values for MBC, MBN, MN, SR and DHEA were higher compared to CT indicating the potential of the practice to improve soil biotic activity relative to conventional tillage practices. No till enhanced surface soil nitrate N and extractable P compared to CT at both sites revealing the long-term potential of NT in improving the supply of these essential plant nutrients compared to CT. Principal component analysis showed that SOC, MN, K, P, MBC, MBN, soil aggregate MWD determined by SW and b were the most sensitive parameters to tillage and crop rotations. Therefore, these parameters could constitute the minimum data set for assessments of the impact of selected CA practices on soil quality attributes.
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Perbandt, Daniela. "Determination of yield and quality parameters of energy crops applying laboratory and field spectroscopy." Kassel Universitätsbibliothek Kassel, 2010. http://d-nb.info/1003606652/34.
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Hausler, Melanie. "Assessment of vegetation parameters in olive trees in the region of Alentejo. A comparison of direct and indirect methods." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4004.
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Mestrado em Engenharia Agronómica - Instituto Superior de AgronomiaVegetation parameters, as the leaf area index (LAI) and the ground cover (GC) are commonly related to biosphere processes, being used in models to estimate yield and crop water requirements. Several direct and indirect methods have been developed in the past decades to determine the LAI. However, a simple approach to assess this parameter is still missing. In this study we tested the operability and precision of different methods to calculate the LAI of 6 and 20 year old olive trees (Arbequina and Cobrançosa), under irrigated and non-irrigated conditions in the region of Alentejo. The average LAI on a projected area basis was estimated to be 5.88 and 2.75 m2 m-2 at the irrigated and non-irrigated sites, respectively, corresponding to 1.01 and 1.05 m2 m-2 on a total area basis. Furthermore, a tool was introduced to simplify the decision making between the use of the LAI and the GC. The determination of the GC is much easier than the LAI in practical uses. The average GC was 5.7 m2 under irrigated and 18.0 m2 under non-irrigated conditions. A detailed comparison between direct and indirect methods is given and the future prospective of the decision making tool is discussed.
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Perbandt, Daniela [Verfasser]. "Determination of yield and quality parameters of energy crops applying laboratory and field spectroscopy / Daniela Perbandt." Kassel : Universitätsbibliothek Kassel, 2010. http://d-nb.info/1003606652/34.
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Götze, Philipp [Verfasser]. "Impact of specialised sugar beet crop rotations on soil fertility parameters and on yield and yield stability of sugar beet / Philipp Götze." Halle, 2017. http://d-nb.info/1137867655/34.
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Ahmadian, Nima [Verfasser]. "Integrating Satellite Remote Sensing and In-situ Measurements to Estimate the Biophysical Parameters of Agricultural crop using Multispectral and Radar Data / Nima Ahmadian." Greifswald : Universitätsbibliothek Greifswald, 2017. http://d-nb.info/1138116963/34.
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Callum, Ian R. "Long-term effects of tillage and residues on selected soil quality parameters." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31202.
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A two year study was initiated in 1999 at the Macdonald Campus Farm, on a 2.4 ha site consisting mainly of St-Amable sand to shallow loamy sand (Typic Endoaquent; Humic Gleysol). The site was planted to alfalfa ( Medicago sativa) prior to the establishment of the experimental design and has been planted to corn (Zea mays L.) since 1991. The experiment was set up as a randomized complete block design and consisted of three tillage levels (NT, no-till; RT, reduced tillage; and CT, conventional tillage) and two residue levels (-R, no residues; +R, with residues). This study was performed in order to ascertain the effect of these management systems on soil organic carbon (SOC), particulate organic matter carbon (POM-C), microbial biomass carbon (MBC) levels and soil physical properties. Soil physical properties measured included bulk density, saturated hydraulic conductivity (Ksat), dry and wet aggregate stability, total porosity, macroporosity at -1 kPa and -6 kPa of matric potential, and moisture content. Crop yield was also measured. Results indicated that lower rates of mineralization of POM-C under NT+R in the surface 0--10 cm led to significantly higher SOC at the same depth. There were no significant differences between treatments at the 10--20 cm depth. The MBC was not a good indicator of the differences in soil organic matter levels between treatments. No-till treatments had higher bulk densities, reduced total porosity and macroporosity, increased moisture content, and increased constant-head measured Ksat. Differences in Ksat as measured with the Guelph permeameter, were not significant between treatments, most likely due to increased earthworm activity in NT. There were no significant differences in crop yield in 1999, but a significantly wetter year in 2000 caused lower grain yields in NT+R compared to NT-R and CT+R.
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Thapa, Shyam. "Optimization of Parameters for the Densification (Pelletization) of Cereal Crop Residues and Feasibility Study of Pellet Plant Development in the State of Arkansas from Economic Perspective." Thesis, Arkansas State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10640883.
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Conventional cereal crop residues, namely, rice ( Oryza sativa L.), corn (Zea mays L.), and wheat (Triticum aestivum L.) is very abundant and readily available widely. It has been a nuisance to agronomic producers to manage these immense “so-called wastes”. The Energy Independence and Security Act (EISA) promulgated by the United States and The EU’s renewable energy directive mandated the substantial incorporation of renewable energy in their final energy consumption. These led to the increase in R&D’s on biomass and bioenergy products in the United States as well.
Hammer mill grinds of different cereal crop residues, rice, wheat, and corn, sieved through 5"/64 , 1"/8 , and 5"/32 hammer mill screen sizes (details in chapter 3) are mixed with different binders namely gelatin, wheat gluten, and dry milk at 1:10, 1:15, and 1:20 proportions (Chapter 4). Applying Taguchi-Grey relational analysis for four factors with three levels each, optimal operating level for the control factors based on multi-response characteristics was determined. The multi-responses used for the study are bulk density, durability, compressive strength, and gross heating values. Binder ratio was most influential in determining pellet quality. Binder type was next influential factor. The combination of factor levels A1B1C3D 1 was found to be optimal conditions for pelletization as final results were confirmed with tests.
The pelletization parameters for making better quality composite pellets were also investigated (in Chapter V). The same Taguchi –Grey relational analysis method was used for optimization. The process (material variables) parameters those are material type, particle size or grind size, binder type, and proportion of binder were closely studied using L9 Taguchi orthogonal array. Binder ratio (blending ratio) has most significant impact, and particle size (Hammer mill grind) has second greatest impact on pelleting composite wastes. Tests conducted employing optimal conditions (A3B3C2D1) has confirmed that better pellets were produced compared with the hypothesized conditions.
The cost analysis using Invest for excel was carried out in order to study the feasibility of solid biofuel project. The biomass assessment using Biopower Atlas and associated GIS tools from NREL demonstrated that the State of Arkansas has agricultural residues sufficient to support 50 kilotons and 66 kilotons biomass pellet plant. Economy of scale effect can be observed when comparing 50 kilotons and 66 kilotons pellet mill. Gelatin-wheat pellet mill at 50 kiloton and even 66 kilotons were predicted to be unprofitable at the current stage. However, analysis results showed pellet produced from pine shavings – wheat residue blends is profitable. Crop residues are promising resources due to its wide distribution and availability. It can be termed as a “Backstop resource” because it is renewable and will be economically viable option as the price of oil and gas become expensive.
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Harena, Tchamse. "Essai de validation et perspectives d'application en agrometeorologie d'un modele de simulation de la croissance et du developpement du mais : ceres-maize." Clermont-Ferrand 2, 1988. http://www.theses.fr/1988CLF2D214.
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Apres une description du modele couple de simulation du bilan hydrique, du developpement et de la croissance, les valeurs simulees sont comparees aux donnees recueillies lors de quatre annees d'experimentation dans le puy-de-dome sur deux varietes de mais (dea et boree). On a constate que du point de vue phenologique le modele presente un retard de precocite et que les valeurs de croissance sont sous estimees. On etudie la sensibilite du modele aux parametres genetiques d'entree et a deux coefficients numeriques (phyllochrone et plastochrone), puis a la variation de l'etat hydrique du sol et a une irrigation intervenant pendant la floraison femelle
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Roux, F. A. "Die invloed van spesifieke grond en klimaats parameters op wingerdprestasie, wynkwaliteit en -karakter." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1343.
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Guerrier, Gilles. "Recherche de tests physiologiques de vigueur germinative en milieu NaCl." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb375980647.
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Paget, Mark Frederick. "Genetic evaluation models and strategies for potato variety selection." Thesis, University of Canterbury. Forestry, 2014. http://hdl.handle.net/10092/9953.
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A series of studies are presented on the genetic evaluation of cultivated potato (Solanum tuberosum L.) to improve the accuracy and efficiency of selection at various stages of a breeding programme. The central theme was the use of correlated data, such as relationship information and spatial and across-trial correlations, within a linear mixed modelling framework to enhance the evaluation of candidate genotypes and to improve the genetic response to selection. Analyses focused on several social and economically-important traits for the enhancement of the nutritional value, disease resistance and yield of potato tubers.
At the formative stages of a breeding scheme, devising a breeding strategy requires an improved understanding of the genetic control of target traits for selection. To guide a strategy that aims to enhance the micronutrient content of potato tubers (biofortification), univariate and multivariate Bayesian models were developed to estimate genetic parameters for micronutrient tuber content from a breeding population generated from crosses between Andean landrace cultivars. The importance of the additive genetic components and extent of the narrow-sense heritability estimates indicated that genotypic 'individual' recurrent selection based on empirical breeding values rather than family-based selection is likely to be the most effective strategy in this breeding population. The magnitude of genetic correlations also indicated that simultaneous increases in important tuber minerals, iron and zinc, could be achieved.
Optimising selection efficiency is an important ambition of plant breeding programmes. Reducing the level of candidate replication in field trials may, under certain circumstances, contribute to this aim. Empirical field data and computer simulations inferred that improved rates of genetic gain with p-rep (partially replicated) testing could be obtained compared with testing in fully replicated trials at the early selection stages, particularly when testing over two locations. P-rep testing was able to increase the intensity of selection and the distribution of candidate entries across locations to account for G×E effects was possible at an earlier stage than is currently practised. On the basis of these results, it was recommended that the full replication of trials (at the first opportunity, when enough planting material is available) at a single location in the early stages of selection should be replaced with the partial replication of selection candidates that are distributed over two locations.
Genetic evaluation aims to identify genotypes with high empirical breeding values (EBVs) for selection as parents. Using mixed models, spatial parameters to target greater control of localised field heterogeneity were estimated and variance models to account for across-trial genetic heterogeneity were tested for the evaluation of soil-borne powdery scab disease and tuber yield traits at the early stages of a selection programme. When spatial effects improved model fit, spatial correlations for rows and columns were mostly small for powdery scab, and often small and negative for marketable and total tuber yield suggesting the presence of interplot competition in some years for tuber yield traits. For the evaluation of powdery scab, genetic variance structures were tested using data from 12 years of long-term potato breeding METs (multi-environment trials). A simple homogeneous correlation model for the genetic effects was preferred over a more complex factor analytic (FA) model. Similarly, for the MET evaluation of tuber yield at the early stages, there was little benefit in using more complex FA models, with simple correlation structures generally the most favourable models fitted. The use of less complex models will be more straightforward for routine implementation of potato genetic evaluations in breeding programmes.
Evaluations for (marketable) tuber yield were extended to multi-location MET data to characterise both genotypes and environments, allowing a re-evaluation of New Zealand MET selection strategies aimed at broad adaptation. Using a factor analytic mixed model, results indicated that the programme’s two main trial locations in the North and the South Islands optimised differentiation between genotypes in terms of G×E effects. There was reasonable performance stability of genotypes across test locations and evidence was presented for some, but limited, genetic progress of cultivars and advanced clonal selections for tuber marketable yield in New Zealand over recent years.
The models and selection strategies investigated and developed in this thesis will allow an improved and more systematic application of genetic evaluations in potato selection schemes. This will provide the basis for well informed decisions to be made on selection candidates for the genetic improvement of potato in breeding programmes.
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Kamacharova, Ilina [Verfasser], and Raimund [Akademischer Betreuer] Erbel. "Prognostische Aussagekraft von klinischen Scoring-Systemen (SAPS II und SAPS3) und laborchemischen Parametern (CRP, IL-6, PCT) bei internistischen Intensivpatienten / Ilina Kamacharova ; Betreuer: Raimund Erbel." Duisburg, 2019. http://d-nb.info/119359085X/34.
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Rodrigues, Wagner Nunes. "Comportamento de grupos de clones de café Conilon, selecionados no norte, na região sul do Estado do Espírito Santo." Universidade Federal do Espírito Santo, 2010. http://repositorio.ufes.br/handle/10/6629.
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Previous issue date: 2010-08-18A cafeicultura é uma atividade de grande importância social e econômica. O Brasil é o maior produtor mundial e o Estado do Espírito Santo é o segundo maior produtor nacional de café, sendo responsável por aproximadamente 70% da produção de café Conilon do País. No citado Estado, a espécie Coffea canephora, em especial a variedade Conilon, é a mais plantada. Existe uma expressiva variabilidade das condições da produção de café nesse Estado: a região ao norte do Espírito Santo é responsável pela maior parte da produção, enquanto o sul ainda apresenta baixo rendimento. Devido à grande importância do café Conilon no Estado do Espírito Santo, o Instituto Capixaba de Pesquisa Assistência Técnica e Extensão Rural (Incaper) estabeleceu um programa de pesquisa em melhoramento genético desde 1985, desenvolvendo e lançando seis variedades para o Estado. Para a caracterização de variedades é feito o agrupamento de clones que apresentem características agronômicas em comum. A partir da época de maturação dos frutos é possível estabelecer três diferentes grupos de clones: precoce, intermediário e tardio. O objetivo deste trabalho foi avaliar três grupos de clones de café Conilon, de diferentes ciclos de maturação, oriundos do banco de germoplasma do norte do Estado, para o estudo de seu comportamento, quanto a diferentes características agronômicas, bem como a estimativa de parâmetros genéticos, quando cultivados na região Sul do Estado. Foram avaliados 60 genótipos ao longo de quatro colheitas, na Fazenda Experimental de Bananal do Norte, do Incaper, situada em Pacotuba, Distrito de Cachoeiro do Itapemirim, no delineamento experimental em blocos casualizados, em quatro repetições, para as características agronômicas: ciclo de maturação, tamanho de frutos, uniformidade de maturação, cor dos frutos, produtividade, porte, vigor, índice de avaliação visual, ocorrência de ferrugem, cercosporiose, mancha manteigosa, seca de ramos, bicho mineiro e chochamento. Foram realizadas análises descritivas, análises de variância individuais e conjuntas, comparação entre as médias e a estimativa de parâmetros genéticos. Na maioria das características estudadas, há diferenças significativas entre os genótipos, que quando associado a altas estimativas de variância genética, coeficientes de variação genotípicos, índice de variação e coeficiente de determinação genotípica, indicam a existência de variabilidade genética entre os materiais. Foram obtidas médias deprodutividades acima de 60 sc ha-1, com genótipos produzindo até 188 sc ha-1, o que mostra que os materiais selecionados no norte podem apresentar elevado potencial produtivo nas condições do sul do Estado. Os dados obtidos não mostram tendência de superioridade de um grupo de materiais em relação ao outro, e são resultados importantes para os programas de melhoramento conduzidos no sul do Estado do Espírito Santo, gerando conhecimentos sobre a variabilidade genética da espécie e obtendo informações úteis na predição de ganhos genéticos, auxiliando na escolha dos materiais genéticos que poderão compor novas variedades clonais melhoradas
Coffee is one of the agribusinesses that have the largest social and economic importance. Brazil stands as the world biggest producer and the State of Espírito Santo is the second largest national producer of coffee, accounting for approximately 70% of the production of coffee Conilon in Brazil. In the State mentioned before, the species Coffea canephora, in particular the variety Conilon, is the most planted. There is a significant variability of the conditions of coffee production within this state: the region north of the Espírito Santo is responsible for most of the production, while the south still has a low yield. Due to the great importance of Conilon coffee in Espírito Santo, the Instituto Capixaba de Pesquisa Assistência Técnica e Extensão Rural (Incaper), established a breeding program since 1985, developing and releasing six varieties for the state. The characterization of varieties is done by the grouping of clones that show agronomic traits in common, by the time fruit ripens three different groups of clones are possible to establish: the early cycles, the intermediate and the late. The aim of this study was to generate biometric information about different characteristics of coffee, to study the isolated behavior of genotypes from different ripening cycles and to generate information on the productive capacity of selected materials in the northern state, when subjected to conditions of cultivation in the south. 60 genotypes were evaluated and over four crops grown in the Experimental Farm of Bananal do Norte, of Incaper, located in Pacotuba, a district of Cachoeiro do Itapemirim, in randomized block design, for the agronomic traits: ripening cycle, fruit size, ripening uniformity, fruit color, productivity, plant size, vigor, visual assessment index, occurrence of leaf rust, brown eye spot, blister spot, dieback, leaf miner and empty fruit locules. Descriptive analysis, analysis of individual and conjunct variance, means comparison and estimation of genetic parameters were made. In most traits, there are significant differences for genotypes, which when associated with high estimates of genetic variance, genotypic coefficient of variation, heritability, and variation index indicate the existence of genetic variability among the materials. The average yields obtained was above 60 sc ha-1, with genotypes producing up to 188 sc ha-1, showing that the materials selected in the north can have high yield potential under the conditions of the southern state. The data showed no trend of superiority of one group over another. The results are important for breeding programs conducted in the southern state of Espírito Santo, generating knowledge about the genetic variability and obtaining useful information in prediction of genetic gain, which will aid in the correct choice of genetic materials that can compose new clonal varieties
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Dassa-Girard, Michèle. "Etude comparee des activites phosphatasiques acides et des parametres hydriques foliaires de cultivars de mil (pennisetum americanum l. ) soumis a des contraintes hydriques." Paris 7, 1987. http://www.theses.fr/1987PA077048.
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Ce travail a porte sur trois cultivars de mil (pennisetum americanum l. ) cultives depuis de nombreuses annees dans des regions du burkina faso a pluviosite moyenne annuelle tres differenciee. Nous avons emis l'hypothese que ces cultivars presentaient des degres d'adaptation a la secheresse relies aux differentes contraintes climatiques de ces regions. Nous avons compare plusieurs criteres physiologiques dont certains semblent lies classiquement a la resistance a la secheresse
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Jordan, Marie-Odile. "Mise en place du systeme racinaire du mais : definition et caracterisation au champ et en conditions controlees des parametres descriptifs du systeme racinaire, construction de l'organigramme d'un modele cinetique." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13329.
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Une analyse bibliographique montre que si l'architecture des parties aeriennes est bien connue chez le mais, il n'en est pas de meme du systeme racinaire. Nous avons donc entrepris un travail de synthese a ce sujet. Dans la premiere partie de cette etude, les parametres descriptifs de la structure racinaire sont definis. Leur evolution au cours du cycle est ensuite caracterisee en conditions habituelles de culture, et, en rhizotrons. Quatre categories de racines primaires ont pu etre mises en evidence
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Mohamed, Nahla Abdel-Fattah Hemdan. "Irrigation systems." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/16977.
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In der Wintersaison 2005-2006 wurde ein Split-Split Plot-Design Feldversuch mit drei Wiederholungen für jede Behandlung von Kartoffeln, als Indikatorpflanze, unter den ariden Bedingungen der Kharga Oasis in der Westlichen Wüste von Ägypten durchgeführt. Drei Bewässerungslevel (100 %, 80 %, und 60 % of ETc) mit Tröpfchenbewässerung, zwei Mulchvarianten (Zuckerrübenabfall ohne und mit 24 ton ha-1) und 4 Kompostraten (0, 12, 24, und 36 ton ha-1) wurden getestet. Generell und als Ergebnis einer Regressionsanalyse der Versuchsvarianten ohne Kompost war die beste Variante die Tröpfchenbewässerung bei 80% ETc unabhängig ob gemulcht oder nicht gemulcht wurde. Andererseits die Variante mit 36 t Kompost und mit 24 t Mulch ergab die besten Ergebnisse bei 60% of ETc sowohl beim Ertrag und den Ertragskomponenten, bei den hydrophysikalischen Eigenschaften, bei der Bodenwasserretention, beim Wasserverbrauch, bei den Pflanzenkoeffizienten, der Wassernutzungseffizienz, der Düngernutzungseffizienz sowie beim Nettogewinn. Wird die Rate der Kompostgabe aber auf 24 ton ha-1 reduziert, die höchsten Nettogewinne bei der lokalen Vermarktung als auch signifikant beim Kartoffelexport werden erreicht.Under the arid condition of Kharga Oasis in the Western Desert of Egypt, split-split plot design field experiment with three replications for each treatment using potato as an indicator plant was carried out during the winter season 2005-2006. Three irrigation levels of water regime (100 %, 80 %, and 60 % of ETc) using drip irrigation system, two treatments of soil covering (sugar cane wastes at the rate of 0 and 24 ton /ha) and compost rates (0, 12, 24, and 36 ton ha-1) were tested. In general and as a result of the triple interaction among the studied treatments, using drip irrigation either with soil mulching or not, 80 % of ETc as a water regime was the best. On the other hand, reducing drip irrigation water level at 60% of ETc in mulched soil that was treated with 36 ton ha-1 of compost recorded the highest values yield and yield components, soil hydrophysical properties, soil water retention, water consumption, crop coefficients, water economy water use efficiency, fertilizer use efficiency, net profit. But reducing the compost rate to 24 ton ha-1 attained the highest net profit for local potato consumption and achieved the best significant net profit for exportation.
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Zbigniewicz, Maria W. "Plant composition, standing crop and environmental parameters in the estuary of the Churchill River, Manitoba." 1986. http://hdl.handle.net/1993/29959.
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Ballester, Berman Josep David. "Retrieval of biophysical parameters of agricultural crops using polarimetric sar interferometry." Doctoral thesis, 2001. http://hdl.handle.net/10045/9203.
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Ballester-Berman, J. David. "Retrieval of biophysical parameters of agricultural crops using polarimetric sar interferometry." Doctoral thesis, 2007. http://hdl.handle.net/10045/9203.
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KRÁL, Radim. "Hodnocení výnosových parametrů hybridního ozimého žita." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-395344.
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The main part of the thesis is evaluation of yield and qualitative parameters of hybrid winter rye. A small plot experiment was made at the Faculty of Agriculture of the University of South Bohemia in České Budějovice (380 m). The trial took place in two years: 2016/2017 and 2017/2018. The effect of sowing (early and late), seed quantity (standard - 2 MKS / ha and reduced - 1 MKS / ha), variety and year were evaluated in three varieties of hybrid rye (Cossani, Performer, Santini). To achieve the most accurate results, all 12 variants were sown in 4 replicates. From the qualitative parameters were determined: Falling number, volume weight, content of N substances. Concerning the yield, use of a standard seed rate (2 MKS / ha) was more stable, with an average yield increase of 0.64 t / ha. The most profitable was the Performer variety, which stood out with a consistently high falling number.
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Heinzel, Vanessa [Verfasser]. "Retrieval of biophysical parameters from multi-sensoral remote sensing data, assimilated into the crop growth model CERES-Wheat / vorgelegt von Vanessa Heinzel." 2008. http://d-nb.info/1000208192/34.
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Glas, Clara Gwendolin Luise. "Bedeutung klinischer und paraklinischer Parameter in Prä-, Peri- und Postnatalphase für die Diagnostik der Early-Onset Sepsis beim Neugeborenen." 2019. https://ul.qucosa.de/id/qucosa%3A70857.
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In dieser retrospektiven Pilotstudie wurde die Aussagekraft klinischer und paraklinischer Parameter in Prä-, Peri- und früher Postnatalphase für die Diagnostik der klinischen Early-Onset Sepsis beim Neugeborenen untersucht. Der postnatal innerhalb von drei Tagen beim Kind gemessene CRP-Wert mit einem Cut-off von 10 mg/l wurde für die Differenzierung klinische Sepsis / keine Sepsis herangezogen. Die Analyse der zwei nach CRP-Werten getrennten Kollektive erfolgte hinsichtlich verschiedener Faktoren (wie z.B. Kreislauf und Laborparameter der Mutter vor der Geburt bzw. Labor – und Kreislaufparameter des Kindes bis 96 h postnatal). In der Auswertung zeigen sich signifikante Unterschiede der einzeln betrachteten Variablen. In einer Multivarianzanalyse konnten keine statistisch relevanten Differenzen bestätigt werden, daher werden weiterführende, prospektive randomisierte Studien zur Evaluation dieses Ansatzes empfohlen. Aufgrund der hohen und signifikanten Unterschiede bei Einzelbetrachtung und der sehr frühen Verfügbarkeit können die mütterlichen Parameter CRP > 12,3 mg/l und Herzfrequenz > 76,5 Schläge pro Minute sowie die unmittelbar postnatal gemessenen kindlichen Laktatwerte > 3,55 mml/l jedoch als wichtige Indikatoren zur Identifikation von Kindern mit einer Early-Onset Sepsis empfohlen werden.
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Düring, Silvia. "Laborchemische und klinische Parameter als Marker der Krankheitsaktivität bei Morbus Crohn und Colitis ulcerosa." Doctoral thesis, 2019. http://hdl.handle.net/11858/00-1735-0000-002E-E617-0.
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Moila, Maserole Mavis. "Effect of arbuscular mycorrhizal fungi and different phosphorus rates on selected soil and growth parameters of two dry bean cultivars." Thesis, 2018. http://hdl.handle.net/10386/2449.
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Thesis (M.Sc. (Agriculture)) --University of Limpopo, 2018Dry bean is one of the most important cash crops and source of protein for small holder farmers. Low yields of dry bean are often reported to be associated with lack of inoculation (Arbuscular mycorrihizal fungi) of seeds prior to planting. Soil phosphorus (P) unavailability is one of the major factors limiting yield of dry bean. Field and Greenhouse experiments were conducted to investigate the response of dry bean cultivars to inoculation and phosphorus application under dry land farming conditions at the Syferkuil experimental farm of University of Limpopo. Both greenhouse and field experiments were carried out as a split-split plot arrangement in randomised complete block design with four replications. Main plot treatment comprised of two dry bean cultivars VIZ, red speckled bean and small white haricot. Arbuscular mycorrhizal fungi inoculation levels (inoculated and uninoculated) were assigned in the sub-plot whilst the sub-sub plot was applied with five phosphorus rates at 0, 20; 40; 60 and 80 kg/ ha using single superphosphate (10.5 % P). The data collected were subjected to analysis of variance using statistical software (ANOVA) STATISTIX 10.0.Dry bean cultivars (red speckled bean and small white haricot bean) were evaluated in a field experiment for their growth, nodulation and yield responses to AM fungi inoculation and different rates of P fertiliser. The results revealed that the red speckled bean had higher number of nodules (45 %), stem diameter 26.96 cm and higher leaf area of 21.05 cm2 as compared to small white haricot bean. The application of P at the rate of 40 kg/ha produced higher grain yield of 743.47 kg/ha as compared to small white haricot bean with 572 kg/ha. The growth parameters such as yield, soil chemical and biological properties did not significantly respond to inoculation (P≤0.05). Red speckled bean and small white haricot bean were evaluated in greenhouse experiment for their growth and nodulation on inoculation and phosphorus fertilizer treatment In the greenhouse experiment phosphorus fertilizer rate showed significant effect on chlorophyll content, leaf fresh and dry weight. The dry bean cultivars were found to be significant to number of nodules, plant vigour and root dry weight. The red speckled bean showed higher growth parameters as compared to small white haricot bean. The application of Arbuscular mycorrhizal fungi (AM fungi) at varying rates did not have any significant influence on all parameters measured in the experiment on both trials. The study needs to be repeated after 4 to 5 years. The findings of this study concluded that P should be applied at the rate of 40 kg P/ha in order to improve the production of dry bean.
NRF (National Research Foundation)
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Raimi, Adekunle. "Quality assessment of commercial biofertilisers and the awareness of smallholder farmers in Gauteng Province, South Africa." Diss., 2018. http://hdl.handle.net/10500/24955.
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This study aimed to evaluate commercial biofertiliser quality and awareness amongst smallholder farmers in Gauteng Province, South Africa. Sixty-seven smallholder farmers were interviewed in Gauteng Province by using a survey method, while the physicochemical and microbiological properties of 13 biofertilisers were evaluated using laboratory experiments. The results showed that awareness and use of biofertiliser are very poor, with 96% of the smallholder farmers surveyed not having biofertiliser knowledge. Furthermore, the products lack basic quality parameters: 54% contained no biofertiliser strain while all the products contained microbial contaminants. The pH, moisture content and viable microbial densities were below the acceptable standards for some of the products. Two fungal and 58 bacterial operational taxonomic units were obtained from the 16S rRNA Sanger sequences while 5 791 OTUs were obtained from the Illumina Miseq system. Approximately 40%, 41% and 59% of the isolates were positive for nitrogen-fixation, siderophore production and phosphorous solubilisation. Overall, there is a need to improve awareness amongst farmers and promote good-quality biofertiliser products for increased crop productivity.Environmental Sciences
M. Sc. (Environmental Science)