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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Comparison of Variable Rate Prescriptions and Optimum Seeding Rate in Soybean [Glycine max (L.) Merr] and the Impact of Soybean Seeding Rate on Combine Fuel Use and Grain Loss at Harvest

Hamman, William Patrick 26 August 2019 (has links)
No description available.
322

Wireless Sensor-based Agricultural Monitoring System

Zografos, Alexandros January 2014 (has links)
Today energy resources are becoming scarcer and therefore more valuable. In conjunction with the population growth over last century, the need for finding new, more efficient, and sustainable methods of agricultural cultivation and food production has become more critical. To facilitate this process, we are designing, building, and evaluating a system for precision agriculture which provides farmers with useful data about the soil, the water supply, and the general condition of their fields in a user friendly, easily accessible manner. Our system aims to make cultivation and irrigation more efficient as the farmer is able to make better informed decisions and thus save time and resources. The diversity of location and climatic effects upon agricultural cultivation, along with other environmental parameters over time makes the farmer’s decision-making process more complicated and requires additional empirical knowledge. Applying wireless sensor networks for monitoring environmental parameters and combining this information with a user-customized web service may enable farmers to exploit their knowledge in an efficient way in order to extract the best results from their agricultural cultivation. The system can scale based on each farmer’s demands and the resulting ensemble of collected information may represent a valuable resource for future use, in addition to its use for real-time decision making. The design of the precision agriculture system contains a prototype solution regarding the sensor platform and a customizable service that can be utilized in different ways and by several entities. / Idag när energiresurser blir allt knappare och knappare blir de även mer värdefulla. I samband med befolkningstillväxten under förra århundradet har behovet av att hitta nya, mer effektiva och hållbara metoder inom jordbruket och livsmedelsproduktion blivit av allt större vikt. . För att underlätta denna process har vi designat, byggt och utvärderat ett system för precisionsjordbruk som ger bönder mer användbara data om jorden, vattenförsörjning och det allmänna tillståndet i sina områden på ett användarvänligt och lättillgängligt sätt. Vårt system syftar till att göra odling och bevattning effektivare då bonden kan fatta bättre underbyggda beslut och därmed spara tid och resurser. Mångfalden av läget och jordbrukets klimatpåverkan, tillsammans med andra miljöparametrar över tiden gör bondens beslutsprocess mer komplicerad än tidigare och kräver ytterligare empirisk kunskap. Att tillämpa trådlösa sensornätverk för övervakning av dessa parametrar och att presentera? denna information med en användarvänlig skräddarsydd webbtjänst kan göra det möjligt för jordbrukare att utnyttja på ett effektivt sätt nåde bästa resultaten från sitt jordbruk. Systemet kan skala utifrån varje bondes krav och den insamlade data kan utgöra en värdefull resurs för ett framtida jordbruk, utöver dess användning för dagens bondes beslut. Utformningen av systemet för precisionsjordbruk innehåller en prototyplösning avseende sensorplattformen och en anpassningsbar tjänst som kan användas på olika sätt och av flera enheter.
323

Sources of Spatial Soil Variability and Weed Seedbank Data for Variable-Rate Applications of Residual Herbicides

Rose V Vagedes (16033898) 09 June 2023 (has links)
<p>Soil residual herbicides are a vital component of the best management practices (BMPs), to provide early-season weed control in most cropping systems. The availability of a biologically effective dose of a soil residual herbicide in the soil solution is dependent on several soil parameters including soil texture, organic matter (OM), and pH.  Soil residual herbicides are currently applied as a uniform application rate over an individual field; yet soil properties can vary spatially within agricultural fields. Therefore, areas of the field are being over- and under-applied when using a uniform application rate. By integrating variable-rate (VR) technology with soil residual herbicides, the correct rate could be applied based on the intra-field soil variability. However, the extent of spatial soil variability within a field and the impact on herbicide application rates has not been well-characterized to inform whether soil residual herbicide applications should move towards variable rate applications. Therefore, the objectives of this research were to 1) determine the extent of intra-field variability of soil texture and organic matter in ten commercial Indiana fields, 2) quantify the reliability of five different combinations of spatial soil data sources, 3) determine the impact of soil sample intensity on map development and the classification accuracy for VR applications of soil residual herbicides, 4) quantify the impact of VR herbicide application on the total amount and spatial accuracy of herbicide applied according to product labels, and 5) determine if the intensive spatial characterization of soil properties is related to weed seedbank abundance and species richness to improve predictive weed management using soil residual herbicides.</p> <p><br></p> <p>Commercial soil data was generated by intensively collecting 60 soil samples in a stratified random sampling pattern in 10 agricultural fields across Indiana. Analysis of this data from commercial fields confirmed inherent field variability that would benefit from multiple management zones according to the labeled rate structures of pendimethalin, s-metolachlor, and metribuzin. Therefore, further research was conducted to determine an accurate and reliable method to delineate the fields into management zones for variable-rate residual herbicide applications based on the spatial soil variability and herbicide labels. </p> <p><br></p> <p>A modified Monte Carlo cross-validation method was used to determine the best source of spatial soil data and sampling intensity for delineating management zones for variable-rate applications of pendimethalin, s- metolachlor, and metribuzin. These sources of spatial soil data included: Soil Survey Geographic database (SSURGO) data, intensive soil samples, electrical resistivity sensors, and implement mounted optical reflectance sensors using VNIR reflectance spectroscopy. The mean management zone classification accuracy for maps developed from soil samples with and without electrical conductivity was similar for 75% of all maps developed across each field, herbicide, and sampling intensity. The method of using soil sampling data combined with electrical conductivity (SSEC) maps was most frequently the top performing source of spatial soil data. The most reliable sampling intensity was one sample per hectare which resulted in lower root mean squared error (RMSE) OM values, higher management zone classification accuracy, and more reliable predictions for the number of management zones within each field. </p> <p><br></p> <p>Using VR maps developed from SSEC with one sample per hectare sampling intensity, additional research was conducted to compare the amount of herbicide and field area that was over-or under-applied with a uniform application rate compared to a VR application for 10 corn and soybean residual herbicides. Although research from our previous study documented that spatial soil variability was extensive enough to require two or more management zones for all fields, the same labeled herbicide dose defined for multiple soil conditions led to 20% of all maps not requiring a variable rate application (VRA). Additionally, no difference was shown in the total amount applied of herbicide in an individual field between a variable and uniform application rate for all herbicides. Nonetheless, nearly half of all VR maps had 10% or more of the field area misapplied with a uniform application rate and justifies further research to determine if the proper placement of residual herbicide adds value through increased weed control in the field areas being under-applied. </p> <p><br></p> <p>Similar to soil residual herbicides, weed seedbank abundance and species richness were impacted by the variable soil conditions present within the field area. The seedbanks favor the establishment in areas of the field that promote vigorous germination, growth, and reproduction next to the competing crop. Therefore, soil sampling and weed seedbank greenhouse grow-outs were conducted in four fields to gain a better understanding in the relationship between the spatial soil and weed seedbank variability. All weed seedbank characteristics were shown to be spatially aggregated. Even though no individual or combination of soil parameters consistently explained the variability of weed seedbank abundance, species richness, or individual weed species across all four fields. However, clay content was the most persistent soil parameter to negatively impact (lower seedbank values) the soil weed seedbank.</p> <p><br></p> <p>Further field studies should be conducted across multiple sites to determine if variable-rate residual herbicide applications aid farmers by reducing the risk of crop injury in over-applied field areas and increased weed control in the areas being under-applied.  These studies should also access whether earlier emergence and/or greater weed densities occur in field areas receiving sublethal herbicide doses compared to areas receiving the optimal application rate. Additional research should investigate the utility of VR residual herbicide applications when tank-mixing multiple products during an application. Particularly, when the soil parameters used for selecting the herbicide rate are not defined the same across herbicide labels </p>
324

PhenoBee: Drone-Based Robot for Advanced Field Proximal Phenotyping in Agriculture

Ziling Chen (8810570) 19 December 2023 (has links)
<p dir="ltr">The increasing global need for food security and sustainable agriculture underscores the urgency of advancing field phenotyping for enhanced plant breeding and crop management. Soybean, a major global protein source, is at the forefront of these advancements. Proximal sensing in soybean phenotyping offers a higher signal-to-noise ratio and resolution but has been underutilized in large-scale field applications due to low throughput and high labor costs. Moreover, there is an absence of automated solutions for in vivo proximal phenotyping of dicot plants. This thesis addresses these gaps by introducing a comprehensive, technologically sophisticated approach to modern field phenotyping.</p><p dir="ltr">Fully Automated Proximal Hyperspectral Imaging System: The first chapter presents the development of a cutting-edge hyperspectral imaging system integrated with a robotic arm. This system surpasses traditional imaging limitations, providing enhanced close-range data for accurate plant health assessment.</p><p dir="ltr">Robust Leaf Pose Estimation: The second chapter discusses the application of deep learning for accurate leaf pose estimation. This advancement is crucial for in-depth plant analysis, fostering better insights into plant health and growth, thereby contributing to increased crop yield and disease resistance.</p><p dir="ltr">PhenoBee – A Drone Mobility Platform: The third chapter introduces 'PhenoBee,' a dronebased platform designed for extensive field phenotyping. This innovative technology significantly broadens the capabilities of field data collection, showcasing its viability for widespread aerial phenotyping.</p><p dir="ltr">Adaptive Sampling for Dynamic Waypoint Planning: The final chapter details an adaptive sampling algorithm for efficient, real-time waypoint planning. This strategic approach enhances field scouting efficiency and precision, ensuring optimal data acquisition.</p><p dir="ltr">By integrating deep learning, robotic automation, aerial mobility, and intelligent sampling algorithms, the proposed solution revolutionizes the adaptation of in vivo proximal phenotyping on a large scale. The findings of this study highlight the potential to automate agriculture activities with high scalability and identify nutrient deficiencies, diseases, and chemical damage in crops earlier, thereby preventing yield loss, improving food quality, and expediting the development of agricultural products. Collectively, these advancements pave the way for more effective and efficient plant breeding and crop management, directly contributing to the enhancement of global food production systems. This study not only addresses current limitations in field phenotyping but also sets a new standard for technological innovation in agriculture.</p>
325

An analysis of precision agriculture in the South African summer grain producing areas / Hendriks J.

Hendriks, Joseph January 2011 (has links)
Both globally and locally, agriculture faces ever increasing challenges such as high input costs, strict environmental laws, decrease in land for cultivation and an increase in demand due to the growing global population. Profitability and sustainability requires more effective production systems. Precision agriculture is identified as such a system and is built upon a system approach that aims to restructure the total system of agriculture towards low input, high efficiency and sustainable agriculture. The aim of this study was to analyse the state of precision agriculture in the summer grain producing areas of South Africa, specifically the North West and Free State provinces. In order to achieve this, a literature study was conducted. During the literature study the term ‘precision agriculture’ was defined and discussed. The precision agriculture cycle and its components were explained and benefits of precision agriculture were identified. The literature study was concluded with identifying and discussing the most widely used and most beneficial technologies as well as reasons for slow adoption. Findings from the literature study were used to investigate the state of precision agriculture locally. In order to achieve this, a quantitative approach was used and information was collected by means of an empirical study using a questionnaire. Questionnaires were distributed to farmers using selling agents of an agricultural company that is well represented in the targeted areas. The data was then statistically analysed. The survey showed that only 52% of summer grain producing farmers in the North West and Free State provinces of South Africa practises precision agriculture as defined in the v literature study. The study also revealed that the majority of precision agriculture farmers are over the age of 40, have more than 16 years of farming experience, are well educated, cultivate more than 1,000 hectares and uses none or little irrigation. The most commonly used precision agriculture technologies were grid soil sampling and yield monitors. The perception among most of the farmers was that precision technologies are not very affordable, not easily available and that it lacks proper testing with regards to efficiency. The group of summer grain–producing farmers that have correctly implemented precision agriculture as per definition stated that the benefits they derived from precision technologies include reduction in input costs, increased outputs and improved management skills. Too high implementation costs and technologies not providing enough benefits were among the main reasons farmers do not implement precision agriculture. It was concluded that a significant effort and amount of work is needed to increase the use of precision agriculture among summer grain–producing farmers in the targeted areas. A consolidated effort from government, agricultural institutions and agricultural companies will be needed to achieve this goal. Implementing precision agriculture as a system will require education (from primary to tertiary institutions) and improved marketing strategies. Only then will precision technologies be able to help meet the future demands placed on the agriculture sector. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.
326

An analysis of precision agriculture in the South African summer grain producing areas / Hendriks J.

Hendriks, Joseph January 2011 (has links)
Both globally and locally, agriculture faces ever increasing challenges such as high input costs, strict environmental laws, decrease in land for cultivation and an increase in demand due to the growing global population. Profitability and sustainability requires more effective production systems. Precision agriculture is identified as such a system and is built upon a system approach that aims to restructure the total system of agriculture towards low input, high efficiency and sustainable agriculture. The aim of this study was to analyse the state of precision agriculture in the summer grain producing areas of South Africa, specifically the North West and Free State provinces. In order to achieve this, a literature study was conducted. During the literature study the term ‘precision agriculture’ was defined and discussed. The precision agriculture cycle and its components were explained and benefits of precision agriculture were identified. The literature study was concluded with identifying and discussing the most widely used and most beneficial technologies as well as reasons for slow adoption. Findings from the literature study were used to investigate the state of precision agriculture locally. In order to achieve this, a quantitative approach was used and information was collected by means of an empirical study using a questionnaire. Questionnaires were distributed to farmers using selling agents of an agricultural company that is well represented in the targeted areas. The data was then statistically analysed. The survey showed that only 52% of summer grain producing farmers in the North West and Free State provinces of South Africa practises precision agriculture as defined in the v literature study. The study also revealed that the majority of precision agriculture farmers are over the age of 40, have more than 16 years of farming experience, are well educated, cultivate more than 1,000 hectares and uses none or little irrigation. The most commonly used precision agriculture technologies were grid soil sampling and yield monitors. The perception among most of the farmers was that precision technologies are not very affordable, not easily available and that it lacks proper testing with regards to efficiency. The group of summer grain–producing farmers that have correctly implemented precision agriculture as per definition stated that the benefits they derived from precision technologies include reduction in input costs, increased outputs and improved management skills. Too high implementation costs and technologies not providing enough benefits were among the main reasons farmers do not implement precision agriculture. It was concluded that a significant effort and amount of work is needed to increase the use of precision agriculture among summer grain–producing farmers in the targeted areas. A consolidated effort from government, agricultural institutions and agricultural companies will be needed to achieve this goal. Implementing precision agriculture as a system will require education (from primary to tertiary institutions) and improved marketing strategies. Only then will precision technologies be able to help meet the future demands placed on the agriculture sector. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.
327

UAV Routing Protocol (URP) for crop health management / UAV Routing Protocol (URP) pour la gestion de la santé des cultures

Mohammad, Ammad Uddin 19 December 2017 (has links)
Les réseaux de capteurs sans fil sont maintenant un moyen crédible de collecte de données sur les cultures. L'installation d'une structure de communication fixe pour relayer les données surveillées depuis la tête de grappe jusqu'à sa destination finale peut être soit impraticable en raison de la topologie du terrain, soit prohibitive en raison du coût initial élevé. Une solution plausible consiste à utiliser des véhicules aériens sans pilote (UAV) comme moyen alternatif de collecte de données et de contrôle de supervision limité de l'état des détecteurs. Dans cet article, nous considérons le cas des parcelles agricoles disjointes comprenant chacune des grappes de capteurs, organisées de manière prédéterminée en fonction des objectifs d'élevage. Cette recherche vise à trouver une solution optimale pour la recherche de UAV et la collecte de données à partir de tous les capteurs installés dans un champ de culture. En outre, le protocole de routage des capteurs tiendra compte d'un compromis entre la gestion de l'énergie et les frais généraux de diffusion des données. Le système proposé est évalué en utilisant un modèle simulé et il devrait trouver une classe parmi toutes les sous-considérations. / Wireless sensor networks are now a credible means for crop data collection. The installation of a fixed communication structure to relay the monitored data from the cluster head to its final destination can either be impractical because of land topology or prohibitive due to high initial cost. A plausible solution is to use Unmanned Aerial Vehicles (UAV) as an alternative means for both data collection and limited supervisory control of sensors status. In this paper, we consider the case of disjoint farming parcels each including clusters of sensors, organized in a predetermined way according to farming objectives. This research focuses to drive an optimal solution for UAV search and data gathering from all sensors installed in a crop field. Furthermore, the sensor routing protocol will take into account a tradeoff between energy management and data dissemination overhead.The proposed system is evaluated by using a simulated model and it should find out a class among all under consideration.
328

Proposta de interconexão do padrão ISO 11783 com redes de sensores sem fio padrão ZigBee. / A proposal for interconnection between ISO 11783 standard network and ZigBee wireless sensor networks.

Barros, Marcelo Freire de 23 November 2010 (has links)
Entre os avanços tecnológicos que visam recuperar o trato da variabilidade espacial e temporal nas culturas agrícolas está a Agricultura de Precisão que busca, além de outros benefícios, melhorar o aproveitamento dos insumos aplicados e a rodutividade, e reduzir o custo de produção e o impacto ambiental causado pelo excesso desses insumos. Para alcançar estes benefícios, recursos de tecnologia da informação e comunicação estão disponíveis em equipamentos agrícolas, tais como sistemas computacionais, sistemas de comunicação de dados sem fio, orientação por satélite por meio dos sistemas de posicionamento global e redes ISO 11783. Também as Redes de Sensores Sem Fio têm sido introduzidas para monitoração do ambiente agrícola. Acredita-se que o desempenho dessas tecnologias possa ser melhorado com a interconexão de ambas as redes, de modo que os dados dos sensores possam ser coletados diretamente pelo computador embarcado no veículo, a partir do instante que este entre no alcance do sinal dos sensores. Neste contexto, este trabalho tem por objetivo propor e demonstrar a viabilidade da interconexão dessas duas redes dentro do contexto da Agricultura de Precisão. Apoiando-se em pesquisa bibliográfica, realizou-se uma comparação entre os modelos ISO/OSI de ambas as redes e identificou-se quais dispositvos de interconexão seriam mais adequados, propondo-se, então, a interconexão. Para demonstrar a sua viabilidade à Agricultura de Precisão, desenvolveu-se um simulador que permitiu realizar um grande número de simulações que consideraram mais de sessenta cenários distintos. Os resultados foram apresentados sob a forma de gráficos, os quais foram analisados considerando-se as limitações impostas por uma aplicação agrícola. Da análise pôde-se concluir que há viabilidade na interconcxão de forma que unidades computacionais ISO 11783 recebam, em tempo real, dados do ambiente obtidos de Redes de Sensores Sem Fio. / Precision Agriculture is one of the technological advances used to recoup the treatment of spatial and temporal variability in agricultural crops. Besides other benefits, it tries to improve the exploitation of applied inputs, improve the productivity and reduce production cost as well as lessen the impact on environment caused by excess of input. To achieve these benefits, information and communication technology are available in agricultural equipment such as computational systems, wireless communication, satellite orientation by the global positioning systems and ISO 11783 networks. Recently, Wireless Sensor Network has been introduced for agricultural environment monitoration. It is believed that the performance of these technologies can be improved with the interconnection of both networks. In this way, sensor data can be collected by the computer embedded in the vehicle, at the moment that the vehicle goes into the sensor signal area. The objective of this work is to propose and demonstrate the viability of this interconnection between the networks ISO 11783 and WSN in the Precision Agriculture context. Based on bibliographical research, both network ISO/OSI models were compared, the most adequate interconnection devices were identified and the interconnection was proposed. To demonstrate the interconnection viality in Precision Agriculture systems a simulator was denveloped which permited hundreds of simulations to be done in dozens of distint scenes. The results were shown in graphs which were analysed considering the agriculture application limitations. From this analisis, it was possible to conclude that the interconnection is viable, so that ISO 11783 computation units receive environmental data obtained by the Wireless Sensor Network in real time.
329

Alocação de tarefas para a coordenação de robôs heterogêneos aplicados a agricultura de precisão / Task allocation for the coordination heterogeneous robots applied to precision agriculture

Fraccaroli, Eduardo Sacogne 05 December 2017 (has links)
O Brasil é uma referência mundial na produção e exportação de citros, entretanto esse cultivo pode sofrer diversos problemas e perdas de produtividade por motivos diversos, como por exemplo, pragas. Para reduzir os riscos e perdas, torna-se interessante o uso de sistemas automatizados de monitoramento, justificando a necessidade de realizar a coleta de dados para determinar diversos fatores. Determinadas plantações, como a de citros, não podem ser monitoradas somente via solo ou somente via imagens aéreas, tornando necessário mesclar ambas as abordagens de acordo com o parâmetro a ser monitorado. Para a realização desse monitoramento devem ser utilizados robôs com habilidades distintas, robôs aéreos e robôs terrestres. Assim, é preciso designar as tarefas que cada robô realizará e também coordenar todos os robôs durante a execução do sistema como um todo, visando otimizar o processo de coleta de dados. Esse problema pode ser analisado e modelado como um problema de alocação de tarefas para robôs (Multi-Robot Task Allocation (MRTA)). Para resolver esse problema propõe-se um framework baseado em técnicas de cobertura de conjuntos e em mecanismo de mercado baseado em leilão. Teste simulados são realizados e demonstram que a presente proposta cumpre o papel na alocação das tarefas aos robôs. Além disso, visando a aplicação da solução proposta é projetado e desenvolvido uma plataforma robótica aérea (quadrirotor) de baixo custo utilizando peças prototipadas. Para o controle de estabilidade dessa plataforma, propõe-se um modelo matemático de acordo com os parâmetros inerciais do quadrirotor. Esse quadrirotor é utilizado em diversas aplicações reais, mostrando que o projeto desenvolvido pode ser reproduzido e destinado a execução de tarefas reais, como por exemplo a coleta de dados na agricultura de precisão. / Brazil is a world reference in the production and export of citrus, although this crop can suffer several problems and losses of productivity for diverse reasons, as for example, pests. In order to reduce risks and losses, it is interesting to use automated monitoring systems, justifying the need to perform data collection to determine several factors. Certain plantations, such as citrus plantations, can not be monitored only via soil or only via aerial images, making it necessary to merge both approaches according to the parameter to be monitored. To perform this monitoring, robots with different abilities, such asunmanned aerial vehicle (UAV) and unmanned ground vehicle (UCV) should be used. Therefore, it is necessary to assign the tasks that each robot will perform and also to coordinate all the robots during the execution of the system as a whole, in order to optimize the process of data collection. The problem can be studied and modeled as a task allocation problem for robots (MRTA). To solve this problem we propose a framework based set covering techniques and auction-based market mechanism. Simulated tests are performed and demonstrate that the present proposal fulfills the role in assigning tasks to robots. In addition, aiming at the application of the proposed solution is designed and developed a low cost aerial robotic platform (quadrirotor) which use prototyped parts. This quadrirotor is used in several real applications, showing that the developed project can be reproduced and destined to perform real tasks, such as data collection in precision agriculture.
330

Mapeamento da variabilidade espacial das plantas daninhas com a utilização de ferramentas da agricultura de precisão. / Mapping weed spatial variability using precision farming tools.

Shiratsuchi, Luciano Shozo 04 December 2001 (has links)
Tradicionalmente o manejo das plantas daninhas é realizado levando-se em consideração a infestação média destas plantas nas áreas agrícolas; sendo então adotadas estratégias de manejo de forma homogênea em toda a área. Porém, as plantas daninhas não se distribuem uniformemente, sendo comum o comportamento contagioso, formando manchas ou "reboleiras". No entanto, a localização e mapeamento de diferentes infestações são tarefas difíceis de serem executadas em larga escala e requerem metodologias adequadas. Desta forma, métodos de determinação dessa variabilidade espacial necessitam de melhores esclarecimentos e estudos científicos. Com o objetivo de estudar o comportamento da variabilidade espacial das plantas daninhas e seu respectivo banco de sementes com a utilização de ferramentas da agricultura de precisão, foram realizados quatro experimentos para avaliar esta variabilidade espacial e temporal e analisar a potencialidade que a mesma pode proporcionar para o manejo racional das plantas daninhas, principalmente a possibilidade da aplicação localizada de herbicidas. O primeiro experimento consistiu do mapeamento do banco de sementes ao longo de dois anos consecutivos no intuito de comparar sua variabilidade espacial com a flora emergente. Concluiu-se que existe uma correlação entre o banco de sementes e a flora emergente e entre bancos de sementes de anos consecutivos, principalmente para as plantas daninhas Ageratum conyzoides L. e Commelina benghalensis L.. Analisando a dependência espacial, foi detectada uma dependência entre 7 e 15 m para o banco de sementes e a flora emergente. Os mapas gerados mostraram uma grande variabilidade espacial das plantas daninhas, sendo observadas algumas tendências de estabilidade ao longo do tempo. No segundo experimento foram feitos dois mapeamentos da infestação da planta Panicum maximum Jacq., um durante a colheita da cultura de milho e outro após a colheita, para fins de aferição do método de mapeamento realizado durante a colheita. Foi constatada uma subestimação de 6% da área infestada pelo método de mapeamento durante a colheita, quando este foi comparado com o caminhamento numa grade regular após a colheita. Os dois métodos foram coincidentes em 45% das áreas marcadas. O terceiro experimento consistiu de uma avaliação da eficácia da aplicação localizada de herbicidas pós-emergentes na cultura da soja, baseada em mapas de infestação das plantas daninhas. Para isto foi feito uma amostragem numa grade de 6 x 6 m e, baseado na infestação em cada célula, foi pulverizado duas doses de herbicidas pós-emergentes dependendo da infestação de cada local. Foi obtida uma economia de produto da ordem de 18 e 44%, sendo a eficácia similar à aplicação convencional utilizando dose única e pulverização uniforme em área total. No quarto experimento foi realizada uma pulverização localizada de herbicida pré-emergente baseada no mapeamento prévio do banco de sementes das plantas daninhas; sendo verificado uma eficácia igual à convencional e uma economia de 22% de produto herbicida. Portanto, técnicas de mapeamento da variabilidade espacial das plantas daninhas são importantes ferramentas para que melhores decisões sejam tomadas dentro dos sistemas de produção agrícola, sendo de extrema urgência um maior conhecimento e embasamento técnico-científico de técnicas agronômicas que considerem esta variabilidade espacial. / Traditionally the weed management has been done considering the overall weed infestation in the whole field and then herbicides are sprayed according to a single weed control recommendation for the field. But weeds are not uniformly distributed and normally have clumped populations showing weed patches presenting high spatial variability. This nature of the weed populations can be mapped, and so it can help the decisions associated with weed management on agricultural systems. However, localization and mapping of the weed clusters are very difficult tasks in large areas, and require adequate methodology. Therefore, determination method of this weed infestation variability in space must be scientifically studied. With the objective of studying the weed spatial variability and temporal behavior of weed seedlings infestations and their respective seed banks, four experiments were conducted to evaluate the spatial temporal behavior of the weeds and the potential of weed mapping technology could bring to the rational weed management. The aim of the first experiment was to evaluate the spatial temporal behavior of the weed seedlings and their respective seed banks using the mapping technology. A grid sampling was used to understand the seedling and seed bank behavior in the space and time. Correlations using "Spearman rank" test were observed, mainly in Ageratum conyzoides L. and Commelina benghalensis L. The spatial dependence was noted between 7 and 15 m for the weed seedlings and seed banks. The weed maps showed that the weeds have a high spatial variability making patches with some temporal stability. In the second experiment two weed surveys were done with the objective of mapping Panicum maximum Jacq. during and after corn harvest. The grid sampling method after harvest corn was used to evaluate the harvest mapping method. It was underestimated about 6% of the weed infestation using the harvest mapping method when it was compared with the grid sampling method after corn harvest. In this experiment the harvest mapping method had just 45% of efficiency in recording weed infestation areas. The third experiment was done in order to analyzed the post emergence herbicide efficacy in soybeans based on weed maps constructed with grid sampling mapping. The weed seedling was counted in a 6 by 6 m grid and, based on weed infestation of each grid, it was sprayed two post emergence herbicide rates according to the weed infestation. It was saved 18 to 44% of herbicides compared to broadcast application with the same herbicide efficacy. In the fourth experiment a pre emergence herbicide application was carried out in soybeans crop based on weed seed bank map and, it was observed that the site-specific application had similar efficacy saving 22% of herbicides. So, the weed mapping technology is an important tool to bear on decisions associated with crop production, and it is a priority for the implementation of this technology multiple sources of scientific knowledge in weed biology and management regarding to the weed spatial variability.

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