Development of a sensor-based harrowing system using digital image analysis to achieve a uniform weed control selectivity in cereals

Using intelligent sensor technology for site-specific weed control can increase the efficacy of traditional weed control implements. Several scientific studies successfully used intelligent sensors for automatic harrow control by taking many different parameters into account such as weed density, soil resistance factor, and plant growth. However, none of the systems was practically feasible because these factors made the control system too complex and unattractive for farmers. Defining only one parameter (crop soil cover) instead of many provides a new and simple approach which was investigated in this work. The first scientific publication focuses on the development, practical implementation and testing of the automatic harrow control system. Two RGB-cameras were mounted before and after the harrow and constantly monitored crop cover. The CSC was then computed out of these resulting images. The image analysis, decision support system and automatic control of harrowing intensity by hydraulic adjustment of the tine angle were installed on a controller which was mounted on the harrow. Eight field experiments were carried out in spring cereals. Mode of harrowing intensity was changed in four experiments by speed, number of passes and tine angle. Each mode was varied in five intensities. In four experiments, only the intensity of harrowing was changed. Modes of intensity were not significantly different among each other. However, intensity had significant effects on WCE and CSC. Cereal plants recovered well from 10% CSC, and selectivity was in the constant range at 10% CSC. Therefore, 10% CSC was the threshold for the decision algorithm. If the actual CSC was below 10% CSC, intensity was increased. If the actual CSC was higher than 10%, intensity was decreased. The new system was tested in an additional field study. Threshold values for CSC were set at 10%, 30% and 60%. Automatic tine angle adjustment precisely realised the three different CSC values with variations of 1.5% to 3%. The next publication discussed and assessed the site-specific field adaptation of the development in cereals. In 2020, three field experiments were conducted in winter wheat and spring oats to investigate the response of the weed control efficacy and the crop to different harrowing intensities, in southwest Germany. In all experiments, six levels of CSC were tested. Each experiment contained an untreated control and an herbicide treatment as a comparison to the harrowing treatments. The results showed an increase in the WCE with an increasing CSC threshold. Difficult-to-control weed species such as Cirsium arvense (L.) and Galium aparine (L.) were best controlled with a CSC threshold of 70%. With a CSC threshold of 20% it was possible to control up to 98% of Thlaspi arvense (L.) The highest crop biomass, grain yield, and selectivity were achieved with an CSC threshold of 2025% at all trial locations. With this harrowing intensity, grain yields were higher than in the herbicide control plots and a WCE of 6898% was achieved. The last scientific article compares pairwise a conventional harrow intensity with automatic sensor-based harrowing intensity. Five field experiments in cereals were conducted at three locations in southwestern Germany in 2019 and 2020 to investigate if camera-based harrowing resulted in a more homogenous CSC and higher WCE, biomass, and crop grain yield than a conventional harrow with a constant intensity across the whole plot. For this purpose, pairwise comparisons of three fixed harrowing intensities (10 °, 40 °, and 70 ° tine angle) and three predefined CSC thresholds (CSC of 10%, 20%, and 60%) were realized in randomized complete block designs. Camera-based adjustment of the intensity resulted in 6-16% less standard deviation variation of CSC compared to fixed settings of tine angle. Crop density, WCE, crop biomass and grain yield were significantly higher for camera-based harrowing than for conventional harrowing. WCE and yields of all automatic adjusted harrowing treatments were equal to the herbicide control plots. In this PhD-thesis, a sensor-based harrow was developed and successfully investigated as an alternative to conventional herbicide application in cereals. A permanent, equal replacement of chemical weed control in arable farming systems can only be achieved using modern, sensor-based mechanical weed control approaches. Therefore, the efficacy of the mechanical weed control method can be improved and increased continuously. It has been shown that the precise adjustment of mechanical weed control methods to site-specific weed conditions allows similar WCE results as an herbicide application without causing yield losses. These findings contribute towards modern plant protection strategies to reduce the herbicide use and to establish the acceptance of technical progress in society.Durch den Einsatz von Sensortechnik bei der mechanischen Unkrautbekämpfung, kann die Effektivität und Auslastung der Maschinen gesteigert werden. Die automatische Anpassung der Striegelintensität durch Sensoren, wurde bereits in zahlreichen wissenschaftlichen Arbeiten untersucht, jedoch hat sich keines der Systeme auf dem Markt etablieren können. Bei diesen Striegel-Prototypen wurden verschiedenste Parameter wie beispielsweise die Unkrautdichte, der Bodenwiderstand oder das Pflanzenwachstum berücksichtigt. Allerdings konnten bisherige Systeme nur einzelne Einflussfaktoren berücksichtigen und sie eigneten sich daher nicht für den großflächigen praktischen Einsatz. Dieses Problem kann umgangen werden, wenn der Fokus auf die gezielte Verschüttung von Unkräutern und Kulturpflanze (CSC) gerichtet wird. Diese neue Vorgehensweise bei der sensorgesteuerten Striegeltechnik bietet einen einfachen und zugleich umfangreichen Ansatz, der alle Pflanzen-, Boden- und Unkrautrelevanten Parameter berücksichtigt und abdeckt. Die erste wissenschaftliche Veröffentlichung befasst sich mit der Entwicklung und einem praktischen Test der automatischen Striegelsteuerung. Hierzu wurden zwei RGB-Kameras vor und hinter dem Striegel angebracht, um den tatsächlichen CSC-Wert zu messen, berechnen und mit einem vorgegebenen CSC-Schwellenwert abgleichen zu können. Die Ansteuerung erfolgte im Anschluss hydraulisch, durch elektrische Signale an das Magnetventil. Wurde der vorgegebene CSC-Schwellenwert unterschritten, wurde die Striegelintensität erhöht. War der tatsächliche, gemessene CSC-Wert über dem vorgegebenen Schwellenwert, wurde die Intensität verringert. In einem ersten Feldexperiment wurde das neue System auf Genauigkeit getestet und mit einem manuell eingestellten Zinkenwinkel verglichen. Hierbei wurden für das automatische System CSC-Schwellenwerte von 10%, 30% und 60% und für die manuelle Ansteuerung drei äquivalente Zinkenwinkel, festgelegt. Es konnten die voreingestellten, automatischen CSC-Schwellenwerte mit einer Präzision bzw. Standardabweichung von 1,5-3% realisiert werden, während die manuell eingestellten Zinkenwinkel eine Standardabweichung zwischen 18-20% aufwiesen. Die nächste Veröffentlichung befasst sich mit der standortspezifischen Feldanpassung des sensorbasierten Striegels im Getreide. Drei Feldexperimente wurden durchgeführt, um die Auswirkungen der Feldanpassung sowohl im Sommer-, als auch Wintergetreide zu untersuchen. In allen Experimenten wurden sechs verschiedene CSC-Schwellenwerte (CSC von 5, 15, 20, 25, 45 und 70%) getestet. Jedes Experiment enthielt eine unbehandelte Kontrolle und eine Herbizidbehandlung als Vergleich. Die Ergebnisse zeigten einen Anstieg des WCE mit einem steigenden CSC-Schwellenwert. Schwer zu bekämpfende Unkrautarten wie Cirsium arvense (L.) und Galium aparine (L.) wurden am besten mit einem CSC-Schwellenwert von 70% kontrolliert. Mit einem CSC-Schwellenwert von 20% war es möglich, bis zu 98% von Thlaspi arvense (L.) zu bekämpfen. Die höchste Kulturpflanzenbiomasse und Kornertrag konnte mit einem CSC-Schwellenwert zwischen 20-25% erzielt werden. Kornertrag war sogar höher als in der Herbizidparzelle. Der letzte wissenschaftliche Artikel vergleicht paarweise eine konventionelle Striegelintensität mit einer automatischen, sensorbasierten Striegelsteuerung. In den Jahren 2019 und 2020 wurden dafür fünf Feldversuche in Getreide an drei Standorten in Südwestdeutschland durchgeführt. Zu diesem Zweck wurden paarweise Vergleiche von drei festen Striegelintensitäten (10 °, 40 ° und 70 ° Zinkenwinkel) und drei vordefinierten CSC-Schwellenwerten (CSC von 10%, 20% und 60%) durchgeführt. Die automatische Anpassung der Intensität führte zu einer 6-16% geringeren Standardabweichung des CSC im Vergleich zu den festen Einstellungen des Zinkenwinkels. Pflanzendichte, WCE, Pflanzenbiomasse und Kornertrag waren beim kamerabasierten Striegeln signifikant höher als beim konventionellen Striegeln. WCE und Erträge aller automatisch eingestellten Striegelbehandlungen waren vergleichbar mit den Herbizid-Kontrollparzellen. In dieser Dissertation wurde ein sensorbasiertes Striegelsystem entwickelt und als erfolgreiche Alternative zur konventionellen Herbizidanwendung und zur Effektivitätssteigerung herkömmlicher Striegel, im Getreide aufgezeigt. Durch eine präzise Anpassung an standortspezifische Unkraut- und Bodensituationen waren nicht nur die Bekämpfungserfolge vergleichbar mit denen einer Herbizidanwendung, sondern es entstanden auch nur geringfügige Pflanzen- bzw. Ertragsverluste. Die Ergebnisse dieser Arbeit haben das Potential Einfluss auf zukünftige Pflanzenschutzstrategien zu nehmen, da sie die Möglichkeiten der mechanischen Unkrautbekämpfung erweitern, den Herbizideinsatz reduzieren und die Akzeptanz des technischen Fortschritts in der Gesellschaft fördern

An investigation into the design of cultivation systems for inter- and intra-row weed control

The aim of this study was to investigate the factors that influence the design of soil engaging systems to mechanically control weeds between plants within the crop row in widely spaced field vegetables. A mass flow soil dynamics model based on particle dynamics was developed to aid designers in determining the lateral and forward displacement of soil as it is undercut by shallow working wide blades. The model was validated in soil bin laboratory experiments and used to design a novel mechanical inter- and intra-row weeding system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

3D machine vision system for robotic weeding and plant phenotyping

The need for chemical free food is increasing and so is the demand for a larger supply to feed the growing global population. An autonomous weeding system should be capable of differentiating crop plants and weeds to avoid contaminating crops with herbicide or damaging them with mechanical tools. For the plant genetics industry, automated high-throughput phenotyping technology is critical to profiling seedlings at a large scale to facilitate genomic research. This research applied 2D and 3D imaging techniques to develop an innovative crop plant recognition system and a 3D holographic plant phenotyping system. A 3D time-of-flight (ToF) camera was used to develop a crop plant recognition system for broccoli and soybean plants. The developed system overcame the previously unsolved problems caused by occluded canopy and illumination variation. Both 2D and 3D features were extracted and utilized for the plant recognition task. Broccoli and soybean recognition algorithms were developed based on the characteristics of the plants. At field experiments, detection rates of over 88.3% and 91.2% were achieved for broccoli and soybean plants, respectively. The detection algorithm also reached a speed over 30 frame per second (fps), making it applicable for robotic weeding operations. Apart from applying 3D vision for plant recognition, a 3D reconstruction based phenotyping system was also developed for holographic 3D reconstruction and physical trait parameter estimation for corn plants. In this application, precise alignment of multiple 3D views is critical to the 3D reconstruction of a plant. Previously published research highlighted the need for high-throughput, high-accuracy, and low-cost 3D phenotyping systems capable of holographic plant reconstruction and plant morphology related trait characterization. This research contributed to the realization of such a system by integrating a low-cost 2D camera, a low-cost 3D ToF camera, and a chessboard-pattern beacon array to track the 3D camera\u27s position and attitude, thus accomplishing precise 3D point cloud registration from multiple views. Specifically, algorithms of beacon target detection, camera pose tracking, and spatial relationship calibration between 2D and 3D cameras were developed. The phenotypic data obtained by this novel 3D reconstruction based phenotyping system were validated by the experimental data generated by the instrument and manual measurements, showing that the system has achieved measurement accuracy of more than 90% for most cases under an average of less than five seconds processing time per plant

Integrating the organic arsenal for weed control in field pea and lentil

Organic weed management in pulse crops is challenging due to their uncompetitive nature in the presence of weeds. Since the use of synthetic herbicides is prohibited in organic production, growers tend to rely heavily on mechanical and cultural weed control methods. To our knowledge, no previous research has directly compared the following in-crop mechanical weed control (MWC) methods: rotary hoe (RH), harrow (H) and inter-row cultivation (IT) combined with the cultural practice of increased crop seeding rate (SR) in organic pulse crops. The objective of this research was to determine the effect of mechanical weed control (RH, H and IT) and crop (SR) alone and in combination on weed suppression and yield in organically grown field pea (Pisum sativum L.) and lentil (Lens culinaris L.). The study was conducted in organically managed cropping systems in Saskatchewan, Canada in 2016 and 2017. Mechanical weed control methods including RH, H and IT were applied in a factorial arrangement with normal and increased SR in organically grown field pea (1 and 1.5X) and lentil (1 and 2X). Averaged over all site-years, all MWC treatments resulted in similar field pea yield increases ranging from 38% to 50%. Paired and multiple treatments reduced weed biomass in field pea by 73% to 86%. Increasing field pea SR 1.5X did not significantly improve weed control, but it did increase field pea yield by 13%. The combination of RH-IT resulted in 40% higher lentil grain yield. Increasing lentil SR to 2X the normal rate resulted in a 23% increase in yield, while weed biomass was reduced by 16%. Combinations of RH-IT and RH-H-IT in lentil resulted in a 76% and 79% decline in weed biomass, respectively. Treatments including RH, provided the greatest spectrum of weed control spectrum in both crops as on average they controlled more than 80% of the green foxtail (Setaria viridis L.), 60% of the wild mustard (Sinapis arvense L.), and 86% of the lambsquarters (Chenopodium album L.). Use of MWC did not provide robust control of redroot pigweed (Amaranthus retroflexus L.) or wild buckwheat (Polygonum convolvulus L.) and stimulated emergence of stinkweed (Thlaspi arvense L.). Our study suggests that effective weed suppression and greater yield can be achieved in an organic crop production system when MWC methods are paired with cultural practice of increased crop SR

Research on organic agriculture in the Netherlands : organisation, methodology and results

Chapters: 1. Organic agriculture in the Netherlands; 2. Dutch research on organic agriculture: approaches and characteristics; 3. Dutch knowledge infrastructure for organic agricultur'; 4. Sustainable systems; 5. Good soil: a good start; 6. Robust varieties and vigorous propagation material; 7. Prevention and control of weeds, pests and diseases; 8. Health and welfare of organic livestock; 9. Animal production and feeding; 10. Special branches: organic greenhouse production, bulbs, ornamentals and aquaculture; 11. Healthfulness and quality of products; 12. Economy, market and chain; 13. People and society. A publication of Wageningen UR and Louis Bolk Institut

Manage Weeds on Your Farm: A Guide to Ecological Strategies

Manage Weeds on Your Farm is a definitive guide to understanding agricultural weeds and how to manage them efficiently, effectively and ecologically—for organic and conventional farmers alike. With the growing spread of herbicide-resistant weeds and with the public’s embrace of sustainably raised foods, farmers everywhere, both organic and conventional, are seeking better ways to eliminate or reduce their use of synthetic herbicides. The ecological approach to weed management seeks to first understand the biology and behavior of problem weeds and then to develop an integrated set of control strategies that exploit their weaknesses. Manage Weeds on Your Farm: A Guide to Ecological Strategies provides you with in-depth information about dozens of agricultural weeds found throughout the country and the best ways of managing them. In Part One, the book begins with a general discussion of weeds: their biology, behavior and the characteristics that influence how to best control their populations. It then describes the strengths and limitations of the most common cultural management practices, physical practices and cultivation tools. Part Two is a reference section that describes the identification, ecology and management of 63 of the most common and difficult-to-control weed species found in the United States. Ecological weed management is knowledge intensive, rather than input intensive. But it doesn’t have to be excessively labor intensive. Manage Weeds on Your Farm shows you how to outsmart your weeds by identifying the right tactic for the right weed at the right time, which will reduce as much as possible the labor required, while ensuring your weeds don’t impact crop yields. Note: Manage Weeds on Your Farm is focused on the weeds of arable cropping systems. It does not discuss the management of weeds in forests, turf, permanent pastures or perennial bioenergy crops. Weed management issues in forage production are discussed to some extent since forages are often rotated with other crops

Sensors Application in Agriculture

Novel technologies are playing an important role in the development of crop and livestock farming and have the potential to be the key drivers of sustainable intensification of agricultural systems. In particular, new sensors are now available with reduced dimensions, reduced costs, and increased performances, which can be implemented and integrated in production systems, providing more data and eventually an increase in information. It is of great importance to support the digital transformation, precision agriculture, and smart farming, and to eventually allow a revolution in the way food is produced. In order to exploit these results, authoritative studies from the research world are still needed to support the development and implementation of new solutions and best practices. This Special Issue is aimed at bringing together recent developments related to novel sensors and their proved or potential applications in agriculture

A Study of Their Practices and Performance

Ganz allgemein zeigen die Ergebnisse dieser Untersuchung, dass die gegenwärtige Lage der Bibliotheken in staatlichen Universitäten durch extrem geringe Ressourcen für die Bücher-, Zeitschriften und Mediensammlungen und hinsichtlich Ausstattung und Personal gekennzeichnet. Private Universitäten haben diese Probleme in weit geringerem Maße. Unter Studierenden, Lehrenden und Universitätsbeamten ist durchaus die Ansicht verbreitet, dass Universitätsbibliotheken eine entscheidende Rolle in Lehre, Forschung und Studium spielen. Man nimmt allerdings auch zur Kenntnis, dass die Universitätsbibliotheken in Kenia, besonders diejenigen der staatlichen Universitäten, keine wirkungsvollen Dienstleistungen erbringen. Dies hat zur Entwertung ihrer Rolle in der Hochschullandschaft geführt. Die Studie zeigt, dass die moderne Informations- und Kommunikationstechnik in die kenianischen Universitätsbibliotheken Einzug gehalten hat. Doch ist die Entwicklung zum einen durch die Finanzierungslücken behindert worden, sodass Computer nicht angeschafft und Netze nicht aufgebaut werden konnten, zum anderen durch das Fehlen von geschultem EDV-Personal und durch die kümmerliche Telekommunikations-Infrastruktur im Lande. Diese Untersuchung kommt zu dem Ergebnis, dass Maßnahmen erforderlich sind, die Situation der Universitätsbibliotheken in Kenia zu verbessern - dies auch als ein Weg, die Qualität des Universitätsstudiums in Kenia zu steigern. Diese Maßnahmen umfassen zunächst die Aufnahme einer langfristigen Planung auf allen Gebieten bibliothekarischer Arbeit. Zweitens sollten die leitenden Bibliothekare die zentrale Bedeutung der Bibliotheken hervor heben, welche ihnen im Zusammenhang der gesamten Universität zukommt. Um nutzbare Quellen der Information zu bleiben, müssen die Universitätsbibliotheken in Kenia, die moderne Informations- und Kommunikationstechnik einsetzen. Die Anwendung neuer Informations- und Kommunikationstechnik kann den Bibliothekaren an den Universitäten helfen, besseren Zugang zu örtlichen und zu globalen Informationen zu schaffen, zum Beispiel durch elektronische Media und Internetzugang.This study argues that the provision of library services in Kenyan public universities is characterised by extremely inadequate resources in terms of funds, information materials, equipment and staff. Private university libraries experience these problems albeit to a lesser degree. Although there is widespread opinion among students, lecturers as well as university administrators that university libraries play a critical role in the teaching, research, and learning activities, there is also awareness that university libraries in Kenya, especially those in public universities are not effectively providing services which has limited their role in research and learning in the university. Finally, modern information and communication technology is being incorporated in the management of university libraries in Kenya. However, this trend has been hindered by first, lack of funds to purchase equipment such as computers and set up networks, secondly by lack of skilled personnel in information technology, and finally by poor telecommunications infrastructure in the country. There is therefore need for adoption of strategic planning in all areas of library management and to remain viable sources of information, university libraries in Kenya have to make use modern information and communication technology. This will enable university libraries to facilitate better access to local and global information for example through electronic and internet media