Dennis Dannehl

Dennis Dannehl
Humboldt-Universität zu Berlin | HU Berlin · Faculty of Life Sciences

Dr. rer. hort.

About

105
Publications
40,851
Reads
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657
Citations
Citations since 2016
45 Research Items
574 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Additional affiliations
October 2014 - April 2015
Plant & Food Research, Palmerston North, New Zealand
Position
  • Scientist
October 2006 - present
Humboldt-Universität zu Berlin
Position
  • Researcher
August 2005 - July 2006
Research Centre Jülich, Germany
Position
  • Scientist
Education
February 2007 - November 2012
Humboldt-Universität zu Berlin, Germany
Field of study
  • Horticultural Science

Publications

Publications (105)
Article
Full-text available
Large quantities of growing media residues that are rich in nutrients are disposed of after their use in hydroponics. The objective of this study was to investigate the benefits of different organic growing media (wood fibers, hemp fibers, sphagnum moss) residues from hydroponic tomato production as a nutrient source to produce Ethiopian kale. The...
Article
Full-text available
Replacement of rock wool by organic substrates is considered to reduce the environmental impact, e.g., through energy savings during production and waste prevention, caused by hydroponically produced crops. A suitable substrate for plant production is characterized by an optimal composition of air- and water-filled pores. In our study, we used hemp...
Article
Full-text available
Concepts of semi-closed greenhouses can be used to save energy, whereas their technical equipment often causes a decrease in the light received by the plants. Nevertheless, higher yields are achieved, which are presumably triggered by a higher CO2 concentration in the greenhouse and associated higher photosynthesis because of the technical cooling...
Article
Full-text available
High-pressure sodium (HPS) lighting is increasingly replaced by LED lighting in lettuce greenhouse cultivation. In contrast to HPS lighting, LEDs do not heat radiation. Therefore, the leaf temperature is significantly lower under LEDs. This raises the question of whether LED lighting has a positive impact on the reduction in water consumption durin...
Article
Full-text available
Light emitting diodes (LEDs) are an energy efficient alternative to high-pressure sodium (HPS) lighting in tomato cultivation. In the past years, we have learned a lot about the effect of red and blue LEDs on plant growth and yield of tomatoes. From previous studies, we know that plants absorb and utilize most of the visible spectrum for photosynth...
Article
Full-text available
In agriculture, the increasing scarcity of arable land and the increase in extreme weather conditions has led to a large proportion of crops, especially vegetables, being cultivated in protected soilless cultivation methods to provide people with sufficient and high-quality food. Rockwool has been used for decades as a soil substitute in soilless c...
Conference Paper
Full-text available
Due to light conditions, cultivation of lettuce on the south side of the buildings is preferable. With regard to heavy metals, our study did not reveal any health risk due to consumption of lettuce produced under urban conditions with different air pollution levels. Nevertheless, the accumulation of heavy metals increased in unwashed and washed sam...
Article
Wiederverwendbares Wasser kommt ohne Desinfektionsmittel nicht aus - vor allem bei der geschlossenen Bewässerung. Chemische Verfahren sind sehr wirkungsvoll, bergen aber die Gefahr von Pflanzenschäden und Desinfektionsrückständen. Ein neues Verfahren soll genau diese Gefahren minimieren. // Zeitschrift Gemüse - Das Magazin für den professionellen...
Article
Consumer and trade organisations demand year-round healthy diets including fresh, high quality vegetables from local producers. However, greenhouse gas emissions (GHG) of heating high-tech greenhouses in northern countries are higher than transporting vegetables produced in southern Europe in unheated tunnels. The aim of this work was to assess GHG...
Chapter
In human nutrition, tomato (Lycopersicon esculentum L.) fruits are an adequate source for important secondary metabolites such as lycopene, β-carotene, ascorbic acid or polyphenols that are antioxidatants (Lai et al. 2007). Consumers demand aromatic and tasty tomatoes, in addition to their health-promoting aspects. The sugar/acid ratio of fruits ch...
Chapter
Adaptation to stress involves the synthesis of plant hormones that induce metabolic responses to help plants to survive under that stress. Notably, the exogenous application of plant hormones on non-stressed plants can change plant growth, yield and the composition of plant metabolites (see 7 Chap. 15) (Franklin 2008; Skirycz et al. 2009). This kno...
Article
Artificial neural networks (ANN) have been successfully used for modelling climate and plant signals in greenhouses. This work shows the combination of two ANN models, built and trained separately, and then coupled together. Both models were trained using a data set consisting of 3 complete cultivation periods (2011 until 2013) of 2 venlo-type gree...
Article
Tested in experimental scale, an innovative system for electrolytic water disinfection in greenhouses (SeWiG) was very efficient. It was developed by Humboldt-Universität zu Berlin and newtec Umwelttechnik GmbH. With scaling up this system for industrial greenhouses, the new technology will be tested, validated and optimized under practical conditi...
Article
Aquaponics combine the production of fish and plants in a sustainable way due to the double use of water and nutrients. Compared to conventional single recirculation aquaponic systems (SRAPS), the double recirculation aquaponic systems (DRAPS) are improved by the combination of two separate recirculating systems: the recirculating aquaculture syste...
Article
The research was focused on the identification of interactions between hypochlorite used as a disinfectant for a recirculating tomato production system and the spread of microorganisms, plant characteristics and fruit quality. Potassium hypochlorite (1% KCLO) supplemented once a week for 90 min into different nutrient solution ranks until a free ch...
Article
Artificial neural networks (ANN) have been successfully used for modelling climate and plant signals in greenhouses. This work shows the combination of two ANN models, built and trained separately, and then coupled together. Both models were trained using a data set consisting of 3 complete cultivation periods (2011 until 2013) of 2 venlo-type gree...
Article
Full-text available
Decoupled aquaponic systems have the potential to become one of the most effective sustainable production systems for the combined production of animal protein and plant crops. Here, recirculating aquaculture systems for fish production are combined with hydroponics for soilless plant production thereby recycling dissolved nutrients derived from me...
Poster
Full-text available
Varying conditions of cultivation of vegetables inside a city’s boundaries were analyzed. As such, in the city of Berlin flower boxes with lettuce were installed at 20 spots at different heights, with different light conditions and air pollution levels. In order to exclude heavy metal uptake due to soil contamination, lettuce was seeded in a standa...
Conference Paper
Full-text available
Zu den großen Herausforderungen des 21. Jahrhunderts gehört die Folgeneindämmung des durch Treibhausgasemissionen (THG-Emissionen) verursachten Klimawandels. Hierbei ist der Agrarsektor ein beachtlicher Emittent, darunter die wachsende Gewächshausbranche mit CO2-Emissionen. Daher erforscht und entwickelt das MinTHG-Konsortium, bestehend aus mehrere...
Poster
Full-text available
Zu den großen Herausforderungen des 21. Jahrhunderts gehört die Folgeneindämmung des durch Treibhausgasemissionen (THG-Emissionen) verursachten Klimawandels. Hierbei ist der Agrarsektor ein beachtlicher Emittent, darunter die wachsende Gewächshausbranche mit CO2-Emissionen. Daher erforscht und entwickelt das MinTHG-Konsortium, bestehend aus mehrere...
Article
Full-text available
The integration of agricultural production systems into urban areas is a challenge for the coming decades. Because of increasing greenhouse gas emission and rising resource consumption as well as costs in animal husbandry, the dietary habits of people in the 21st century have to focus on herbal foods. Intensive plant cultivation systems in large ci...
Article
In contrast to conventional single recirculation aquaponic systems (SRAPS), the innovative double recirculating aquaponic system (DRAPS) provides an opportunity for intensive fish and plant production. This system is based on two separate recirculating systems, a recirculating aquaculture system (RAS) and a closed hydroponic system, whereby the com...
Conference Paper
Full-text available
Projektziel ist, ein Gewächshausmanagementsystem zur Effizienzsteigerung und Entscheidungsfindung in der Unterglasproduktion zu etablieren. Dieses ermittelt anhand gigantischer Datenmengen verschiedener Gewächshaussensoren optimale Kulturführungsstrategien. Dabei sollen unterschiedliche Zielgrößen wie reduzierter Ressourcenverbrauch oder maximaler...
Article
The increase of global population causes rising food demand and concomittantly scarcity of resources. These facts including global warming need the further development of resource-efficient food production systems such as double recirculating aquaponic systems (DRAPS). This recent technology is suitable for intensive food production with minimal re...
Article
Numerous investigations into the abiotic elicitation of plant responses with UV-B radiation, temperature, drought, CO2, nutrients, heavy metals and wounding have been carried out in the agronomic sector and are described in various reviews. However, it is not clear if electricity can be classified as an abiotic stress elicitor to affect plants. Whi...
Poster
Full-text available
Over time the human population has become increasingly urban. The proportion of city dwellers increased from 30% in 1950 to 66% in 2015. Due to this concentration of people in densely-built areas, a rethinking of agricultural and horticultural production is needed urgently. While the demand for fresh vegetables and other natural resources such as w...
Poster
Full-text available
Der deutsche Gartenbau befindet sich im Spagat zwischen einem hohen internationalen Wettbewerb einerseits und einem starken Preisdruck von Seiten der Abnehmer andererseits. Hinzukommt, dass der Lebensmitteleinzelhandel verstärkt Informationen zum Ressourceneinsatz einfordert. Infolgedessen gewinnt in gartenbaulichen Produktionsbetrieben die ressour...
Article
Full-text available
Vegetable amaranth (Amaranthus cruentus L.) is gaining importance among the African indigenous leafy vegetables (AIVs) in the diets of many households in Africa. However, improper processing, handling, and storage of AIVs often result in faster deterioration thus high quantitative and qualitative losses with reduced availability of these highly nut...
Conference Paper
Full-text available
An increasing amount of greenhouse vegetables is produced using hydroponic systems. The used mineral fertilizers are often generated in energy consuming processes (esp. nitrate in Haber-Bosch) or gained from finite resources (esp. phosphate rock). Recovering the respective nutrients from waste streams is a promising option to make crop production m...
Article
The trend in greenhouse automation systems is to listen to plant signals while trying to minimize the ecological footprint of the vegetable production. In this work,we present a model based on artificial neural networks (ANN), which can be used to support the measuring of plant signals and help to improve the reliability of the data collected. This...
Article
Full-text available
Growing environmental and sustainability concerns have driven continual modernization of horticultural practices, especially for urban farming. Controlled environment and soilless production methods are increasing in popularity because of their efficient resource use and intensive cropping capabilities. However, some popular substrates used for hyd...
Article
A dynamic artificial neural network was developed to predict tomato yield in two high-technology greenhouses located at Humboldt University of Berlin. One is a reference greenhouse, the other is a semi-closed greenhouse, called a solar collector. Both greenhouses have a surface area of 307 m2, and they are equipped with a phytomonitoring system for...
Article
Aquaponics for intensive crop production is a highly complex system in which three different biological systems (fish, plants, and nitrifying bacteria) with different requirements must be merged. Finding the right combination is a serious challenge and the dependencies avoid a high productivity until now. Therefore, a unique and innovative double r...
Article
Effects of organic waste from hydroponic system added with minerals (organo-mineral fertilizer) and synthetic fertilizer on major polyphenols of red oak leaf lettuce using HPLC-DAD-ESI-MS3 were investigated. Interestingly, contents of the main flavonoid glycosides and caffeic acid derivatives of lettuce treated with organo-mineral fertilizer were e...
Poster
Full-text available
Currently, about 33% of Germany’s annual electricity is generated from renewable sources like wind and sun. Until 2030, the German government wants to increase this proportion to 50%. Other EU countries have similar plans. Predictive models indicate that this aim will lead to an increase in volatility of the energy supply and will also affect elect...
Article
Full-text available
Production of indigenous African leafy vegetables such as African nightshade (Solanum scabrum Mill.), whose high nutritional and medicinal value is well documented is still limited due to insufficient preharvest techniques. Electric current is known to improve quality in food crops. Therefore, in the present study, the effects of direct-electric-cu...
Article
Full-text available
Die Minimierung von Chlorat bei der elektrolytischen Gießwasserdesinfektion ist aufgrund problematischer Chloratrückstände in pflanzlichen Lebensmitteln von Bedeutung. Im Hinblick auf verfahrenstechnische Optimierungsvorschläge wurde daher am Beispiel einer Salzelektrolyseanlage (Einkammersystem) geprüft, wie viel Chlorat beim Herstellungsprozess d...
Article
Full-text available
To the background of discussions on problematical residues in plant-derived foods, the procedure for minimising chlorate content in the electrolytic disinfection of irrigation water is of great importance. As a source of adjustment recommendations was investigated, on the basis of a brine electrolysis plant (single chamber system), how much chlorat...
Article
Recently, official food surveillance discovered high residues of chlorate (ClO3 −) and perchlorate (ClO4 −) in different plant-based foods, which was the start of a big discussion in the EU Commission. There is currently no knowledge about possible ClO3 − uptake quantities in vegetable, when hypochlorite (ClO−) is used as a disinfectant in plant pr...
Chapter
Full-text available
Im ZINEG-Projekt wurden an mehreren Standorten Zukunftskonzepte für Unterglaskulturen entwickelt mit dem Ziel, den Energieverbrauch wesentlich zu senken und CO2-Emissionen zu reduzieren. An den Standorten Berlin, Hannover, Schifferstadt und Osnabrück entstanden Projekte mit unterschiedlichen Konzepten aber gleichgerichteter Zielsetzung. Die Pflanze...
Article
Full-text available
Physical and chemical disinfection methods are used or are under investigation in greenhouse facilities to minimize the occurrence of pathogens and the application of pesticides in recirculating systems. Since the most of these methods differ in their effectiveness, more investigation is needed to produce healthy plants in a sustainable way. Theref...
Article
Tomato yields often vary from week to week, so the ability to accurately predict them would give producers a competitive advantage. As a result there has been interest from growers and researchers about tomato yield prediction. The purpose of this study is to predict tomato yield in a semi-closed and reference experimental greenhouses, located at H...
Article
The determination of leaf area is essential to understand the interaction between plant development and prevailing environmental factors during the growing season. In particular, the precise estimation of the leaf area index (LAI) is a prerequisite for modelling of canopy energy and mass fluxes, especially of canopy transpiration. Therefore, variou...
Article
This study evaluated if an Artificial Intelligence climate forecasting model can be considered as a useful tool for saving energy in semi-closed greenhouses. Preliminary results are presented on the 5-Minutes prediction of the internal air temperature and humidity modeled with Artificial Neural Networks (ANN). Since the final goal of the simulation...
Article
This study evaluated if an Artificial Intelligence climate forecasting model can be considered as a useful tool for saving energy in semi-closed greenhouses. Preliminary results are presented on the 5-Minutes prediction of the internal air temperature and humidity modeled with Artificial Neural Networks (ANN). Since the final goal of the simulation...
Article
The water and carbon footprint of the presented dried tomato value chain is compared to the conventional process. The coupling of pre- and post-harvest processes, namely growing and drying respectively, is analyzed for resource consumption optimization. The growing system of tomatoes (Solanum lycopersicon L. cv, Pannovy) in an energy efficient gree...
Article
Full-text available
To reduce the rock wool waste, the present study is focused on the evaluation of sheep wool, cultivated Sphagnum biomass and hemp, which may be used as replacement for rock wool as growing substrate for hydroponic tomato production. As such, physical and chemical properties of substrates, the plant growth, yield, fruit characteristics, as well as p...
Presentation
Full-text available
Seit vielen Jahren wird das Konzept semigeschlossenes Gewächshaus für den Gemüsebau weiterentwickelt. Ziel ist es, den Heizenergiebedarf zu senken, die durch Verwendung fossiler Brennstoffe entstehenden CO2-Emissionen drastisch zu vermindern und höhere Erträge durch länger zu realisierende CO2-Anreicherung am Tage zu erzielen. Für die Wirtschaftlic...
Presentation
Full-text available
We present an application of time-series prediction to the climate inside a greenhouse. We use an Artificial Neural Network (ANN) model to predict the air temperature and relative humidity inside the greenhouse 5 minutes in advance. Such a model generates a One Step Prediction (OSP). We iterate this OSP to get Long-Term Predictions (LTP), thus gene...
Article
Full-text available
A confined closed greenhouse (CGH) was applied to save energy and to investigate how tomatoes respond to specific microclimatic con-ditions. As such, new dynamic set-points for precise climate control were used in the CGH compared to those applied in a conventional greenhouse. Based on the reduced ventilation frequency in the CGH, the results showe...
Article
Full-text available
A semi-closed greenhouse was used for sustainable tomato production and to investigate the effects of the prevailing climate conditions within this greenhouse on different plant parameters of tomatoes. Compared to conventionally cultivated tomato plants, the leaf area index, the number of trusses and the yield of marketable fruit of tomato plants e...
Article
Das Prinzip geschlossener Gewächshäuser zur Nutzung solarer Überschusswärme stellt einen ressourcenschonenden Ansatz hinsichtlich des Energieaufwands im geschützten Gemü-seanbau dar. Dabei wird überschüssige Wärmeenergie mittels Kühlsystem dem Gewächs-haus entzogen und in einen Wärmespeicher geleitet (Abb. 1). Diese kann wiederum für Heizzwecke ein...
Article
Full-text available
2009 to 2014, the joint research program ZINEG is carried out in Germany. Its main aim is to reduce the consumption of fossil fuels and hence the CO2 emissions up to 90% for production in greenhouses. At Humboldt University the research is focused on using a greenhouse system as solar thermal collector with above-ground heat storage. During the tom...
Article
An advanced prototype of a phytomonitor was developed at Humboldt University in the frame of the national ZINEG project for low energy greenhouses (www.zineg.de). Ten leaf cuvettes were allocated to different tomato leaves in the canopy to get a representative average of the gas exchange of younger and older leaves under shaded and non-shaded condi...
Chapter
To increase the intake of secondary plant compounds, the consumer can either increase consumption of fruit and vegetables or choose species that contain a high content of health-promoting plant compounds. Even within one species the content of phenolics can vary considerably. This effect is due to differences among cultivars or can be caused by sev...
Presentation
Full-text available
Die Entwicklung im Unterglasanbau zeigt, dass heutzutage Gemüse auf hohem Niveau produziert wird. Combined Farming spiegelt dabei nur einen Sektor wider, der in der Vergangenheit mit der Kombination aus intensivem Gemüseanbau und der Fischproduktion oder der Algenproduktion in Verbindung gebracht wurde. Zukunftsorientiert wird eine weitere Form die...
Poster
Full-text available
Die Klimaregelung in Gewächshäusern erfolgt meist nach fest eingestellten Sollwerten (z.B. für Tag-/Nacht-Temperatur, maximale Luftfeuchte, CO 2 -Begasung und Zusatzbelichtung). Die Festlegung der Sollwerte erfolgt dabei häufig nach Erfahrungswerten zur Kulturführung und ökonomischen Kennzahlen, die individuell an die aktuellen Rahmenbedingungen an...
Conference Paper
Full-text available
Angesichts wachsender Energiekosten und Umweltbelastungen durch fossile Brennstoffe ist die Steigerung der Energieeffizienz bei Gewächshäusern von großer Bedeutung. Daher wurde die ZukunftsInitiative NiedrigEnergieGewächshaus (ZINEG) initiiert. Das Gesamtziel der von 2009 bis 2014 durchgeführten nationalen Verbundforschung war es, den fossilen Wärm...
Article
Based on the fact that several regions worldwide and even in Germany are affected by water deficit problems, a new agronomic approach was developed to produce tomatoes (Solanum lycopersicum L.) in a sustainable way. The main objective of this study was to investigate the effects of a special solar collector greenhouse consisting of finned tube heat...
Conference Paper
Full-text available
Da durch die Herstellung und Entsorgung der Steinwollsubstrate die Umwelt zusätzlich belastet wird, wurden alternativ zu diesem Substrat vier organische Substrate, pflanzlichen (ungereinigte Schafwolle, Torfmoos und Hanf) und synthetischen (Plyurethanschaum [PUS]- BVBSublime) Ursprungs auf ihre Eignung für die hydroponische Tomatenproduktion unters...