Nikolaos Katsoulas
@uth.gr
Department of Agriculture Crop Production and Rural Environment
University of Thessaly
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Despoina Georgiou, Stylianos Exarhopoulos, Aggelos Charisis, Savvas Simitsis, Georgia Papapanagiotou, Christina Samara, Matina Katsiapi, Georgios Kountrias, Sofoklis Bouras, Nikolaos Katsoulas,et al.
Springer Science and Business Media LLC
AbstractThe green microalga Monoraphidium sp. has potential for biodiesel production since it grows fast and can accumulate high levels of lipids. However, there is a lack of information on the potential use in human nutrition. In this work Monoraphidium sp. was characterized in terms of macronutrients with a special focus on the fatty acid profile of the lipid fraction and on the amino acid profile of the proteins. Furthermore, aiming at nutrient valorization, various methods for lipid extraction that could be used in the production of high quality and safe foods were investigated. To this end, the focus was on cell disruption methods in order to optimize oil recovery. The Monoraphidium sp. biomass had a high protein concentration (44.5 %) and a relatively low lipid concentration (12.5 %) but was rich in ω-3 fatty acids demonstrating its high nutritive value. Regarding cell disruption, ultrasonication and high-speed homogenization were insufficient to disrupt cells under the conditions examined. On the other hand, the effectiveness of the ball milling was regulated via processing time and water-to-biomass ratio and complete cell disruption could be achieved by this method. For lipid extraction, solvent extraction using a mixture of food-grade hexane and ethanol resulted in an oil recovery of 70.4 %, whereas using ethanol alone as an environmentally friendly solvent resulted in an oil recovery equal to 54 %. Supercritical CO2 extraction resulted in a lower oil recovery (25 %), whereas ethanol addition, as a cosolvent to CO2, significantly increased the oil recovery (60 %).
Georgios Nikolaou, Damianos Neocleous, Evangelini Kitta, and Nikolaos Katsoulas
Springer Science and Business Media LLC
AbstractThis study aimed to determine cucumber crop coefficients under different greenhouse microclimatic conditions, parameterizing the Priestley-Taylor reference evapotranspiration model. Crop evapotranspiration was directly measured with the use of lysimeters, and crop coefficients were computed following the two-step climate FAO 56 methodology. Greenhouse compartments (i.e., cooled or uncooled) showed reference evapotranspiration differences of up to 12% in an autumn-winter crop. The results presented cucumber crop coefficient values from the initial to the late-season growth stages from 0.45 to 0.94 depending on the greenhouse climate. Based on the greenhouse hourly microclimatic variation of KC, it is recommended not to apply a KC as a constant for transpiration estimation even at greenhouses located within the same region Regression analysis relating crop coefficients with leaf area revealed very high correlation coefficients for the equations tested. The results indicated that evapotranspiration can be modeled satisfactory based on a significant relationship between crop coefficient and simple measurements of the leaf area index (i.e., KC = 0.447 × LAI).
Maria Aslanidou, Angeliki Elvanidi, Anastasia Mourantian, Efi Levizou, Eleni Mente, and Nikolaos Katsoulas
MDPI AG
Aquaponics is currently undergoing a transformation into an intensive food production system. The initially applied systems focused on small-scale, fish-centric coupled (CAP, the aquaculture, and the hydroponic units are arranged in a single loop, and the water flows continuously from the fish tanks to the plant unit and back) aquaponics. More recently, the primary area of research interest has shifted toward larger-scale, plant-centric decoupled (aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently) systems, aiming to achieve greater economic benefits and employ more environmentally friendly practices. The objective of this study was to address gaps in the expansion of decoupled larger-scale aquaponics and to provide a comprehensive understanding of the water and nutrient flow in the system. For this purpose, experiments were performed in a greenhouse on CAP and DCAP systems, while this study also included measurements in a pure hydroponic system (HP). This study presents an assessment of the water and nutrient flow in four different crops: basil; cucumber; parsley; and tomato, all co-cultivated with a tilapia aquaculture system. Significant nutrient deficiencies and imbalances were identified in the CAP solution, leading to pronounced impacts on nutrient assimilation, particularly for fruiting vegetables. However, the average nutrient use efficiency (NUE) for nitrogen, phosphorous, potassium, and calcium was found to be 42% higher in the CAP treatment compared to HP and DCAP treatments. The nutrient solution in the DCAP treatment did not exhibit differences in water quality parameters and nutrient efficiency when compared to HP, resulting in similar effects on nutrient assimilation. Nonetheless, it was observed that DCAP plants exhibited superior NUE compared to HP plants.
G Papapolymerou, N Gougoulias, M.N. Metsoviti, N Katsoulas, I.T. Karapanagiotidis, D Kasiteropoulou, A Mpesios, and A Papadopoulou
Elsevier BV
Eleni Karatsivou, Angeliki Elvanidi, Sofia Faliagka, Ioannis Naounoulis, and Nikolaos Katsoulas
MDPI AG
Minimum environmental impact and improved resource efficiency is attainable for soilless cascade systems where the nutrient solution drained from a primary (donor) crop is reused to fertigate a secondary (receiver) crop. However, it is not clear whether the nutrient solution drained from the primary crop can completely satisfy the needs of a secondary crop and if the productivity of the secondary crop is compromised. To test this hypothesis, a prototype soilless cascade system was developed and evaluated. To assess the performance of the system in terms of yield, water and nutrient productivity, a tomato crop was used as the primary crop, while lettuce, spinach and parsley were tested as secondary crops under different drainage management strategies. Measurements of plant growth, crop fresh and dry matter production, leaf chlorophyll and nutrient content, and photosynthesis rate were performed in the secondary crops. In addition, the water productivity and nutrient use efficiency for the fertigation of the primary and secondary crops were recorded. The results showed that the yield of the cascade spinach crop increased by up to 14% compared to the control treatment (monoculture of secondary crop fertigated by standard nutrient solution). The yield of the lettuce and parsley crop was not affected by the reuse of the tomato crop drainage solution. The water productivities of the lettuce, spinach and parsley plants fertigated with pure drainage solution were 50%, 30% and 14% higher than in the control treatment, respectively. The nitrogen and phosphorus use efficiency was improved by more than 50% compared to the control treatments.
Catherine Baxevanou, Dimitrios Fidaros, Chryssoula Papaioannou, and Nikolaos Katsoulas
MDPI AG
The climate crisis and energy price increases make energy supply a crucial parameter in the design of greenhouses. One way to tackle both these issues is the local production of energy from renewable sources. Since the permitted photovoltaic power installation on a greenhouse roof is limited by the need for an adequate amount of photosynthetically active radiation at the crop level, the necessity of designing a hybrid production system combining different renewable sources, storage systems, and conventional sources arises. The present work addresses the multifactorial problem of the optimal design (in terms of energy production quality, produced electricity price and CO2 emissions) of a hybrid power generation system (photovoltaics/wind turbine/accumulators/oil generating unit) to meet greenhouse needs. The design accounts for the needs of production (for tomato cultivation) for different combinations of production and energy equipment (for microclimate management). Extended parametric studies for available solar and wind potential and energy demand are used to generalize the conclusions. Special attention is given to the contribution of various wind turbine sizes. The effect of greenhouse orientation and of photovoltaic modules arrangement on arched roofs is also examined and the different greenhouse energy systems are assessed in terms of energy cost and environmental footprint.
Georgios Nikolaou, Damianos Neocleous, Evangelini Kitta, and Nikolaos Katsoulas
Elsevier BV
Eleftheria-Maria Pechlivani, Anastasia Kapetanakou, Sofia Faliagka, Nikolaos Giakoumoglou, Fotini Salta, and Nikolaos Katsoulas
IEEE
This multidisciplinary study examines the understanding and application of agro-ecological practices (AOPs) and digital and space-based technologies (DSTs) within Greece's agricultural sector, for testing and demonstrating systemic innovations in support with the European Union's (EU) Farm-to-Fork (F2F) strategy, which aims to reduce reliance on hazardous pesticides, minimize nutrient losses from fertilisers, and target zero pollution of water, soil, and air while also reducing fertiliser use. By adopting a multi-actor and cross-sectoral approach that includes practitioners (primary producers, processors, retailers, food service providers, consumers), citizens from farm, and public and private institutions (NGOs, industry, governmental institutions.), this study ensures a comprehensive and actionable outcome tailored to Greece's regional and sectoral contexts. Despite a high level of familiarity with AOPs across all groups, the study highlights a considerable gap in awareness and application of the F2F strategy and DSTs, particularly among practitioners. However, the benefits of AOPs and DSTs are recognized by all F2F stakeholders, indicating potential paths for promoting more sustainable practices in systemic innovation. The findings underscore the need for increased educational initiatives and collaborative efforts between all the multi-actors of the F2F chain to enhance the understanding and acceptance of the Green Deal and F2F strategy goals, AOPs, and DSTs within the Greek agricultural and agri-food sector.
Agoustina Galitsopoulou, Eleftheria-Maria Pechlivani, Stefanos Tsachouridis, Sofia Faliagka, Nikolaos Giakoumoglou, Angeliki Elvanidi, and Nikolaos Katsoulas
IEEE
This multidisciplinary study unveils the dynamics, practices, and awareness levels among farmers and primary producers (agricultural producers), as well as merchandisers and standardizers. It focuses on the European Union (EU) Green Deal's Farm to Fork (F2F) strategy, aiming to build upon a cross-disciplinary approach on securing food supply in a sustainable way, managing risks and food safety. Data were gathered through targeted attributed questionnaires in Agri-retail supply chain, revealing certification status, pesticide and fertilizer's application methods, technology adaptation, and understanding of sustainable food and agroecological transition goals. The results show a diverse landscape among agricultural producers regarding certification and technology adaptability and a varied attitude towards organic farming. Merchandisers and standardizers, while generally more certified, encounter barriers to promoting organic alternatives. The need for targeted informational campaigns and support mechanisms to foster alignment with the Farm to Fork's sustainable goals is emphasized.
N. Katsoulas, A. Elvanidi, E. Karatsivou, and V. Vassiliadis
International Society for Horticultural Science (ISHS)
A. Elvanidi and N. Katsoulas
International Society for Horticultural Science (ISHS)
N. Katsoulas, M. Aslanidou, D.K. Papanastasiou, and V. Anestis
International Society for Horticultural Science (ISHS)
Carmen L. Manuelian, Sophie Valleix, Héloïse Bugaut, Birgit Fuerst-Waltl, Luciana da Costa, Sara Burbi, Ulrich Schmutz, Adrian Evans, Nikolaos Katsoulas, Sofia Faliagka,et al.
Informa UK Limited
Anastasia Mourantian, Maria Aslanidou, Eleni Mente, Nikolaos Katsoulas, and Efi Levizou
PeerJ
Background Aquaponics is an innovative farming system that combines hydroponics and aquaculture, resulting in the production of both crops and fish. Decoupled aquaponics is a new approach introduced in aquaponics research for the elimination of certain system bottlenecks, specifically targeting the optimization of crops and fish production conditions. The aquaponics-related literature predominantly examines the system’s effects on crop productivity, largely overlooking the plant functional responses which underlie growth and yield performance. The aim of the study was the integrated evaluation of basil performance cultivated under coupled and decoupled aquaponic systems compared with a hydroponic one, in terms of growth and functional parameters in a pilot-scale aquaponics greenhouse. Methods We focused on the efficiency of the photosynthetic process and the state of the photosynthetic machinery, assessed by instantaneous gas exchange measurements as well as photosynthetic light response curves, and in vivo chlorophyll a fluorescence. Light use efficiency was estimated through leaf reflectance determination. Photosynthetic pigments content and leaf nutritional state assessments completed the picture of basil functional responses to the three different treatments/systems. The plant’s functional parameters were assessed at 15-day intervals. The experiment lasted for two months and included an intermediate and a final harvest during which several basil growth parameters were determined. Results Coupled aquaponics resulted in reduced growth, which was mainly ascribed to sub-sufficient leaf nutrient levels, a fact that triggered a series of negative feedbacks on all aspects of their photosynthetic performance. These plants experienced a down-regulation of PSII activity as reflected in the significant decreases of quantum yield and efficiency of electron transport, along with decreased photosynthetic pigments content. On the contrary, decoupled aquaponics favored both growth and photochemistry leading to higher light use efficiency compared with coupled system and hydroponics, yet without significant differences from the latter. Photosynthetic light curves indicated constantly higher photosynthetic capacity of the decoupled aquaponics-treated basil, while also enhanced pigment concentrations were evident. Basil functional responses to the three tested production systems provided insights on the underlying mechanisms of plant performance highlighting key-points for systems optimization. We propose decoupled aquaponics as an effective system that may replace hydroponics supporting high crops productivity. We suggest that future works should focus on the mechanisms involved in crop and fish species function, the elucidation of which would greatly contribute to the optimization of the aquaponics productivity.
Jose Ignacio Marín-Guirao, Francisco César Páez-Cano, María del Carmen García-García, Nikolaos Katsoulas, and Miguel de Cara-García
MDPI AG
Grey mould caused by Botrytis cinerea is an endemic disease in greenhouse tomato crops in the Mediterranean Basin, where the scarcity of heating systems together with the winter weather conditions makes the use of fungicides necessary. The availability of fungicides for organic tomato production is limited, and traditionally, farmers have used copper-based formulations. In the present work, in vitro tests with twelve commercial formulations resulted in cinnamon extract and potassium hydrogen carbonate (PHC) showing high efficacy in the inhibition of B. cinerea growth. Both formulations were evaluated in on-farm greenhouse trials conducted for two seasons (2019/2020 and 2020/2021) in three greenhouses located in Almería, Spain. In terms of controlling Botrytis, PHC showed efficacy results comparable to or even better than those that have been obtained for copper oxychloride. Weather conditions outside and inside the greenhouse were conducive to the onset and development of the disease. Tomato variety selection and pruning practices (flush cuttings) were the main factors that reduced the use of copper-based formulations or any other fungicide to prevent grey mould infection. Smart and integrated management of the mentioned factors could lead to the substitution of copper to control Botrytis in the crop system studied here.
Angeliki Elvanidi and Nikolaos Katsoulas
MDPI AG
Greenhouse climate control systems are usually based on greenhouse microclimate settings to exert any control. However, to save energy, water and nutrients, additional parameters related to crop performance and physiology will have to be considered. In addition, detecting crop stress before it is clearly visible by naked eye is an advantage that could aid in microclimate control. In this study, a Machine Learning (ML) model which takes into account microclimate and crop physiological data to detect different types of crop stress was developed and tested. For this purpose, a multi-sensor platform was used to record tomato plant physiological characteristics under different fertigation and air temperature conditions. The innovation of the current model lies in the integration of photosynthesis rate (Ps) values estimated by means of remote sensing using a photochemical reflectance index (PRI). Through this process, the time-series Ps data were combined with crop leaf temperature and microclimate data by means of the ML model. Two different algorithms were evaluated: Gradient Boosting (GB) and MultiLayer perceptron (MLP). Two runs with different structures took place for each algorithm. In RUN 1, there were more feature inputs than the outputs to build a model with high predictive accuracy. However, in order to simplify the process and develop a user-friendly approach, a second, different run was carried out. Thus, in RUN 2, the inputs were fewer than the outputs, and that is why the performance of the model in this case was lower than in the case of RUN 1. Particularly, MLP showed 91% and 83% accuracy in the training sample, and 89% and 82% in testing sample, for RUNs 1 and 2, respectively. GB showed 100% accuracy in the training sample for both runs, and 91% and 83% in testing sample in RUN 1 and RUN 2, respectively. To improve the accuracy of RUN 2, a larger database is required. Both models, however, could easily be incorporated into existing greenhouse climate monitoring and control systems, replacing human experience in detecting greenhouse crop stress conditions.
I.T. Karapanagiotidis, M.N. Metsoviti, E.Z. Gkalogianni, P. Psofakis, A. Asimaki, N. Katsoulas, G. Papapolymerou, and I. Zarkadas
Elsevier BV
Paraskevi Stathopoulou, Adamantia Asimaki, Panagiotis Berillis, Nikolaos Vlahos, Efi Levizou, Nikolaos Katsoulas, Ioannis T. Karapanagiotidis, Christos I. Rumbos, Christos G. Athanassiou, and Eleni Mente
MDPI AG
The aim of this study is to investigate the effect of 10 and 20% replacement of fishmeal (FM dietary group) with the superworm Zophobas morio larvae meal (ZM10 and ZM20 dietary groups) on the growth performance of sea bass (Dicentrarchus labrax) and lettuce plants (Lactuca sativa) reared in aquaponics. Ninety juvenile sea bass with an average body weight of 21.55 g/individual were placed in aquaponic fish tanks, together with 24 lettuce plants with an average initial height of 8.90 cm/plant and an average number of leaves of 5.75/plant over a 45-day trial period. At the end of that period, all feeding groups exhibited high survival. In fact, ΖΜ10 and ZM20 groups showed similar fish weight gain and specific growth rate (SGR) (p > 0.05), but significantly lower SGR (p < 0.05) than the FM group. Nevertheless, final fish body weight and length were similar (p > 0.05) for all feeding groups. No plant mortality was observed during the 45-day study period. All three aquaponic systems resulted in similar leaf fresh weight, as well as fresh and dry aerial biomass. At the end of the experimental period, plants in the third system showed higher fresh leaf weight, total weight of fresh leaves, total dry aerial biomass, and total produced biomass compared to the other two systems. The results of the present study show that fish fed with the ZM10 diet had higher weight gain (WG) than fish fed with the ZM20 diet, while the SGRs for ZM10 and ZM20 were similar. Both ZM10 and ZM20 diets result in efficient lettuce production. This study also provides data that enlighten the feasibility of integrating insect meals as fish feeds for aquaponics which helps towards the development of an ento-aquaponic approach.
C. Kittas, W. Baudoin, E. Kitta, and N. Katsoulas
International Society for Horticultural Science (ISHS)
Evangelia Tsoumalakou, Eleni Mente, Konstantinos A. Kormas, Nikolaos Katsoulas, Nikolaos Vlahos, Panagiotis Kapsis, and Efi Levizou
MDPI AG
In aquaponics, a closed-loop system which combines fish and crop production, essential nutrients for plant growth are often at sub-optimal concentrations. The aim of the present study was to identify system limitations and thoroughly examine the integrated response of its components to minimal external inputs, notably crop’s functional parameters, fish performance, and microorganism profile. Lettuce and red tilapia were co-cultivated under only Fe and Fe with K supplementation and their performance was evaluated against the control of no nutrient addition. Photosynthesis, the photosynthetic apparatus state, and efficiency, pigments, leaf elemental composition, and antioxidant activity of lettuce were monitored throughout the growth period, along with several parameters related to water quality, fish growth, plant productivity and bacterial community composition. Nutrient deficiency in control plants severely impacted gas exchange, PSII efficiency, and chlorophyll a content, from day 14 of the experiment, causing a significant increase in dissipation energy and signs of photoinhibition. Fe+K input resulted in 50% and two-fold increase in lettuce production compared with Fe and control groups respectively. Nutrient supplementation resulted in higher specific growth rate of tilapias, but did not affect root microbiota which was distinct from the water bacterial community. Collectively, the results emphasize the importance of monitoring crop’s functional responses for identifying the system’s limitations and designing effective nutrient management to sustain the reduced environmental footprint of aquaponics.
Dietmar Schwarz, Matthew Tom Harrison, and Nikolaos Katsoulas
Frontiers Media SA
Chryssoula Papaioannou, Nikolaos Katsoulas, and Evangelini Kitta
MDPI AG
The goal of this research was to compare and evaluate the measurements taken by different instruments regarding alterations while varying the ultraviolet (UV)-blocking property of cladding material during its usage under real greenhouse conditions. The UV-blocking covering material, low-density polyethylene (LDPE), is enriched with additives that are scattered in several layers during the manufacturing process, resulting in the reinforcement of its properties mechanically as well as optically. The duration of this study was three years, and the instruments used were: (a) sensors measuring the UV radiation reaching the earth’s surface in its A and B components; and (b) a portable spectroradiometer capable of measuring the transmissivity of a material, only in the UV-A region. Three covering materials were used with different UV radiation transmissivity. The transmittance was measured both in the laboratory (on samples taken from the roof) and in the field (where the greenhouses were located). Equations were defined to describe the variation in UV radiation transmission increase rate as a function of field exposure time. Lastly, it is important to note that the specific UV radiation sensors were extremely accurate.
Sofia Faliagka and Nikolaos Katsoulas
Elsevier BV
Sofoklis Bouras, Dimitrios Antoniadis, Georgios Kountrias, Ioannis T. Karapanagiotidis, and Nikolaos Katsoulas
MDPI AG
The ability of microalgae, such as the rich in docosahexaenoic acid (DHA) heterotrophic marine microalgae Schizochytrium limacinum SR21, to utilize nutrients in their culture media derived from low-cost nutrient sources makes them a promising low-cost alternative source for the production of useful substances used in aqua feeds. The assessment of culture parameters, one of which is the pH, for every different nutrient growth medium used for microalgae cultivation is important, as they affect the biomass and secondary metabolite microalgae production. This study assessed the effect of different growth medium pH levels (6, 7, 8 and 9), at laboratory and pilot scale systems, on S. limacinum biomass productivity, lipid accumulation, proximate composition, carbon assimilation and DHA. The microalgae were cultivated in growth media containing two different alternative low-cost nutrient sources: (a) crude glycerol derived from biofuel industry as carbon source and (b) effluent digestate from biogas production of livestock decomposition as a source of nutrients and trace elements. It was found that a neutral pH (7) was the optimum level, as it enhanced biomass productivity of the lab and pilot scale cultivation systems at 44.9 g L−1 and 11 g L−1 and DHA content at 7.5% and 19% of the total lipid content, respectively.
N. Katsoulas, S. Faliagka, A. Bari, and Y. Naounoulis
VDI Verlag