Nikolaos Katsoulas

University of Thessaly | UTH · Department of Agriculture Crop Production and Rural Environment

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 rece...

This 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. Greenho...

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 conditio...

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 second...

The autotropic, heterotrophic and mixotrophic cultivation mode of the microalgae Microchloropsis gaditana was studied. Three sets of experiments were carried out: In the first set, six experimental groups were tested; one autotrophic, one heterotrophic and four mixotrophic where cultivation modes carried out and biomass productivities were compared...

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...

Over the last decade, the total population of the sub-Saharan region of Africa has been increasing rapidly at a rate of more than 3% annually, with urbanization expected to be approximately 40% of the total population by 2050. Parallel growth has not been achieved in the agricultural sector in West Africa, with vegetable production and consumption...

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 copp...

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 co...

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...

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,...

The present study evaluated the effects of replacing fishmeal protein by Chlorella vulgaris meal and fish oil by a blend of Schizochytrium sp. and Microchloropsis gaditana on growth, feed utilization, muscle fatty acid composition and liver histology of Sparus aurata. Fish were fed twice a day for 12 weeks, six isonitrogenous (52% CP) and isoenerge...

The Priestley–Taylor α coefficient was adjusted to the surrounding environment in a Mediterranean greenhouse. The estimated values of α were 0.86 and 0.72 in greenhouse compartments equipped with a forced air ventilation system or wetted evaporative-pad system, respectively. The proposed α coefficient values observed were not equivalent to typical...

Insect proof screens were coated with silica (SiO2) nanoparticles using the plasma coating process. The work studied whether a screen coated by SiO2 nanoparticles could be more effective on insects' control than a non-coated screen. Thus, the insect control properties of 25- and 40-mesh screens were studied. Besides, a series of experiments were pe...

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 a...

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 c...

Harmonization of global geopolitical directions was realized at COP26 when more than 150 countries pledged to the Glasgow Climate Pact, resulting in unified aspirations to constrain global average temperature rise to 1.5°C and well below 2°C by 2050. Successful achievement of COP26 outcomes demands urgent, deep and sustained reductions in global gr...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Increasing agricultural systems’ resource efficiency is the key action for producing adequate food quantities in semi-arid Mediterranean regions while coping with water scarcity, environmental constraints and economic issues. Optimisation of irrigation and fertigation practices imposes different approaches, considering plant-water-soil relationship...

Countries located in the Mediterranean region share many common features in terms of agricultural sustainability and economic realities of modern farming, as they are affected by water scarcity, energy use and climate suitability. Greenhouses are considered as a mitigation measure to combat climate change and as a sustainable production system. The...

Open-source devices are widespread and have been available to everyone over the past decade. The low cost of such devices boosts the creation of instruments for various applications such as smart farming, environmental monitoring, animal behavior monitoring, human health monitoring, etc. This research aims to use statistical methods to assess agree...

Presentations from the FAO Working Group on Greenhouse Crop Production in South-East Europe, 26 September 2021

Cascade hydroponics, that is, the application of the circular economy concept in greenhouse hydroponic crops, may be considered as an alternative means to increase water and nutrient use efficiency in greenhouses. In such systems, the drained nutrient solution from a crop may be used as input in a second crop. However, the second (secondary) crop i...

Nowadays, there is a great need and public concern for reduced use of hazardous pesticides in horticulture and implementation of alternative approaches for rational pests and diseases suppression. This goal is approached by integrating crop protection measures and non-chemical measures or applying crop protection products only when needed, thus eli...

In a cascade hydroponic system, the used nutrient solution drained from a primary crop is directed to a secondary crop, enhancing resource-use efficiency while minimizing waste. Nevertheless, the inevitably increased EC of the drainage solution requires salinity-tolerant crops. The present study explored the salinity-tolerance thresholds of basil t...

This work aims at using the Computational Fluid Dynamic (CFD) approach to study the distributed microclimate in the leaf boundary layer of greenhouse crops. Understanding the interactions in this microclimate of this natural habitat of plant pests (i.e., boundary layer of leaves), is a prerequisite for their control through targeted climate managem...

The aim of this study is to investigate the effect of three daily fish feeding frequencies, two, four and eight times per day (FF2, FF4, and FF8, respectively) on growth performance of sea bass ( Dicentrarchus labrax )and lettuce plants ( Lactuca sativa ) reared in aquaponics. 171 juvenile sea bass with an average body weight of 6.80 ± 0.095 g were...

Silicon dioxide (SiO2) has been extensively studied as an alternative method to pest management chemical applications in agriculture. The present work aimed to evaluate the insecticidal efficacy of different SiO2 nanoparticle formulations and their effectiveness when integrated into the textiles of an insect-proof net. For this reason, Sitophilus o...

The objective of this chapter is to describe the most common soilless culture system (SCS) irrigation and fertigation methods. The chapter summarizes common types of irrigation/fertigation system and types of management system. It then discusses the shift to real-time plant-based sensing and monitoring systems together with models to analyze this d...

BACKGROUND The use of water containing Ca(HCO3)2 at excessively high concentrations in closed hydroponic crops can cause Ca²⁺ accumulation in the recycled nutrient solution (NS) and concomitantly negatively affect yield and product quality. The aim of the study was to determine maximum Ca²⁺ concentrations that do not harm the crop and to simulate t...

Aerodynamic and canopy resistances have long been considered to be of key interest in model equation parameterization, particularly for the accurate estimation of crop evapotranspiration. However, model parameters applied in greenhouses showed variation affected by the micrometeorological environment. Three experiments were carried out in a plastic...

The use of several plant protection inputs of mineral origin, such as copper, sulphur or mineral oils is seen as contentious by many consumers and stakeholders within the organic sector. Although the use of these inputs is legal in organic systems and also applied in non-organic agriculture, their use by organic growers raises questions for organic...

The circular economy in agriculture aims to reduce waste while also making best use of residues by using economically viable processes and procedures to increase their value. In this study a two-level cascade cultivation system was set up under greenhouse conditions. The research was focused on the identification of crop species as secondary crops...

Several greenhouse energy saving technologies and management strategies have been developed in order to meet the needs for implementation of production systems with low and efficient energy use and low CO2 emissions. Towards this aim, a number of greenhouse concepts that make use of these technologies have been developed and tested, such as the clo...

Urban outdoor thermal conditions, and its impacts on the health and well-being for the city inhabitants have reached increased attention among biometeorological studies during the last two decades. Children are considered more sensitive and vulnerable to hot ambient conditions compared to adults, and are a�ected strongly by their thermal environmen...

A three-year experiment was carried out in Central Greece to assess the use of different tillage practices (Conventional, Reduced, and No tillage) for seedbed preparation, in a double cropping per year rotation of irrigated and rainfed energy crops for biomass production for first- and second-generation biofuel production. A life cycle assessment (...

Precision Agriculture (PA) is a crop site-specific management system that aims for sustainability, adopting agricultural practices more friendly to the environment, like the variable rate application (VRA) technique. Many studies have dealt with the effectiveness of VRA to reduce nitrogen (N) fertilizer, while achieving increased profit and product...

Insect proof nets are widely used in agriculture as mechanical and physical barriers to regulate pest populations in a greenhouse. However, their integration in the greenhouse ventilation openings is highly associated with the decrease of air flow and the adequate ventilation. Thus, there is need for alternative pest management tools that do not im...

The sustainability of irrigated agriculture is threatening due to adverse climate change, given future projections that every one in four people on Earth might be suffering from extreme water scarcity by the year 2025. Pressurized irrigation systems and appropriate irrigation schedules can increase water productivity (i.e., product yield per unit v...

Pure polyethylene (PE) is enriched with several additives to make it a smart application material in protected cultivation, as a cover material for either greenhouses or screenhouses. When this material completely or partially absorbs ultraviolet (UV) solar radiation, then it is called UV blocking material. The current work presents a review on the...

The necessity to ensure the quality of food by simultaneously reducing the environmental footprint due to the extensive use of convectional insecticides has led to an increase in the efforts towards the development of non-chemical control strategies. Silicon dioxide is considered as a promising alternative active ingredient for the control of vario...

The simultaneous use of crude glycerol and effluent from anaerobic digestate, both wastes derived from the biofuel industry, were tested in the frame of circular economy concept, as potential low-cost nutrient sources for the cultivation of rich in docosahexaenoic acid (DHA) oil microalgae strain Schizochytrium limacinum SR21. Initially, the optima...

A solution to the problem of reduction of available photosynthetically active radiation (PAR) due to the cover with conventional opaque photovoltaics (PV) of greenhouses is the use of semitransparent PV. The question is how dense the semitransparent PV should be and how dense the coverage should be in order not to burden plant growth. The present p...

The microclimate and cucumber soilless crop response in an evaporatively cooled greenhouse were studied in Cyprus during spring. Measurements were carried out in two greenhouse compartments: (1) a compartment in which a wet pad and fan system for evaporative cooling of the greenhouse environment was operated, and (2) a compartment in which greenhou...

In this research, the effect of solar irradiance on Chlorella vulgaris cultivated in open bioreactors under greenhouse conditions was investigated, as well as of ratio of light intensity in the 420–520 nm range to light in the 580–680 nm range (I420–520/I580–680) and of artificial irradiation provided by red and white LED lamps in a closed flat pla...

The effect of different environmental conditions on the growth rate, biomass production, nutrient composition, and phenolic content of the microalgae species Chlorella vulgaris, Botryococcus braunii, Chlamydomonas reinhardtii, Euglena gracilis, and Nannochloropsis oculata was investigated. The experiments were conducted in open bioreactors in a gre...

Models for the evapotranspiration of greenhouse crops are needed both for accurate irrigation and for the simulation or management of the greenhouse climate. For this purpose, several evapotranspiration models have been developed and presented, all based on the Penman–Monteith approach, the “big-leaf” model. So, on the one hand, relatively simple m...

Two experiments were conducted in different cropping seasons under Mediterranean climatic conditions to investigate the impact of two cooling systems (fan-pad evaporative as opposed to fan ventilation) on greenhouse microclimate and soilless cucumber growth. The second objective of the experiment was to determine the most appropriate irrigation reg...

In areas characterized by mild winter climate, pepper is frequently cultivated in unheated greenhouses in which the temperature during the winter may drop to suboptimal levels. Under low temperature (LT) conditions, the uptake of nutrients may be altered in a different manner than that of the water and thus their uptake ratio, known as uptake conce...