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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 greenhouse to evaluate microclimate effects on resistances of a soilless cucumber crop. The regression analysis of canopy-to-air temperature (Tc − Ta) difference on air vapor pressure deficit (VPD) was substituted into the energy balance equation for the estimation of aerodynamic and canopy resistance values. As expected, a fan and pad evaporative cooling system proved to be the more efficient method of decreasing crop temperature (Tc) compared to the forced air ventilation system. The estimated transpiration by the Penman–Monteith model based on calculated aerodynamic and canopy resistance values successfully validated values measured with lysimeters in different growing periods. In this article, we report for the first time the calculation of aerodynamic and canopy resistance values inside a greenhouse based on equations for an open field that were found in the literature. Results may be helpful in Mediterranean greenhouses for direct determinations of plant water evaporative demand and smart climate control systems.
Georgios Nikolaou; Damianos Neocleous; Evangelini Kitta; Nikolaos Katsoulas. Estimation of Aerodynamic and Canopy Resistances in a Mediterranean Greenhouse Based on Instantaneous Leaf Temperature Measurements. Agronomy 2020, 10, 1985 .
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Evangelini Kitta, Nikolaos Katsoulas. Estimation of Aerodynamic and Canopy Resistances in a Mediterranean Greenhouse Based on Instantaneous Leaf Temperature Measurements. Agronomy. 2020; 10 (12):1985.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Evangelini Kitta; Nikolaos Katsoulas. 2020. "Estimation of Aerodynamic and Canopy Resistances in a Mediterranean Greenhouse Based on Instantaneous Leaf Temperature Measurements." Agronomy 10, no. 12: 1985.
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 volume of water consumed by the crop) and reduce the evaporative or system loss of water as opposed to traditional surface irrigation methods. However, in water-scarce countries, irrigation management frequently becomes a complex task. Deficit irrigation and the use of non-conventional water resources (e.g., wastewater, brackish groundwater) has been adopted in many cases as part of a climate change mitigation measures to tackle the water poverty issue. Protected cultivation systems such as greenhouses or screenhouses equipped with artificial intelligence systems present another sustainable option for improving water productivity and may help to alleviate water scarcity in these countries. This article presents a comprehensive review of the literature, which deals with sustainable irrigation for open-field and protected cultivation systems under the impact of climatic change in vulnerable areas, including the Mediterranean region.
Georgios Nikolaou; Damianos Neocleous; Anastasis Christou; Evangelini Kitta; Nikolaos Katsoulas. Implementing Sustainable Irrigation in Water-Scarce Regions under the Impact of Climate Change. Agronomy 2020, 10, 1120 .
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Anastasis Christou, Evangelini Kitta, Nikolaos Katsoulas. Implementing Sustainable Irrigation in Water-Scarce Regions under the Impact of Climate Change. Agronomy. 2020; 10 (8):1120.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Anastasis Christou; Evangelini Kitta; Nikolaos Katsoulas. 2020. "Implementing Sustainable Irrigation in Water-Scarce Regions under the Impact of Climate Change." Agronomy 10, no. 8: 1120.
In this study, we investigated the effect of individual and combined applications of manganese (Mn) and zinc (Zn) chelates on common bean grown in hydroponics (nutrient film technique—NFT) on physiological and agronomical responses. Inorganic sulphate forms of Mn and Zn were compared to their synthetic chelate forms, in the replenishment nutrient solution (RNS). Nutrient (N, P, K, Ca, Mg, Fe, Mn, Zn and Cu) to water uptake ratios (termed uptake concentrations; UCs), growth, pods yield and quality, photosynthetic parameters and tissue nutrient status were evaluated in different cropping seasons (spring-summer and autumn-winter crops). Mean UCs of nutrients ranged as follows: 10.1–12.4 (N), 0.8–1.0 (P), 5.2–5.6 (K), 1.8–2.2 (Ca), 0.9–1.0 (Mg) mmol L−1; 12.2–13.4 (Fe), 5.2–5.6 (Mn), 4.4–4.9 (Zn), 0.9–1.0 (Cu) μmol L−1. Tissue macronutrient status remained unaffected in both seasons, however, Mn chelates in the RNS affected Fe within plants. Pod yield and quality, growth, photosynthesis and water uptake did not differ among treatments; however, seasonal variations are presented. Results suggest that the chelate forms of Mn and/or Zn in the refill solution for NFT-grown beans do not lead to any changes, adding superiority in the yield, photosynthesis, and nutritional status of the crops compared to their mineral forms.
Damianos Neocleous; Georgios Nikolaou; Georgia Ntatsi; Dimitrios Savvas. Impact of Chelated or Inorganic Manganese and Zinc Applications in Closed Hydroponic Bean Crops on Growth, Yield, Photosynthesis, and Nutrient Uptake. Agronomy 2020, 10, 881 .
AMA StyleDamianos Neocleous, Georgios Nikolaou, Georgia Ntatsi, Dimitrios Savvas. Impact of Chelated or Inorganic Manganese and Zinc Applications in Closed Hydroponic Bean Crops on Growth, Yield, Photosynthesis, and Nutrient Uptake. Agronomy. 2020; 10 (6):881.
Chicago/Turabian StyleDamianos Neocleous; Georgios Nikolaou; Georgia Ntatsi; Dimitrios Savvas. 2020. "Impact of Chelated or Inorganic Manganese and Zinc Applications in Closed Hydroponic Bean Crops on Growth, Yield, Photosynthesis, and Nutrient Uptake." Agronomy 10, no. 6: 881.
This study was conducted in order to investigate possible quality changes in Cyprus’ groundwater resources over a 10-year period of pumping and to check the suitability of primary irrigation water. Water samples (n = 890) from private wells in agricultural areas were analyzed from 2009 to 2018 to determine various physicochemical properties. The sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) were also calculated to evaluate potential soil degradation issues. Sodium, chloride and sulphate were found to be the predominant ions in groundwater. Quality evaluation showed possible restrictions in groundwater use for irrigation in relation to its salt content and the toxicity of specific ions having adverse effects on sensitive and several moderately sensitive crops. In particular, an increasing trend was observed in pumped groundwater for boron ion concentrations. Nevertheless, all samples evaluated were suitable for irrigation in terms of soil sodicitation and soil infiltration rate. This study indicates that in order to maintain long-term agricultural sustainability it is imperative to develop strategic plants to mitigate the adverse effects of water-pumped quality deterioration on soils and crops. Precision agriculture techniques may be adapted for better water and nutrient input/output management, thus protecting groundwater from salinization in agricultural areas. These results, among others, may be a useful tool to enhance the ability of Cyprus’s agricultural water sector to adapt to observed and anticipated climate impacts.
Georgios Nikolaou; Damianos Neocleous; Christos Christophi; Theodosia Heracleous; Marinos Markou. Irrigation Groundwater Quality Characteristics: A Case Study of Cyprus. Atmosphere 2020, 11, 302 .
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Christos Christophi, Theodosia Heracleous, Marinos Markou. Irrigation Groundwater Quality Characteristics: A Case Study of Cyprus. Atmosphere. 2020; 11 (3):302.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Christos Christophi; Theodosia Heracleous; Marinos Markou. 2020. "Irrigation Groundwater Quality Characteristics: A Case Study of Cyprus." Atmosphere 11, no. 3: 302.
N. Katsoulas; Georgios Nikolaou; Damianos Neocleous; C. Kittas. Microclimate and cucumber crop transpiration in a greenhouse cooled by pad and fan system. Acta Horticulturae 2020, 235 -240.
AMA StyleN. Katsoulas, Georgios Nikolaou, Damianos Neocleous, C. Kittas. Microclimate and cucumber crop transpiration in a greenhouse cooled by pad and fan system. Acta Horticulturae. 2020; (1271):235-240.
Chicago/Turabian StyleN. Katsoulas; Georgios Nikolaou; Damianos Neocleous; C. Kittas. 2020. "Microclimate and cucumber crop transpiration in a greenhouse cooled by pad and fan system." Acta Horticulturae , no. 1271: 235-240.
This study was commissioned to study the effect of the growing season on the antioxidant components of greenhouse sweet pepper crops, which is of scientific interest because of their possible beneficial health effects. The total antioxidant activity (estimated by ferric reducing antioxidant power-FRAP assay) major antioxidants (ascorbic acid, phenolics and carotenoids) and taste fruit quality characteristics (soluble solids, titratable acidity, dry matter and sugars) were recorded in soilless-grown sweet pepper cultivars of red, orange, yellow and green color at four harvesting season months, i.e., February (winter), May (spring), July (summer) and October (autumn). The results showed seasonal variations in antioxidant components and activity of pepper fruits. In most cases measured parameters showed higher values in spring (May) and summer (July) compared with winter (February) and autumn (October) growing seasons. This study indicates that during late autumn and winter, lower levels of solar irradiance, ultraviolet radiation and temperature in Mediterranean greenhouses can be insufficient to stimulate phytochemicals production in peppers; thus, plant–light interception must be more actively managed.
Damianos Neocleous; Georgios Nikolaou. Antioxidant Seasonal Changes in Soilless Greenhouse Sweet Peppers. Agronomy 2019, 9, 730 .
AMA StyleDamianos Neocleous, Georgios Nikolaou. Antioxidant Seasonal Changes in Soilless Greenhouse Sweet Peppers. Agronomy. 2019; 9 (11):730.
Chicago/Turabian StyleDamianos Neocleous; Georgios Nikolaou. 2019. "Antioxidant Seasonal Changes in Soilless Greenhouse Sweet Peppers." Agronomy 9, no. 11: 730.
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 regime (between 0.24 and 0.32 L m−2) in relation to crop water uptake and greenhouse fertigation effluents. The use of a fan ventilation system enhanced the vapor pressure deficit; thus, the crop transpiration improved by 60% in relation to the transpiration rates of plants grown under the fan-pad system. Higher transpiration rates alleviated the heat load as the external–inside greenhouse air differences declined from 6.2 °C to 3 °C. The leaf–air temperature differential indicated that plants were not facing any water stress conditions for both cooling systems tested; however, fan ventilation reduced drainage emissions outflows (95% decrease) compared with evaporative cooling. Results also demonstrated that an irrigation regime of 0.24 L m−2 can be applied successfully in soilless cucumber crops, keeping the drainage to a minimum (20% of the nutrient solution supply). These results suggest that fan ventilation cooling system in conjugation with an appropriate irrigation regime prevents overheating and minimizes the nutrient and water losses in spring-grown soilless cucumber crops in Mediterranean greenhouses without compromising yield.
Georgios Nikolaou; Damianos Neocleous; Nikolaos Katsoulas; Constantinos Kittas. Effects of Cooling Systems on Greenhouse Microclimate and Cucumber Growth under Mediterranean Climatic Conditions. Agronomy 2019, 9, 300 .
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Nikolaos Katsoulas, Constantinos Kittas. Effects of Cooling Systems on Greenhouse Microclimate and Cucumber Growth under Mediterranean Climatic Conditions. Agronomy. 2019; 9 (6):300.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Nikolaos Katsoulas; Constantinos Kittas. 2019. "Effects of Cooling Systems on Greenhouse Microclimate and Cucumber Growth under Mediterranean Climatic Conditions." Agronomy 9, no. 6: 300.
Precision agricultural greenhouse systems indicate considerable scope for improvement of irrigation management practices, since growers typically irrigate crops based on their personal experience. Soil-based greenhouse crop irrigation management requires estimation on a daily basis, whereas soilless systems must be estimated on an hourly or even shorter interval schedule. Historically, irrigation scheduling methods have been based on soil or substrate monitoring, dependent on climate or time with each having both strengths and weaknesses. Recently, plant-based monitoring or plant reflectance-derived indices have been developed, yet their potential is limited for estimating the irrigation rate in order to apply proper irrigation scheduling. Optimization of irrigation practices imposes different irrigation approaches, based on prevailing greenhouse environments, considering plant-water-soil relationships. This article presents a comprehensive review of the literature, which deals with irrigation scheduling approaches applied for soil and soilless greenhouse production systems. Irrigation decisions are categorized according to whether or not an automatic irrigation control has the ability to support a feedback irrigation decision system. The need for further development of neural networks systems is required.
Georgios Nikolaou; Damianos Neocleous; Nikolaos Katsoulas; Constantinos Kittas. Irrigation of Greenhouse Crops. Horticulturae 2019, 5, 7 .
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Nikolaos Katsoulas, Constantinos Kittas. Irrigation of Greenhouse Crops. Horticulturae. 2019; 5 (1):7.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Nikolaos Katsoulas; Constantinos Kittas. 2019. "Irrigation of Greenhouse Crops." Horticulturae 5, no. 1: 7.
Three experiments (spring and autumn-winter seasons) with soilless cucumber crop (cv. Phenomeno) were conducted in order: (i) to calibrate the simplified Penman -Monteith model equation as affected by greenhouse microclimate (ii) to validate the prediction efficiency of the model at different climatic conditions and (iii) to establish a relationship between transpiration and leaf temperature. To determine Penman-Monteith model parameter variables related to the plants such as transpiration and leaf area index (LAI), so as environmental variables (i.e., radiation, temperature, humidity) were recorded. The results revealed that the determined model parameters were suitable for the whole cucumber cultivation cycle and a wide range of climatic conditions. However, parameterization of the model using autumn-winter crop data revealed superiority compared to spring data, as indicated by the correlation coefficients. Model validation showed a good fit between simulates and measures allowing implementation in commercial soilless practices. With respect to greenhouse microclimate, cooling affected daily mean air temperature and vapor pressure deficit, so as model coefficients. Leaf temperature indicated a good correlation with transpiration and the prediction equation was validated under different greenhouse climatic conditions. These results may be of value in Mediterranean greenhouses, enabling a more efficient water resource management without significant losses in agricultural productivity.
Georgios Nikolaou; Damianos Neocleous; Constantinos Kittas Nikolaos Katsoulas. Modelling transpiration of soilless greenhouse cucumber and its relationship with leaf temperature in a Mediterranean climate. Emirates Journal of Food and Agriculture 2018, 911 -920.
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Constantinos Kittas Nikolaos Katsoulas. Modelling transpiration of soilless greenhouse cucumber and its relationship with leaf temperature in a Mediterranean climate. Emirates Journal of Food and Agriculture. 2018; ():911-920.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Constantinos Kittas Nikolaos Katsoulas. 2018. "Modelling transpiration of soilless greenhouse cucumber and its relationship with leaf temperature in a Mediterranean climate." Emirates Journal of Food and Agriculture , no. : 911-920.
Span>An experiment with a soilless cucumber crop (cv. Phenomeno) was conducted in order to evaluate the influence of two different cooling systems (i.e., whitewash as opposed to fan-wetted pad evaporative) on the greenhouse microclimate and on plant growth under high 0.32 mm and low 0.24 mm irrigation dose treatments. The results revealed that the transpiration rate was higher in the whitewash compartment, which resulted in less outflow of nutrient solution into the environment. In regards to the total greenhouse water use efficiency, no differences were obtained between the two different cooling systems, taking into account the amount of water used by the evaporative system per se. Irrigation doses tested did not significantly affect crop production. According to the results obtained, whitewash shading proved to maintain greenhouse cucumber growth and production throughout the spring cropping period in comparison with the use of an evaporative cooling system.
Georgios Nikolaou. Dynamic assessment of whitewash shading and evaporative cooling on the greenhouse microclimate and cucumber growth in a Mediterranean climate. 2018, 1 .
AMA StyleGeorgios Nikolaou. Dynamic assessment of whitewash shading and evaporative cooling on the greenhouse microclimate and cucumber growth in a Mediterranean climate. . 2018; ():1.
Chicago/Turabian StyleGeorgios Nikolaou. 2018. "Dynamic assessment of whitewash shading and evaporative cooling on the greenhouse microclimate and cucumber growth in a Mediterranean climate." , no. : 1.
Three irrigation frequencies were applied on a soilless cucumber crop, in a greenhouse located in the coastal area of southern Cyprus. Irrigation scheduling was based on solar radiation and performed whenever accumulated solar radiation energy outside the greenhouse reached 1.3 MJ m-2 [High Irrigation Frequency (HIF)], 1.9 MJ m-2 [Medium Irrigation Frequency (MIF)] and 3.0 MJ m-2 [Low Irrigation Frequency (LIF)]. The amount of water applied was 0.192 Kg m-2, 0.288 Kg m-2 and 0.448 Kg m-2 for high, medium and low irrigation frequencies, respectively. Appropriately, the total volume of water applied was identical in each of the three cases. In order to study the effects of irrigation frequency on cucumber crops, multiple measurements were taken; the fresh and dry weight of plant organs (i.e. leaves, stem and fruit), marketable fresh yield production, and microclimate variables for a 75 day period, beginning in April and ending in June. The results revealed that the irrigation frequency did not influence the cucumber crop’s growth and production. Plants at LIF were facing water stress conditions, as estimated from leaf temperature and stem micro variation measurements. However, HIF increased the transpiration rate of the plants, resulting in less water and nutrient losses.
Georgios Nikolaou; Damianos Neocleous; Nikolaos Katsoulas; Constantinos Kittas. Effect of irrigation frequency on growth and production of a cucumber crop under soilless culture. Emirates Journal of Food and Agriculture 2017, 863 -871.
AMA StyleGeorgios Nikolaou, Damianos Neocleous, Nikolaos Katsoulas, Constantinos Kittas. Effect of irrigation frequency on growth and production of a cucumber crop under soilless culture. Emirates Journal of Food and Agriculture. 2017; ():863-871.
Chicago/Turabian StyleGeorgios Nikolaou; Damianos Neocleous; Nikolaos Katsoulas; Constantinos Kittas. 2017. "Effect of irrigation frequency on growth and production of a cucumber crop under soilless culture." Emirates Journal of Food and Agriculture , no. : 863-871.
Georgios Nikolaou. Irrigation Management Techniques Used in Soilless Culture. 2021, 1 .
AMA StyleGeorgios Nikolaou. Irrigation Management Techniques Used in Soilless Culture. . 2021; ():1.
Chicago/Turabian StyleGeorgios Nikolaou. 2021. "Irrigation Management Techniques Used in Soilless Culture." , no. : 1.