Special Issue "Characteristics and Technology in Mediterranean Agriculture"

,

,

Choi-Hong Lai

,

Juan Antonio Martínez-Lao

,

and

María Ángeles Moreno-Teruel

Agronomy 2023, 13(2), 602; https://doi.org/10.3390/agronomy13020602 - 20 Feb 2023

Viewed by 579

Abstract

Permeability and inertial factor are the most relevant variables in the Forchheimer equation. They are important to estimate pressure drop when a fluid flow is passing through a porous media. However, in the insect-proof screens field, the existing models to date are still [...] Read more.

Permeability and inertial factor are the most relevant variables in the Forchheimer equation. They are important to estimate pressure drop when a fluid flow is passing through a porous media. However, in the insect-proof screens field, the existing models to date are still providing a poor predictive accuracy, in part due to they are based on 2D porosity of screens. This work provides novel models for permeability and inertial factor, which are developed from experimental data of insect-proof screens in a wind tunnel and the analytical estimation of 3D porosity. Instead of fitting models directly on observed training data values of permeability and inertial factor, we propose to focus the modelling efforts on finding models dependent on the 3D porosity through the constants in the pressure drop of Forchheimer equation. Since two screens can have the same 2D porosity but different 3D porosity, this makes also models more reliable. The combination of all these aspects has led to parametric models that overcome by far predictions by previous models in the literature. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Effect of Greenhouse Film Cover on the Development of Fungal Diseases on Tomato (Solanum lycopersicum L.) and Pepper (Capsicum annuum L.) in a Mediterranean Protected Crop

by

Eugenio Ávalos-Sánchez

,

,

,

,

Fátima Baptista

,

Patricia Marín-Membrive

and

María Ángeles Moreno-Teruel

Agronomy 2023, 13(2), 526; https://doi.org/10.3390/agronomy13020526 - 11 Feb 2023

Viewed by 844

Abstract

Greenhouses on the Mediterranean coast mainly use plastic materials as their cover. The influence of light exerted by these materials directly affects the crops by modifying the environment in which they develop. The aim of this study was to analyze the effect of [...] Read more.

Greenhouses on the Mediterranean coast mainly use plastic materials as their cover. The influence of light exerted by these materials directly affects the crops by modifying the environment in which they develop. The aim of this study was to analyze the effect of the use of two plastic films in an experimental greenhouse on the development of fungal diseases in two spring–summer crop cycles: tomato (Solanum lycopersicum L.) from February to July 2021 and pepper (Capsicum annuum L.) from February to July 2022. The study was carried out in Almeria (Spain) in a multispan greenhouse divided transversely into two sectors by a polyethylene sheet. A commercial film was installed in the east sector (90% of transmissivity and 55% diffusivity) and an experimental film was installed in the west sector (85% of transmissivity and 60% diffusivity). In addition, the effect of the yield and quality of the harvested fruit was determined. In this study, two diseases were established naturally on the crop: (i) powdery mildew (Leveillula taurica) in both the tomato and the pepper crop cycles and (ii) early blight (Alternaria solani) in the tomato. The analyses of both diseases showed that the areas of the greenhouse that used the plastic cover, which presented a lower sunlight transmissivity, showed higher levels of disease than the areas that used the plastic cover that allowed greater transmissivity of light within the greenhouse, differing statistically in some phases of the crop. The marketable yield was 4.2% (for tomato) and 3.1% (for pepper) higher in the sector with the experimental film with high transmissivity. For both crops, the quality of the fruits did not show statistically significant differences. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Influence of the Diffusivity and Transmittance of a Plastic Greenhouse Cover on the Development of Fungal Diseases in a Cucumber Crop

by

Eugenio Ávalos-Sánchez

,

,

,

,

,

Fátima Baptista

and

Agronomy 2022, 12(11), 2743; https://doi.org/10.3390/agronomy12112743 - 04 Nov 2022

Cited by 1 | Viewed by 656

Abstract

Mediterranean greenhouses are usually covered by plastic materials (films); these films allow light to pass through them, modifying some of their characteristics. The properties of the plastic cover influence the development of greenhouse crops. In addition, it can influence the stresses that the [...] Read more.

Mediterranean greenhouses are usually covered by plastic materials (films); these films allow light to pass through them, modifying some of their characteristics. The properties of the plastic cover influence the development of greenhouse crops. In addition, it can influence the stresses that the plants endure and the development of fungal diseases in the crop. The aim of this study is to analyze the effect that an experimental film cover, with high transmittance and high light diffusivity, produces on the development of fungal diseases on a cucumber crop (Cucumis sativus L.). Two different film covers were compared: (i) commercial film (transmittance of 85%; diffusivity of 60%); and (ii) experimental film (transmittance of 90%; diffusivity of 55%). The study was carried out across two autumn–winter crop cycles in a multi-span greenhouse divided into two isolated sectors. Three fungal diseases caused the main damage to the cucumber crop: downy mildew (Pseudoperonospora cubensis), powdery mildew (Sphaerotheca fuliginia) and gummy stem blight (Didymella bryoniae). In the case of powdery mildew, a greater severity in the sector was observed with the commercial film in comparison with the sector with the experimental film, with significant statistical differences between the two sectors in both crop cycles. Downy mildew and gummy stem blight were fungal diseases with less presence than downy mildew, and a greater presence of these two fungal diseases in the sector with the commercial film was also observed in both crop cycles. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Nitrogen Effect on Fruit Quality and Yield of Muskmelon and Sweet Pepper Cultivars

by

Rafael Grasso

,

M. Teresa Peña-Fleitas

,

,

,

,

and

Agronomy 2022, 12(9), 2230; https://doi.org/10.3390/agronomy12092230 - 19 Sep 2022

Cited by 1 | Viewed by 1186

Abstract

Yield and fruit quality are two of the most important parameters for the profitability of vegetable crops. In commercial vegetable production, nitrogen (N) is commonly applied in excess, which is associated with nitrate (NO₃⁻) leaching loss. In addition, excess N [...] Read more.

Yield and fruit quality are two of the most important parameters for the profitability of vegetable crops. In commercial vegetable production, nitrogen (N) is commonly applied in excess, which is associated with nitrate (NO₃⁻) leaching loss. In addition, excess N application may affect yield and fruit quality. The aim of this study was to evaluate the effect of N applications of very deficient N (N1, 2 mmol L⁻¹), deficient N (N2, 8 mmol L⁻¹), and conventional N (N3, 14 mmol L⁻¹), according to local fertigation practices, in soil-grown muskmelon and sweet pepper crops in Almeria, South-Eastern Spain. The evaluation was conducted in three cultivars of each species. The yield and the fruit quality parameters of firmness, colour, total soluble solids (TSS) and morphometric variables were evaluated in two years for each species. For most parameters in both species, the effects of N, when significant, occurred regardless of cultivar. In muskmelon and sweet pepper, application of 8.2 mmol N L⁻¹ (i.e., N2) was sufficient to achieve a maximum yield of 6.7 and 7.4 kg m⁻², respectively. In muskmelon, very deficient N application led to an increase of 58% in the percentage of fruit discarded, mostly due to malformed and undersized fruits. Fruit firmness and red–green axis coordinate (a*) were not consistently affected by N in any of the crops. However, the fruit lightness (L*) increased with N addition in both species, likely because of increased chlorophyll pigments. With N addition, fruit TSS slightly decreased in muskmelon and slightly increased in sweet pepper. However, fruit TSS of both species were within reference values for commercialisation in the three N treatments. There were differences in yield between cultivars in muskmelon but not in sweet pepper, likely due to differences in fruit number in muskmelon. There were differences between cultivars in TSS and colour a* coordinate in both muskmelon and sweet pepper. Cultivars with higher TSS and a* coordinate will likely be more desirable for consumers because of the sweeter taste and more intense orange colour in muskmelon and reddish colour in sweet pepper. Overall, our manuscript showed that N application can be reduced, relative to the conventional N application, without reducing yield or fruit quality in muskmelon, yet additional studies should be conducted in sweet pepper to complement the results of the 2020 crop. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Effect of Different Substrates, and Irrigation with Water with Different Saline Concentrations, on the Development of Tomato Fungal Diseases in an Almería-Type Greenhouse

by

Eugenio Ávalos-Sánchez

,

,

Francisco D. Molina-Aiz

,

Juan Reca

,

Patricia Marín-Membrive

and

Diego L. Valera-Martínez

Agronomy 2022, 12(5), 1050; https://doi.org/10.3390/agronomy12051050 - 27 Apr 2022

Cited by 1 | Viewed by 1113

Abstract

The aim of this research was to assess the effect of both the salinity level and the type of growing system on the vegetative health of a tomato crop (Solanum lycopersicum). The study was carried out in Almería (Spain) in a [...] Read more.

The aim of this research was to assess the effect of both the salinity level and the type of growing system on the vegetative health of a tomato crop (Solanum lycopersicum). The study was carried out in Almería (Spain) in a local typical greenhouse. Two different growing media were tested: (i) the artificial soil “enarenado” and (ii) a coconut fiber substrate. Each of these growing media was irrigated with water with three different saline concentrations: (i) T1 with an electrical conductivity of 0.6 dS/m, (ii) T2 with 1.5 dS/m, and (iii) T3 with 3.0 dS/m. Using the European and Mediterranean Plant Protection Organization (EPPO) regulations, two diseases were identified: (i) powdery mildew (Leveillula taurica) with a lower disease incidence in tomato plants grown in soil and in plants irrigated with decreasing salinity treatments and (ii) crown and root rot in tomato (Fusarium f. sp. radicis-lycopersici) with a lower incidence in tomato plants grown in soil and a higher incidence in tomato plants grown in coconut substrate. A higher yield was observed in tomato plants transplanted in enarenado than in coconut substrate, although a higher level of Brix degrees was observed in the crops with higher disease severity and salinity stress. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Analysis of Turbulent Air Flow Characteristics Due to the Presence of a 13 × 30 Threads·cm⁻² Insect Proof Screen on the Side Windows of a Mediterranean Greenhouse

by

Francisco-Javier Granados-Ortiz

,

,

Francisco D. Molina-Aiz

,

Choi-Hong Lai

,

María de los Ángeles Moreno-Teruel

and

Diego L. Valera-Martínez

Agronomy 2022, 12(3), 586; https://doi.org/10.3390/agronomy12030586 - 26 Feb 2022

Cited by 3 | Viewed by 1001

Abstract

Insect-proof screens are a frequent passive method to restrict the entrance of insects into greenhouses. However, the installation of these screens also has a negative effect on natural ventilation, which is reflected in the turbulence and velocity of the airflow inside the greenhouse. [...] Read more.

Insect-proof screens are a frequent passive method to restrict the entrance of insects into greenhouses. However, the installation of these screens also has a negative effect on natural ventilation, which is reflected in the turbulence and velocity of the airflow inside the greenhouse. The turbulent characteristics of airflow through an insect-proof screen installed in the greenhouse windows have not been studied thoroughly in the literature. The present work focuses on the use of two simultaneous 3D sonic anemometers to study the impact of the use of a 13 × 30 threads·cm⁻² insect-proof screen on the turbulence properties of the micro and microscale airflow turbulence. Four tests have been carried out in windward-oriented side windows of a Mediterranean greenhouse. Results demonstrate that the approach of using two simultaneous 3D sonic anemometers for the first time allows one to observe that the effect is different for the three components of the velocity vector field, and there is a strong connection between the simultaneous conditions inside and outside of the greenhouse. Useful information and data on the effect of using a 13 × 30 threads·cm⁻² insect-proof screen are also provided. To give details on the impact of screens in the turbulent properties of ventilation is essential for any commercial distribution, as well as providing important data in the design and development of more efficient insect-proof screens. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

The Influence of Different Cooling Systems on the Microclimate, Photosynthetic Activity and Yield of a Tomato Crops (Lycopersicum esculentum Mill.) in Mediterranean Greenhouses

by

María Ángeles Moreno-Teruel

,

,

,

Patricia Marín-Membrive

,

and

Agronomy 2022, 12(2), 524; https://doi.org/10.3390/agronomy12020524 - 19 Feb 2022

Cited by 3 | Viewed by 1396

Abstract

The purpose of this study was to analyse the effect of different evaporative cooling systems compared to natural ventilation on the microclimate, photosynthetic activity and yield of a tomato crop (Lycopersicum esculentum Mill.) in a spring-summer cycle. In this study, the expenditure [...] Read more.

The purpose of this study was to analyse the effect of different evaporative cooling systems compared to natural ventilation on the microclimate, photosynthetic activity and yield of a tomato crop (Lycopersicum esculentum Mill.) in a spring-summer cycle. In this study, the expenditure of electricity and water caused by the different refrigeration systems and their economic cost was analysed. The study was carried out in three multi-span greenhouses: (i) a greenhouse with evaporative pads and fans and natural ventilation (PS + NV); (ii) a greenhouse with a fog system and natural ventilation (FS + NV); (iii) a greenhouse only with natural ventilation (NV). The photosynthetic activity was higher in the greenhouse with natural ventilation (14.7 µmol CO₂ m⁻² s⁻¹) than in the greenhouse with the pad-fan system (14.6 µmol CO₂ m⁻² s⁻¹; without a statistically significant difference) and in the greenhouse with fog system (13.4 µmol CO₂ m⁻² s⁻¹; with a statistically significant difference). The production was higher in the greenhouse with the pad-fan system (5.0 kg m⁻²) than in the greenhouse with natural ventilation (4.8 kg m⁻²; without a statistically significant difference) and in the greenhouse with a fog system (4.5 kg m⁻²; with a statistically significant difference). In general, photosynthetic activity and crop production increased as the maximum temperature (and the number of hours of exposure to high temperatures) decreased. It has been observed that the improvement in temperature conditions inside the greenhouses in spring-summer cycles produces increases in the photosynthetic activity of the tomato crop and, consequently, growth in production. The energy and water consumption derived from the use of active-type cooling systems have not been offset by a representative improvement in photosynthetic activity or crop production. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Economic Analysis of the Use of Reclaimed Water in Agriculture in Southeastern Spain, A Mediterranean Region

by

María. J. López-Serrano

,

Juan F. Velasco-Muñoz

,

José A. Aznar-Sánchez

and

Isabel M. Román-Sánchez

Agronomy 2021, 11(11), 2218; https://doi.org/10.3390/agronomy11112218 - 02 Nov 2021

Cited by 4 | Viewed by 1402

Abstract

In a global context where agriculture is the major consumer of water, there is a pressing need to look for alternative water resources. In light of there being a lack of studies that compare the use of diverse water alternatives in different crops, [...] Read more.

In a global context where agriculture is the major consumer of water, there is a pressing need to look for alternative water resources. In light of there being a lack of studies that compare the use of diverse water alternatives in different crops, the overall objective of this research is to evaluate the impact generated by the use of tertiary water from an economic and financial perspective and compare it with groundwater and desalinated water. To reach this objective, a detailed study of the cost structure of greenhouse investment has been developed. Furthermore, the most traditional indicators for investment profitability have been calculated for the three different water alternatives: tertiary water, groundwater and desalinated water. The cost analyses demonstrate the relative short reach that the price of water has in an area of greenhouse agriculture exploitation, which provides a margin of increasing water costs while still allowing for economic profit. Taking into account the three water resources considered, evidence shows that the use of tertiary water is not only financially and economically viable but is also the best alternative water resource above desalinated water in terms of profitability and sustainability. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Monitoring Optical Tool to Determine the Chlorophyll Concentration in Ornamental Plants

by

Rafael Jiménez-Lao

,

Pedro Garcia-Caparros

,

Mónica Pérez-Saiz

,

Alfonso Llanderal

and

María Teresa Lao

Agronomy 2021, 11(11), 2197; https://doi.org/10.3390/agronomy11112197 - 30 Oct 2021

Cited by 3 | Viewed by 1473

Abstract

The accurate estimation of leaf photosynthetic pigments concentration is crucial to check the plant´s health. Traditional methods of measuring photosynthetic pigments involve complex procedures of solvent extraction followed by spectrophotometric determinations. Portable plant instruments such as Soil Plant Analysis Development (SPAD) meters can [...] Read more.

The accurate estimation of leaf photosynthetic pigments concentration is crucial to check the plant´s health. Traditional methods of measuring photosynthetic pigments involve complex procedures of solvent extraction followed by spectrophotometric determinations. Portable plant instruments such as Soil Plant Analysis Development (SPAD) meters can facilitate this task for the speed and simplicity of the measures. The relationship between chlorophyll index obtained by SPAD-502 and pigment concentration in several ornamental species can help in the management of ornamental plant production. Two trials have been carried out in two different growing seasons (spring and summer) and facilities (greenhouse and open air), involving 30 ornamental species. There was a high linear relationship between concentrations of Chla and Chlb, as well as between Chlt and Ct in different species studied under greenhouse and open field conditions. The ratio between Chla and Chlb was higher at open field conditions and similar between Chlt and Ct. There was also a good relationship between Chlorophyll index and Chlt under both growing conditions, as well as between Chlorophyll index and Ct under greenhouse conditions. However, linear relationships with different slopes were observed for groups of species at open field conditions. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

Low Tunnels inside Mediterranean Greenhouses: Effects on Air/Soil Temperature and Humidity

by

María de los Ángeles Moreno-Teruel

,

Francisco D. Molina-Aiz

,

,

María de los Ángeles Moreno-Teruel

,

Fátima J. F. Baptista

and

Diego L. Valera-Martínez

Agronomy 2021, 11(10), 1973; https://doi.org/10.3390/agronomy11101973 - 30 Sep 2021

Cited by 1 | Viewed by 1779

Abstract

The main objective of this work was to analyze the microclimate generated inside a low tunnel (floating row cover) installed in an Almería-type greenhouse. Low tunnels are commonly used in the open field to protect plants against insect attack and to improve the [...] Read more.

The main objective of this work was to analyze the microclimate generated inside a low tunnel (floating row cover) installed in an Almería-type greenhouse. Low tunnels are commonly used in the open field to protect plants against insect attack and to improve the production of muskmelon and strawberry. Floating row covers can also be used inside greenhouses during the first few weeks after the transplantation of muskmelon and watermelon crops in spring-summer cycles. This work was carried out during the first weeks of a watermelon culture (Citrullus lanatus Thunb.) growing with a polyethylene row cover inside an Almería-type greenhouse (2115 m²). Air temperature and humidity, plant temperature and soil temperature and humidity were measured in the greenhouse inside and outside the row covers. During the three days of measurement, all greenhouse vent openings were closed. The use of the low tunnels increased average air temperature around plants from 24.0 ± 9.0 °C to 26.9 ± 9.7 °C. A maximum difference in air temperature of about 5.9 °C was observed at noon. The average daily temperature of the crop was 28.2 ± 11.8 °C inside the row cover and 24.6 ± 8.9 °C without it. Similarly, the absolute humidity of air was clearly higher inside the low tunnel (0.0201 ± 0.0098 g/g) than around the plant rows without floating cover (0.0131 ± 0.0048 g/g). The soil temperature was also higher inside the low tunnel compared to the area without this second plastic cover. The effect of the tunnel decreased with depth, with average temperature differences of 1.2 ± 0.5 °C on the soil surface and 0.6 ± 0.5 °C at 20 cm depth. Full article

(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)

► Show Figures

Figure 1

Open AccessArticle

The Effect of Diffuse Film Covers on Microclimate and Growth and Production of Tomato (Solanum lycopersicum L.) in a Mediterranean Greenhouse

by

,

,

,

and