Shading Nets Research Articles

ECONOMICAL EVALUATION OF MANGO (CV. KEITT) TREES UNDER COLOURED SHADE NETS

This study explored the economical viability of five different coloured shade nets (White, yellow, red, blue and black) on mango production (Mangifera indica L. cv. Keitt). This study investigated the climatic parameters in terms of light intensity, minimum and maximum air temperature, relative humidity and plant growth across 2019 and 2020 seasons. When compared to open field conditions, coloured shade nets resulted in higher maximum temperatures and relative humidity. The black net cover and open field treatments gave the lowest mango yield compared to all greenhouse net cover. When compared to the other treatments, the use of white or yellow nets resulted in a considerable increase in the number of fruits and total yield per plant. According to prevailed conditions, it could be concluded that optimum microclimate for growing mango in similar conditions could be obtained under white and yellow nets compared to the other net covers. Black greenhouse net cover gave the lowest productivity during the experimental duration. Production costs, total revenue, net return and ratio of total revenue to cost for Keitt mango in Egypt are presented in this study. The result shows that the net return for white net reached 15777 Egyptian pound (LE) and LE 15270 per m2 in 2019 and 2020 respectively, which was 2.63 times those grown in the open field (LE 5980 and LE 5081 per 2000 m2) in 2019 and 2020 respectively. However, Revenue to cost ratio was found higher in white net in both seasons which were 1.9 and 1.8 respectively.

Modification of Light Characteristics Affect the Phytochemical Profile of Peppers

Capsicum is one of the most economically important genera in the Solanaceae family. Capsicum fruits (peppers) are rich in phytochemicals with high nutritional value and significant health-promoting characteristics. The phytochemical profile of peppers consists of capsaicinoids, carotenoids, and phenolics, primarily. Currently, most of the pepper production is carried out under protected horticulture conditions. The objective of this article was to provide a comprehensive review on how light characteristics and manipulation by different horticultural technologies can affect the biosynthesis and accumulation of phytochemicals in Capsicum fruits. The use of shade nets or plastic covers to reduce light intensity does not seem to yield consistent responses on the phytochemical profile, as the final profile results from the interaction of several factors. Other factors involved in the accumulation of phytochemicals include temperature, water availability and plant nutrition. Exposure of plants to supplemental light with specific wavelengths (using LEDs) seems to result in a more precise stimulation of specific metabolites. In this article, we examine the effects of light irradiance and spectrum on the specific phytochemicals of Capsicum fruits.

Efeect of Environmental Parameters on Chrysanthemum Different Colour Low Tunnel Shade Nets and Different Colour Mulches

Shade nets are used for controlling the crop growth and improving crop productivity. A field experiment was conducted under shade net to determine the effect of environmental parameters on chrysanthemum under on different colour low tunnel shade nets. The experiment had split plot design consisting of different colour shade nets as main plots i.e., white shade net, green shade net, black shade net and open field condition and different mulches as a sub plots i.e., white colour plastic mulch, silver colour plastic mulch, black colour plastic mulch, jute mulch and no mulch. White colour shade net significantly increased the soil moisture and lowered the soil temperature compared to other colour shade nets. During the experimental period, maximum temperature (37.90 °C) was recorded under control condition followed by black shade net (35.80 °C) and green shade net (34.60 °C). Minimum temperature (33.00 °C) was recorded under white shade net. Maximum relative humidity (86.20 %) was recorded under white shade net followed by green shade net (82.30 %) and black shade net (79 %). Minimum relative humidity (77 %) was recorded under control condition. Maximum light intensity (49600 Lux) was recorded under control condition followed by white shade net (46800 Lux) and green shade net (37,000 Lux). Minimum light intensity was recorded under black shade net (33210 Lux). The results of biometric parameters depicted higher growth and yield parameters for chrysanthemum grown under white shade net with white plastic mulch. The yield of Chrysanthemum was increased in white shade net (8.75 t ha-1) than the black shade net (4.43 t ha-1). Chrysanthemum grown in open fields and without mulch produced lower growth and yield.

Growth, Photosynthesis, and Gene Expression of Bermudagrass in Response to Salinity and Shade Stress

Soil salinization is an environmental problem globally. Bermudagrass (Cynodon dactylon) has long been used for soil restoration in saline-alkali land. Urbanization and the compound planting pattern combining trees, bushes, and grasses induced shading are becoming one of the most significant environmental constraints on the management of bermudagrass, which directly affects photosynthetic characteristics. Salinity and shade have become the most important environmental constraints on lawn development and implementation. Previous studies have shown that the plant physiological response under combined stress was different from that under single stress. The purpose of this research was to investigate the effects of salinity stress, shade stress, and the combined stress on bermudagrass. Shade nets were used to simulate shade stress to 85% shade. The NaCl concentration gradient for salinity stress was 1.0% for 7 days, 1.5% for 7 days, and 2.0% for 13 days, respectively. The combined stress combines the two approaches mentioned previously. The results showed that the salinity stress significantly inhibited the plant height, leaf relative water content, chlorophyll content, the chlorophyll a fluorescence induction (OJIP) curve and other photosynthetic parameters of bermudagrass while increasing electrolyte leakage when compared with control. Shade stress significantly enhanced the plant height, chlorophyll content, electrolyte leakage, the OJIP curve, and other photosynthetic parameters. Under the combined stress, the plant height and relative water content did not change significantly, but the photosynthetic parameters such as chlorophyll content and the OJIP curve increased. Furthermore, under the combined stress, the photosynthesis-related genes were regulated. Salinity stress inhibited the photosynthetic ability of bermudagrass more than shade stress, while the combined stress exhibited a considerably better photosynthetic ability. These findings provide information for the usage of bermudagrass in salinized shade conditions.

Sombreamento melhora a produtividade de berinjela e pimentão em casa-de-vegetação no verão

ABSTRACT Shading is a way of cooling in hot and sunny areas to modify the microclimate and improve crop growth. This study aimed to evaluate the effect of shading treatments on eggplant and sweet pepper growth, under plastic house conditions, at the beginning of the summer, when there are high temperatures and solar radiation intensity. The plastic covers were lifted at the beginning of April and the shading nets used in May and June. The shading treatment improved the plant height, vegetative weight, number of fruits per plant, fruit weight, plant yield and total yield per plastic house for both crops, especially for the sweet pepper. The sweet pepper hybrid (Charisma) and the local variety of eggplant showed the highest values for most of the studied characteristics.

Growth and development of Greek basil variety Medinette in greenhouses and shade netting

Growth parameters were evaluated in plants of Ocimum basilicum L. variety Medinette, in two indoor production environments: a greenhouse and a shade net. Plant height, number of branches and leaves per plant, and leaf area were measured. Growth parameters such as leaf area index (LAI), relative growth rate (RGR) and net assimilation rate (NAR) were estimated up to 45 days after transplanting (ddt). The plant and its organs showed sigmoidal growth in the two protected environments. Growth kinetics, height, number of leaves and branches produced per protected environment showed significant differences (P≤ 0.05), these parameters being higher for plants grown in shade netting. The physiological efficiency parameters showed an IAF of 0.53 and 1.28 for plants grown in greenhouse and shade net, respectively. The CRT presented the maximum value (0.14 mg mg-1 day-1) at 35 ddt for plants grown in shade net. The TAN was 0.078 mg cm2 day-1 for plants in the shade net. Temperature and relative humidity conditions in the greenhouse caused a reduction in growth and physiological efficiency indices in basil.

Microplastics contamination and characteristics of agricultural groundwater in Haean Basin of Korea

The quality of groundwater is critical to human health. MPs have access to groundwater from the soil, polluted by various agricultural activities. However, to date, there have been no studies on the occurrence of MP in groundwater from an agriculture field without any adjacent sources of contamination, such as nearby landfills. In this study, the occurrence and distribution of MPs in groundwater of an agricultural area in the Haean Basin, Korea, without any definite source of pollution, was examined. MP and groundwater samplings were conducted in the dry season in 2020, the wet and dry seasons in 2021, respectively. In this study, the reliability of MP analysis was improved through good practices from laboratory to field campaigns, collecting large groundwater samples (300–500 L) volumes. Any involvement of plastic materials was avoided during the full procedures as possible and. Detailed investigation was conducted for the distribution of potential plastics sources like mulching, plastic covers, dripping pipes and shading nets, and hydrogeological properties affecting MPs occurrence. Groundwater MP concentrations of 0.02–0.15 particles/L (median = 0.06 particles/L), 0.02–2.56 particles/L (median = 0.43 particles/L) and 0.20–3.48 particles/L (median = 0.83 particles/L) were found in three rounds of sampling that comprised of the exploratory investigation in 2020, the wet season, and the dry season in 2021, respectively. The identified polymer types were polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS) and polyamide (PA). The MPs concentrations showed no statistically significant seasonal variation but revealed an apparent strong positive correlation (r = 0.71) of MPs with the amount of groundwater use. Findings of this study need more clarification from repeated samplings for multiple years. This study reveals the occurrence of MPs in groundwater in Korea for the first time to the best of our knowledge.

Shading Net and Partial Covering Plastic Film Do Not Affect Phenology, Photosynthetic Activity or Fruit Quality Traits of Kensington Pride Mango.

Mango cultivation in a protected environment is becoming widespread in the Mediterranean basin where the species has to face unfavorable weather conditions which do not occur in its native cultivation areas. Besides open-air cultivation, greenhouses-and other protection systems such as shading nets and partial covering of plastic films-have been tested recently. In this study, we focused on assessing the effect of a shading net, and a partially covering plastic film, on the development of "Kensington Pride" mango fruit skin-color, its final quality, and the plants' photosynthetic activity. A new method of measuring mango skin-color on different sides of the fruit is proposed. No difference was observed with regard to the observed parameters between the plants cultivated under the two different protection systems and those growing in the open air. It can, therefore, be stated that such cultivation techniques do not alter the development of the mango fruit and its appearance, nor the plant's photosynthetic activity.

Crescimento, desenvolvimento e qualidade do gladíolo ‘White Goddess’: época de cultivo, tela de sombreamento e cobertura do solo

ABSTRACT To reduce the risks associated with the production of gladiolus flowers in the climatic conditions of southwestern Paraná, Brazil, this study characterized the growth, development, and floral stem quality of plants cultivated under different-colored shade nets and mulching in four growing seasons. The gladiolus cultivar ‘White Goddess’ was grown in beds with and without mulching in the soil. Three shade nets individually stained black, silver and red all with 35% shading, were used in this study, and an additional treatment (control) in which plants were grown in full sun. Growth (LAI and height), development (cycle in days, and degree-days), and flower quality (size and stem damage) were evaluated in eight plants in each treatment. Plants were distributed in a randomized block design in a factorial scheme (season x mulching x shade screen). The cycle ranged from 66 to 89 days and 1732 to 1268°C day. The mean difference of the cycle between treatments was 3 days. Less floral stem damage happened under silver net and was more in full sun. The shading net associated with mulching favored the growth characteristics of the plants, and in autumn, the flowers had the highest quality standard.

The Yield, Chemical Composition, and Antioxidant Activities of Essential Oils from Different Plant Parts of the Wild and Cultivated Oregano (Origanum vulgare L.)

The present study focuses on the yield, chemical composition, and antioxidant activity of essential oils from different parts (flowers or leaves/stems) of cultivated plants grown under pearl shade nets with a 40% shaded index or in nonshaded plants and wild-grown oregano. The chemical composition of isolated essential oils was determined by GC/MS and GC/FID. Antioxidant activity was determined using the DPPH assay. The highest yield of oregano essential oils (OEOs) was obtained in cultivated shaded plants (flowers) at 0.35 mL/100 g p.m., in contrast to nonshaded plants (flowers), where the yield of OEOs was low (0.21 mL/100 g p.m.). Qualitative and quantitative analyses of the OEOs identified 16–52 constituents that varied with origin and plant organs. The oxygenated sesquiterpene caryophylleneoxide (7.4–49.9%) was predominant in all the essential oil samples. Other major constituents were sesquiterpene hydrocarbon-germacrene D (8.4–22.5%) and (E)-caryophyllene (8.5–10.8%), monoterpene hydrocarbon-sabinene (1.6–7.7%), and oxygen-containing monoterpenes-terpinen-4-ol (1.5–7.0%). The plant part has a significant effect on the antioxidant activity of OEOs, while the influenceof modified light under the shade nets is significantly lower. The OEOs from wild flowers showed the highest antioxidant activity, with an EC50 value of 4.78 mg/mL. OEOs from cultivated nonshaded plants (flowers) recorded the lowest antioxidant activity with an EC50 value of 24.63 mg/mL. The results suggest that the yield and quality of OEOs can be scaled-up by optimizing plant production in comparison with wild-growing plants. The content and quality of OEO can be increased by optimizing its production compared to plants from the spontaneous flora. Adequate cultivation techniques, such as shading, can achieve high-quality oregano yields and better quality parameters in terms of specific OEO components and meet the different requirements of the market and industrial sectors.

Environments and substrates for “pimenta-de-cheiro” (Capsicum chinense Jacq.) seedling production in the Amazon savana

Quality seedlings production is one of the most important steps in the cultivation of vegetable species. In this sense, the objective was to evaluate the influence of different environments and substrates on the production of “pimenta-de-cheiro” (Capsicum chinense Jacq.) seedlings in Boa Vista, Roraima. An experiment was installed in a completely randomized design (CRD), with treatmentsarranged in subdivided plots. Five environments were evaluated: AG - agricultural greenhouse; TV35 - red shading net with 35% shading (red ChromatiNet®); TV50 - red shading net with 50% shading (red ChromatiNet®); TP35 - silver shading net with 35% shading (ChromatiNet® silver) and TP50 - silver shading net with 50% shading (ChromatiNet® silver) and four substrates: O -OrganoAmazon®; OP - OrganoAmazon® and PuroHumus®; OPSE (OrganoAmazon®, PuroHumus®, soil and manure) and OPSEC (OrganoAmazon®, PuroHumus®, soil, manure and carbonized rice husk). On the TP35 and TP50 shading nets, the C. Chinense grown on the OP substrate showed high Dickson’s quality index (DQI). The combination agricultural greenhouse (EA) and OPSE substrate promoted superior quality Capsicum chinense seedlings. The substrates OPSEC and OPSE are more affordable alternatives for the production of Capsicum chinense seedlings. Shading nets, associated with the alternative substrates, do not favor the production of quality Capsicum chinense seedlings under Amazon savanna conditions.

Carbon dioxide and light curves and leaf gas exchange responses to shade levels in bell pepper (Capsicum annuum L.)

Vegetable crops grown under shade nets typically show increased yield and quality. However, little is known about the photosynthetic responses at various CO2 and light levels under nets. This study aimed to determine carbon dioxide (A/Cc) and light (A/I) curves and leaf gas exchange response of bell pepper plants grown under nets at various shade levels. Experiments were conducted in the spring-summer of 2016 and 2018 in Tifton, Georgia (GA), USA, with five shade treatments [0 % (open field), 30 %, 47 %, 63 %, and 80 %]. The A/Cc curves revealed that plants grown at 30 % shade and in the open field had similar carboxylation, electron transport, and triose phosphate utilization rates. The A/I curves showed that gross and net photosynthesis were highest at 30 % shade. The 30 % shade had similar stomatal conductance, intercellular CO2, electron transport rate, and water use efficiency compared to the open field. The A/Cc and A/I curves and the leaf gas exchange parameters explained the intrinsic causes for the higher net photosynthesis at 30 % shade than in open-field bell pepper. The information from A/Cc-curves, A/I-curves, and leaf gas exchange is applicable in modeling photosynthesis and predicting primary productivity for C3 plants in elevated-CO2 and altered-light environments.

Oil Palm (Elaeis guineensis Jacq.) Shaded Model at Immature Stage II and Application of Arbuscular Mycorrhizal Fungi (AMF) on Growth and Yields of Soybean (Glycine max (L.) Merrill

The practice of intercropping soybeans among oil palm trees is an approach used to optimize plantation land. Oil palm (OP) at the second immature stage (IS-2) or the age of 2 years provides shade of around 40%. This research aimed to observe soybean growth and yields under shade conditions close to those of oil palm shading conditions at IS-2 and to determine the optimal dosage of Arbuscular Mycorrhizal Fungi (AMF) to apply to the soybeans. The shade intensity treatment used artificial shading nets close to actual shade intensity in OP plantation, i.e., 40% shading. The experiment was conducted at the Experimental Station, Faculty of Agriculture, Universitas Padjadjaran, from October 2019 to January 2020. The experimental design used was a split-plot design with shade intensity as the main plots (0 and 40%) and AMF dosage as subplots, consisting of six treatments of 0, 2, 4, 6, 8, and 10 g/plant, with each treatment repeated four times. The results showed that at 10 weeks after planting, the interaction effect of 40% shade intensity with a dosage of 10 g AMF per plant resulted in the highest chlorophyll index. Independently, the AMF dosage of 10 g per plant produced the maximum plant height, number of productive branches, dry weight of plants, and number of seeds per pod.

Influence of Coloured Shade Nets On Growth And Biochemical Constituents In Four Species of Ocimum

Effects of different coloured shade nets (red, green, black, green, white net) and control (without net) on the biochemical and growth responses in four Ocimum spp. namely O. tenuiflorum L., O. sanctum L., O. basilicum L. and O. gratissimum L. were investigated. Results showed that plants kept under red net consistently outperformed other treatments recording significantly higher growth and biochemical characteristics for all selected Ocimum spp. after 120 days of transplantation. Parameters like shoot length (128.77 ± 4.00 cm), root length (81.48 ± 0.75 cm), leaf number (319.10 ± 3.38), total fresh biomass (158.17 ± 12.82 g/plant) and total dry biomass (63.88 ± 1.37 g/plant) witnessed a 3.38, 2.95, 2.76, 4.17 and 5.16% increase, respectively under red net over control. Plants under red net also recorded a significant increase of 9.68, 14.10 and 28.18% for total phenols (127.50 ± 2.95 mg/g DW), flavonoids (18.33 ± 2.71 mg/g DW) and alkaloids (32.31 ± 2.87 mg/g DW), respectively. Bangladesh J. Bot. 51(3): 547-554, 2022 (September)

Effect of UV LED Intensity on The Growth of Red Lettuce in Indoor Hydroponics

Microclimate control is increasingly widespread in limited agricultural environments. This is especially important for the cultivation of plants that tolerate significantly different thermal and hygrometric conditions. Nevertheless, there is much to be done in automation and control technology in this area to achieve the best results in both quantitative and qualitative terms of the product. This applies especially to horticultural crops that are sensitive to the cultivation environment and microclimate. This work aims to characterize the microclimate parameters in a confined agricultural environment with perforated ducts for air conditioning supply. For this work, a microclimate control unit was used instead of a lettuce crop. It was placed into a confined agricultural environment at different locations in the space to obtain the main microclimate parameters. After setting the input of the microclimate environment, the instrument measured a series of physical quantities (temperature, radiant temperature, humidity, and air velocity). Tests were carried out by taking the optimum day temperature constant for growing lettuce and by varying the supply airflow rate by setting the fan speed at 30%, 50%, and 80%. The results of these tests are essential for performing real-time control of the microclimate environment and for managing parameters for optimization of the entire system. In addition, the air velocity test showed adequate velocity reduction and good air mixing. The values obtained are generally acceptable for indoor cultivation and the conditions created are suitable for growing plants in such an environment. Light is an essential need for plants so that plants can carry out the photosynthesis process properly. In indoor DWC hydroponics system, the source of UV light is LED lights for plants. Some of the advantages of using LED light include a small light spectrum, less heat production, low power consumption, and wavelengths of 660 m and 450 m that are needed by plants. This research project aims to create a DWC hydroponic system for growing red lettuce in an indoor hydroponics and see the effect of LED grow light on the growth of red lettuce. DWC hydroponics uses AB-Mix nutrients that are channeled through inch PVC pipes using pump power. The hydroponic rack used has a height of 1.7 m and a width of 40 cm and has 3 shelves, where each shelf has 9 nutrient containers. The red lettuce plants in the DWC system were provided with different light treatments by installing shading nets with different percentages of light penetration, namely, 75%, 50%, and 0%. From the results of these treatments, the average yield of red lettuce was 300 grams on the top shelf, 400 grams on the middle shelf, and 600 grams on the bottom shelf.

Black Shade Net Effects on Soil Properties and Cabbage Water Use Efficiency in Humid Coastal Environment

Cabbage is a popular vegetable grown in Kenya for food and income generation. Despite the important role played by the crop within the country, current climate change effects and population pressure pose a need for increasing production through utilization of available resources. A study was therefore conducted to evaluate the effects of black shade net on soil properties and cabbage water use efficiency in humid coastal environment. Black shade nets of 0%, 50% and 70% shading intensity and two cabbage types (Brassica rapa and Brassica oleracea) were evaluated in Randomized complete block design with three replications. 0% represented open field. Data collected included: soil chemical characteristics, soil moisture content, air temperature, fresh head weight, dry matter weight, and water use efficiency. Data obtained were subjected to analysis of variance using general linear model SAS Computer package version 9.1 and means separated using Tukey’s test at 5%. From the findings obtained, the use of black shade net of 70% and 50% shading significantly increased soil moisture content by 5.1% and 2.6% than open field. Maximum air temperature in 70% and 50% shade nets was lower than open field by 4.6⁰C and 1.8⁰C respectively while minimum air temperature under 70% and 50% shade nets was higher than open field by 2.7⁰C and 1.6⁰C respectively. Brassica rapa from 70% shading had 35% more fresh weight per plant than open field while those from 50% had 30%. Brassica oleracea from both 70% and 50% shading had 44% and 29% more fresh weight per plant respectively than those from open field. Although shade nets did not have significant effect on availability of nutrients within soil solution, Brassica rapa under 70% shading recorded 49% higher water use efficiency than open field while, 50% shading recorded 50% more WUE than open field. Brassica oleracea under 70% shading recorded 41% higher water use efficiency than open field, while 50% shading recorded 25% increase than open field. Owing to the fact that shade nets did not have significant effect on available nutrients within the soils but significantly influenced WUE, there is need for further studies to understand the effects of shade nets on cabbage nutrient use efficiency under the same environment.

Impact of Different Colour Low Tunnel Shade Nets and Mulches on Water use Efficiency and Nutrient use Efficiency in Chrysanthemum

An investigation was carried out in an experimental field of the College of Agricultural Engineering, University of Agricultural Sciences, Raichur, to investigate the effect of different coloured low tunnel shade nets and different mulches on water use efficiency and nutrient use efficiency of chrysanthemum. The results revealed that the values of daily evapotranspiration under different colours’ low tunnel shade net were less than the values of evapotranspiration under open field for all months. It is because of the green-house effect and low radiation. The values of ET during the seasons were lower under white-coloured shade net compared to open field conditions. The results indicate that significant irrigation water savings occur in chrysanthemums under different coloured low tunnel shade nets as compared to open field cultivation. It is also found that the chrysanthemum crop requires approximately 31%, 28%, and 23% less water under white, green, and black shade net compared to the total water required under open field cultivation. The highest water use efficiency was recorded with the white colour low tunnel shade net (28.78 kg ha-1 mm-1) and this was followed by the green shade net (28.64 kg ha-1 mm-1), black shade net (13.09 kg ha-1 mm-1) and lowest water use efficiency was recorded under open field conditions (10.58 kg ha-1 mm-1). Among the different mulches, the highest water use efficiency was recorded by the use of white coloured mulch (24.36 kg ha-1 mm-1) and this was followed by silver mulch (21.75 kg ha-1 mm-1), black mulch (20.82 kg ha-1 mm-1), and jute mulch (19.38 kg ha-1 mm-1). The lowest water use efficiency was recorded where mulch was not used (15.05 kg ha-1 mm-1). The highest nutrient use efficiency was recorded with the white colour low tunnel shade net (Nitrogen (N)=72.51 kg ha-1, Phosphorous (P)=12.37 kg ha-1 and Potassium (K)=73.84 kg ha-1 ) and this was followed by the green shade net (N=66.77 kg ha-1, P=10.28 kg ha-1 and K=64.33 kg ha-1), open field conditions (N=58.08 kg ha-1, P=8.72 kg ha-1 and K=56.36 kg ha-1) and lowest nutrient use efficiency was recorded under black shade net (N=51.60 kg ha-1, P=6.98 kg ha-1 and K=49.75 kg ha-1). Among the different mulches, the highest nutrient use efficiency was recorded by the use of white colour mulch (N=77.53 kg ha-1 P=11.74 kg ha-1 and K=73.20 kg ha-1) and this was followed by silver mulch (N=70.50 kg ha-1, P=10.61 kg ha-1 and K=66.86 kg ha-1), black mulch (N=65.08 kg ha-1, P=9.51 kg ha-1 and K=64.09 kg ha-1), and jute mulch (N=57.75 kg ha-1, P=8.96 kg ha-1and K=64.09 kg ha-1). The lowest nutrient use efficiency was recorded where mulch was not used (N=40.22 kg ha-1, P=7.11 kg ha-1 and K=44.44 kg ha-1). The results indicated that there is a bright scope for cultivation of chrysanthemum under white colour low tunnel shade net with white plastic mulch.

Aroma Profile and Antioxidant Activity of Sweet Basil Aqueous Extracts Affect by Light Modification

This study examines the action of light modifications by different shade nets (pearl, red and blue color nets with a shade index of 50%) in relation to unshaded plants from the open field on the relative effects on changing basil aroma profile and antioxidant activity. The most abundant components were linalool, 1,8-cineole and myrcene. Aqueous extracts were isolated from basil leaves using maceration and ultrasound-assisted extraction. Yield of total extractive matters depends on both the extraction technique applied and the growing conditions used. The highest yield of total extractive matter (30.50 g/100g) was obtained by maceration from open field-grown basil. The highest content of total phenols (106.52 mg GAE/g), flavonoids (19.74 mg RE/g) and antioxidant activity (EC50 - 7 µg/mL) was found under a red net. The isolated water extracts are a source of natural antioxidants with potential application in the food and pharmaceutical industries.

Plant water status, plant growth, and fruit yield in bell pepper (Capsicum annum L.) under shade nets

Shade nettings can be an effective technology for producing bell pepper under warm conditions. The physiological mechanisms through which shade nets improve plant growth and fruit yield are still not fully understood. The objectives were to determine the effects of shade level on plant and soil water status, plant growth and fruit yield of ‘Aristotle’ bell pepper. Trials were conducted in the spring/summer of 2017 and 2018 in Tifton, GA, following a randomized complete block design with five shade levels [0% (open field), 30%, 47%, 63%, and 80%]. Photosynthetic photon flux rate (PPFR) and leaf temperature decreased while soil water content and leaf water potential increased with shade level, indicating reduced plant water use due to reduced evaporative demand under shaded conditions. Increased shade levels resulted in enhanced plant growth in part because of improved plant water status. Total fruit yield and number of sunscalded fruit diminished with increasing shade level, while marketable yield was maximal at 30% shade. The incidences of soil-borne diseases [Phytophthora blight (Phytophthora capsici) and southern blight (Sclerotium rolfsii)] decreased with increasing shade levels. Overall, a shade level of 30% was found to be optimal and allowed production of maximal fruit yield through improving water availability (plant and soil water) and minimizing abiotic (drought, light, temperature) and biotic (pathogens) stresses.

Effects of Shade Nets on The Microclimate and Growth of Tomato

This study evaluated the effects of the shading nets with photoselective features, with an open-field control. The green-shade net with shading intensity of 40% and the blue, pearl, and yellow-shade nets with shading intensity of 75% were used as netting materials. The total radiation and photosynthetically active radiation (PAR) transmittance of the shade nets were analyzed. The environment conditions such as air temperature, relative humidity and canopy temperature were measured with the aid of appropriate sensors. Tomato growing was realized in the aim to determine the effects of shade nets on the crops cultivated under the shade nets, in contrast to the open field conditions. Vegetative growing parameters, fruit quality parameters and the yield were assessed in the study. This investigation revealed that shading resulted in an evident increase in the total yield and the pearl-shade nets should be the better choice for producing a high quality tomato crop, based on PAR transmittance (between 44.8 and 52.8%).