Shade Index Research Articles

Measuring shaded bike lanes for heat stress mitigation with deep learning: A case study in Amsterdam, Netherlands

As global warming intensifies and heatwaves become more frequent, thermal comfort has emerged as a crucial factor in creating habitable and equitable urban environments. Cities worldwide are promoting sustainable transportation and reducing vehicle usage by enhancing cycling infrastructures. However, the thermal comfort of cyclists has often been neglected, with most research focusing on pedestrians. This study introduces a framework for evaluating shade levels along the bike lanes by incorporating a ‘Shade Index’ that quantifies street shadiness. Utilizing deep learning techniques, the index analyzes street view images from various bike lane locations to evaluate the contribution of trees and buildings in providing shade. The application of this framework is a shade rating map of the bike lanes in Amsterdam, providing cyclists with alternatives that prioritize coolness over the shortest routes typically suggested by map applications, particularly useful during warmer weather. The study identifies significant variability in shade provision, with central urban areas typically more shaded than outlying regions. The workflow can be adapted to other cities to enhance shade provision for cycling infrastructures.

Influence of plant community on Aedes albopictus (Diptera, Culicidae) oviposition behaviour: Insights from a Spanish botanical garden

Mosquitoes are capable of transmitting pathogens of both medical and veterinary significance. Addressing the nuisance and vector roles of Aedes albopictus through surveillance and control programs is a primary concern for European countries. Botanical gardens provide suitable habitats for the development of Ae. albopictus and represent typical points of entry of invasive species. To assess the oviposition preferences alongside various biotic parameters (plant species community, shade index, and flowering), we conducted a study in a botanical garden of Sóller (Mallorca, Balearic Islands, Spain). A total of 6,368 Ae. albopictus eggs were recorded in 36 ovitraps positioned and revised every 15 days in seven different habitats over six months in 2016. Zero-inflated and generalized linear mixed-effects models were used to analyse Ae. albopictus habitat preferences. The number of eggs increased throughout the sampling period, peaking in September. The oviposition rates showed a patchy distribution, with Ae. albopictus showing preference for oviposition in laurel forest and cropland habitats. A positive effect of large leaves and presence of flowers on the oviposition of Ae. albopictus were also recorded. This study provides valuable information into the behaviour of Ae. albopictus in botanical gardens, which is essential data for informing surveillance and control programs.

Chemical Composition and Bioactivity of Dill Seed (Anethum graveolens L.) Essential Oil from Plants Grown under Shading

This study determined the content and composition of dill seed (Anethum graveolens L.) essential oil under varying light conditions: non-shaded plants in open fields and plants covered with pearl shade nets (40% shade index). Essential oil was extracted using Clevenger hydrodistillation. The essential oil content was 4.63% for non-shaded plants and 4.81% for shaded plants. GC/MS analysis revealed twenty-one and twenty-two components in dill seed from non-shaded and shaded plants, respectively. The terpenic fraction of essential oil from non-shaded plants consisted mainly of oxygen-containing monoterpene derivatives (53.6%), with carvone (46.1%) as the primary component, followed by monoterpene hydrocarbons (46.4%), predominantly limonene (43.8%). Essential oil from shaded plants contained a higher content of carvone (49.8%) and a lower content of limonene (37.8%) compared to essential oil from non-shaded plants. Non-shaded plant essential oil exhibited stronger antioxidant activity (EC50 value: 26.04 mg mL−1) than shaded plant essential oil (54.23 mg mL−1). Dill seed essential oil showed the most potent antimicrobial activity (disc diffusion method) against Escherichia coli (inhibition zone: 15–18 mm). Shaded plants demonstrated a positive influence of essential oil against Klebsiella pneumoniae. Carvone and its derivatives, as the main components, hold significant potential in the food industry and alternative medicines. A practical implication of this study could be higher plant densities or intercropping of dill, as it thrives with minimal light.

Phytochemical composition and antimicrobial activities of the essential oils from summer savory (Satureja hortensis L.) growing in shading condition

This study was conducted to investigate the effect of plant shading (covered by pearl shade nets with a 40% shade index or nonshading plants from open field) on the content and composition of essential oils extracted from summer savory (Satureja hortensis L.) during the flowering stage cultivated under the ecological conditions of Serbia. The summer savory essential oil (SSEO) was extracted by Clevenger hydrodistillation. According to the GC/MS analysis of the SSEO, twenty-five and twenty-six components were detected in the non-shaded and shaded plants, respectively. The yield of SSEO from non-shaded plants was 1.64%, while SSEO from plants covered by shade nets was 1.76%. Carvracol (48.7–53.25%) and γ-terpinene (32.7%–36.8%) were found to be the main components in SSEO, followed by p-cymene (3.4%-3.2%), α-terpinene (2.9%-3.5%) and limonene (1.9-1.3%). In the DPPH assay, SSEO showed an IC50 of 0.99 μg mL−1 in shaded and an IC50 of 1.01 μg mL−1 in non-shaded plants. Additionally, SSEO exhibited strong antibacterial activity against Escherichia coli (44.3–48 mm inhibition zone), Bacillus subtilis (34.7–41.0 mm), Klebsiella pneumoniae (28.3–29.0 mm) and Proteus vulgaris (21.0–24.3 mm). A possible practical application of this study would be to grow summer savory at higher plant densities, or as an intercrop, because it does not require too much light for production.

Qualitative Analysis of the Cooling Potential of the Streetside Vegetation of Kharagpur, West Bengal, India

The urban heat island (UHI) effect is a major challenge in contemporary urban planning. The large number of paved surfaces, anthropogenic activities and combustion of fossil fuels are the major contributors of this phenomenon. Urban green spaces are known to mitigate the UHI. Since streets constitute a major portion of the urban areas, greening the streets can help reduce heat stress significantly. To study the impact of orientation and density of the street side vegetation on their cooling potential in Kharagpur, West Bengal, India.
 A suitable site, meeting the orientation and the density of vegetation criteria, was chosen for collecting the primary data through an instrument survey. Ambient temperature, surface temperature and solar radiation data was collected from the thirteen cross-sections marked across the site. As part of the preliminary data processing, relative variations of ambient temperature, surface temperature and the solar radiation attenuation was calculated. The values pertaining to these three secondary parameters were used to form matrices corresponding to each of the trees of each of the cross-sections. These matrices were then compared with their corresponding matrices to estimate which side exhibited a higher cooling potential. Besides, a colour-coded matrix was also generated from the calculated shade index to evaluate the amount of incident solar radiation blocked by each of these trees.
 This study corroborates the previous findings that the shade providing trees can alter the microclimate of the area. Besides, it was also observed that the Northern pavements of the east-west oriented streets are cooler than the Southern pavement. Furthermore, it was also noticed that if the crown of the tree is present at a greater height from the ground, then lower solar angle results in less blockage of the incident solar radiation. Also, it was evident that a higher density of tall, shade providing trees, maximally block incident solar radiation on a street. This study can help in understanding the pattern of cooling potential of the street side vegetation in a warm and humid climatic zone like Kharagpur so that the plantation can be planned judiciously.

Optimizing the Seasonal Shade and Ultraviolet Protection of a Suburban Playground by Utilization of the Playground Shade Index.

The Playground Shade Index (PSI) is introduced as a design metric for assessing the shade and solar ultraviolet (UV) protection provided by eight different cloth weave shade structures currently utilized in public playgrounds across a regional city located in southern Queensland, Australia. The PSI, expressing the ratio of available ambient solar UV exposure relative to the UV exposure received by a shaded 184 m2 playground surface over a whole day in midsummer and midwinter, is used to determine the best design and aspect of all eight existing structures. Unlike subjective shade audits that may only consider the type of shade structure, the number and characteristics of surrounding trees, and surface materials available at a given site, the PSI considers, in addition to previous factors, the available sky fraction and the direct solar UV contribution underneath the shade structure over a full day. By considering the in situ UV protection characteristics of the shade structure, the PSI has demonstrated its value as a robust design metric. Of the eight shade structure styles examined, this research presents the most likely structure best suited for UV protection over the two solar UV extremes in summer and winter, including optimal structure aspect.

The Playground Shade Index: A New Design Metric for Measuring Shade and Seasonal Ultraviolet Protection Characteristics of Parks and Playgrounds.

Current shading strategies used to protect outdoor playgrounds from harmful solar radiation include the placement of artificial cloth weaves or permanent roofing over a playground site, planting trees in proximity to playground equipment, and using vegetation or surface texture variations to cool playground surfaces. How and where an artificial shade structure is placed or a tree is planted to maximize the shade protection over specific playground areas, requires careful assessment of local seasonal sun exposure patterns. The Playground Shade Index (PSI) is introduced here as a design metric to enable shade and solar ultraviolet exposure patterns to be derived in an outdoor space using conventional aerial views of suburban park maps. The implementation of the PSI is demonstrated by incorporating a machine learning design tool to classify the position of trees from an aerial image, thus enabling the mapping of seasonal shade and ultraviolet exposure patterns within an existing 7180 m2 parkland. This is achieved by modeling the relative position of the sun with respect to nearby buildings, shade structures, and the identified evergreen and deciduous tree species surrounding an outdoor playground.

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.

Revealing Physiochemical Factors and Zooplankton Influencing Microcystis Bloom Toxicity in a Large-Shallow Lake Using Bayesian Machine Learning.

Toxic cyanobacterial blooms have become a severe global hazard to human and environmental health. Most studies have focused on the relationships between cyanobacterial composition and cyanotoxins production. Yet, little is known about the environmental conditions influencing the hazard of cyanotoxins. Here, we analysed a unique 22 sites dataset comprising monthly observations of water quality, cyanobacterial genera, zooplankton assemblages, and microcystins (MCs) quota and concentrations in a large-shallow lake. Missing values of MCs were imputed using a non-negative latent factor (NLF) analysis, and the results achieved a promising accuracy. Furthermore, we used the Bayesian additive regression tree (BART) to quantify how Microcystis bloom toxicity responds to relevant physicochemical characteristics and zooplankton assemblages. As expected, the BART model achieved better performance in Microcystis biomass and MCs concentration predictions than some comparative models, including random forest and multiple linear regression. The importance analysis via BART illustrated that the shade index was overall the best predictor of MCs concentrations, implying the predominant effects of light limitations on the MCs content of Microcystis. Variables of greatest significance to the toxicity of Microcystis also included pH and dissolved inorganic nitrogen. However, total phosphorus was found to be a strong predictor of the biomass of total Microcystis and toxic M. aeruginosa. Together with the partial dependence plot, results revealed the positive correlations between protozoa and Microcystis biomass. In contrast, copepods biomass may regulate the MC quota and concentrations. Overall, our observations arouse universal demands for machine-learning strategies to represent nonlinear relationships between harmful algal blooms and environmental covariates.

Shading of Medical Plants Affects the Phytochemical Quality of Herbal Extracts

The manipulation of light intensity by shade nets can lead to exchanges in the phytochemical quality and antioxidants ofsome herbs. This study aimed to determine whether shading by pearl nets (50% shade index) could improve the bioactive compounds in several medicinal herbs such as thyme (Thymus vulgaris L.), marjoram (Origanum majorana L.), oregano (Origanum vulgare L.), lemon balm (Melissa officinalis L.), and peppermint (Mentha piperita L.), and their correspondingherbal extracts during a four-week maceration process in ethanol. Oregano and thyme provided the highest yield of total extractive substances (TES) from both shaded and non-shaded plants. Among all studied herbs, the highest level of antioxidants, expressed as total phenolic content (TPC) was found in extracts from shaded plants of lemon balm. Herbal extracts produced from non-shaded thyme and marjoram had higher flavonoid contents compared to herbal extracts from shaded plants. Accumulation of the investigated secondary metabolites depends more on the specificity of a plant species rather than light intensity. This study was an initial step in the production of medicinal plants with an increased quantity of antioxidant and other bioactive compounds during the maceration process in extracts, aimed to be used as natural alcoholic productwith added value.

Efficiency of Basil Essential Oil Antimicrobial Agents under Different Shading Treatments and Harvest Times

The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of 50% and full sunlight exposure (control plants)), harvested at different times. The antimicrobial activity of basil essential oils (BEOs) obtained from all samples was determined for four microorganisms, while determinations for an additional five microorganisms included samples from non-shaded plants, plants grown under red and pearl nets, and second harvest of plants grown under blue net. Basil essential oil exhibited antimicrobial activity surpassing the activity of relevant commercial antibiotics regardless of growing conditions in the case of B. cereus, K. pneumoniae and C. albicans, while superior antimicrobial activity was exhibited in the case of essential oils from plants grown under blue nets in the case of S. aureus, E. coli and P. vulgaris. The influence of the application of colored shading nets was highly significant (p < 0.01) in the cases of all analyzed microorganisms except C. albicans and P. aeruginosa, while the influence of harvest time was proven in the cases of all microorganisms except K. pneumoniae. ANOVA proved that antimicrobial activities are highly dependent on the methods of plant production, shading treatment, and harvest time. Obtained results are discussed in relation to previously determined composition and yield of essential oils from basil grown under shade nets and harvested in different periods.

Urban Green Areas and Woody Plant Composition: Dwelling Space Quality Factor in the Klokočina Housing Estate

Abstract The environment of a city is influenced by global and local climate changes, pollution load from transport, industry and local heat sources. Green spaces as part of the urban green infrastructure fulfil multiple ecosystem services and improve the environmental and residential quality of a city. The level of positive effects of green spaces depends on their area, distribution within the city and the proportion of trees. The aim of the paper was to evaluate land cover structure in a selected segment of the housing estate Klokočina in Nitra, Slovakia. The evaluation focused on the share of biologically active and inactive surfaces, as well as the parameters of woody plant structure in green spaces. Green areas account for 58.70%, while built-up areas, parking lots and roads cover in total 41.30%. Biologically inactive anthropogenic horizontal and of building envelope areas represent 67.30%. Biologically active green areas represent 32.70%. The share of areas with tree crown overlap on horizontal areas is 20.82%, other areas are paved surfaces or grassland. We calculated the indices of the quality of green spaces from the individual categories of areas: proportional green area index (PGAI), effective green area index (EGAI) and tree shade index (TSI). The tree species composition consists of 36 deciduous and 11 coniferous tree species, and 20 shrub species. We evaluated the biometric traits of trees as the tree height, crown width, stem girth and tree vitality class (TVC). The correlations between tree traits were statistically tested with a significant result. In the group of biologically active areas of greenery, we propose to increase the proportion of trees, to establish more natural lawns and xerophyte flower beds. In the category of inactive areas, we propose the reconstruction of parking lots to grass paved surfaces.

A Method of Identifying Rust Status of Dampers Based on Image Processing

As one of the important antivibration fittings in transmission lines, the damper's accurate location, the quick detection of damper rust defect, and the timely remedial measures are all of great significance to ensure the reliable transmission of electric energy. Considering the background complexity of the damper image and harmfulness of its rust defect, a method for identifying the rust status of damper based on image processing is proposed in this article. First, the damper image acquired by the image acquisition device is grayed, and the feature enhancement of the damper region is completed by the local difference processing, the edge strength mapping based on the anisotropic Gaussian kernel directional derivative and the image fusion, and so on. Second, the segmentation of damper is completed by the threshold segmentation and the morphological treatment. Finally, the rust parameters of the damper area, which are the rusty area ratio (RAR) and the color shade index (CSI) are presented, by which the identification of the rust status can be defined as the rust-free, slight rust, medium rust, and severe rust. The results show that the segmentation and accurate identification of the rusted dampers can be completed by the proposed method. The total identification rate of the rusted dampers can reach 93% even under the complex background. The method is new and effective for identifying the rust status of damper.

From energy performative to livable Mediterranean cities: An annual outdoor thermal comfort and energy balance cross-climatic typological study

With the rise of awareness of health and well-being in cities, urban environmental analysis should expand from energy performance to new environmental quality-based considerations. The limited potential to annually evaluate outdoor thermal comfort, predominant among these considerations, has restricted the exploration of the interrelations between urban morphology and annual energy performance. This study aims to bridge this gap by capitalizing on the new capabilities of Eddy3D – a Grasshopper plugin which enables effective calculations of hourly microclimatic wind factors via OpenFOAM which in turn are used to generate annual outdoor thermal comfort plots. Using this method, a parametric study was conducted for different typology and density scenarios in three different hot climatic contexts in Israel. The automated analytical workflow evaluated a total of 60 design iterations for their energy balance, outdoor thermal comfort autonomy (OTCA) and self-shading levels using the shade index. The high correlation found here between the annual shade index and the OTCA, across all climatic contexts, shows the potential of the shade index to serve as an effective indicator, in these contexts, for comparative or optimization outdoor comfort studies. Further results are both the superiority of the courtyard typology in both energy and outdoor comfort studies, and the contrasting impact of higher density on the annual energy balance (lower performance) and outdoor thermal comfort (higher performance) in hot climates. The annual plots of both the energy balance and OTCA reveal various seasonal and monthly trends in the three different climatic zones which can lead to localized and seasonal urban design strategies.

Bioactive constituents of red and green lettuce grown under colour shade nets

The objectives of this study were to investigate the effects of coloured shade-nets (pearl, blue, or red all with a 50% shade index) compared to non-shaded plants on quality traits on the Discoa and ICE 40102 (green-leaf) and Eglantine (red-leaf) lettuce cultivars. Total chlorophyll content depended on the shading and lettuce genotype. The chlorophyll a and b contents were higher in shaded than unshaded plants. The cv. Eglantine had the highest total chlorophylls (637.03 μg∙g-1 F.M.) content. The highest carotenoid content was in leaves of cv. Discoa under pearl nets (208.89 μg∙g-1 F.M). The highest total phenols content (76.70±1.9 mg∙g-1 GAE D.M.) was in cv. Discoa under red shade; the highest flavonoids content was for cvs. Discoa (42.97) and Eglantine (42.91 mg∙g-1 RU D.M.) under blue shade. The blue and pearl shade nets resulted in slightly higher flavonoid contents in lettuce leaves compared to unshaded plants. The cv. Eglantine, under blue shade had the highest antioxidant capacity (EC50 - 0.197 mg∙mL-1). Red lettuce cv. Eglantine could be recommended for production due to its higher antioxidant properties. Generally blue shade can be used to retain antioxidant capacity.

Shade maps for prioritizing municipal microclimatic action in hot climates: Learning from Tel Aviv-Yafo

This article presents a methodology for evaluating microclimatic summer conditions across an entire city, focusing on the provision of outdoor shade as a primary comfort indicator. Based on high-resolution 2.5D and 3D mapping of buildings, ground surfaces, and tree canopies in Tel Aviv-Yafo, a city of hot-summer Mediterranean climate, we employed a detailed calculation of solar exposure of streets and open spaces (public and private) using commonly available GIS algorithms. The raw results of these calculations were used for calculating summer Shade Index values for every street segment and neighbourhood of the city, which were then plotted to a comprehensive 'shade maps' reflecting the city's spatial hierarchy of shade. The shade maps, combined with analysis of tree canopy cover on similar scales, enabled to relate building and tree morphologies to outdoor shade conditions. For prioritizing intervention of local planning authorities in improving poor shade conditions or conserving highly-shaded locations, we related the climatic analysis to space-syntax classification of streets according to their potential to attract pedestrian movement, and produced a city-wide map that highlighted streets that have high pedestrian movement potential while requiring high levels of shade intensification or conservation.

New technology in basil production with high essential oil yield and quality

Light modification by colour shade net manipulation plays an important role in the synthesis of bioactive compounds and has been shown to affect quantity and quality of essential oils in basil. In the present study, basil was grown in the soil under net-house cover by pearl and red nets (50% shade index), or in unshaded condition (open field-control). Sweet basil (Ocumum basilicum L. cv. ‘Genovese’) were used to determine whether different times of harvest could improve yield, chemical composition of essential oils and antioxidant activity under light stress conditions. The lowest accumulation of essential oils was observed in the second harvest from unshaded, control plants (1.02 mL/100 g) while the highest oil accumulation was achieved in first harvest from red nets (3.23 mL/100 g). The main constituents found in the oil were linalool (46.7–53.9%), eugenol (9.7–20.9%), 1,8-cineole (8.7–15.3%), epi-α-cadinol (3.3–4.5%) and α-trans-bergamotene (2.2–3.4%). Light manipulation by color shade nets also increased antioxidant activity. Plants grown under blue shade nets from the second harvest are characterized by the highest eugenol content (20.9%) and highest antioxidant activity (efficient concentration - EC50, 0.003 mg mL−1). Direct sowing, high plant density, colour shade nets and successive harvests represents a new technology in basil production with high essential oil yield and quality.

The Role of Hillshade, Aspect, and Toposhape in the Woodland Dieback of Arid and Semi-Arid Ecosystems: A Case Study in Zagros Woodlands of Ilam Province, Iran

Abstract Soil moisture plays a key role in the ecological capability of arid and semi-arid woodland. Reducing soil moisture due to frequent droughts causes pest prevalence and disease outbreak and the consequence of forest dieback. On the other hand, soil moisture is strongly correlated with the amount of radiation received on the Earth’s surface. The sun’s radiation is traditionally described often by aspect and sometimes by toposhape. The use of the hillshade map for estimating solar radiation is possible through developing GIS. The present study aimed to compare the relationship and the ability of these indices to describe the phenomenon of arid and semi-arid woodland decline better and more accurately in a case study in the west of Iran. To this aim, the aspect and toposhape layers were generated in 5 and 12 classes, respectively. Then, the hillshade map in range of 0-255 was made during the peak of summer heat. The comparison of the dieback ratio in the three characteristic histograms showed that the shade index, unlike the other two indicators, had a significant effect on forest drought (R2=0.91 for linear equation and R2=0.94 for quadratic equation). The results indicated that the application of hillshade in describing and analysing ecological processes by relying on soil moisture such as woodland dieback is superior to the other two indicators. It is suggested that this index be used to obtain a risk model to predict woodlands dieback which are under the pressure of frequent droughts due to climate change or other mortal factors.

Effects of shade location and protection from direct solar radiation on the behavior of Holstein cows.

Two trials (E1 and E2) were performed to assess the behavior of eight Holstein dairy cows with 367 ± 58kg of body weight and 10.52 ± 0.08kg of milk yield. A 4 × 4 Latin square design (four periods of lactation and four levels of solar blockage) with four paddocks was used. Each paddock contained a wood shading structure covered with a cloth that blocked 30% (T1), 50% (T2), 70% (T3), or 100% (T4) of direct solar radiation. In the first trial (E1) each shade structure was located approximately 40m from the feeder and water troughs; in the second trial (E2), the distance was reduced to 5m. Air temperature (TA, °C), relative humidity (RH, %), wind speed (U, ms-1), black globe temperature (TG, K), mean radiant temperature (TMR, K), radiant heat load (RHL, Wm-2), and local shortwave radiation (RS, Wm-2) were recorded at 15-min intervals from 08:00 to 17:00h. Four behavioral activities were recorded: grazing, eating at the feed trough, ruminating, and idling. For each of these activities, animal posture (lying or upright) and location (under shade or exposed to sunlight) were recorded. The meteorological conditions showed similar variations from 8:00 to 17:00h between the two trials. However, the air temperatures in E1 were lower (± 2°C) than those in E2. In a PCA analysis, the first and the second principal components explained 56.87% and 21.85%, respectively, of the total variation in the behavioral variables. Under the E1 conditions, the animals did not seek shade, whereas in E2, the dairy cows spent 35 ± 5% of their time lying and idling in the shade. At a solar radiation blockage of 100%, cows were in the shade more than 60% of the time due to the intensity of solar radiation, which was 722.19 ± 14.59Wm-2 at 11:45. In a PCA analysis, the first and the second principal components explained 65.18 and 22.3%, respectively, and 87.48% together, of the total variation in the original variables. Consequently, it was possible to develop a shade index (IST) based on the first two components. In E1, animals spent very little time in the shade, spending only 0.15% of total time under the shade, irrespective of blockage. However, E2 cows used shade, reaching almost 80% of time under the shade, at midday, when the blockage was 100%.

Sowing operation direction and population densities in corn growing

ABSTRACT Among the factors that may influence corn yield are sowing operation direction and plant population, since they alter the shade index between crop rows, and consequently the efficiency of interception of the photosynthetically active radiation by the leaves of plants. The aim of this study was to evaluate the influence of sowing direction and plant populations on P2830VYH hybrid corn yield. The experiment was conducted at the facilities of FCAV-UNESP, latitude 21º 14’ S and longitude 48º 16’ W in Jaboticabal (SP). The treatments were composed of three sowing directions (North-South, Northeast-Southwest, and East-West) and three population densities (40,000, 60,000 and 80,000 plants ha-1). The treatment with 80,000 plants ha-1 had the lowest cost per sack of corn and profitability 21% higher than that of the treatment with 60,000 plants ha-1, and 45% higher than that of the treatment with 40,000 plants ha-1. Sowing direction had no influence on grain yield when environmental conditions were favorable to the development of the crop. Lower plant densities lead to higher individual results in relation to the number of cobs, length of cobs and number of grains per row.