Shade Levels Research Articles

Improving Yield and Quality of ‘Balady’ Mandarin Trees by Using Shading Techniques and Reflective Materials in Response to Climate Change Under Flood Irrigation Conditions

Considering climate change predictions, it is logical to anticipate detrimental effects on the mandarin tree, an essential citrus crop. Therefore, scientists should promptly focus on developing methods to enhance its resistance to climatic stress effects such as sunscald. This study assesses the strategies employed in ‘Balady’ mandarin trees when covered by shading nets of varying colors and percentages (white 50%, green 50% or 63%, black 50% or 63%), as well as the application of reflective materials (kaolin at 4% and CaCO3 at 3%) on the micro-climate of orchards, leaf, and fruit surface temperatures, fruit sunburn%, productivity, and fruit quality. The results indicated that shade nets effectively reduced temperature and enhanced humidity, especially during the period from June to September, when compared to open-field treatments. Black shade nets, particularly those with a shading level of 63%, demonstrated the most notable decrease in canopy temperature and an elevation in humidity, surpassing the performance of green and white shade nets. The present study found that shade nets and reflecting materials like kaolin and calcium carbonate significantly reduced fruit sunburn. Trees without shade had a sunburn rate of 8.74%, while those with shade treatments suffered no sunburn. Kaolin foliar spray at a concentration of 4% and calcium carbonate at a concentration of 3% reduced sunburn incidence to 3.64% and 7.32%, respectively. These treatments also reduced the intensity of sunburn. All treatments increased fruit yield % compared to the control and yield efficiency (kg/m2), especially the trees covered with white shade net of a 50% shading rate provided the highest values (43.70 and 40.17%) and (5.24 and 5.47 kg/m2) compared to other treatments in both seasons, respectively. Trees covered with a white shade net of a 50% shading rate, followed by a green shade net of 50% and a 63% shading rate, as well as a black shade net of 50% and a 63% shading rate, tended to improve the physical and chemical fruit properties. Therefore, it could be recommended that trees be covered with a white shade net of a 50% shading rate or a green shade net of a 50 and 63% shading rate in summer months due to its beneficial impact on mitigating fruit sunburn damage and enhancing the productivity and quality of ‘‘Balady’’ mandarin trees. Hence, shade nets can be a beneficial technology to protect citrus fruits from sunburn without affecting fruit quality in commercial citrus farms.

Pollination‐related plant traits under environmental changes: Seasonal and daily mismatches produce temporal constraints

Abstract Pollination is a key tenet of ecosystem sustainability and food security, but it is threatened by climate change. While many studies investigated the response of plant‐pollination traits to temperature, few attempted multifactorial and integrative approaches with multiple floral traits. We determined which plant‐pollination traits were disrupted by environmental changes and the consequence for plant fitness. We focused on the thermogenic plant, Arum italicum, which relies on floral scent and heat production to attract its pollinators with a deceptive strategy. In a field mesocosm, we measured the response of floral phenology, thermogenesis traits, scent and plant fitness to experimental changes in shade level, water supply and soil temperature. In the laboratory, we exposed plants to extreme heat to determine the thermoregulation ability at high temperatures. Plant fitness decreased dramatically in response to soil warming and the level of shade. While both factors caused a lower number of inflorescences, soil warming was mostly responsible for the crash in number of fruits. The plant traits related to thermogenesis and scent were relatively resilient to the environmental changes in the mesocosm and were unlikely to produce the observed decrease in plant fitness. First, environmental changes only weakly modified the scent composition. Second, the appendix regulated its maximal temperature almost perfectly, while stamen regulated imperfectly. In the laboratory experiment, the appendix maintained a thermal gradient supposedly to improve scent emission while stamen became cooler than ambient air, possibly preventing the pollinators from overheating within the floral chamber. By contrast, the phenology of flowering was drastically modified. Flowers appeared earlier in the season in response to soil warming (by 39 days) or absence of shade (by 19 days). At the daily scale, flowering hour did not change across the season resulting in plants flowering before sunset late in the season and before the pollinator activity window (mostly nocturnal). The strong shift observed in the flowering period may induce a temporal mismatch with this pollinator both early and late in the season when the insects may not be active so early in the spring and during daytime, respectively, thereby altering plant fitness. Read the free Plain Language Summary for this article on the Journal blog.

Comparative Study of Ginger Cultivars under Shading Conditions in a High Tunnel

Ginger (Zingiber officinale Rosc.) is a valuable sciophyte crop used as a spice or fresh herb in culinary dishes and for treating medical issues such as osteoarthritis, neurological diseases, vomiting, and asthma. The demand for ginger in the United States is remarkably high; it is produced commercially and exclusively in Hawaii but can only meet ∼20% of US demand. Light for ginger growth may be more important than is often assumed, but the roles of light in ginger growth and rhizome yield are not fully understood. We hypothesized that artificial shade would produce the highest yielding ginger compared with no shade. This study evaluated the impact of different shading suited for ginger growth and rhizome yield of different cultivars grown in a high tunnel. There were three levels (0%, 22%, and 40%) of shade using RCBD design. We analyzed the overall yield (weight) of ginger and the specific yield (weight) of different rhizome parts (biological root, edible root, and seed ginger) per plant in addition to plant growth data. Data were analyzed for 2018 and 2019, and shade conditions influenced ginger growth and yield. There was no significant difference between shade conditions or cultivars, but general trends found that data differed between the two growing seasons. In 2018, Chinese White and Hawaii Yellow produced a better (higher) yield under 0% and 40% shade. However, in 2019, Chinese White and Hawaii Yellow produced the highest total yield under 22% shade, but Bubba Blue produced the highest overall yield at 0% shade.

Towards a high resolution simulation framework for building integrated photovoltaics under partial shading in urban environments

This paper presents a framework for modeling the performance of photovoltaic (PV) systems, which is intended to be used in the design, optimization, and deployment of PV systems in urban environments. Urban PV and building integrated PVs (BIPV) are a crucial component of the transition to a low-carbon society. However, existing frameworks for simulating PV systems accurately characterize PV under partial shading, leading to performance gaps with systems deployed in environments such as cities where shading is more common than in large open fields. In this paper, we extend a framework from literature for modeling parametric BIPV arrays using a power model that characterizes IV-curves at the PV cell. We describe the framework and perform a validation against a measured rooftop PV array dataset. We then evaluate the extended framework to other PV modeling and simulation frameworks found in the literature through the simulation of a simplified facade under various levels of shading. Results show that the extended framework is necessary to account for partial shading, but there may be use cases when lower resolution frameworks may be just as accurate. Amongst the frameworks a range of predicted power outputs under the shading conditions was observed; from 6% to 846% with a mean of 162% from the other frameworks relative to the proposed framework. The range is due to the extensive set of conditions tested, where it was observed that in conditions where shading is present but sparse, there is a larger range of predicted output from the various frameworks. Whereas in conditions where shading coverage is high this range is lower. Lastly, we demonstrate the use of the framework on three arrays. Again it was observed that homogeneous shading conditions may not require the level of resolution provided by the proposed framework, while heterogeneous could benefit the most from the approach. This indicates, and is discussed in the paper, that modelers should consider the shading conditions present when deciding on which framework to apply.

Effects of turfgrass canopy shade levels and quantum spectrum on the germination and development of smooth crabgrass (Digitaria ischaemum)

AbstractSmooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] is one of the most troublesome summer annual weeds in cool‐season turfgrass. Field experiments demonstrated a strong relationship between spring photosynthetic active radiation reaching the soil surface and the resulting smooth crabgrass cover in Kentucky bluegrass (Poa pratensis L.) 2/3 months later in summer. Both smooth crabgrass and canopy penetrating light were consistently reduced by higher mowing heights. Follow‐up experiments in controlled environments were initiated to improve our understanding of how light quality and quantity influence smooth crabgrass germination and growth. Smooth crabgrass germination was ≥99% following exposure to blue, red (R), far red (FR), both R and FR light pulses, or complete darkness treatments. A second germination experiment examined six levels of turfgrass canopy shade (0%, 24%, 44%, 77%, 90%, and 100% photosynthetic photon flux density [PPFD] reduction) and found that smooth crabgrass germination was ≥99% for all treatments. These experiments indicate that light quality and quantity do not affect smooth crabgrass germination. A greenhouse experiment examined five levels of turfgrass canopy shade (0%, 44%, 59%, 81%, and 91% PPFD reduction). Smooth crabgrass quantum and PSII (Photosystem II) operating efficiency increased in response to shade, while leaf number and thickness, specific leaf weight, tillering, mass, electron transport rate, and stomatal conductance decreased with increasing shade. Overall, the results demonstrate that smooth crabgrass is able to germinate regardless of canopy density, but seedling growth, development, and plant function are diminished in a dense turfgrass canopy shade.

Landscape forest cover and local vegetation structure mediate multitrophic relationships but not the leaf damage in cacao trees

Cacao is the most important agricultural product in the southern region of Bahia state, Brazil, with 70 % of its production occurring under the traditional agroforestry where cacao is mostly shaded by native trees. This traditional system allows to reconcile the production with the maintenance of the portion of original biodiversity. However, increased deforestation and intensified agroforestry management aimed at boosting productivity may impact the diversity of native species and the services they provide. In this context, our aim was to disentangle the role of landscape forest cover and the local vegetation complexity on predation of caterpillars and herbivory of cacao plants located in agroforestry systems. The study was conducted across 18 cacao agroforest sites in southern Bahia located in landscapes with different amounts of forest cover. We assessed predation rate using dummy caterpillars, sampling understory birds and arthropods and collected leaves of cacao trees to analyze damage by herbivory. We also measured shading levels and the abundance of cacao trees in each agroforestry. Predation pressure on dummy caterpillars was positively influenced by the abundance of total predators and the level of landscape forest cover and negatively by the number of cacao trees. Even so, we found no evidence that landscape, local features or the actual invertebrate assemblages (predators or herbivores) influenced the cacao leaf damage. The findings highlight the multifaceted interactions between ecological factors, predation pressure, and leaf damage within cacao agroforestry systems.

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.

Impact of shading heaviness on voltage, current and power of the solar photovoltaic string

The short-term power output variability of solar photovoltaic (PV) systems caused by passing clouds is becoming a major concern for grid operators. As the penetration of utility-scale PV systems boosts, the rapid power fluctuations greatly challenge the grid's transient stability. A photo voltaic system is greatly vulnerable to Partial Shading. The performance analysis of PV systems clearly suggests that the maximum power of partially shaded PV systems is inversely proportional to the heaviness of shading. However, some literatures are not of the same opinion; for them, the maximum power of a partially shaded system is invulnerable to shading heaviness, often at certain critical points. According to research on the P-V characteristic curve under various numbers of shaded modules and shading levels, the irradiance of the shaded modules reaches a certain turning point or critical point. The PV array becomes insensitive to high-level shading, categorically for the series topology. This paper presents an experimental results of performance parameters with varying shading heaviness. The experiment is performed on a Photovoltaics string of series connected modules, a 119KW grid-connected rooftop solar power plant using the Power Quality analyser for continuous recording of various parameters under changing shading heaviness. The degree or heaviness of shading decides the critical point. The critical point can vary based on the number of the shaded modules.

The elderly falling detection based on improved YOLOv8

Accidental falls are one of the major safety problems that cause the injury and death of the elderly over 65 years old in China. In the face of the lack of accuracy of existing fall detection technologies in dealing with complex environments such as object occlusion and illumination changes, this study based on the improved algorithm of YOLOv8, this study introduces a multi-head attention mechanism to improve the accuracy, robustness, universality and scalability of fall detection. The main goal of this work is to improve the YOLOv8 model's structural adjustments, which include adding a multi-head attention mechanism to improve the model's capacity to identify important characteristics. This method enables the model to learn several features of the input data in separate representational subspaces at the same time, leading to more accurate fall behavior identification and localization. The modified model was tested in several fall scenarios, including ones with varying illumination and shade levels, in the experimental section. This technique outperforms the original YOLOv8 model, achieving 79.4% mAP@0.5 on the dataset, according to a comparison of performance benchmarks. In summary, YOLOv8's multi-head attention method adds to the fall detection algorithm's detection accuracy while simultaneously.

Effect of nitrogen fertilization and shading on morphogenesis, structure and leaf anatomy of Megathyrsus maximus genotypes.

The use of exotic grasses of African origin for pastures in Brazil has been a major advancement in livestock production, but little is known about the responses of these grasses to nitrogen fertilizers associated with shading. In this study, the morphogenetic, structural, and leaf anatomical characteristics of Megathyrsus maximus cultivars' Tamani and Quênia were investigated as a function of N dose and shade. Morphogenetic and structural characteristics and leaf anatomy were studied under three shading levels (0, 30, and 50 %) and four N doses (0, 100, 200, and 300 kg N ha-1) to simulate growth in a silvopastoral system. When comparing the cultivars, Quênia was more efficient in terms of phyllochron up to fertilization with 100 kg N ha-1. The leaf senescence rate of Tamani was higher than that of Quênia at the 30 and 50 % shade levels. The total area (TA) occupied by leaf tissues decreased in Quênia as a function of the increase in N fertilization, whereas the TA of Tamani did not change. The thickness of the adaxial epidermis was greater in Quênia (0.68 µm) than in Tamani (0.50 µm) when not fertilized. The area occupied by the mesophyll was greater in both cultivars when they received fertilization equivalent to 300 kg N ha-1. Quênia grass has a smaller phyllochron than Tamani grass, due to the rapid reconstruction of its photosynthetic apparatus, especially when it receives higher levels of nitrogen fertilization. However, Tamani grass has a greater distribution of plant tissues. The mesophyll area is larger in Tamani grass due to the greater presence of chloroplasts, which facilitates digestion by animals. The Tamani modified the leaf anatomical tissues more significantly in relation to shading, whereas the Quênia modified them in relation to N fertilization, which reinforces the suggestion of a more appropriate use of Tamani in silvopastoral systems.

Enhancing Gardenia Leaf Nutrients via Shading, Vermicompost, and Chelated Iron

This study aimed to investigate the impact of shading, vermicompost, and chelated iron on the leaf content of certain elements in Gardenia jasminoides plants. Conducted at a private nursery in Erbil during the 2022 agricultural season, the experiment utilized gardenia plants propagated by cuttings and grafted onto one-year-old rootstocks. Over five months (April to October 2022), the effects of two shading levels (0% and 75% direct sunlight), vermicompost application at two levels, and chelated iron application at three levels (0, 0.1, and 0.2 g.L-1) were assessed. Results indicated that 75% shading significantly increased leaf nitrogen (1.72%) and iron content (73.94 mg.kg-1). Vermicompost at 25% significantly enhanced leaf nitrogen (1.75%), phosphorus (0.248%), potassium (1.36%), and iron (67.95 mg.kg-1). Chelated iron at 0.2 g.L-1 markedly improved leaf nitrogen (1.78%), phosphorus (0.256%), potassium (1.28%), and iron (78.45 mg.kg-1). The study utilized one-year-old uniform seedlings, grown in 15-liter pots with river loam soil, and standard care practices were followed. Data analysis was performed using ANOVA and Duncan’s Multiple Range Test at a 0.05 significance level. The findings suggest that specific shading, organic fertilizer, and chelated iron treatments can significantly enhance the nutrient content of gardenia leaves, potentially improving plant health and growth.

Effects of intercropping on the herbage production of a binary grass-legume mixture (Hedysarum coronarium L. and Lolium multiflorum Lam.) under artificial shade in Mediterranean rainfed conditions

Growing perennial legumes in the understory layer in agroforestry systems is a strategy to improve the sustainability of agricultural systems, i.e., by increasing land productivity, fostering carbon sequestration and nutrient cycling and reducing reliance on inorganic nitrogen fertilizers for tree crops. In many parts of Central Italy, sulla, a biennial autochthonous legume, is widely adopted in forage cropping systems for its productivity and nutritive value and it is often intercropped with ryegrass for a better utilization as grazed temporary grassland. To evaluate the agronomic performance of these perennial species grown under different levels of light reduction, an artificial shade plot trial was established in the coastal plain of Pisa, Central Italy, with the aim to simulate the effect of tree presence with different levels of shade intensification in rainfed conditions. The experiment layout complies with a 2-way completely randomized design with four replicates. The two factors tested were the forage species (namely sulla, ryegrass and their intercropping) and the level of shade (no shade, moderate shade − 30% light reduction-, and intense shade − 50% light reduction-). Shading significantly reduced the above ground biomass (AGB) production, especially for the intense shading (on average about − 20% with respect to the full sun). The mixture resulted as the most productive crop, yielding on average about + 30 and + 40% AGB in comparison to sulla and ryegrass pure stands, respectively. The findings about the effect of the shading on AGB production showed that mixture was a suitable sward, especially under moderate shading conditions. Further studies are needed with the purpose to investigate the productive performance of these swards in real agroforestry conditions.

Exploring the Adaptation of Native Shrub Species to Different Levels of Shading: Augmenting their Sustainable Exploitation Framework

Abstract The environmental adaptation potential of regional wild germplasm resources should be investigated in a species-specific manner in terms of the sustainable exploitation of underutilized native species. In the current work, three fruit/ornamental shrub species (Rosa canina L., Sambucus nigra L. and Cornus sanguinea L.) originating from regional wild germplasm of Greece with a previously set domestication framework have been investigated in terms of their environmental adaptation to different levels of shading. To this end, targeted experimentation was conducted on ex situ adapted material by applying different shading levels (0%, 30% and 60% shading) in purpose-built netting tunnels. Rosa canina showed similar growth patterns among the shading levels applied but with increased chlorophyll fluorescence patterns and increased abaxial leaf stomatal density with increased shading. Sambucus nigra showed similar results to R. canina in photosynthetic efficiency and leaf stomatal density but with additional effects on plant growth patterns. Cornus sanguinea, on the other hand, was not affected by shading level in the measured parameters. These results outline the adaptation potential in a species-specific manner of the studied species to shading in terms of adding novel exploitation options for agroecosystems, agroforestry, and landscape management in peri-urban green spaces and peri-urban forest understory enrichment to mitigate climate change impacts in temperate and semi-arid climates. Study Implications: This study explores the adaptation potential to increasing levels of shading of ex situ adapted germplasm of wild origin of three underutilized shrub species with known multifaceted value. The work builds on the sustainable utilization framework of the focal species in terms of novel exploitation options in landscape management for peri-urban green spaces and peri-urban forest understory enrichment for enhancing biodiversity and soil erosion protection. Therefore, this work offers an example of an underlying research line towards systematized screening and utilization of wild plant species for climate change impact mitigation in agroecosystems, agroforestry, and landscape management in temperate semi-arid climates.

CARACTERÍSTICAS ESTRUTURAIS E PRODUTIVAS DO CAPIM MOMBAÇA SOB SOMBREAMENTO, NA FASE DE ESTABELECIMENTO

Forage grasses can be subjected to conditions that reduce the amount of light, either through intercropping with annual crops or through integration with tree species (silvopastoral system). Therefore, the objective of this work was to evaluate the productive and structural characteristics of grass. mombaça (Megathyrsus maximus), in the establishment phase, subjected to four levels of artificial shading (0, 30, 50 and 70%). The experimental design was completely randomized, with five replications. For this, plant height - PH, tiller length - TL, leaf/stem ratio (LSR), leaf dry mass, stem, dead and total material, tiller population density, individual tiller weight and number of leaves were evaluated. living and dead. Shading of 50% induced greater production of total dry mass (TDM), with no significant effect of TDM for the full sun and 30% treatments. A reduction in the number of tillers (NL) was observed as light was restricted, as well as an increase in plant height, tiller length and tiller dry weight. It is noteworthy that the highest average heights were found in 50 and 70% shading, as well as the highest individual tiller weights. The lowest production of total shoot dry mass and lowest LSR were found in the most severe shading. From the analysis of all variables, it can be inferred that mombaça grass presents better acclimatization in the range of 30 and 50% shading, which gives this cultivar good phenotypic plasticity, thus, the establishment of pasture is recommended in light to moderate shading. Therefore, the mombaça forage grass has potential for use in the silvopastoral system.

Vertical Agrivoltaics System on Arable Crops in Central France: Feedback of the First Year of Operation

Since the development of Agrivoltaics with panels placed above the plants, a new system is tested with vertical mounted bifacial photovoltaic panels, of which we present the results of the first year of two experimental sites. Such installations bring a lower shading level on the plant compared to fixed tilt or single axis tracking systems and could potentially suit fields with crops having low demands of shading. However, unlike more standard PV systems, few studies have detailed the effects of such devices on field crops. In this first experimental year, bifacial vertically mounted PV system showed interesting results with a stable or even a slight increase in annual crop yields. Also, harvest quality indicators are maintained or present favorable evolution indicating a high potential of vertical PV systems for Agrivoltaics.

Neutral interactions between native Alternanthera sessilis and exotic Alternanthera philoxeroides along a light gradient under tropical climatic conditions

AbstractRiparian ecosystems are under a serious threat of invasion due to the clearance of riparian vegetation, which allows for increased light levels at ground level. This study presents the interactions between native Alternanthera sessilis (L.) R. Br. ex DC and invasive Alternanthera philoxeroides (Mart.) Griseb. during the colonization stage along a light gradient under tropical climate conditions. We conducted a 6 week growth experiment with monocultures of A. philoxeroides and A.sessilis and mixed communities of two species under four light levels (100%, 46%, 26% and 14% of full sunlight). Exposure to full sunlight (nearly 1800 μmol m−2 s−1) resulted in a significantly high biomass accrual in both species. However, biomass accrual did not correlate with the light intensity. At higher shade levels, reduction of lateral spread and shoot/root ratio was observed. Community composition had no influence on biomass accrual or morphological variations. Plasticity index values were approximately same in both species. Total relative yield was approximately two in all shade conditions, indicating that the two species interact neutrally along the light gradient. Therefore, the results of the study indicate that increased light levels will accelerate the proliferation of both species in riparian zones. Nevertheless, increased or decreased shade is unlikely to alter neutral interactions between A. philoxeroides and A. sessilis.

Accuracy of Simscape Solar Cell Block for Modeling a Partially Shaded Photovoltaic Module

With half-cut photovoltaic (PV) modules being the dominant technology on the market, there is an increasing necessity for accurate modeling of this module type. Circuit simulators such as Simulink are widely used to study different topics regarding photovoltaics, often employing a solar cell block available from the Simcape library. The purpose of this work is to validate this model against measurements for a partially shaded half-cut PV module. Diverse shading scenarios are created by varying the number of shaded substrings, the number of shaded solar cells in the substring, and the shading level. For every shading scenario, the PV module’s I-V curve is measured, along with in-plane irradiance, air temperature, and module temperature. A comprehensive evaluation of simulation accuracy is presented. The results confirm a high accuracy of the model with mean nRMSE values of 2.2% for I-V curves and 2.8% when P-V curves are considered. It is found that the simulation errors tend to increase when increasing the number of shaded substrings. At the same time, no obvious dependency of simulation accuracy on the shading level or the number of shaded solar cells in the substring is found.

Performance improvement of PV systems during dynamic partial shading conditions using optimization algorithms

PV power plants encounter varying levels of irradiance, temperature fluctuations, and partial shading because of the differences in sunlight conditions. Partial shading can cause an increase in the power loss, leading to a reduction in efficiency. Maximum Power Point Tracking (MPPT) is of utmost importance in the functioning of photovoltaic (PV) systems for electricity generation because it is indispensable for maximizing power extraction from PV modules, thereby increasing the overall power output. In situations where partial shading is present, the utilization of MPPT algorithms to achieve maximum power output becomes complex because of the existence of multiple distinct peak power points, each having a unique local optimum. To overcome this issue, a method is proposed that uses Darts Game Optimization (DGO), a game-based optimization process, to efficiently determine and extract the maximum power from various local optimal peaks. A population-based optimization method known as the Darts Game Optimization algorithm exists. In this approach, the optimization process begins by creating a population of random players. Then, the algorithm iteratively updates and improves the population to search for the best player or solution. In this study, the DGO algorithm was applied to the MPPT process for voltage optimization in the PV procedure. The DC-DC converter is utilized to capture the maximum available power, and the findings demonstrate that the DGO algorithm efficiently identifies the global maximum, resulting in accelerated convergence, reduced settling time, and minimized power oscillation. Through simulations, the feasibility and effectiveness of the DGO centered MPPT approach was confirmed and compared with MPPT algorithms relying on perturb and observe (P&O) and Particle Swarm Optimization (PSO). The simulation results offer compelling evidence that the DGO algorithm, as proposed in this study, proficiently traces the global maximum, thereby substantiating its practicality and efficiency.

Evaluation of the initial growth of Shorea platyclados wildlings through the application of mycorrhizal biofertilizer under different levels of shading

The obstacles to the propagation of Shorea platyclados involve the uncertain flowering and fruiting seasons, the recalcitrant nature of the seeds, and the dependence on shade for growth. Furthermore, a mutualistic symbiosis, called mycorrhizae, usually exists between the roots and fungi, similar to other species of Dipterocarpaceae. This consequently hinders the regeneration process, which in turn may threaten the sustainability of this species in the wild. Ex-situ conservation using wildings is one of the measures that can be taken to overcome this issue. This study aimed to assess the initial growth of S. platyclados seedlings by administering different amountsof mycorrhizal biofertilizers under varying shade conditions at four and eight weeks of age in the nursery. A randomised complete block design was employed with the dose of biofertilizer as the treatment (0, 2.5, 5, 7 and 9 g/polybag) and shade as the group (0, 50, 60 and 70%). Observations were taken in the nursery at four and eight weeks of age. The observation parameters included the survival percentage, height growth, diameter growth, and vigour of the seedlings. There were significant differences in percentage of survival. Still, significant differences in height growth were observed with different doses of biofertilizer and shading at both four and eight weeks of age. Significant differences in diameter growth were observed with different doses of biofertilizer at both four and eight weeks of age, but not with different shades. No significant differences were observed for seedling vigour with different doses of biofertilizer and shade at both four and eight weeks of age. The optimal amount of biofertilizer was 5 g/polybag, resulting in maximum growth. This was achieved in a shade of 60%.

Changes and dynamics of the main quality components in tea leaves of 4 tea cultivars during the shading process

The purpose of this study was to analyze the relationship between different shading conditions, picking time for main quality components of tea. The main quality components of 4 tea cultivars [Camellia sinensis (L.) O. Kuntze], including the separated tea shoot tissues (leaves, buds, stems), under 4 shading rates during the traditional 20-day shading period were examined. Results showed the Chlorophyll contents after 12 days of shading treatment were significantly higher than control, but after that it ceased increasing significantly Initially, the theanine, total free amino acid, caffeine, and tea polyphenol contents showed decreased trend but then leveled off after 12 days. The increase of free amino acids, caffeine, chlorophyll and the decrease of tea polyphenols induced by shading were mainly determined by shading level and tenderness. Meanwhile, shading changed the proportion of main quality components in tea leaves and stems, long-term shading does not promote high quality matcha. All of the results indicated the quality of matcha with grade 1 could be produced by shading rate of 80 % and shading for 12 days. Appropriate shading time and shading rate are beneficial to improve the quality of Matcha.