High-resolution digital elevation models (DEMs) of permanently shadowed regions (PSRs) at the lunar South Pole are crucial for upcoming exploration missions. Recent advances, such as high-resolution images acquired from ShadowCam, utilize indirect lighting to image PSRs. This provides data for the Shape from Shading (SFS) technique, which can extract subtle topographic details from single-image to reconstruct high-resolution terrain. However, traditional SFS methods are not suitable for complex secondary scattering scenes in PSRs with multiple secondary light sources. To address this issue, a novel secondary scattering SFS (SS-SFS) method is developed for pixel-wise 3D reconstruction of PSR surfaces, which utilizes indirect illuminated imagery and the corresponding low-resolution DEM to generate DEM with high resolution matches the input image. The proposed method effectively extracts and simplifies multiple incident facets associated with each shadowed facet through clustering, while constructing and optimizing the SS-SFS loss function. Experiments were conducted using ShadowCam images of two areas including both PSRs and temporary shadowed areas, to demonstrate the performance of the proposed method. The SS-SFS DEMs effectively capture intricate topographic details, and comparisons with adjusted Lunar Orbiter Laser Altimeter laser points indicate that the SS-SFS DEMs exhibit high overall accuracy. The high-resolution slope map of PSRs was calculated based on the SS-SFS DEMs, and overcome the limitation that surface slope is relatively underestimated from LOLA DEMs. Additionally, the SS-SFS DEMs were comprehensively compared with the traditional SFS DEMs generated using Narrow Angle Camera imagery in a small temporarily shadowed area, revealing strong consistency and further validating the effectiveness of detailed reconstruction. Overall, the proposed SS-SFS method is essential for generating high-resolution DEMs of PSRs, supporting future lunar South Pole exploration missions.
Introduction Paris polyphylla var. chinensis (Franch.) Hara (P. polyphylla) is a perennial medicinal plant with a reputation for therapeutic properties. It is imperative to study the photochemical processes of P. polyphylla in order to determine the optimal levels of shading and moisture management for its cultivation in artificial environments.Methods In this study, six shading levels (no shading, 30%, 50%, 70%, 80% and 90% shading) and three soil water contents (20%, 40% and 60% of the soil water saturation capacity) were established to determine the appropriate shade intensity and soil moisture content for the growth of P. polyphylla.Results The results showed that only the low shade groups (no shade and 30% shade) showed irreversible damage to the daily photosynthetic dynamics of the plant over the course of a day. It is important to note that excessive light can damage not only the quantum yield for electron transport (phi Do) and PSII light quantum yield (Fv/Fm), but also various physiological mechanisms that can lead to overall plant damage and a decline in organic matter. A comparison of Fv/Fm during the midday period showed that the optimum shade intensity is between 50% and 70%. Low shading can significantly increase light use efficiency (LUE), but also reduces net photosynthetic rate (Pn) and transpiration (Tr), indicating the negative effect on P. polyphylla growth. Considering the balance between growth rate and damage incidence, 50% shade should be the optimal treatment for P. polyphylla, followed by 30% and 70% shade. It was also observed that treatment with low soil water content (20%) significantly reduced Pn and LUE, while increasing stomatal conductance (gs) and water use efficiency (WUE). This is associated with a decrease in the light response curve, indicating that low soil moisture inhibits the growth of P. polyphylla and increases the likelihood of irreversible light damage, so the optimum soil moisture content for P. polyphylla should be above 20%.Discussion Considering the economic benefits and the growth and health of P. polyphylla in artificial cultivation, it is recommended that shade be controlled at around 50% while maintaining soil moisture between 40% and 60% of water content.
Context. The incorporation of trees into integrated crop-livestock systems (ICLS) has been encouraged because of their role in climate change mitigation through plant and soil carbon sequestration. One challenge is to minimize competition (especially for light) and the damage caused by cattle to trees. Aim. This study sought to evaluate the performance of beef heifers grazing on cool-season grasses in two ICLS, crop-livestock (CL) and crop-livestock with immature Eucalyptus grandis trees (CLT), at two nitrogen (N) rates (50 and 150 kg/ha) on pasture. Because these were the first stocking seasons after tree planting, the physical impact of animals (e.g. debarking) on the trees was also evaluated. Methods. The experimental design was randomized blocks with treatments arranged in a 2 x 2 factorial scheme (2 systems x 2 N fertilization rates), with three replicates. Forage production (as dry matter, DM) and animal performance were evaluated for 2 years. Key results. Total forage production and liveweight (LW) gain per area over 117 days of grazing were on average higher for CL (6736 +/- 565 kg DM/ha and 505 +/- 58.6 kg LW/ha respectively) than for CLT (5455 +/- 372 kg DM/ha and 364 +/- 42.3 kg LW/ha), regardless of N rate, and even at similar sward heights (similar to 24 cm). The damage caused by heifers to the bark of the trees was classified as high intensity in 91.1% of the trees, even after the trees had reached a diameter at breast height of 9.9 cm. Conclusions. The interaction between livestock and trees was detrimental to the system's productivity, affecting pasture growth, animal performance and the quality of trees as sawn wood. This finding underscores the importance of selecting appropriate tree species, plant density and species arrangement in ICLS. Implications. Lower tree densities (<237 trees/ha) and preventive measures regarding the use of E. grandis in CLT systems with cool-season grasses are necessary in subtropical regions.
Crop management affects the anatomical and physiological characteristics of gladiolus floral stems. Particulary, shading screens are important in gladiolus production. The aim of the study was to evaluate the meteorological conditions, physiological indicators, stomatal characteristics, and quality of gladiolus flower stems grown in different seasons under shading screens and mulching. Field experiments were conducted during the four growing seasons: 1 (March-June 2019), 2 (August-November 2019), 3 (August-November 2020), and 4 (OctoberDecember 2021). Gladiolus cv. White goddess was grown in beds with and without mulch. Shading treatments included 35% black, silver, and red shading screens, and an unshaded control. Weather conditions during four growing seasons over two years were within the range of maximum and minimum temperatures suitable for the crop. The black and red shading screens resulted in higher stomatal density (374.9; 362.0 stomatal mm-2), which improved the photosynthetic rate of the leaf resulting in greater flower stem length (116.32 cm) and number of florets (19.00) in the red shading screen. The highest relative chlorophyll index (57.75) was recorded in season 2, which contributed to a greater accumulation of assimilates and resulted in longer stems and better-quality florets. Planting under a red shading screen and mulched soil produced longer stems (8.60 %; 9.05 %, respectively), and a greater number of florets in seasons 2 (8.43 %) and 4 (14.74 %), compared to growing unshaded control. The lowest percentage of damage to flower stems was found in the silver shading screen (3.6%) and mulched soil (6.7%). Long flower stems without damage to the sepals and petals, and with a large number of florets are of better quality, have greater ornamental value and are more attractive to flower consumers. Our results showed that planting in seasons 2 and 4, and using red shading screens and mulching soil, are sustainable and conservation soil-management practices to provide a favorable environment which allowed us to obtain high-quality gladiolus flowers. The results of this study are parameters for future research with different soil mulchings and shading screen colors.
Most studies attribute the glacier mass balance within High Mountain Asia (HMA) to climate change, ignoring the influence of its complex terrain. Knowledge of the influence of this complex terrain is crucial for understanding the spatial variability in its mass balance. However, there is a lack of any systematic assessment of this influence across HMA. Therefore, in this study, we used the glacier outlines and raster data (SRTM DEM, slope and aspect) to calculate the topographic shading of all 97,965 glaciers within HMA during the ablation period, which is regarded as a major index of the influence of complex terrain on the mass balance. The results showed that 27.19% of HMA glacier area was subjected to topographic shading, and regional differences were significant with respect to both their altitudinal and spatial distributions. The topographic shading contributed to the protection of the smallest glaciers from solar illumination. Furthermore, we found a significant correlation between the topographic shading and mass balance in these small north-facing glaciers. However, these small glaciers were most prevalent in the north-facing orientation, especially in West Kunlun, East Kunlun, Inner Tibet Plateau and Qilian Shan, where shading was found to increase with decreases in the glacier area. This indicates that complex terrain can affect the spatial distribution of the mass balance by altering the solar illumination pattern.
提出了一种基于Shape-from-Shading的月球表面三维形状恢复算法。首先分析了在太阳光照射下月球表面成像模型,建立了使用Lommel-Seeliger反射模型描述的反射图方程。然后用有限差分近似微分运算,将反射图方程所示的一阶变系数线性偏微分方程进行离散化处理,得到关于表面高度函数的代数方程。进而采用超松弛迭代法进行求解,获得月球表面三维高度函数值。最后使用合成图像和实际月球图像进行三维形状恢复仿真实验。实验结果表明提出的算法可以有效地恢复月球表面三维形状。