Agroforestry has the potential to enhance climate change adaptation. While benefits from agroforestry systems consisting of cash crops and shade trees are usually attributed to the (shade) trees, the trees can also have negative impacts due to resource competition with crops. Our hypothesis is that leaf phenology and height of shade trees determine their seasonal effect on crops. We test this hypothesis by categorizing shade tree species into functional groups based on leaf phenology, shade tree canopy height and shade tree light (wet and dry season) interception as well as the effects. To this end, leaf phenology and the effects on microclimate (temperature, air humidity, intercepted photoactive radiation (PAR)), soil water, stomatal conductance and cocoa yield were monitored monthly during wet and dry seasons over a two-year period on smallholder cocoa plantations in the northern cocoa belt of Ghana. Seven leaf phenological groups were identified. In the wet season, highest buffering effect of microclimate was recorded under the trees brevi-deciduous before dry season. During dry season, high PAR and lowest reduction in soil moisture were observed under the trees in the group of completely deciduous during dry season. The evergreen groups also showed less reduction in soil water than the brevi-deciduous groups. In the wet season, shade tree effects on cocoa tree yields in their sub canopy compared to the respective control of outer canopy with full sun ranged from positive (+10 %) to negative (-15 %) for the deciduous groups, while yield reductions for the evergreen groups ranged from -20 % to -33 %. While there were negative yield impacts for all phenological groups in the dry season, the trees in completely deciduous during dry season group recorded least penalties (-12 %) and the trees with evergreen upper canopy the highest (-35 %). The function of shade trees in enhancing climate resilience is therefore strongly dependent on their leaf phenological characteristics. Our study demonstrates how the key trait leaf phenology can be applied to successful design of climate-resilient agroforestry systems.

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.

The vertical temperature distribution in the permanently shaded region (PSR) has a significant impact on the temporal and spatial distribution of the cold trap. To obtain the vertical temperature profile of the PSR, an inversion method that fuses microwave and infrared brightness temperature (TB) data is proposed. In the inversion process, the infrared data were initially used to derive the optimal value of the H-parameter that controls the density profile. Subsequently, high-frequency (37 and 19.35 GHz) microwave TB data were used to ascertain the range of surface density, whereas low-frequency (3 GHz) microwave TB data were used to determine the range of bottom density. A fixed correction was applied to the 3-GHz brightness temperature data to account for the calibration error. Due to the inherent uncertainties associated with the thermal model, both the Hayne and Woods' models were used in the inversion process, yielding disparate results. The PSR in the Haworth impact crater was selected as a case study for the inversion. The Woods' model was found to provide a superior explanation for the microwave observation. The optimal surface density of the PSR of the Haworth crater was determined to be within the range of 1200-1300 kg m(-3), while the bottom density was within the range of 2100-2200 kg m(-3). The inverted vertical temperature distribution in the PSR of Haworth crater indicates that the depth of the cold trap can reach approximately 8.5 m. In addition, the impact of heat flow on microwave TB is discussed.

The photogeologic analysis of the ShadowCam images of the permanently shadowed floor and lower parts of inner slopes of the near-polar lunar crater Shoemaker confirmed the conclusion of Basilevsky and Li (2024)that the surface morphology of the Shoemaker floor is dominated by a population of small (D < 1 km) craters. Future studies hopefully will allow to describe the morphology and morphometry (especially d/D) of the decameter- scale craters seen in the ShadowCam images. The surface of the lower parts of inners slopes of crater Shoemaker, which are permanently shadowed, has the elephant hide texture, that is also typical for normally illuminated slopes. So, most issues of the surface morphology were found to be identical or very close to those in normally illuminated regions of the Moon. The new finding in permanently shadowed areas is the presence of lobate-rimmed craters, whose morphology is probably indicative of water ice in the target material.

Climate change mitigation requires creative solutions to reduce greenhouse gases (GHG). Little research has been performed on GHG emissions from shaded turfgrass systems, resulting in a lack of best management practice (BMP) development. The aim of this research was to investigate the soil flux of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) as impacted by shade [shade (98.8%) versus sun (100%)] and differing sources (fast- versus slow-release) and rates (147 versus 294 kg ha-1 yr-1) of nitrogen (N) fertilizers on creeping bentgrass putting greens. The results show that emissions of soil CO2 and soil N2O are significantly lower in shaded plots versus sunny plots. The presence of N fertilizer significantly increased soil CO2 emissions over unfertilized plots. Quick-release N fertilizer fluxed significantly more soil N2O than the slow-release N fertilizers. Turfgrass color was significantly higher on the sunny green versus the shaded green except in late summer. Turfgrass quality was significantly higher for the shaded green versus the sunny green. Milorganite improved turfgrass quality whereas urea decreased turfgrass quality due to fertilizer burn. When N is needed to improve turfgrass color and quality, the use of slow-release N sources should be a BMP for shaded greens.

Our study is based on a photogeological analysis of the hill -shade images produced from the LOLA digital terrain models and on a stereometric analysis of LROC NAC images. Our results demonstrate that surface morphology of the permanently shadowed floor of crater Shoemaker is nearly identical to that of the regularly illuminated mare surface at the Lunokhod-2 working area and the surface of the highland plain of the Apollo -16 landing site, being dominated by populations of craters smaller than 1 km in diameters. Craters on the Shoemaker floor have approximately the same depth -to -diameter ratios as those within the Lunokhod-2 and Apollo -16 areas. The observed surface morphology of the Shoemaker floor is the result of meteorite bombardment like in other areas of the Moon. Within the permanently shadowed surface areas we detected no morphological peculiarities that could result from the absence of the diurnal temperature variations that excludes the temperature -related creep component of the downslope material movement. This probably means that in the areas with regular solar illumination, the role of the downslope movement of debris by thermally induced creep mechanisms is secondary compared to shaking by close and distant meteorite impacts and locally by moonquakes.

Future human space exploration missions are planned to take humans into permanently shaded regions (PSRs) at the lunar south pole. These areas are among the coldest places in the Solar System and represent a novel operational environment for spacesuits. In addition to this technical challenge, there is scientific interest in volatiles that are cold trapped in PSRs. This paper presents results from several simulations performed to assess the effect of the thermal interactions between the lunar surface and a comparatively warm spacesuit in a permanently shadowed crater on the Moon. After the tools used to perform the simulations and their limitations are discussed, two scenarios are introduced: a crater scenario to investigate the extent and magnitude of the thermal influence of the spacesuit in realistic setting, and a flat plane scenario that is used to analyze the effect of different astronaut translation speeds on the surface temperature changes. While the results show a significant change in lunar surface temperature of up to 60 K within 1.5 m of the astronaut, the effective sink temperature for the spacesuit only changes by a few degrees Kelvin, which is not large enough to have any implications on the design of the spacesuit system. Due to the low thermal conductivity of the lunar regolith and radiation being the dominant mode of heat transfer, the surface temperature increase is only significant for very slow translation rates or periods during which the crewmember remains stationary. The absolute temperature increase can be large enough to release volatiles from their entrapment, which in turn may necessitate a spacesuit design that radiates less heat to protect science objectives. However, further research and experimentation is necessary to determine which species are most susceptible in specific surface compositions and at which temperatures.

Near-surface temperatures of permanently shadowed regions (PSRs) on the Moon provide fundamental information for water ice exploration. Seasonal temperature variations of PSRs are found in both Chang'E-2 microwave radiometer data and Diviner Lunar radiometer observations. Furthermore, unusual microwave brightness temperature variations between February 2011 and May 2011 of double-shaded PSRs are shown in the Chang'E-2 observational data, i.e., that the minimum microwave brightness temperature occurs before the time when the infrared brightness temperature reaches the minimum in double-shaded PSRs. To interpret this phenomenon, the 1-D thermal model and the microwave radiation transfer model are used. In the thermal model, the reradiation energy from the illuminated area is estimated by effective solar irradiance, which is an analytic solution for the radiative equilibrium temperature in the shadowed area of a spherical bowl-shaped crater. In the simulation, an assumed internal 0.4 W/m(2) heat flow beneath the lunar surface made a plausible fit to the unusual variations during some lunations. However, this is a huge value compared with the well-known heat flow value of about 0.018 W/m(2). Furthermore, it is difficult to obtain this extra heat energy by lateral conduction below the surface in a large impact crater due to the small thermal conductivity of the lunar regolith. Finally, the unusual microwave brightness temperature (TB) changes are concluded to be caused by a calibration problem after excluding other possible reasons. In addition, a statistical correction method is applied to revise the problematic TB data to obtain the proper variation trend of the brightness temperature.

The permanent shaded regions (PSRs) at the lunar poles receive no direct solar illumination throughout the year, so their temperatures are extremely low. The PSR is mainly heated by the radiation heat flow and the scattered solar radiation from the sunlit crater wall. The temperature distribution in the PSR and its diurnal and seasonal variations have been calculated using the ray-tracing method, which determines the radiation heat flow and the scattered solar radiation. In this article, the radiation heat flows were calculated by anisotropic emissivity of the PSR, and the scattered solar radiation was calculated using the lunar Lambert model. To conform to the Diviner IR temperature data, the 1-D heat conduction equation was solved with modified heat conductivity (an important parameter of the regolith media). As an example, the daytime and nighttime temperatures in the Hermite-A crater at the North Pole during summer and winter were numerically simulated and were compared with the Diviner IR data. In addition, rocks near the central peak of the crater in the PSR may enhance the nighttime temperature. This was validated by the PSR images captured by the Lunar Reconnaissance Orbiter Camera (LROC), the Miniature Radio Frequency instrument data on the LRO, and the numerical simulations.

Water (ice, liquid, or vapor) is a critical driver of future exploration, and methods of its detection and characterization are a high priority for upcoming lunar missions. Thus, we assess the potential for alteration products resulting from water-ice liberated during various impact events in the lunar polar regions. In this work, we estimate the maximum amount and duration of melted, vaporized, or sublimed water-ice during representative post-impact environments using a model of bulk heat transfer. Our model is sensitive to heat loss by radiation, initial and final near-surface temperatures, and pre-existing water-ice abundance and distribution. Mineral dissolution rates in aqueous solution are used as a metric for potential chemical alteration in the presence of liberated water-ice following an impact. We find that the modeled timescales and potential for water liberation and reactivity are compatible with near-surface chemical alteration in some lunar post-impact environments. While initial surface temperatures less than similar to 110 K are adequate to maintain near-surface ice reservoirs at the lunar poles, when heated, pore pressures below a depth of similar to 35 cm are potentially adequate to sustain liquid water. Mild near-surface environments (e.g., similar to 5 degrees C) lasting a few decades, allow for aqueous alteration of sensitive minerals such as olivine, apatite, and glassy materials. Higher temperatures favor degassing of H2O, but vapor-phase interactions may occur. The limited amounts of available water will likely result in reactions with only the most sensitive minerals such as glasses and Fe-metal. Over time, secondary mineralization would be mixed into the upper few meters of the lunar regolith through subsequent bombardment, assuming it escapes later intense heating events; however, surface exposures would be suttected to space weathering. Nonetheless, based on our modeling, future explorers should consider instrumentation capable of detecting minor to trace amounts of impact-induced chemical alteration in the upper few meters of the lunar surface.