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The growth performance of short-rotation woody coppice (SRWC) is strongly influenced by successful establishment in the initial months after planting. Future climates, expected to be warmer due to elevated atmospheric CO2 (eCO2), may bring about more frequent soil droughts alongside increased vapour pressure deficit (eVPD). Hence, this growth chamber experiment aimed to explore the interactive effects of eVPD, eCO2, and soil drought on growth and physiology traits of juvenile hybrid poplars under warmer climates. Our findings with juvenile hybrid poplar J-105 revealed that eVPD resulted in reductions in leaf area (–21%), root (–20%) and stem biomass (–9%), as well as in net assimilation (–15%), stomatal conductance (–26%), and transpiration (–13%). However, these decreases were relatively minor compared to the compensating effect of eCO2, which generally exerted a stronger influence than eVPD. While soil drought emerged as the primary growth-limiting factor in our study, elevated VPD is not expected to pose a significant additional threat to central European SRWC plantations of juvenile hybrid poplars under future conditions of ongoing climate change.

In the Czech Republic, soil moisture content during the growing season has been decreasing over the past six decades, and drought events have become significantly more frequent. In 2003, 2015, 2018 and 2019, drought affected almost the entire country, with droughts in 2000, 2004, 2007, 2012, 2014 and 2017 having smaller extents but still severe intensities in some regions. The current methods of visiting cadastral areas (approximately 13,000) to allocate compensation funds for the crop yield losses caused by drought or aggregating the losses to district areas (approximately 1000 km 2 ) based on proxy data are both inappropriate. The former due to the required time and resources, the later due to low resolution, which leads to many falsely negative and falsely positive results. Therefore, the study presents a new method to combine ground survey, remotely sensed and model data for determining crop yield losses. The study shows that it is possible to estimate them at the cadastral area level in the Czech Republic and attribute those losses to drought. This can be done with remotely sensed vegetation, water stress and soil moisture conditions with modeled soil moisture anomalies coupled with near-real-time feedback from reporters and with crop status surveys. The newly developed approach allowed the achievement of a proportion of falsely positive errors of less than 10% (e.g., oat 2%, 8%; spring barley 4%, 3%; sugar beets 2%, 21%; and winter wheat 2%, 6% in years 2017, resp. 2018) and allowed for cutting the loss assessment time from eight months in 2017 to eight weeks in 2018. [ABSTRACT FROM AUTHOR]

The increased frequency and intensity of drought events are among the major impacts of climate change in various regions worldwide, including Central Europe. These changes have increased the demand for precise drought monitoring and forecasting tools and their validation. The Czech Drought Monitoring System, which is widely utilized across Central Europe, provides daily soil moisture monitoring and medium-range forecasts using the SoilClim model. The main objective of this study was to describe and evaluate the spatiotemporal reliability of these forecasts. The forecasting performance was evaluated for three variables (relative soil moisture content, soil moisture deficit, and drought intensity) and was evaluated using Pearson's correlation, mean bias error, and mean absolute error. All the statistical analyses were performed on data from the years 2019 to 2021 aggregated at the administrative district level in the Czech Republic. The growing season data were analyzed in detail to assess the forecasting accuracy during spring and summer. Furthermore, the ability to forecast rapid changes in the soil moisture content according to changes in meteorological variables, such as precipitation and air temperature, was evaluated. Our findings demonstrate that the SoilClim model forecasts are accurate and suitable for practical applications in sectors such as agriculture and forestry. The lowest reported correlation between the monitored and forecasted values was +0.68 for nine-day forecasts at a soil depth of 0–40 cm. For shorter forecast periods of one and four days, the correlation values were +0.80 or greater. For drought intensity, the errors did not exceed one category of drought severity. We identified summer as the most dynamic season, with corresponding variations in the soil moisture and meteorological forecasting accuracy. This study validates the ability of the Czech Drought Monitoring System to provide reliable soil moisture forecasts, thus contributing to our ability to manage and mitigate drought impacts effectively. • Local soil moisture forecasts were generally highly accurate. • Drought intensity forecast errors did not exceed one severity class. • Soil moisture forecasts were more accurate than meteorological variable forecasts. • The highest uncertainty in the soil moisture forecasts was observed during summer. • Rapid soil drying was reliably predicted from soil moisture forecasts. [ABSTRACT FROM AUTHOR]

The design, fabrication and characterization of quantum cascade detectors are described. They are tailorable infrared photodetectors that are based on intersubband transitions in semiconductor quantum wells that does not need an external bias voltage due to their asymmetric conduction band profile.

Intercropping switchgrass ( Panicum virgatum L.) with loblolly pine ( Pinus taeda L.) has been proposed for producing bioenergy feedstock in the southeastern United States. This study investigated switchgrass growth and pine-switchgrass interactions at two established experimental fields (7-year-old Lenoir site and 5-year-old Carteret site) located on the coastal plain of eastern United States. Position effects (edge and center of switchgrass alley in intercropping plots) and treatment effects (intercropping vs. grass-only) on aboveground switchgrass growth were evaluated. Interspecific interactions with respect to capturing resources (light, soil water, and nitrogen) were investigated by measuring photosynthetically active radiation ( PAR) above grass canopy, soil moisture, and soil mineral nitrogen contents. Switchgrass growth was significantly ( P = 0.001) affected by treatments in Lenoir and by position ( P < 0.0001) in both study sites. Relative to the center, PAR above grass canopy at edge in both sites was about 48% less during the growing season. Soil water content during the growing season at the edge of grass alley was significantly ( P = 0.0001) lower by 23% than at the center in Lenoir, while no significant ( P = 0.42) difference was observed in Carteret, in spite of more grass growth at center at both sites. Soil mineral nitrogen content at the center of intercropping plots in Lenoir (no fertilization during 2015) was significantly ( P < 0.07) lower than at the edge during the peak of growing season (June, July, and August), but not during early and late parts of growing season (May, September, and November). Position effects on soil water and mineral nitrogen were less evident under conditions with higher external inputs (rainfall and fertilization) and lower plant uptake during nongrowing seasons. Results from this study contributed to a better understanding of above- and belowground pine-switchgrass interactions which is necessary to properly manage this new cultivation system for bioenergy production in the southeastern United States. [ABSTRACT FROM AUTHOR]

Multibeam emission and spatial wavelength demultiplexing in semiconductor lasers by patterning their facets with plasmonic structures is reported. Specifically, a single-wavelength laser was made to emit beams in two directions by defining on its facet two metallic gratings with different periods. The output of a dual-color laser was spatially separated according to wavelength by using a single metallic grating. The designs can be integrated with a broad range of active or passive optical components for applications such as interferometry and demultiplexing., Physics

An ultra-broadband distributed-feedback quantum cascade laser array was fabricated, using a heterogeneous cascade based on two bound-to-continuum designs centered at 8.4 and 9.6 mum. This array emitted in a range over 220 cm-1 near a 9-mu m wavelength, operated in pulsed mode at room temperature. The output power of the array varied between 100- and 1100-mW peak intensity., Engineering and Applied Sciences

Above canopy eddy covariance (EC) derived forest carbon fluxes might be biased due todecoupling and insufficient mixing between above and below canopy air masses andconsequently missing soil respiration components in the above canopy derived data. Themost common way to address insufficient mixing across the canopy is to filter theabove canopy derived fluxes at a certain u∗-threshold. However, at some sites likee.g. at the current study site Bílý Kříž (49˚ 30′N, 18˚ 32′E; 800–900 m a.s.l.)located in the Moravian-Silesian Beskydy Mountains, the Czech Republic, it isnot possible to identify a u∗-threshold due to the complexity of the surroundingterrain. The Bílý Kříž experimental forest is a ∼ 40 years old Norway spruce(Picea abies /L./, Karst) monoculture with a leaf area index of ∼ 9 m2 m−2 in 2016.Eddy covariance measurements of energy and trace gas fluxes have a more thandecade long tradition at this site. The EC tower is situated close to a ridge on a steeproughly south oriented planar slope with a regular inclination of 13˚. North of thesite, there is a W-E-oriented mountain crest with a shallow saddle. The ridge andslope force the flow above the canopy in two main regimes, namely upslope anddownslope. Recently, an additional below-canopy EC system was installed at the study site to supportthe interpretation of the above canopy derived EC data. Amongst others, such abelow-canopy system provides readings of the standard deviation of vertical wind(σw). The correlation of σw between above and below canopy EC measurementsremarkably differs for the cases of decoupling and the cases of full coupling betweenbelow and above canopy air masses. Thus, once an objective site-specific thresholdin this σw correlation is experimentally determined, it can be used as an EC fluxfiltering approach to improve the representativeness of the above canopy derivedfluxes. With this study we aim to assess decoupling with a set of two-level filtering approachesbased on 1 year (August 2017 – July 2018) of vertical wind measurements above and belowthe canopy: i) σw (described above), ii) telegraphic approximation (w) which identifiesperiods where the vertical wind above and below the canopy is directed in the samedirection and considers these periods as coupled, iii) cross correlation maximum(w) which is used as measure for maximum of below-above canopy coupling. Thevalue ranges and characteristics of these 3 measures throughout the seasons willbe given and ways to identify filtering thresholds will be discussed. We furtherevaluate the effect of these filtering approaches on the above canopy derived carbonfluxes. Finally, recommendations shall be derived how to treat carbon exchangeEC data at forested sites in complex terrain in the most proper way to minimizepotential biasing effects by decoupling on the above canopy derived carbon fluxes. [ABSTRACT FROM AUTHOR]