We compared the effects of young high-density plantations of three native trees (legumes: Albizia lebbeck, A. procera and a non-legume: Tectona grandis) and one fast growing woody grass species (Dendrocalamus strictus) on carbon and nutrients stock and their accretion rates in a redeveloping soil. This soil was the early phase of mine spoil restoration in a dry tropical environment. The soil bulk density and accumulation rates of C, N and P at 0-10 and 10-20 cm soil depth were determined in 4-to 5-year-old plantations. The total nutrient stock of soil C, N, P significantly varied in redeveloping soil according to plantation type, plantation age and soil depth. A. lebbeck greatly improved C and N content followed by D. strictus, A. procera and T. grandis plantations. However, accretion rates of C and N were substantially high in the D. strictus plantation. Therefore, D. strictus, contributed significantly to the redevelopment of mine spoil soils. In the case of total P nutrient, A. procera showed the greatest amount among the plantations but the accretion rate was also high for T. grandis followed by A. procera, A. lebbeck and D. strictus. This study indicates that all N-fixing species may not be equally efficient in improving soil qualities especially N in the soil.

As a novel X-ray focusing technology, lobster-eye micropore optics (MPO) feature both a wide observing field of view and true imaging capability, promising sky monitoring with significantly improved sensitivity and spatial resolution in soft X-rays. Since first proposed by Angel, the optics have been extensively studied, developed and trialed over the past decades. In this Letter, we report on the first-light results from a flight experiment of the Lobster Eye Imager for Astronomy, a pathfinder of the wide-field X-ray telescope of the Einstein Probe mission. The piggyback imager, launched in 2022 July, has a mostly unvignetted field of view of 18.°6 × 18.°6. Its spatial resolution is in the range of 4′–7′ in FWHM and the focal spot effective area is 2–3 cm2, both showing only mild fluctuations across the field of view. We present images of the Galactic center region, Sco X-1, and the diffuse Cygnus Loop nebular taken in snapshot observations over 0.5–4 keV. These are truly wide-field X-ray images of celestial bodies observed, for the first time, by a focusing imaging telescope. Initial analyses of the in-flight data show excellent agreement between the observed images and the on-ground calibration and simulations. The instrument and its characterization are briefly described, as well as the flight experiment. The results provide a solid basis for the development of the present and proposed wide-field X-ray missions using lobster-eye MPO.

Soil nitrogen (N) availability is one of the limiting factors for plant growth on sandy lands. Little is known about impacts of afforestation on soil N availability and its components in southeastern Keerqin sandy lands, China. In this study, we measured N transformation under sandy Mongolian pine (Pinus sylvestris var. mongolica Litv.) plantations of different ages (grassland, young, middle-aged, close-to-mature) and management practices (non-grazing and free-grazing) during the growing seasons using the ion exchange resin bag method. Results showed that, for all plots and growing season, soil NH þ 4 -N, NO À 3 -N, mineral N, and relative nitrification index, varied from 0Á18 to 1Á54, 0Á96 to 22Á05, 1Á23 to 23Á58 mg d À1 g À1 dry resin, and 0Á76 to 0Á97, respectively, and NO À 3 -N dominated the available N amount due to intense nitrification in these ecosystems. In general, the four indices significantly increased in the oldest plantation, with corresponding values in non-grazing sites lower than those in freegrazing sites ( p < 0Á05). Our studies indicated that it is a slow, extended process to achieve improvement in soil quality after afforestation of Mongolian pine in the study area.